4500 rpm cutout

[My90tsiawd]

This all started when i blew a timing belt on my 90 talon tsi awd. I rebuilt the cylinder head putted it back on and then started having problems. The car would run fine until i had driven it for about 20 minutes then it was terrible. At this time it was my only car so I had to run it like this for a while. Then i made a boost leak tester and have found a huge boost leak right after the compressor housing. Fixed it. Then found another one at the IC outlet. Fixed it. Now nothing seems to leak but the car won't have any power past 4500 rpm. I read a lot on it and ended up checking all the ignition system. The coil looked pretty bad and so did the wires so for a cheap fix I made a coil on plug system to make sure that it's the ignition. I know that the stock ignition is better but for a $40 fix i needed to try it. Idle got a lot better and i can now run the car for long period of time without having to unplug the maf to run right. But it still won't push past 4500 rpm. I'm starting to think about fuel issue or something like that. Could i have damaged anything by running it with the boost leak. Thanks for reading this and for trying to help me out.

It's been more than a year since I last felt it's real power. At least I got another car so I can leave the talon in the garage until it's fixed.
BTW the car is all stock but for the coil on plug system.

 

[My90tsiawd]

Ok, I won't be working on the car for the next few weeks but I'd like to know if a bad vacuum hose connection could cause this since the problem started after engine rebuild. If not then I'll change ECU capacitors and/or try a scrapyard ECU. I'd prefer capacitors only cause i'm not sure I can find a 90 ECU at this scrapyard, Yeah after 2 years of DSMing I finally found a srapyard that carries DSM parts (Owner's son raced DSM's )

 

[rlacasse1]

ill look for the right COP diagram and see if i can find it. i couldnt see the one in the link you had. but ill look and try to find it. or ill just look at my car and tell you.

 

[rlacasse1]

oh try a coil pack to instead of the COP it might help incase something is wrong with the wiring

 

[My90tsiawd]

Well my car is a 90 so it has very specific electronic parts, escecially the coil wich has 4 pins instead of 3 for all other years DSM's. If I can get one I will do so but I doubt I can. I know It really looks like an ignition problem but I'm starting to think it may be an ECU problem even more since I saw this from another thread I think it may apply to my case too

You just don't have enough information to really diagnose the problem. A massive leak in the charge piping could cause this also. Could be capacitors in the ECU.. etc.

It was originally posted by forcefed86. I don't know if I can quote from another thread the "official" way...

 

[rlacasse1]

i know what you mean about the 90 TSI. that is what i have. im just saying ive read where people say COPs are no good without aftermarket ignition crap. don't remember what exactly. and the stock coil can handle quite a bit of power. and about the boost leak it can cause it. have you looked for leaks.

 

[My90tsiawd]

Yeah I've done boost leak tests and I keep doing some everytime I have a doubt about it . My BLT results are in previous posts. People seemed to find them normal. And for the COP, people say that it is a downgrade from the stock ignition but it still supposed to work fine and take 12 PSI but could misfire on higher boost.

 

[My90tsiawd]

I just got my ECU sent to me (I am miles away from the car) and it has no apparent sign of leaking capacitors. I now have another thing I think of, the coolant temperature sensor. The car does get worse after the engine is heated up to normal operating temperature it starts running really rich, smoking black and sputtering. My question is Can a bad coolant temperature sensor cause the car to cut out like that at 4000-4500 rpm. I already know it CAN change AFR but can it cause anything worse than that. I hadn't ever think about the CTS before because the gauge signal is OK but I just learned that the car uses 2 different sensors for gauges and ECU.

 

[sighless]

i just trailer'd home my first turbo car today. a 95 TSi Awd.

im seeing the same thing about 4500rpms it starts to sputter..

where should i start? ive checked most things you would on a normally aspirated engine.
im not quite sure how to do a boost test.

does anyone know?

also. what does a stock 2g run for turbo pressure? my car has an aftermarket boost gauge, and it shows just over 10psi.

 

[My90tsiawd]

First thing to check on a turbo car I think would be a boost leak test. It is very simple to do, you just need some rubber or silicone tube that fits the outside of the compressor housing inlet and something to cap the other end in wich you must put a valve to put air in the system by. Put air in with a compressor then you can have someone in the car looking at the boost gauge to see if it's dropping and the person near the engine bay listens for leaks. You should fix any leaks. If you're not sure about your results (because it's very unlikely to completely hold boost). There is a lot of threads in which people ask questions about their BLT results. Your results should already have been talked about. If i'm not wrong I think a 2G should be at about 14 psi so 10 seems low.

I'd check this first. If you still have problems after this I'll tell you all what I've been checking and we'll finally find both of our problems

Good luck.

 

[sighless]

where would i cap the other end? cant i just put the tester on the intake side of the turbo and put some pressure into it?

