In summary, once my 2004 Ford Focus 1.8 Tdci (100bhp) gets up to operating temperature as in the temp needle is pointing straight up there is a misfire between 2000 & 3000 rpm in any gear when you are trying to drive steadily at a constant speed. You can feel the engine kicking it's missing so much. If you accelerate it's fine and if you lift off it's fine but it's driving me nuts because i've tried so much to remedy it which i'll describe below. You can feel the resistance until you pass 3000rpm and it's like it clears and carries on.

The problem started in September and I was driving home with my third newborn from the hospital, the engine light came on, but nothing felt different probably because we were so knackered. The next morning I plugged the laptop in and had a look through forscan which reported: P0401 Egr system insufficient flow detected. This came as a bit of a surprise as it's blanked off at both ends with a solid plate and had been so for the six months prior when i got the car.

I removed the pipe off the inlet and to be fair it was full of crud so i sprayed some choke and carb cleaner in and did my best to scoop it out. I probably dislodged something as the car was not happy when i started it afterwards and it threw out a lot of smoke and it was only after this that I can remember this problem happening. The problem never happens when cold, only when the engine has warmed up and is completely bamboozling me.

The injectors failed a leakback test so i replaced all four in the hope that this would sort it but no. It did fix the cold starting issues and smoking on initial startup. I have had the clutch & DMF changed as it transpired that the DMF was badly worn but this hasn't cured the issue either. There is still a vibration coming through the car so I am going to replace all three mounts but i don't think that it is related to this problem. I have changed the glowplugs as i read that these can sometimes cause issues but that didn't work. I have replaced the fuel filter twice, cutting one open to check for metal filings/swarf etc and it was clear. I have changed the IMV valve and the fuel rail pressure sensor again without success. I have replaced the MAF and MAP sensors with no joy. The cyclinder head temp sensor and oil pressure sensor were also changed, no difference. I even replaced the accelerator pedal just to rule that out but nothing changed. The EGR solenoid was making some squeaky noises when operating so i replaced that for a second hand one and made no difference.

I bought the car £250 spares or repair as the turbo had gone, i replaced that and cleaned it up and it went well, but then i had the issue with the car cutting out when driving, new camshaft and crankcase sensors didn't fix it, but replacing the engine wiring loom from another focus did. The car has done 82k miles but checking the MOT history it's probably closer to 140k. It came with no service history but i've done everything imaginable since obtaining the car. Despite the age it's in very good condition and i enjoy working on it. It's obviously something that changes or switches on when the car is at operating temp otherwise it'd happen when it was cold as well. The car has been remapped by myself with a bluefin and i have removed that and tried it and there is no difference whatsoever with the map installed and the standard ecu map. There are no fault codes on the ecu and the engine light doesn't come on when it's misfiring

Could the EGR valve really cause this much trouble even though it's blanked off? I do have a spare one in the shed sourced from eBay which just requires a bit of cleaning. I can change it myself its just a lengthy and awkward job. I spoke to my local garage and they do not believe that the fuel pump is failing as it starts first time on the button straight away when cold or hot so there are no fuel pressure problems.

I apologise for the lengthy post but wanted to cover in as much detail what i've tried already and as a first post i hope that i don't cause too many headaches 😛

1 hour ago, sdt492 said:

P0401 Egr system insufficient flow detected. This came as a bit of a surprise as it's blanked off at both ends with a solid plate

There is no EGR flow sensor on any of the Fords I have looked at, and certainly not on my Mk2 1.8TDCI.

The EGR flow is calculated by comparing the MAF reading with a computed engine air flow based on RPM, MAP and Inlet Air Temp (IAT). Since engine air flow includes re-circulated gas and MAF does not, the difference is EGR flow. So there are a lot of potential causes. I would think MAF is suspect no 1, since MAP is compared to turbo operation, and usually gives DTCs if badly out. Minor errors in MAF will not flag a MAF DTC, but may make the EGR seem wrong. But I see MAF has been replaced. That is no 100% guarantee, it is a unit that is hard to calibrate or test, and replacements can be faulty. I guess all hoses & the intercooler have been checked for leaks.

It is odd that these engines tolerate blanked EGRs, mine does too. But maybe it is inside their tolerance range, and a faulty MAF has taken it that bit too far.

