I just recently picked up a 91 GTIR, which was said to have an turbo actuator problem. I brought it home with limited boost, turned out to be a boost leak. After fixing the boost leak, It boosted fine but had some ignition problems while rpms climed it would cut in and out. Swapped the spark plugs and took it out for spin. During the drive I took it to full boost once and power cutout as if it had a boost leak, limped it home with no power sounding like it was farting, couldnt get the car going past 60kms/hr. Took a look at all the couplers, doesnt look to have a leak.
When Parked:
No engine light, I have checked for codes.
When the car is idling, its fairly ruff.
When I rev it, its rough but smooths past 3000.
When I unplug the maf, it runs rougher.
Added grounds to the engine to bat and chassis
Checked the new spark plugs, 3 have black carbon but one is fairly clean, none are wet.
Second drive:
Rough getting up to speed but better than previous drive, maybe because the engine is colder?
Crusing with 10 percent throttle negative boost runs fairly smooth
Crusing with boost, bucking really rough and hesitant.
Trying not to throw money replacing everything as my budget is very tight, and i just bought this car.
looks like your injectors are trying to compensate for your cylinder that is not working or not working well, unless you have brown deposits on that spark plug. does your engine sounds like a subaru at idle ?
looks like maybe a injector stopped working or your ignition leads are bad
Looks like its a dead injector. Ill have to swap it out and see if that was related to initial ignition problem.
check your blow off valve
check your det sensor, just b/c it doesnt code doesnt mean its not putting u into limp mode
check your maf
check your maf ground resistenace
hard to say i'd use a consult cable to log what all your sensors are showing
car's 25 years old
things go, fuel pump, cap n rotor, injectors, wires, plugs, fuel filter, mafs.. i'd check it all
What about his 3 black coated spark plugs and the 4th one being clean ? His symptoms are too alike the ones I had with my ga16de sentra when a injector died
When you put the engine under a load does it hold at a certain rpm and just not accelerate? I may have had a simular problem. It wasn't the injectors. Try replacing the cap, rotor, and spark plug wires before you go through the trouble of changing an injector. Also make sure the gap on your spark plugs is 026 on the inches side of a capper.
Heres where I am at:
Tested all injectors, pulled and cleaned them. Tested with 9v bat on bench. Reinstalled in differnt order.
Once again ran engine, pulled cylinder 1 injector wire swapped it with cylinder 2. No differnce, still running on 3.
Noticed a light ticking from valve train, pulled valve cover. Everything normal visually.
Right now it does not look like an electrical/sensor issue. But im taking it one step at a time.
Advised there could be no compression on 1st cylinder. Will leakdown test tomorrow. Wish me luck.
if you have a cylinder with no compression you'll have to rebuild yours or find another one in good condition, in the best condition it should give 160 psi per cylinder
Compression came back good. Found the problem with cylinder 1 by chance. I did not push the plug wire in completely and it started firing normally, but when i clicked it in it started misfiring. Bad plug wire, swapped it for a wire off my ka24de temporarily.
Right now its not very drivable but idles and revs smoothly with no load. When driving under 3500rpm it cuts in and out of power, can not build any boost till 3500rpm. Even when it boosts has a serious lack of power.
next on the list, pick up some oem plug wires for g20.
Um shot in the dark here. Do you have a bov? And are there any vacuum lines with cracks in it?
Front mount intercooler with factory BOV
Horrible bumper cut for the front mount.
Here is what im dealing with: