850 turbo: massive stuttering/hesitation

[RickHaleParker]

I don’t see a check engine light anywhere. Save to assume it burned?

Burned out or somebody treated the symptoms by removing the bulb out instead of fixing a problem.

[850T5Ritalia]

Had some time today. What I found:

I don’t have the obd port? Instead I found that I can read codes under the hood with the pin and the terminals that correspond with fuel system, ignition etc.. so that’s what I did first.

Found code 143 and 121. MAF and Knock sensor. MAF seems logical since I took that off to see if it made some difference.

I also took of the more accessible IC piping for inspection and checked the vac hoses from the turbo to the pressure regulator etc.

I found some oil in the hoses at the turbine side.. turbo seals?

After resetting the codes and placing the IC piping back it runs better. But still not smooth like before. So something changed but it’s not clear to me what made the difference.

I will check which codes come back and replace the sensors. Still a bit odd that it runs better than before since I didn’t found any leaks or improper installed hoses.

[erikv11]

Oil in the intercooler hoses is completely normal, very unlikely there is any leak of any consequence.

It's common for the intercooler path to leak at the hose clamps, you probably cinched up something that was leaking. Sounds like you need to get art the rest of the intercooler path.

Flat out replacing a sensor isn't always the right course of action for a particular code, might want to post up any codes for troubleshooting advice.

[greg850r]

It's common for the intercooler path to leak at the hose clamps, you probably cinched up something that was leaking. Sounds like you need to get art the rest of the intercooler path.

Exactly what I was thinking. Symptom of an intercooler hose leak.

[shegarty]

Yep it's burned out.

Should be next to the Service light, no? +1 on replacing ALL your vacuum lines before bothering with a smoke test. Also, a visual inspection of the turbo would be in order - remove the intake pipe and check for shaft play and make sure there are no coolant or oil leaks. You will also want to check the TCV (turbo control valve), I think there is a post in the repair section somewhere on how to do this.

[erikv11]

Yep it's burned out.

Should be next to the Service light, no? ...

correct

[hausmeister]

I had missing and hesitation issues on my NA, Ignition was the cause. If the car is an unknown I'd replace the entire ignition system anyways just to be safe. (Coil not neccesarily)
From my experience it is best to just go ahead and replace all the vacuum lines. All of them. And the intercooler hoses, etc. On my T5-R I had issues everywhere, simply because that stuff was so old. Depends on how it was maintained I guess.

[erikv11]

The car is almost 25 years old, same for all those rubber hoses under the hood ... replacing every vacuum line is the way to go if you plan to drive the car much at all. Get yourself a baseline.

[850T5Ritalia]

Thanks for all the great input! Since I don’t have much time I try to do some little diagnoses from time to time. After resetting the codes from the A2 terminal (fuel system) I didn’t found one returning after driving for a while. It blinked 1-1-1. So the front knock sensor and MAF sensor codes are gone.

I will diagnose the ignition codes today and go ahead and order new vacuum and silicon IC hoses. Also I plan on replacing the exhaust manifold so a good time for an overall inspection of the turbo and replacing of all the gaskets. In the process why not take off the TB for a clean and some new gaskets.

That should tackle all the possible leaks. Also wanna take out the fuel pump but found the lock ring to be very very tight.. I need to buy a tool to get the thing loose and check the fuel pump.

About the CEL. On the European models I think it’s on the left side. I tried to locate it with a flash light since it doesn’t light up.. I can see a vaguely ‘engine symbol’ in orange next to the SRS light. Not sure though, gonna pull the dash anyway so I’ll find it.

Quick question: I read the turbo goes on the manifold without a gasket but that it’s possible to place a gasket.. I got myself a Japanifold and was wondering if the turbo bolts on without a gasket like the OEM?

[850T5Ritalia]

Got it solved. Cleaning all the electrical connectors and refitting the IC piping together with replacing a couple vacuum hoses did the job.

Replaced the bulb from the CEL which was indeed next to the service Light on the far right of the cluster. It’s a lambda symbol on my car. It works

Gonna go ahead and replace all IC piping anyway together with plugs, wires etc to complete a full ‘stage 0’.

Thanks for the great help! Awesome forum