Ford Focus Limp mode

[Robfagha]

Hello

 

i have a 2005 Ford Focus 1,6TDCI wagon

i bought the car knowing that it didnt run properly, kind of as a project.

The car had fault codes relating to underboost. But a new turbo came with the car, so i replaced it and fault those codes disappeared. Thankfully.

When the car starts, it runs as is should for 5-10 seconds. It then goes into sort of a limp mode, no power, not exceeding 3000rpm. But i have no powertrain og engine warning light. Absolutely nothing.

I do have a U1900 fault code for some canbus fault.

I have tried everything i have found on different forums, replaced fuel filter, replaced glow plugs and relay etc (due to glow plug fault code)

previous owner had a problem with the instrument cluster, but he repaired it. Not a perfect repair, since the speedometer can drop 10 km/h every now and then.

i suspect the Instrument cluster is still messing around with the systems.

i plan to replace it, i have ordered equipment for programming the «new» cluster, but i thought that i want someone elses opinion on this!

Very thankful for any response!

[sushilovin]

When you say "not exceeding 3000rpm", is it a hard limited, as in you hit it and no more power, that's it, or is it like a soft limit that can be exceeded but is very difficult to do so? I have the latter on mine with underboost, but I do get the first when the "Engine Malfunction" message appears on the dash. Speaking of, do you get the Engine Malfunction message, or just a rev limit?

I think the U1900 is mostly a meaningless code, I have it on mine too but doesn't affect operation or driving.

[Robfagha]

On 11/19/2020 at 8:06 PM, sushilovin said:

When you say "not exceeding 3000rpm", is it a hard limited, as in you hit it and no more power, that's it, or is it like a soft limit that can be exceeded but is very difficult to do so? I have the latter on mine with underboost, but I do get the first when the "Engine Malfunction" message appears on the dash. Speaking of, do you get the Engine Malfunction message, or just a rev limit?

I think the U1900 is mostly a meaningless code, I have it on mine too but doesn't affect operation or driving.

Its a hard limit, will rev slowly up to 3000 and then it holds it there while im getting black smoke out of the exhaust.

No engine malfunction light, just loss of power and rev limit.

Funny thing is, when i start the engine and test it, it will rev normally, i can rev it up and down 3000-4500rpm, but when i stop and let it slow down to idle and try again, the problem is back. Wont go over 3000rpm, revs slowly up to 3000, black smoke and all.

[sushilovin]

15 hours ago, Robfagha said:

Its a hard limit, will rev slowly up to 3000 and then it holds it there while im getting black smoke out of the exhaust.

No engine malfunction light, just loss of power and rev limit.

Funny thing is, when i start the engine and test it, it will rev normally, i can rev it up and down 3000-4500rpm, but when i stop and let it slow down to idle and try again, the problem is back. Wont go over 3000rpm, revs slowly up to 3000, black smoke and all.

Hm, interesting. With mine, it usually makes an alarm sound and shows "Engine Malfunction" on the little display when it's not happy.

Have you got any readouts for boost pressure while driving? The black smoke suggests to me that it's running rich because it can't get enough air, but you say you've already replaced the turbo with a new one. 

Is the car a mk1 or mk2? And what horsepower rating does it have?

[Robfagha]

18 hours ago, sushilovin said:

Hm, interesting. With mine, it usually makes an alarm sound and shows "Engine Malfunction" on the little display when it's not happy.

Have you got any readouts for boost pressure while driving? The black smoke suggests to me that it's running rich because it can't get enough air, but you say you've already replaced the turbo with a new one. 

Is the car a mk1 or mk2? And what horsepower rating does it have?

Its an Mk2 with 1.6Tdci 110bhp.

Really weird problem actually, i would love some fault codes or malfunction light so i can locate the problem. 
but without codes or lights, its impossible

[Mertens Jelle]

The U1900 code is comming from the cluster itself probably bad connection in the cluster itself.

You could also get that code just for plugging in the forscan adapter so could have nothing to do with it...

Since you say that the speedo drops sometimes i would start within the cluster itself and check for any bad solder points? 

Is your car a keyles entry and start? Because if it is, programming the keys is not as simple as you would think...

[Robfagha]

4 hours ago, Mertens Jelle said:

The U1900 code is comming from the cluster itself probably bad connection in the cluster itself.

You could also get that code just for plugging in the forscan adapter so could have nothing to do with it...

Since you say that the speedo drops sometimes i would start within the cluster itself and check for any bad solder points? 

Is your car a keyles entry and start? Because if it is, programming the keys is not as simple as you would think...

Its thankfully a normal key system. 
havent seen any bad solderings inside the cluster, so i will try with the new cluster when it arrives!

have read that a faulty cluster can make some weird things happen, so i hope the new one will sort it out 😫

[Mertens Jelle]

Wish you luck trying to program it, your going to need it 😛

[Robfagha]

On 11/23/2020 at 7:25 AM, Mertens Jelle said:

Wish you luck trying to program it, your going to need it 😛

Programming done, Forscan made it super easy 😁

But my issue is still there, barely any power, cant exceed 3000rpm, no fault codes, nothing 😠
Cant believe it doesnt find anything wrong about itself.

Any ideas what to check for next?

[Robfagha]

When the car is stationary, and i rev the engine. Should i get movement from the variable turbo geometry actuator? 
i get live readout that it is giving orders rangung from 50-98% but the lever is not moving. 
Can this be something to check out?

[Mertens Jelle]

Did you check al the common faults like bad plugs or injectors? Fuell pump about to go out?
Clean air filter, good fuel, etc... ?

[Mertens Jelle]

Try to upload a readout of the forscan DTC's?

[sushilovin]

Sorry @Robfagha, haven't checked the forum in a few days. If you have the 110bhp model, it will be the Variable Geometry Turbo. Live data readouts from Forscan/your OBD app could help with diagnosing why it's going into limp mode and point towards the fault.

[sushilovin]

Woopsie, sorry I missed your comment about the VGT actuator not moving. Yep, definitely check that out. Looks for leaks in the vacuum line between the actuator and the boost regulator. If you find nothing there, it may be the regulator itself. You need to get the car up and under it to reach the regulator, I believe. If the VGTDC readout is changing but the actuator is not, there is almost certainly either 1) a vacuum leak or 2) the vanes in the turbo are sticky and coked up. You can test for carbon and sticky vanes by simply pushing down on the actuator when the engine is off (or vacuum line disconnected). You should be able to move it up and down with little pressure. Failing that, probably a vacuum leak or dodgy regulator.

[Robfagha]

On 11/26/2020 at 9:47 PM, sushilovin said:

Woopsie, sorry I missed your comment about the VGT actuator not moving. Yep, definitely check that out. Looks for leaks in the vacuum line between the actuator and the boost regulator. If you find nothing there, it may be the regulator itself. You need to get the car up and under it to reach the regulator, I believe. If the VGTDC readout is changing but the actuator is not, there is almost certainly either 1) a vacuum leak or 2) the vanes in the turbo are sticky and coked up. You can test for carbon and sticky vanes by simply pushing down on the actuator when the engine is off (or vacuum line disconnected). You should be able to move it up and down with little pressure. Failing that, probably a vacuum leak or dodgy regulator.

Read your answer but forgot to reply!

Im able to move it up and down with little pressiure.

Connected a new pipe between regulator and turbo with same result: Works fine when keeping the rpm over 1000-1500 and revving it up and down between 1500-4000, but when dropping rpm to idle It wont go past 3000-3500rpm anymore.

Turbo actuator and VGT moves fine when everything seems fine, but when dropping rpm du itle, i get same issue with little movement in actuator.

If its not the regulator, it has to be a system failure in PCM or something.

Receiving a new regulator today, will update post when i have replaced it!

[Robfagha]

On 11/26/2020 at 9:47 PM, sushilovin said:

Woopsie, sorry I missed your comment about the VGT actuator not moving. Yep, definitely check that out. Looks for leaks in the vacuum line between the actuator and the boost regulator. If you find nothing there, it may be the regulator itself. You need to get the car up and under it to reach the regulator, I believe. If the VGTDC readout is changing but the actuator is not, there is almost certainly either 1) a vacuum leak or 2) the vanes in the turbo are sticky and coked up. You can test for carbon and sticky vanes by simply pushing down on the actuator when the engine is off (or vacuum line disconnected). You should be able to move it up and down with little pressure. Failing that, probably a vacuum leak or dodgy regulator.

