Yet more engine issues
Moderators: jifflemon, coyote1980, Rachel
Yet more engine issues
Hi friends,
having sorted the missfiring issues due to a bad distributor isolation, I have been driving for almost an year an almost perfect engine.
But from last few weeks I am having yet more issues.
This happens mostly on low engine speed and moderate trhottle application: the car as massive flat spots and almost stalls.
Going uphill withbpassengers is a nightmare, I have to keep revs high and not pass a quarter throttle.
On intersections if I do a brisk acceleretion from neutral, it almost dies. I have to be well over 2000rpm an very slowly release the clutch.
At high RPM and wide open throttle it still happens noticeably
Already tried:
Checking leaks (at least in the easiest spots)
Swapping MAFs
Disconnected MAF for a test drive with zero difference
Swapping ecu (robou and standard)
Other back ground
Idles perfectly, coast perfectly
Fuel filter replaced around two years.
Injectors cleaned a year ago.
Any Idea?
I an starting to get fed up. One thing gets fixed and then another appens.
having sorted the missfiring issues due to a bad distributor isolation, I have been driving for almost an year an almost perfect engine.
But from last few weeks I am having yet more issues.
This happens mostly on low engine speed and moderate trhottle application: the car as massive flat spots and almost stalls.
Going uphill withbpassengers is a nightmare, I have to keep revs high and not pass a quarter throttle.
On intersections if I do a brisk acceleretion from neutral, it almost dies. I have to be well over 2000rpm an very slowly release the clutch.
At high RPM and wide open throttle it still happens noticeably
Already tried:
Checking leaks (at least in the easiest spots)
Swapping MAFs
Disconnected MAF for a test drive with zero difference
Swapping ecu (robou and standard)
Other back ground
Idles perfectly, coast perfectly
Fuel filter replaced around two years.
Injectors cleaned a year ago.
Any Idea?
I an starting to get fed up. One thing gets fixed and then another appens.
Re: Yet more engine issues
So, as you mentioned a Robou ECU, I'm presuming you're turbo?
Does it boost ok?
Did it start suddenly or has it been gradually getting worse?
Any changes done prior to it starting?
Does it idle correctly?
Does it boost ok?
Did it start suddenly or has it been gradually getting worse?
Any changes done prior to it starting?
Does it idle correctly?
Re: Yet more engine issues
Hi, yeah I forgot its a 91 turbo.
Idles perfectly.
I noticed it about two weeks ago. I think when it appeared, it appeared full on. Perhaps getting a bit worse now.
BR
Idles perfectly.
I noticed it about two weeks ago. I think when it appeared, it appeared full on. Perhaps getting a bit worse now.
BR
Re: Yet more engine issues
Perform a reset on the roboumod and check if the problem is right there from the beginning. Both ECUs may be in some loop as a result of turbo spikes or some ignition anomaly. Also check the vacuum in the air pipe to the ECU. This is no cure but it may give a direction of where to find a solution.
Too old to bother
480 Turbo midst '91
480 Turbo midst '91
Re: Yet more engine issues
Hi thanks for the help.
I Did a reset via the jumpers for 30 seconds (engine hot). Problem was there from the start.
I then umpluged the pipe conecting to the ecu. I could feel good vacuum. I also could feel bost (I drove a bit with the pipe unconnected).
While driving, it stuttered so bad that the 3rd gear got disengaged at WOT around 3000RPM.
Not sure what is happening
I Did a reset via the jumpers for 30 seconds (engine hot). Problem was there from the start.
I then umpluged the pipe conecting to the ecu. I could feel good vacuum. I also could feel bost (I drove a bit with the pipe unconnected).
While driving, it stuttered so bad that the 3rd gear got disengaged at WOT around 3000RPM.
Not sure what is happening
-
- Can tell where the 480 was built
- Posts: 317
- Joined: Sat Jan 11, 2014 3:44 pm
- Location: Aberdeenshire, Huntly
Re: Yet more engine issues
Might be an odd suggestion or maybe something you've checked, is the air filter still in ok condition? not totally choked up? or at the other end of the spectrum doesn't have a massive hole in it?
the other thing that crossed my mind is a dying fuel pump/blocked gauze on the fuel pump pick up
Another thing to check would be the crank sensor and all its associated wiring, the signal can be susceptible to interference from other frequencies if the earth for the sensor is dodgy and for that reason, you could be randomly losing crank signal and therefor randomly losing spark.