 

[deerhunter0881]

http://www.dsmtuners.com/forums/art...209898-build-boost-leak-tester-your-to4e.html here is how too make one. put it on the turbo add air like 10 psi over what you run will be good.

 

[My90tsiawd]

What I was saying about a one end capped rubber pipe with a valve is just a cheap way to make yourself a tester. If you already have one just put some pressure in the inlet of the turbo with it and listen for leaks.

 

[sighless]

do you know what size i should use for a stock 95 talon?

the car is outside the city on my parents farm, and i would like to pick up the parts before going out there.

 

[My90tsiawd]

2.5 inch should be perfect. I think mine is 2.5 inch O.D. so it has to strech a little to get on the turbo but it works fine. T-25 (wich is the stock 2G turbo) is about the same size so anything that's about that size should be fine. Rubber or silicone will stretch a lot so a little bigger or smaller shouln't matter.

I'm in the same situation as you as I can only work on the car by weekends so I know how it feels. For this reason I can't give you the diameter for sure but I just checked up there.http://www.dsmtuners.com/forums/420a-bolt-tech/193682-t25-inlet-diameter.html
It's on 420a tech but it talks about T-25.

 

[sighless]

i didnt get to leak test mine this weekend.. i did get my rust fixed up on my strut towers though..

i noticed on mine if you floor the throttle it will sputter about 4500rpms and at 5000rpms it clears up and runs strong.

 

[sighless]

did you ever figure out what it was that was causing your cut out?
i havent been able to get at my car for over a month. ive been looking for the rubber cap, at home depot and what not. i cant find a 2.5" only have 3" in my area. im not quite sure the 3 inch will seal up properly.

 

[My90tsiawd]

Well I almost gave up for the car now that I have another one to move myselft, and now the snow started falling on the talon. I might do some final tests before the car is really buried up but I really can't figure out what it is and i'm out of ideas of what to check up.

Any suggestions are welcome

P.S. For you boost leak tester I'm about sure that 3" will be too big. And also don't get discouraged like me.

 

[sighless]

well i think my alternator is going. and maybe it just cant keep up the power to spark at those high rpms?? im hoping its something easy like that. when my e-test was done my car only showing 11volts.

 

[richardc475]

Change your plugs, ngk bpr6es, gap them to .028 .

On my last dsm It would do the same thing, the gap on the plugs constantly changed causeing the issue you are describing. So everytime my car was acting up I would pull to the side of the road, re gapp the plugs, and off I go good as new.

 

[EclipticalGS]

Change spark plugs, gap .028
Change plug wires.
Could be your CAS, your cam angle sensor, they go sometimes
Check your Mas. that can go too.
Make sure there arent any stray connectors anywhere.

I had a 95 eclipse that i was driving one day and i went around a turn, start to accelerate and ding,ding,ding at 4500 rpms. CEL went on, it was a bad crank sensor, but i dont know if 1G's have crank triggers....

 

[sighless]

wouldn't a sensor give a CEL? i have no check engine lights showing on my car.

those are the same plugs my sled takes..

i saw earlier someone said gap em to .033-.038

 

[sighless]

i think i may have found my problem..
i changed my alternator and it got twice as bad.. it would bog as soon as the boost started to build..

in the midst of changing the altenator i knocked off a wire that goes to the oil pressure gauge..
when i noticed that one, and went to solder it back together i found another one that went right beside it, the previous owner had cut the wire and twsited it back together.

i soldered that one and the car now runs almost perfect.

if i press the pedal to the floor i get a slight hesitation like the blink of an eye and the interior lights completely black out like clicking a switch on and off.. then it goes like hell

 

[My90tsiawd]

There is hope ahead!!

With the summer approaching I started thinking about my abandonned Talon (didn't work on it since Dec. 09). So I took the ECU out and brought it to an electronic store to get the capacitors changed. They did change the capacitors and told me that they were leaking and that the caps acid had burned connection on the board so that 3 connexions were off. Now I just can't wait to put the ECU back in and to test the car. I've been through several tests that never fixed my problemed but this time I REALLY think I got it.

I needed to share it with you guys and I'll keep you updated with the results.

 

[sighless]

thats awesome news..
i hope thats not my problem..

im going to check my ecu tomorrow.

i just got back from the junkyard today, and picked up a new coil and transistor.. so hopefully that will help me out.

 

[My90tsiawd]

Finally the car runs like it used to be. It was a bad ECU after all. As I said in a previous post the capacitors had leaked and their acid had burned connections on the board. I'm not the first one to do it but I suggest that everyone who doesn't know when the capacitors were changed last choose have them changed. They're about 50¢ each and they could save you a lot of trouble.

Thanks for everyone's help on that one.