New line, new regulator, still same problem.

 

any other ideas? Im totally out of ideas, i think its weird that when dropping it down to idle makes it go into some sort of limp mode !

[Tdci-Peter]

8 hours ago, Robfagha said:

Works fine when keeping the rpm over 1000-1500 and revving it up and down between 1500-4000, but when dropping rpm to idle It wont go past 3000-3500rpm anymore.

Turbo actuator and VGT moves fine when everything seems fine, but when dropping rpm du itle, i get same issue with little movement in actuator.

I think I would test the vacuum pump next. Maybe the vacuum is ok at start, but drops away as soon as the engine idles a bit, and can't recover. I think these vacuum pumps need a decent amount of oil in them to operate efficiently. Poor vacuum would also make the brakes feel a bit hard, but it does not sound like you have been able to do much road testing.

I would also try to record some data, MAP, MAF, rpm, throttle, VGTDC & maybe fuel rail pressure & EGR (but too many readings at once can get a bit confusing, and slow down the data rate.) Trying to get readings from start, revving, then idle & then revving in limited mode. See if one of the sensors shows a particularly odd change. I don't think the turbo actuator has a sensor, so you can't detect that. Only by looking at it, which needs an assistant really.

It is strange that no underboost DTC comes up when it goes into turbo-less, black smoke mode. But the software in that engine's ECU is very strange in many ways!

[Robfagha]

On 12/4/2020 at 12:26 AM, Tdci-Peter said:

I think I would test the vacuum pump next. Maybe the vacuum is ok at start, but drops away as soon as the engine idles a bit, and can't recover. I think these vacuum pumps need a decent amount of oil in them to operate efficiently. Poor vacuum would also make the brakes feel a bit hard, but it does not sound like you have been able to do much road testing.

I would also try to record some data, MAP, MAF, rpm, throttle, VGTDC & maybe fuel rail pressure & EGR (but too many readings at once can get a bit confusing, and slow down the data rate.) Trying to get readings from start, revving, then idle & then revving in limited mode. See if one of the sensors shows a particularly odd change. I don't think the turbo actuator has a sensor, so you can't detect that. Only by looking at it, which needs an assistant really.

It is strange that no underboost DTC comes up when it goes into turbo-less, black smoke mode. But the software in that engine's ECU is very strange in many ways!

I dont think the vacuumpump is the issue in this case, as the actuator is fully engaged when it goes into this limp mode thing. 
I believe there must be something that relates to engine speed, but i just cant figure out what it is! 

I will do some more testing with the readouts on forscan. 
 

Edit: I know the previous owner blocked the Egr, can this cause something like my problems?

[Robfagha]

I have now done, cant find anything abnormal with sensors or anything. Still getting limp mode when dropping it below 1000rpm.

 

i have absolutely no idea anymore

pcm failure?

[sushilovin]

Hi @Robfagha,

Sorry for not checking in in a while. This actually sounds very similar to the exact issue I'm having with my car too. I haven't replaced the regulator or the line yet, but what you describe about dropping it to low revs is exactly what I have. If I keep it above 2k revs or so, or keep the exhaust really hot, it seems to work alright. 

The rev limit you spoke about previously is also familiar. There are two types of "rev limit" that I've encountered. One where it's a hard limit put in by the ECU where it will stop DEAD at around 2800 revs and will not go over that no matter how hard you push (like a traditional petrol rev limiter), and a second limit where there isn't a reliable number, and you CAN rev past it, but it's really slow and barely moves.

I get the second type quite a lot, and in your recent post, it sounds like you do. My best guess at this issue so far is that something is stopping the vanes from being as "open" as they should at higher revs, meaning exhaust gas can't escape the cylinder on the exhaust stroke, meaning the engine can't make as much power on the next power stroke because there is still left over exhaust gas. I haven't figured out yet whether that "something" is a mechanical something, electrical, or carbon build up. This is where I am with my car. I want to also say that my EGR is blocked too. I am now wondering if this is the cause of the issues you and I are facing. My EGR was causing shuddering and bunny hopping in the low revs, so I just blanked it instead of replacing it.

