Robfagha

Ford Focus Limp mode

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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!

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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.

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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.

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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?

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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

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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...

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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 😫

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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?

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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?

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

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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.

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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.

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