Misfires in a certain RPM range I would put as injector problems, but as these have been changed, MAF is another possibility. I think the Delphi Injectors on the Mk1 require programming to the ECU, I guess this has been done via Forscan if needed. The VDO injectors on the Mk2 need no calibration data entering.

Regarding fuel pump problems, Forscan is the best tool. It can monitor the fuel rail pressure during start-up and when running. It should climb very quickly to about 200Bar (20,000kPa) when starting, then the engine will fire up. When running it should follow the accelerator pedal quite closely, peaking at 1500Bar (150,000kPa). Those are figures for my Mk2, I have seen similar figures for a Mk1 though.

Thanks for the reply Peter. The MAF on the car now is the one it came with and appears to be the original one. I bought a new one off eBay which is obviously not a genuine Ford one and a second hand one and they all acted the same. Once it stops raining I will retry them in the name of science 🙂 The spare MAP sensor I have is again a second hand one bought off eBay and when tried last time there was no noticeable difference but again I am not against swapping them. The only thing I haven't done is take each vacuum hose out one by one and inspect them intimately for cracks/leaks etc

I changed the intercooler recently as part of the elimination process incase there was a non-obvious fault with it. When i acquired the car one of the hoses had split going to the intercooler so i replaced the lot for an uprated silicon set.

The injectors were programmed correctly as you rightly said using Forscan using the correct firing order and not cylinder number. I will monitor the fuel pressure again using Forscan but the numbers seem familiar from when i looked into them abeit some time ago now.

10 hours ago, sdt492 said:

I will monitor the fuel pressure again using Forscan

A graph capturing the hesitations might possibly be useful. One showing RPM, APP, FRP, MAP & MAF as a minimum, I would suggest. Unfortunately the data rate is too slow and variable to be able to really distinguish cause from effect, so it is not very likely to be 100% diagnostic.

Looking at the vacuum operated EGR on the Mk1, it looks like there is no valve position feedback signal from the EGR valve, though some manifolds do have an electrical connector. It makes me wonder if some of these cars do have a DPFE sensor. It would be obvious by the pair of hoses linking it to the EGR valve. But it does seem to be mainly American petrol engines that commonly have the DPFE sensor.

You do seem to have checked or changed just about everything! One item that it could be is engine compression. If there was any solid matter released when cleaning the inlet pipe, it could have put a dink in a valve seat or something. When cruising at a steady 60 or below on a flat road, the fuel demand is low, and on my car the turbo is only giving a small boost (1.2Bar abs typ.) So the engine will be running very lean, and may be more susceptible to a compression reduction.

If I am at a steady speed of 50 or more, I will usually be in 5th, with the engine rpm at 1700 to just over 2000, though. Max torque is below 2000rpm on these engines. (1900 on mine).

23 hours ago, Tdci-Peter said:

Regarding fuel pump problems, Forscan is the best tool. It can monitor the fuel rail pressure during start-up and when running. It should climb very quickly to about 200Bar (20,000kPa) when starting, then the engine will fire up. When running it should follow the accelerator pedal quite closely, peaking at 1500Bar (150,000kPa). Those are figures for my Mk2, I have seen similar figures for a Mk1 though.

You're spot on with your figures there, fair play. The initial reading when cold was 600kPA rising to approx 22'500kPA when starting, I took the car for a trip and the peak reading I saw was about 144'500kPA. The figures followed closely the accelerator pedal usage,

The egr valve on my model has no electrical connectors or sensors whatsoever.

I swapped the maf & map today for spares which I had and there was no chance which tbh was to be expected.

When idling there is still a vibration coming though the chassis from the engine, so my first plan is to change the mounts to rule that out. I have branded replacements in the shed. I was disappointed that changing the clutch & dmf didn't sort that out.

I hadn't thought about damage to the valves etc until you mentioned it and the next logical course of action would be a compression test but I will put my hands up and openly say that I have no experience of doing one and would ahve to book it into my local mechanic to do that.

When i changed the turbo, i blanked the egr valve off at both ends. I rmoved the plate closest to the egr valve and replaced it with the metal gasket. I will do the saem at the turbo end just to say that i've done it and to tick it off the list of potential causes.