Here's something for you to try: Disconnect the vacuum line to the turbo actuator and go for a drive. I leave it just detached, but you can cover it with something to prevent dust. I'd wait till it's a dry day so you don't get water in that tube. This will leave the vanes all the way open all the time, making it more like a conventional turbo than a variable one and decreases the back pressure. I'm almost certain, based on what you've described, that you'll notice the car is much more responsive in the bottom end and can easily rev all the way to redline in all gears (abiding the speed limit) because there is no trapped exhaust, but you'll lose top end power and only make around 70bhp max. Give it a go and tell me how that goes.

Following that, I have a few questions:

1) how is your fuel economy with this issue? I drove the same route twice, once with the turbo actuator connected, giving me less than 40mpg, and another where I disconnected the turbo actuator (which makes it act like a conventional turbo) and got over 58mpg out of it.

2) do you have a diagnostic plug in? Please provide real time data from your car with the turbo actuator connected. In particular, you want to look at the calculated boost pressure. It should be no higher than around 18psi max. You say you can build boost if you keep the revs high, so build boost and floor is and see what you get. Mine frequently makes over 21psi which triggers the "Turbo boost limit exceeded" error code P0234. Speaking of...

3) are you getting any error codes now? Have you tried another reader or app? These cars seem pretty smart and it seems crazy you haven't gotten a code with the issues you're having. Data readouts would be invaluable.

4) are you still getting no movement in the actuator arm after replacing the regulator? Like, no movement, AT ALL? Can you feel a vacuum through the pipe?

Sorry that this post is so incredibly long, it's been a while since I've popped on here and now that it sounds like the same issue as my own, I can speak with more experience rather than just shooting blind shots. With you mentioning the EGR, I am very tempted to try un-blanking my EGR to see if that fixes it. I have time off over Christmas so I'll give it a go and get back to you on this post.

Best of luck to you and hope you enjoy your holidays! Hope to hear from you soon.

[Robfagha]

On 12/24/2020 at 6:00 PM, sushilovin said:

Hi @Robfagha,

Sorry for not checking in in a while. This actually sounds very similar to the exact issue I'm having with my car too. I haven't replaced the regulator or the line yet, but what you describe about dropping it to low revs is exactly what I have. If I keep it above 2k revs or so, or keep the exhaust really hot, it seems to work alright. 

The rev limit you spoke about previously is also familiar. There are two types of "rev limit" that I've encountered. One where it's a hard limit put in by the ECU where it will stop DEAD at around 2800 revs and will not go over that no matter how hard you push (like a traditional petrol rev limiter), and a second limit where there isn't a reliable number, and you CAN rev past it, but it's really slow and barely moves.

I get the second type quite a lot, and in your recent post, it sounds like you do. My best guess at this issue so far is that something is stopping the vanes from being as "open" as they should at higher revs, meaning exhaust gas can't escape the cylinder on the exhaust stroke, meaning the engine can't make as much power on the next power stroke because there is still left over exhaust gas. I haven't figured out yet whether that "something" is a mechanical something, electrical, or carbon build up. This is where I am with my car. I want to also say that my EGR is blocked too. I am now wondering if this is the cause of the issues you and I are facing. My EGR was causing shuddering and bunny hopping in the low revs, so I just blanked it instead of replacing it.

Here's something for you to try: Disconnect the vacuum line to the turbo actuator and go for a drive. I leave it just detached, but you can cover it with something to prevent dust. I'd wait till it's a dry day so you don't get water in that tube. This will leave the vanes all the way open all the time, making it more like a conventional turbo than a variable one and decreases the back pressure. I'm almost certain, based on what you've described, that you'll notice the car is much more responsive in the bottom end and can easily rev all the way to redline in all gears (abiding the speed limit) because there is no trapped exhaust, but you'll lose top end power and only make around 70bhp max. Give it a go and tell me how that goes.

Following that, I have a few questions:

1) how is your fuel economy with this issue? I drove the same route twice, once with the turbo actuator connected, giving me less than 40mpg, and another where I disconnected the turbo actuator (which makes it act like a conventional turbo) and got over 58mpg out of it.

2) do you have a diagnostic plug in? Please provide real time data from your car with the turbo actuator connected. In particular, you want to look at the calculated boost pressure. It should be no higher than around 18psi max. You say you can build boost if you keep the revs high, so build boost and floor is and see what you get. Mine frequently makes over 21psi which triggers the "Turbo boost limit exceeded" error code P0234. Speaking of...

3) are you getting any error codes now? Have you tried another reader or app? These cars seem pretty smart and it seems crazy you haven't gotten a code with the issues you're having. Data readouts would be invaluable.

4) are you still getting no movement in the actuator arm after replacing the regulator? Like, no movement, AT ALL? Can you feel a vacuum through the pipe?

Sorry that this post is so incredibly long, it's been a while since I've popped on here and now that it sounds like the same issue as my own, I can speak with more experience rather than just shooting blind shots. With you mentioning the EGR, I am very tempted to try un-blanking my EGR to see if that fixes it. I have time off over Christmas so I'll give it a go and get back to you on this post.

Best of luck to you and hope you enjoy your holidays! Hope to hear from you soon.

Hi!

i totally forgot to reply after doing more tests to the car.

As you describes about the second rpm limit, thats the issue i face, its not a hard limit but more of av restriction in the turbovanes since i can get it past 3000 but not at the speed it should do it.

As i earlier mentioned if i am lucky, i can reset the PCM and start the car up and the engine behaves normally as long as i dont let it drop down to idle. If i do so the problem is starting again.

i did not see any difference in vane operation after replacing the regulator, it works fine when the engine is working as it should, closed at low rpms and open at higher revs, but when i drop RPM to idle, it and barely moves when im revving the engine. 
So it might seem like the pcm is signaling to the regulator that the engine is not at the revs it should be for opening the vanes. 
So the problem is finding out wether the vnt is regulated by turbo boost or engine revs.

the car has now been sitting over the holidays, and after being without battery, the speedometer doesnt work now. 

So I am now at that point that i consider to just wreck the car.

But i cant get it out of my head because it seems that its a small electrical problem, so in fear of loosing too much money, i hope to get it working properly so i can sell it and get my money back 😂 

[Robfagha]

On 12/24/2020 at 6:00 PM, sushilovin said:

Hi @Robfagha,

Sorry for not checking in in a while. This actually sounds very similar to the exact issue I'm having with my car too. I haven't replaced the regulator or the line yet, but what you describe about dropping it to low revs is exactly what I have. If I keep it above 2k revs or so, or keep the exhaust really hot, it seems to work alright. 

The rev limit you spoke about previously is also familiar. There are two types of "rev limit" that I've encountered. One where it's a hard limit put in by the ECU where it will stop DEAD at around 2800 revs and will not go over that no matter how hard you push (like a traditional petrol rev limiter), and a second limit where there isn't a reliable number, and you CAN rev past it, but it's really slow and barely moves.

I get the second type quite a lot, and in your recent post, it sounds like you do. My best guess at this issue so far is that something is stopping the vanes from being as "open" as they should at higher revs, meaning exhaust gas can't escape the cylinder on the exhaust stroke, meaning the engine can't make as much power on the next power stroke because there is still left over exhaust gas. I haven't figured out yet whether that "something" is a mechanical something, electrical, or carbon build up. This is where I am with my car. I want to also say that my EGR is blocked too. I am now wondering if this is the cause of the issues you and I are facing. My EGR was causing shuddering and bunny hopping in the low revs, so I just blanked it instead of replacing it.

Here's something for you to try: Disconnect the vacuum line to the turbo actuator and go for a drive. I leave it just detached, but you can cover it with something to prevent dust. I'd wait till it's a dry day so you don't get water in that tube. This will leave the vanes all the way open all the time, making it more like a conventional turbo than a variable one and decreases the back pressure. I'm almost certain, based on what you've described, that you'll notice the car is much more responsive in the bottom end and can easily rev all the way to redline in all gears (abiding the speed limit) because there is no trapped exhaust, but you'll lose top end power and only make around 70bhp max. Give it a go and tell me how that goes.