Just spitballing idea's, might have already checked these things but you never know
the other thing that crossed my mind is a dying fuel pump/blocked gauze on the fuel pump pick up
Another thing to check would be the crank sensor and all its associated wiring, the signal can be susceptible to interference from other frequencies if the earth for the sensor is dodgy and for that reason, you could be randomly losing crank signal and therefor randomly losing spark.
Just spitballing idea's, might have already checked these things but you never know
'91 480 ES 2.0l 16v 'Williams' Conversion - 212bhp/230nm
'90 940 GL 2.0l Estate
'08 XC90 D5 SE Premium
'90 940 GL 2.0l Estate
'08 XC90 D5 SE Premium
Re: Yet more engine issues
Guys, one more question. If it is air or vacum leak related, wouldn't disconnect the maf make itba bit better. At least for low revs?
Re: Yet more engine issues
So, this weekend I started my teardow.
I disconnected all pipework form the maf till the manifold (included) all pipes were ok even the ones that attach to the turbo.
The throttle body was rather oily, as well as the TPS sensor. The oil came from the cranckcase breeder valve. This, because the trhottle body had oil on the engine side, the intake one was clean. Also regarding the 4 manifold pipes that connect to the engine, they were oil free.
Rotor and spark related stuf were ok.
The only thing that I think was bad was the fuel pressure regulator valve. I connected a pipe to the return side, and at idle it did not let any fuel return. Is this supposed to work that way?
Is there any way to test it?
Can it be the cause of the issue?
I was trying to look for some replacement but am not able to find any.
Does anyone know where to get one?
Thanks
I disconnected all pipework form the maf till the manifold (included) all pipes were ok even the ones that attach to the turbo.
The throttle body was rather oily, as well as the TPS sensor. The oil came from the cranckcase breeder valve. This, because the trhottle body had oil on the engine side, the intake one was clean. Also regarding the 4 manifold pipes that connect to the engine, they were oil free.
Rotor and spark related stuf were ok.
The only thing that I think was bad was the fuel pressure regulator valve. I connected a pipe to the return side, and at idle it did not let any fuel return. Is this supposed to work that way?
Is there any way to test it?
Can it be the cause of the issue?
I was trying to look for some replacement but am not able to find any.
Does anyone know where to get one?
Thanks
Re: Yet more engine issues
You found the culprit, I suppose. Start by replacing the filter, no harm done anyway. If still no return the pump should be checked.
Too old to bother
480 Turbo midst '91
480 Turbo midst '91
Re: Yet more engine issues
Thanks for the help.
I'll try to source one.
Oh and btw I also disconnected the line that comes from the pump and connects to the injector rail (on the 4th cylinder side) when crancking, a good anount of fuel came out.
BR
I'll try to source one.
Oh and btw I also disconnected the line that comes from the pump and connects to the injector rail (on the 4th cylinder side) when crancking, a good anount of fuel came out.
BR
Re: Yet more engine issues
HBOL gives volume per minute from each injector type , useful as a starting point if not enough fuel???
Alan
480 ES 2litre 'Celebration' ? , C30 1.8ES, SS1
480 ES 2litre 'Celebration' ? , C30 1.8ES, SS1
Re: Yet more engine issues
Hi friends,
Unfortunately the regulator did not solve the issue.
Took it also to volvo dealer but without success.
If I ever find the cause, I'll keep you posted.
Cheers
Unfortunately the regulator did not solve the issue.
Took it also to volvo dealer but without success.
If I ever find the cause, I'll keep you posted.
Cheers
Re: Yet more engine issues
Hi everyone,
I was being dumb. I did not understood that the pump was at fault as you sugested.
I replaced it and no more issues.
Thank you very much for the help.
I was being dumb. I did not understood that the pump was at fault as you sugested.
I replaced it and no more issues.
Thank you very much for the help.