Massive overfuelling on 87 944 turbo at full throttle
- Thread starter ukmastiff
- Start date
Boost leak (top of dump valve or intercooler junctions)
temp sensor faulty (the blue one at front of head)
weak wastegate - though boost would drop off - boost enhancer would help as would shims
faulty FPR (fuel pressure regulator)
AFM Spring needs moving tighter if its runnning rich - have played with them in the past successfully (but wont make a difference) much over 4,500 rpm
boost leak again
Its not all bad it will be faster when sorted,
Tony
temp sensor faulty (the blue one at front of head)
weak wastegate - though boost would drop off - boost enhancer would help as would shims
faulty FPR (fuel pressure regulator)
AFM Spring needs moving tighter if its runnning rich - have played with them in the past successfully (but wont make a difference) much over 4,500 rpm
boost leak again
Its not all bad it will be faster when sorted,
Tony
ukmastiff
New member
Theres no update on my car yet. Andrew has plenty of 944's and other Porsche in there and has a good two weeks of work on. The car park was jammed on my arrival.
I dropped the car off so he has it and he will try and look at it for me this week if he can but I dont expect instant when turning up on short notice. As soon as he gives me an update I'll let you know. He did hint when I dropped it off that he favours a 'leek' as the likely cause himself but we will see. Promax have Bosch sealed refurbed MAFS if one is needed but I get the impressin he thinks its not the MAF.
Promax is such a bad place for me to get to , I can actually get to Birmingham quicker , I must find a sneeky route !
Cheers
Mas
Mas
I dropped the car off so he has it and he will try and look at it for me this week if he can but I dont expect instant when turning up on short notice. As soon as he gives me an update I'll let you know. He did hint when I dropped it off that he favours a 'leek' as the likely cause himself but we will see. Promax have Bosch sealed refurbed MAFS if one is needed but I get the impressin he thinks its not the MAF.
Promax is such a bad place for me to get to , I can actually get to Birmingham quicker , I must find a sneeky route !
Cheers
Mas
Mas
peanut
Active member
yes that sounds like a distinct possibility. Does the car have a cold start injector like the S2? if so it would be worth running the car with the cold start injector electrical connecter disconnected and see if there is any improvement.
A fuel pressure guage will let you see what the fuel pressure is whilst running. Over-pressure might cause injectors to leak .
ukmastiff
New member
I just had an update from Andrew at Promax as follows.
There was a loose pipe on the turbo coming off under boost. He has cleaned replaced and test driven the car and that is sorted. This totals 1.25 hours labour. He has told me the car is still running rich though which considering the MAF has been tampered with
( and alledgedly put back !) doesnt suprise me. We shall see if the MAF is relevent as they will look in to the 'rich running' and sort it out I'm sure.
So all those who suspected a leak ( including Promax) gold star , well gold for him as he actually found it , silver for all the others lol.
Regards Mas
There was a loose pipe on the turbo coming off under boost. He has cleaned replaced and test driven the car and that is sorted. This totals 1.25 hours labour. He has told me the car is still running rich though which considering the MAF has been tampered with
( and alledgedly put back !) doesnt suprise me. We shall see if the MAF is relevent as they will look in to the 'rich running' and sort it out I'm sure.
So all those who suspected a leak ( including Promax) gold star , well gold for him as he actually found it , silver for all the others lol.
Regards Mas
sawood12
New member
Double gold star for DivineE for pointing out it wasn't the AFM as the AFM is redundant for fuelling at WOT. Certainly not a gold star for the chap at the rolling road place for suggesting it was the AFM. Just goes to show you shouldn't trust your car with anyone other than a Porsche Specialist, or someone who fully understands the Motronic. They are worth their weight in gold.
This reminds me of a thread I read a few years ago of some poor 944 turbo owner who took their car to a Scooby tuning specialist who ran the car on the rolling road, saw the black knob of an MBC, gave that a tweak to release an extra 30 or so BHP with the owner ending up with a blown engine a few days down the line.
