Intermittant power loss on 2.2DTi

[stevemann]

Hi,
This is my first post and may be going over old ground, but any help or links are appreciated. I've got a 2003 Signum 2.2DTi which I guess has the Y22DTR engine which has done 70k. Everything runs fine 99% of the time...however a few months ago I started to get a power loss and stall when I was trying to gently apply throttle while cruising in 5th at around 1200rpm. Engine would restart fine and there was no spanner error. This seems to have mutated into a diiferent kind of stall; after a couple of hours motorway cruising, the engine will lose power/stall and restart itself in 2 second pulses. Not great at 70mph. When it's in this mode it will also stall at junctions, unless the revs are kept up. It will then recover and be fine. Always starts fine from cold and runs smooth. Fuel consumption is godd at 50mpg. Again, no spanner error on the dash. I've read the pending error codes and have got at various times P0638, P0400 and the MAF error. Tried replacing the MAF with an aftermarket one and that made the car very jerky between 1 - 2,000 rom, so the original MAF is back in. I've checked the vacuum pipes I can get to and they seem fine. What I think is the EGR on the front of the engine seems to move OK in-situ, but hasn't been taken out yet. The fault is annoying but not yet permanent to make it an easy fix at main dealer. Cheers

[Celes]

P0638 is Throttle Actuator Control Range/Performance. Common problem
Try giving it a good clean with carb or brake cleaner

[stevemann]

Thanks. I had the upper part of the throttle body off this afternoon and it was sooty & sticky but the butterfly still moved fine. I've cleaned it up as best as I can and see how it goes. Could take some time with an intermittant problem. Next step would be to take the EGR off & do the same? I've read one thread where you need to drill out a pin to get to the solenoid in the EGR, is that the case for the 2.2DTi?

[brifen]

Thanks. I had the upper part of the throttle body off this afternoon and it was sooty & sticky but the butterfly still moved fine. I've cleaned it up as best as I can and see how it goes. Could take some time with an intermittant problem. Next step would be to take the EGR off & do the same? I've read one thread where you need to drill out a pin to get to the solenoid in the EGR, is that the case for the 2.2DTi?

No, it is on the CDTI engines you can drill out a hole. On the DTI engines you just take off and clean.

Bri.

[Celes]

Thanks. I had the upper part of the throttle body off this afternoon and it was sooty & sticky but the butterfly still moved fine. I've cleaned it up as best as I can and see how it goes. Could take some time with an intermittant problem. Next step would be to take the EGR off & do the same? I've read one thread where you need to drill out a pin to get to the solenoid in the EGR, is that the case for the 2.2DTi?

Note that the throttle body should be "shiny" when cleaned squirt loads of carb cleaner

[ptrehearn152]

hi p0638 is throttle position sensor, if it on the throttle body they are £150+vat from stealers. check conections are good first and check connection at accelerator pedal. this fault is a real pig to determine as i have the same problem. you'll see that the sensor has a lot of flex in it even though it is fastened securely, my theory is this is half the problem. you will find it on top of the throttle body at the back, it's the sensor nearest the offside.

[stevemann]

Thanks for suggestions. I've cleaned the throttle body & the EGR, checked the throttle connections at the pedal and all the vac lines but am still getting the problem. Is it possible to check the operation of the EGR or best to try another from a scrappy?

[stevemann]

Still have the problem, but it's changed a bit. I now often get a "hunting" type idle when warmed up with the revs swinging from about 500 to the usual 900/1000rpm. The engine can sit like this for several minutes without actually stalling. Giving it some revs blows out some black smoke but it'll then return to the pulsing mode. It'll then start up fine from cold and pull fine under load. A few theories are around about supermaket diesel and fuel pumps/regulators. I've just changed onto Esso from Tesco diesel with no improvement.

Any ideas guys? The only good news is that it's starting to move from intermittant to permanent fault!

[stevemann]

Oh, btw. I don't get a spanner light with this problem and I recently reread the codes and there were no codes stored. So I presume the problem isn't with any of the sensors/electronics but more mechanical???

[stevemann]

Finally some progress on my stalling fault. Simply disconnected the vacuum pipe from the actuator that drives the air flap in the throttle body! Blanked off the vac pipe and the car starts fine, runs fine, turns off fine and gives 50mpg, no spanner light.

I know this isn't getting to the root cause (which may be the TPS or something else) but is a v. cheap solution & makes me wonder what the air flap is for?? Over complicated way of stopping mice getting into the engine??