I appreciate your help, keep throwing ideas at me 🙂

I'd say usual cause is a split turbo pipe, esp. once hot and at that rev range. But you've replaced all yours with silicon..... 🤔 Doh! 

11 hours ago, sdt492 said:

keep throwing ideas at me

It is all I can do, I can not think of any definite answer that you have not already tried!

I have had a lot of problems with my EGR, starting in 2012. It put the MIL on, and gave error codes like P0490, Circuit High. It sounded like an electrical problem, and it was. The Mk2 has a fully electric EGR actuator: motor & feedback pot. I blanked it off when it gave problems, and tried repairing the actuator a few times. It worked for a few months usually, then played up & I re-blanked it. Ford do not supply the actuator, and like the Mk1, the valve is built into the inlet manifold, a pig of a job. But the actuator part is easy to remove. So I had to wait for an enterprising Chinese company to spot the market, and make them.

Finally in 2018, the price of a new replacement  actuator came down to under £50, so I fitted it, and it has been fine since. The ECU seems to prefer having the EGR working & unblanked, and I think fuel economy has improved slightly. From data logs, I could see the ECU was aware of the blanking, it slammed the valve from full open to full closed while blanked, then with the blank removed, I could see it controlling the valve in mid position while idling and cruising. I fitted an in-car display of valve position (& other stuff like MAP & ECT) during the investigations!

If there is any point to this here, it is to show that a working EGR is not as bad as painted, and having it blanked will alter the behavior of the ECU in some way, even if no warning light comes on. That will apply to the Mk1 as much as the Mk2. I regard blanking as a good diagnostic test, and a short term fix for failing EGRs prior to a better repair, as opposed to a long term fix.

A Diesel only needs fuel and compression to operate, unlike a petrol engine which also needs ignition. So misfires are rarer. Valve leakage or injector problems can cause misfires on individual cylinders. Fuel pressure dips on a common rail would be much slower, with a significant power drop for a noticeable time, rather than the sharp jerk or vibration of a misfire. The EGR valve and the Turbo vanes/wastegate are the only other likely causes of power dips, I have experienced dips due to the EGR, they are minor, not really noticed by a passenger, but a driver will feel the slight power change that does not match any accelerator movement.

It could be a log would show a difference between single firing events, and longer events, but I am not entirely confident of this, the data rate is probably too low and variable. Feel & sound is probably a better guide.

 

On 1/19/2020 at 12:09 PM, Tdci-Peter said:

If there is any point to this here, it is to show that a working EGR is not as bad as painted, and having it blanked will alter the behavior of the ECU in some way, even if no warning light comes on. That will apply to the Mk1 as much as the Mk2. I regard blanking as a good diagnostic test, and a short term fix for failing EGRs prior to a better repair, as opposed to a long term fix.

*** FIXED ***

So, it turned out that I had two separate problems one of which I'm indebted to Tdci-Peter for pointing me in the right direction. 

When I blanked off my egr valve, I placed solid blanking plates on both ends of the pipe. I removed them and replaced the pipe with the original metal gaskets. I took it for a drive and it seemed a lot better but there was still a vibration and the occasional missing from the engine. There was also the smell of exhaust fumes inside the car. 

With the bonnet up, everytime you revved the car you could see the exhaust fumes coming from the back of the engine, on closer inspection I could feel the escaping gases on the back of my hand around the inlet manifold but could not pinpoint where they were coming from. 

The attached photo shows the egr pipe after only an hour of driving and clearly shows the escaping gases. By chance I used a mirror to see the underside of the egr valve and the surface was a mess and looked like it had the remains of gasket sealer on it which had hardened and created an uneven surface which no gasket would have sealed. A bit of elbow grease to wire brush the surface clean and a replacement egr pipe from the shed and all is at last well with no performance deficit at all I'm pleased to report. The misfire has completely gone. 

I treated the car to an oil change and whilst the engine was running I could see the bottom gearbox mount moving a lot. Removal of that mount revealed that it had failed with the rubber in the middle breaking right through on both sides. This had not entered my mind as the mount was only six months old if that. Replacement fitted, job done. It now drives as well as a sixteen year old car can be expected. 

Thanks for the help as this problem(s) was driving me nuts. 

GR8 update and resolution! 👍