This reminds me of a thread I read a few years ago of some poor 944 turbo owner who took their car to a Scooby tuning specialist who ran the car on the rolling road, saw the black knob of an MBC, gave that a tweak to release an extra 30 or so BHP with the owner ending up with a blown engine a few days down the line.
bennyboy
New member
Might I have the same problem as this chaps? Every now and again recently my car has stuttered, very, very quickly, and then been fine again. Except today, after driving it for 5 minutes I had one of these stutters, and then it gradually got worse and worse until the engine just cut out at low revs. Anyway, the recovery man came out, checked the plugs and they were pretty black, which obviously suggested overfueling. The engine would start, then choke and finally cut out. So we ran the engine without the air filter in and it was fine, so I think the air/fuel mix is wrong. Could it be an air leak somewhere? I think the air filter is fairly new, but it's just the standard Mahle unit. I've always wondered about the benefits of a performance air filter, but I'm not convinced that would solve my problem. I think the car has always run a little rich, confirmed by the last two MOT testers. Where should I start? Thanks in advance...
ukmastiff
New member
My car apparently had 2 problems. I say this because the symtoms I described were caused by a loose hose on the turbo and this was cured. However the car is still with Promax in a queue 
as they have told me it is sill running rich despite the 'cutting out at full throttle' fault being cured. I cant tell you what causing it to run rich until Promax tell me. A little knowledge being a dangerous thng I won't comment on yours but thought I'd let you know what was the score with mine so far. Apparently the fuel pressure regulater has been checked by Promax and is O.K and the MAF checked appears O.K so logically these two things must be ruled out on yours I suppose ? and probably a hundred things I dont know of.
Regards
Mas
as they have told me it is sill running rich despite the 'cutting out at full throttle' fault being cured. I cant tell you what causing it to run rich until Promax tell me. A little knowledge being a dangerous thng I won't comment on yours but thought I'd let you know what was the score with mine so far. Apparently the fuel pressure regulater has been checked by Promax and is O.K and the MAF checked appears O.K so logically these two things must be ruled out on yours I suppose ? and probably a hundred things I dont know of.Regards
Mas
peanut
Active member
with your own thread probably [
]Trouble with joining another thread is the replies can become a bit confusing and the problem with your car probably isn't due to the same cause as benny's
I would start by disconnecting the electrical connector to one of your injectors and run it. if there is any improvement however slight it might suggest one or more of you injectors are sticking open and leaking. If you don't use your car regularly the additives in your fuel form a laquer which can make the injector solenoids sticky especially if you let your tank run dry anytime.
Does your car have a cold start injector ? if so try disconnecting that once its running and see if that helps ..again possibly a faulty engine temperature sensor or a leaky cold start injector
ukmastiff
New member
O.K now I do hav ean update on the overfuelling car tale , basically I'm £560 poorer and the car has a new Air Flow Meter. Promax fixed the loose pipe they found on the turbo but the car was still apparently running too rich. Some fault finding later and a new AFM (Bosch refurb unit) was fitted so the car I am told is now running correctly.
I know the AFM was always a likely suspect and TBH I dont think Mr Rolling Road is to blame. It had clearly been cut open and resealed before and as I mentioned the adjustment was right up one end on the screw which is not the norm from what I have read.
It will be interesting to get the car back and see does it drives any better than it did when I bought it and also does it do a few more miles to the gallon. I know we don't buy these cars for economy but assuming the AFM was always knackered it must do a few more MPG now. The fuel tank has super unleaded in it at the moment so it will be a fair test drive.
I'll drive the car back from Bedfordshire in a few days and close this particular tale with my opinion on how the car is driving. I would have liked to have spent that £560 on servicing and 'improving' the car but since we own Porsche cars we're going to take the odd hit arent we !
Regards Mas
I know the AFM was always a likely suspect and TBH I dont think Mr Rolling Road is to blame. It had clearly been cut open and resealed before and as I mentioned the adjustment was right up one end on the screw which is not the norm from what I have read.
