Help! Car won't go past 4500rpm

[punker462606]

First I'm not sure were I should post this but I have a 92 talon tsi awd auto. Mods are a 16g turbo with a 17 psi wastegate and a manual boost controller set on its lowest setting. I have a front mount intercooler, k&n filter, gutted cat, "fart can" muffler(previous owner), 255 fuel pump and rewire, evo 560cc injectors, boost gauge, oil pressure gauge, and a nb a/f gauge not hooked up. I have a safc 2 that I just put in and I followed the road race engineering and used there base tune for what I have. I do have a pocket logger. No wideband as of yet will be next purchase.

Ok now to the problems:
1) The automatic shifts whenever it wants to and sometimes gets stuck in gear (1,2,3 doesn't matter it's been sttuck in them all) and have to restart to get to normal. I plan to change the filter and fluid soon however the fluid is clear and non contaminated and at the proper level.
2) With the automatic concern comes another, the car won't rev past 4500rpms. It pulls and boost hard till that point, the boost gets to 13-15psi at 68% throttle acording to the logger and just starts going crazy and it hits a brick wall, if it does shift to the next gear its fine but it still shifts at 4000rpm. Also if you cruise in a higher gear and it decides to downshift were it would be above 4500rpm it just stalls the motor to 4500rpm untill you back out of it.

I'm making a boost leak tester tomorrow at work just to make sure that isn't an issue, I've checked mechanical timing and all marks line up, and I've checked electric timing and its set at 8 degrees. Checked plugs which are band new and it looks like they've been running alittle rich but no to bad gaped at .030 but i'm not having a misfire issue. With the logger there are low knock counts while cruising around parking lots but on the road theres the occasional 1-2 count but nothing major and timing is not getting pulled untill you let off the throttle.

Let me know if you have any questions to help out. Mods if this isn't where this thread goes move it please.

 

[BurrowZ]

That really sounds like a bad TPS to me.

When my ECU fried it wouldn't take many different inputs, and TPS was one. It was erratic and sometimes never shifted.

So could be a TCU or ECU. Pull 'em out and smell 'em!

 

[punker462606]

Ok will do after work tomorrow thanks.

 

[Janaelen]

I second what BurrowZ said. I had the same issue on my '97 automatic GST and a replacement ECU fixed the problem. Unfortunately, all sensors read well so it didn't set any red flags off until after I stripped half the electrical system down.

Pull the ECU, look it over closely and take a smell. If you notice a burnt smell, swelling/leaking caps or burnt traces, try swaping it out for another. If not, try checking coil packs, TCU, transmission fluid color and smell, and TPS sensor.

Good luck and keep us posted.

 

[mb3000]

Bad caps can also leave a rotten fish smell, so make sure to sniff for that.

 

[munkey42085]

I'm having the exact same problem with my 92 tsi. Our mods are spot on the same... I've done everything the op post did plus checked ecu, tps, and maf to no avail. My car still won't rev past 4500 and shifts when it wants when it shifts at all. It spends alot of time stuck in either 2nd or 3rd. Now in park it'll rev to 5500, according to fsm that's the rev limit in park.Any help or ideas would be great. I'm going to check the tcm this weekend other than that I'm stumped

 

[BurrowZ]

I'm having the exact same problem with my 92 tsi. Our mods are spot on the same... I've done everything the op post did plus checked ecu, tps, and maf to no avail. My car still won't rev past 4500 and shifts when it wants when it shifts at all. It spends alot of time stuck in either 2nd or 3rd. Now in park it'll rev to 5500, according to fsm that's the rev limit in park.Any help or ideas would be great. I'm going to check the tcm this weekend other than that I'm stumped

As stated above, pull your TCU out and smell it.

 

[punker462606]

Ok finally had time to check my tcu and the capacitors were leaking.

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[munkey42085]

Just a little update. Ok boost leak test has revealed some insightful information, and I've rebuilt throttle body and have new injector seals on the way this should take care of the boost leak. Also installing an innovate lc-1 with db blue gauge today, and the tcu is off at a repair shop so hopefully that can be fixed. The only other thing is what would keep causing the cel to come on for the o2 sensor? I'm logging logging with mmcd and o2 is doing exactly what its supposed to. Could being too rich or too lean cause this? I'm just praying its not an ecu issue my dsm is breaking the bank as they can do at times...

 

[munkey42085]

Ok everyone been a while since I updated this. I blew my motor and decided to gut the car will have a full auto swap if anyone's interested. I just got tired of fighting the previous owners screw ups and figured is spend the money gettin my 89 tsi back up and goin. Thanks for the help, just pm me if you need anything for a 92 auto.