TSi won't rev higher than 3500-4k in gear

[91_stealth17]

As the title states, my 1990 tsi won't push past about 3500-4k rpms while driving. If I'm parked in neutral it'll go to redline no problem. But while driving it won't exceed any more than 4k. I pressure tested it and there are no leaks. Compression is at 150 psi on all four. Timing is correct. Starts and idles great and runs perfect up to the 4k but just won't go past that no matter if i try to creep past it or WOT. It happens in every gear, in 1-3rd it's more of a violent shut off similar to a fuel cut and in 4-5th it's more of a stutter and lack of power to accelerate. I put a fuel pump from a stealth tt that should supply about 180 lph so that should be adequate. The original one was whining extremely loudly so that's why i swapped it out. The only thing I can think of is possibly a faulty ecu? I know the guy who owned it a couple people before me and he said it had a new ecu in it when he sold it but I don't know if that one stayed with it. I'm kind of out of ideas so any suggestions would be appreciated.

 

[DSMTalonTsiAwd]

Sounds like your Ecu got fried. I had the same symptoms when my ecu got fried. The fuel pump was really loud for me as well, and I couldnt go past 3k rpms.

 

[YanDsm]

it could be a bad knock sensor or broken knock sensor wire that makes the ecu think that there is knock when there is not. It happened to me. Take a look at that!!!

 

[91_stealth17]

I'll see if i can get a hold of a known good ecu and try that. The wiring to my knock sensor looks good. Tested resistance on the harness side and there was resistance. The sensor still has the silicon on it and i don't have a CEL on so i think it's good.

 

[97SPYDER210]

I had the same problem. First check the timing. Then connect the timing light to each plug wire and rev the engine see if the light stays on. My coils were out of spec and caused the spark to stop when I rev the engine about 3000 on two cylinders.

 

[91_stealth17]

The timing is all the way it should be. As far as connecting a timing light to the plug wires I don't know if that'd be effective since it only has a problem when under load, when in neutral it'll go through the rpm's just fine.

 

[SleepinGVR4]

See if you can borrow or find a working ecu to see if that changes anything.

 

[97SPYDER210]

That's bc you don't have a load on the engine. When in neutral you can rev to red line with only 2 cylinder working bc it has no load. It does sound like a spark or fuel injector problem.

 

[Lou98GSX]

cover all your basics . start with checking your timing belt and make sure all the marks line up . check fuel pressure and also drop the down pipe and try driving the car maybe the flex section collapsed

 

[91_stealth17]

Alright the snow has finally gone down enough to start working on it again. A couple days ago I got it at least limping and took it out on the road and was still having the problem of not being able to push to redline and felt like it was only running on a couple cylinders. Then it backfired really loud and completely died and wouldn't start again. That turned out to be a blown fuse so i replaced that and it started right up but now none of my gauges work. The rest of the fuses are good. I regapped my plugs since I read that could cause the stalling issue and started it up and ran great on all four for about 15 seconds and then went back to only a couple cylinders. So i went and unplugged all the injectors but one to see which ones were firing. The one closest to the passenger side would even start and run on it's own. The other three would just cough and fire a little when they were the only one hooked up. Any ideas on what to do next?

 

[Jward5]

I dont believe its an ecu problem. Sounds like you have some faulty wiring going to either your coil or injectors. Id start by taking off the tape on those wires and see if you can find and spots where there are cracks or just sketchy looking spots on the wires.

 

[91_stealth17]

I took a look at the injector harnesses and they're a little corroded and the wires seem kinda brittle so I ordered new harnesses and I'll give that a try.

Also when i pulled the plugs the third one looked carbon fouled. The rest looked good though. I also had a similar problem with my first talon with the third cylinder giving me problems. Not sure if anyone else has had the same thing happen or why that would be.

Thanks for the help!

 

[91_stealth17]

Figured out the misfire problem! The clip on my power transistor unit was missing so at times the bottom half of the harness would vibrate off and lose connection. So now all four are firing great but it's still stalling.

After fixing the clip on the ptu i took it for a spin and it had decent power up until 3-4k range and then it feels like the engine completely dies for a second and then comes back on again over and over again until I let off the throttle. So I drove it at lower rpm for about a half mile and it was fine. Then for some reason I couldn't hardly touch the throttle without it bucking and dying. Any suggestions?

Timing is correct, the plugs are gapped correctly, they plugs look normal (cardboard color), compression is good, new fuel pump so that should be good. I don't know what else to do.

 

[jasonj92]

I have a 90 tsi that runs fine if u want to try my ecu let me know.
I'm about 30 mins east of Fargo

 

[V8srslow]

A clogged cat can cause power issues under load also. Even without code. Can run it off down pipe see if it helps.

 

[91_stealth17]

Over the weekend I decided to pull the return hose off the regulator and there wasn't any fuel getting my the regulator so I tore into it a bit more and found my fuel filter was pretty plugged up so i replaced it and now im getting better fuel pressure.

So now it will start and run great for about a minute or two but then it'll start to stutter and rpms go down and then my fuel pump starts to whine really loud and the car dies. I can't even tap the throttle to bring it back, it just bogs down if i touch the pedal.

Im thinking maybe there's something getting sucked up to the pump and causing it to starve so I'll take another look this weekend but is there any other things that could cause similar symptoms?

Also the only gauge in the car that is working is the speedo. No tach or temp or anything but i think that's a separate problem. Fuses are good.

I think I may get an afpr because of the 255 lph pump I installed while still on a stock regulator and injectors so my fuel pressure is most likely too high.

Would high fuel pressure cause the issue of starting but then dying after idling for a couple minutes? I was thinking the fuel pump was whining really loud because of sucking something up to the bottom but maybe it's trying to push too much fuel and the regulator can't keep up?