It will be interesting to get the car back and see does it drives any better than it did when I bought it and also does it do a few more miles to the gallon. I know we don't buy these cars for economy but assuming the AFM was always knackered it must do a few more MPG now. The fuel tank has super unleaded in it at the moment so it will be a fair test drive.
I'll drive the car back from Bedfordshire in a few days and close this particular tale with my opinion on how the car is driving. I would have liked to have spent that £560 on servicing and 'improving' the car but since we own Porsche cars we're going to take the odd hit arent we !
Regards Mas
poprock
New member
I think I'm "˜lucky' to have had an accident involving a flooded road and flooded engine which caused me to get a brand new AFM fitted under insurance. It's one of those parts that I reckon should probably be refreshed on a twenty-odd year old car but is so expensive I would probably never have done it.
Glad you're all sorted Mas, bet she goes well now! You have the added bonus of Promax knowing your car in advance of taking it in for a bit of boost one day "¦
Glad you're all sorted Mas, bet she goes well now! You have the added bonus of Promax knowing your car in advance of taking it in for a bit of boost one day "¦
ukmastiff
New member
Well the saga re the overfuelling etc ends here you may be pleased to know []
Today I picked up the car from Promax , though officially they are closed today.
Yes the car does have a new AFM , and I cant say if the rolling road garage spoiled it as I cant prove either way but one thing is a fact. The car ran perfectly well when it went in to the rolling road garage ( overfuelling maybe but it ran very well) and when it came out it coughed like a dog ! and kept stalling if you put your foot down. The only reason I didnt throw it back at them was I wouldnt let them near my car again !
When the car went in to Promax , it coughed like a dog and when it came out it ran like a swiss watch so you work it out ?
The AFM was indeed 180 odd plus VAT which I think is very fair and yes they did spend about 5 hours diagnosing and fixing two faults plus roadtesting and fitting an AFM etc.
Personally I am very pleased with the results. I'd have preferred 3 hours labour or 2 hours but who wouldn't []
It does make me wonder how many folk have their 23 year old cars actually running right and how many ( like I did) just genuinely think their car runs right. I will still put the car on a rolling road and will still publish the BHP but I can tell you it is now not missing one single beat and holds the boost all the way as it used to so whatever power it does or doesnt have , it goes rather well.
Cheers
Mas
]Today I picked up the car from Promax , though officially they are closed today.
Yes the car does have a new AFM , and I cant say if the rolling road garage spoiled it as I cant prove either way but one thing is a fact. The car ran perfectly well when it went in to the rolling road garage ( overfuelling maybe but it ran very well) and when it came out it coughed like a dog ! and kept stalling if you put your foot down. The only reason I didnt throw it back at them was I wouldnt let them near my car again !
When the car went in to Promax , it coughed like a dog and when it came out it ran like a swiss watch so you work it out ?
The AFM was indeed 180 odd plus VAT which I think is very fair and yes they did spend about 5 hours diagnosing and fixing two faults plus roadtesting and fitting an AFM etc.
Personally I am very pleased with the results. I'd have preferred 3 hours labour or 2 hours but who wouldn't [
]It does make me wonder how many folk have their 23 year old cars actually running right and how many ( like I did) just genuinely think their car runs right. I will still put the car on a rolling road and will still publish the BHP but I can tell you it is now not missing one single beat and holds the boost all the way as it used to so whatever power it does or doesnt have , it goes rather well.
Cheers
Mas
andy watson
Moderator
Mas,
Glad to hear you all back up and running, I have been following this thread as my S has been diagnosed by OPC as over fuelling from a failing MAF, having seen one of your earlier posts, I have contacted Andy at Promax and shall be placing an order for a refurbished unit from them.
Thanks
Andy
Glad to hear you all back up and running, I have been following this thread as my S has been diagnosed by OPC as over fuelling from a failing MAF, having seen one of your earlier posts, I have contacted Andy at Promax and shall be placing an order for a refurbished unit from them.
Thanks
Andy
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