Following that, I have a few questions:

1) how is your fuel economy with this issue? I drove the same route twice, once with the turbo actuator connected, giving me less than 40mpg, and another where I disconnected the turbo actuator (which makes it act like a conventional turbo) and got over 58mpg out of it.

2) do you have a diagnostic plug in? Please provide real time data from your car with the turbo actuator connected. In particular, you want to look at the calculated boost pressure. It should be no higher than around 18psi max. You say you can build boost if you keep the revs high, so build boost and floor is and see what you get. Mine frequently makes over 21psi which triggers the "Turbo boost limit exceeded" error code P0234. Speaking of...

3) are you getting any error codes now? Have you tried another reader or app? These cars seem pretty smart and it seems crazy you haven't gotten a code with the issues you're having. Data readouts would be invaluable.

4) are you still getting no movement in the actuator arm after replacing the regulator? Like, no movement, AT ALL? Can you feel a vacuum through the pipe?

Sorry that this post is so incredibly long, it's been a while since I've popped on here and now that it sounds like the same issue as my own, I can speak with more experience rather than just shooting blind shots. With you mentioning the EGR, I am very tempted to try un-blanking my EGR to see if that fixes it. I have time off over Christmas so I'll give it a go and get back to you on this post.

Best of luck to you and hope you enjoy your holidays! Hope to hear from you soon.

Hi again

i took some readouts, in this picture engine is getting power and revs as normal. But starts faulting at around ‘16.06. 

[Tdci-Peter]

13 hours ago, Robfagha said:

in this picture engine is getting power and revs as normal. But starts faulting at around ‘16.06. 

I can see it does just what you said. At the 1st drop to idle after t=0 (I assume that is start), the ECU refuses to drop the VGTDC below about 50%, and it looks like the turbo does not cut in as a result of this.

But everything looks sluggish to me. FRP seems to be following RPM, not APP. I would expect FRP to follow APP, so as to put more fuel into the engine, then RPM & MAF to follow that. Could it be due to delays in a wireless ELM perhaps? But the TPMODE (Partial Throttle vs Closed Throttle) seems to follow APP ok.

If it is an ECU fault, then it is a very odd one, seems to work ok one second, then not so well the next, but it is still doing part of the job. If it is another sensor, then it is not obvious what. Have you tried adding DTC count to the PID list? That would show if & when the ECU picked up on a fault.

A trace from my car (different engine I know, but same principle):

This show the extent to which I expect FRP to follow APP. Opening the throttle needs to put more fuel in first and foremost. Everything else follows that. MAP, turbo and more air is useless without more fuel.

That snippet is 5th gear (90-110 kph), so allows engine operation to be seen more clearly, without rapid rpm variations which can make diagnosis harder.

 

[sushilovin]

On 2/3/2021 at 10:04 PM, Robfagha said:

Hi!

i totally forgot to reply after doing more tests to the car.

As you describes about the second rpm limit, thats the issue i face, its not a hard limit but more of av restriction in the turbovanes since i can get it past 3000 but not at the speed it should do it.

As i earlier mentioned if i am lucky, i can reset the PCM and start the car up and the engine behaves normally as long as i dont let it drop down to idle. If i do so the problem is starting again.

i did not see any difference in vane operation after replacing the regulator, it works fine when the engine is working as it should, closed at low rpms and open at higher revs, but when i drop RPM to idle, it and barely moves when im revving the engine. 
So it might seem like the pcm is signaling to the regulator that the engine is not at the revs it should be for opening the vanes. 
So the problem is finding out wether the vnt is regulated by turbo boost or engine revs.

the car has now been sitting over the holidays, and after being without battery, the speedometer doesnt work now. 

So I am now at that point that i consider to just wreck the car.

But i cant get it out of my head because it seems that its a small electrical problem, so in fear of loosing too much money, i hope to get it working properly so i can sell it and get my money back 😂 

Hi Rob,

Hope you had a good holiday period.

I ended up un-blanking the EGR on Christmas day, took it for a drive with little improvement. My hypothesis being that if the EGR is closed (or faulty, in addition, in my case) then the soot is not being burnt off properly and may be sticking to the turbo vanes.

I called around a few garages trying to find anyone that does turbo reconditioning but none do, just wanted to replace the turbo, but that would mean doing the EGR too. The Ford specialist (not a dealership) in my town quoted £750 for a new turbo plus labour, £300 for an EGR, both official Ford parts. Over a grand.

I have tried to get the turbo off once but it was cold, my wrench slipped on a bolt that was too long for my sockets and I cut my finger and gave up... LOL. Cleaning oil out of a fresh wound is no fun.

I'm at the same point as you to be honest mate. Wondering if it's easier to scrap the car, it's a 10 plate so getting on a bit, and makes funny noises in other places. Worried I could do a turbo and then the clutch go or something dumb like that. Cambelt needs doing too... It's a nice car, especially with the Titanium trim, and I'd love to keep it, but the cost for amending a new car on my insurance at my age (after buying a new one too) is almost criminal. Probably would be ***** cheaper to rebuild the whole engine...

One thought I had to carry it through until the cambelt snaps is an aftermarket turbo controller, where custom levels can be set and it will adjust appropriately, regardless of preset values, but probably not worth it either.

I need to get it to a garage, I'm stumped trying to do this myself. If it's too pricey... Well I'll just run the thing into the ground. Only had the car 6 months or so, bought for less than £1500, and like you, I'm worried it COULD be cheap, but could also be twice the value of the vehicle.

I'm sorry I can't help more Rob. I'm at wits end. I do really hope you get your car sorted without too heavy a hit to the wallet, but I wouldn't hold your breath. Please do keep us updated, I'll continue to check in and if I decide to pay to get it sorted, I'll let you know how it goes.

Good luck to you bud.

[sushilovin]

On 2/5/2021 at 10:31 PM, Tdci-Peter said:

I can see it does just what you said. At the 1st drop to idle after t=0 (I assume that is start), the ECU refuses to drop the VGTDC below about 50%, and it looks like the turbo does not cut in as a result of this.

But everything looks sluggish to me. FRP seems to be following RPM, not APP. I would expect FRP to follow APP, so as to put more fuel into the engine, then RPM & MAF to follow that. Could it be due to delays in a wireless ELM perhaps? But the TPMODE (Partial Throttle vs Closed Throttle) seems to follow APP ok.

If it is an ECU fault, then it is a very odd one, seems to work ok one second, then not so well the next, but it is still doing part of the job. If it is another sensor, then it is not obvious what. Have you tried adding DTC count to the PID list? That would show if & when the ECU picked up on a fault.

A trace from my car (different engine I know, but same principle):

This show the extent to which I expect FRP to follow APP. Opening the throttle needs to put more fuel in first and foremost. Everything else follows that. MAP, turbo and more air is useless without more fuel.

That snippet is 5th gear (90-110 kph), so allows engine operation to be seen more clearly, without rapid rpm variations which can make diagnosis harder.

 

Although I've basically signed off from this issue, just wanted to reply to this.

VGTDC shouldn't go below 50% in neutral anyway (assuming Rob's readouts are in neutral). At idle, they should sit at around 70% as the higher the percentage, the most "closed" the vanes are. I'm making this assumption based on how quickly the revs fluctuate, I would expect it to be smoother if the vehicle was moving.

FRP may be acting in the way you describe if my assumption that Rob's readouts were taken in neutral is correct. The engine is under no load, so FRP only needs to increase with revs as the revs increase instantly with APP unlike when you increase the load when the vehicle is moving. Hope I've explained what I'm trying to say well enough.

From what I can tell based on the data in my car, the VGTDC readouts are correct, but the vanes are mechanically not in the right position, restricting exhaust and trapping it in the engine before the next engine cycle. Rob describes similar symptoms to my car, but I can't say for certain it's the same issue.

I'd like to hang around and see what you think of this issue, Peter. As I say, I've basically given up with mine, but maybe there's still hope for Rob's yet. Cheers.