91 stealth rt/tt

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trplc21
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91 stealth rt/tt

Post by trplc21 » Wed Mar 25, 2015 2:42 am

I bought this car about a year ago and it had all sorts of issues resolved most of them and some of them have returned. However, I am fairly certain that it is the emc/ecu resistors that have failed again. I am wondering what peoples opinions are in regards to replacing or repairing the module. basically the car gets to around 2k rpms and fall on its face. I am in the Mankato area and I am curious if anyone is available to look at this car and possible give me some advice. Like I said I only recently purchased the car and I know it has lots of aftermarket add-ons but I don't really know what I have or how to work them. I have wanted one of these cars since I could first drive now I have one and I am a bit overwhelmed. I have been in the automotive industry for 16 years but not into aftermarket super tuning stuff. Please help me out. thanks

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curt_gendron
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Re: 91 stealth rt/tt

Post by curt_gendron » Wed Mar 25, 2015 11:45 am

Welcome to the board.

So what do you mean "fall on its face?" Does the RPMs drop off and the car dies? Does the car sputter at 2k? Is this happening during load driving, or just idling? Its hard to troubleshoot car problems over the internet, so give as much info about the problem as possible.

The stock ECU is very well known to get leaky capacitors and cause all sorts of bizarre problems. But if your car is heavily modified then it really introduces about 100 other potential problems too.

later,
Curt
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trplc21
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Re: 91 stealth rt/tt

Post by trplc21 » Wed Mar 25, 2015 12:12 pm

Yes, my apologies. It doesn't completely die it basically cuts out and gets very lean on the fuel air gauge. It sputters and looses all power it does it more drastically when you are under load but if you accelerate slowly you can't get much higher than 2500 Rs. It never seems to have any issues at idle. Also I am not just looking for internet help. I would be willing to pay someone for their time based on the value of their knowledge. I am definitely over my head even if the ECU is the core problem at hand I still done really know what the car all has in and under it.

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Re: 91 stealth rt/tt

Post by curt_gendron » Wed Mar 25, 2015 3:30 pm

It kind of sounds like a tuning issue. Do you know what kind of fuel controller it has? Also the injector size and turbo size would help. You'll most likely need tuning help to fix it. I suppose it could have a boost leak somewhere??

If your car was mostly stock, I'd guess it was the ECU, but since it sounds like it has a lot of mods, I'd guess a tuning problem. Who did you buy the car from? Some of us may know about the car already.

I personally have never tuned a 3/S before, so I won't be much help if that is what it needs. I'm hoping Andy Pickle will chime in. He lives in Shakopee, and he might be willing to give you some in person help. He does a fair amount of car wrenching on the side for people.

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Re: 91 stealth rt/tt

Post by trplc21 » Wed Mar 25, 2015 4:59 pm

Most recently it was purchased in new Ulm from a guy (wirtzberger)that didn't want to fix it. He had it for a few years and stored it a lot or so he says. Apparently before that it came from Pennsylvania. At that point I had to fix some gear box issues and replace some of the capacitors and after that the car ran great. I had someone look at the ECU but he is no longer in the area. It has the older super air flow converter II, the injectors I believe there are 550 cc injectors in it. It has a blitz controller for the turbo timer and the adjuster on it. But I was told the turbos are only factory. It has a Borla exhaust under it. It has several other guards and things that I don't understand. There is also a palm 3 that came with it that was used as a data logger but I don't know how to use that either. Is there anything else you would like to know?

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Re: 91 stealth rt/tt

Post by apickle » Fri Mar 27, 2015 2:01 am

Do you know if the SAFC is actually set correctly? Could be it just doesn't have the proper adjustments set for the 550cc injectors, which aren't really necessary if it's just running the factory turbos. Is the MAF actually plugged in? There's any number of things it could be, unfortunately. If nothing else has changed, I'd start by checking the wiring on the SAFC and the MAF, and making sure the MAF readings look sane. Could be a bad MAF, bad ECU again, or even a bad FPR.

edit: Reading more of the problems, I'd start by checking the FPR, and fuel pressure in general. Could be a dying fuel pump, or a failed FPR that's not letting you build and maintain pressure as the engine revs. You'll need an actual fuel pressure test setup to test it, like one of the OTC kits with the sandwich adapter for in between the pressure line and the rail.
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trplc21
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Re: 91 stealth rt/tt

Post by trplc21 » Fri Mar 27, 2015 5:43 pm

I don't have the ability to check the MAF readings my plan of attack is to get his resistors replaced again and see how much of a turd it is after that. Andy, do you have any interest in having a look at my car? I would pay you of course. The pump has been replaced recently not sure on the FPR though. As for the SAFC I haVe it all set to 0 because I was trying to figure out what was going on with it. So that all needs to be readjusted after is runs properly again.

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Re: 91 stealth rt/tt

Post by curt_gendron » Fri Mar 27, 2015 5:57 pm

Having the SAFC zeroed out could actually cause the issues you are having. The SAFC properly set is a key part of the car running smoothly.
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Re: 91 stealth rt/tt

Post by trplc21 » Fri Mar 27, 2015 6:03 pm

Yes, but, these problems started when it had some what of a tune on it. So I started trying to adjust it to make it better and nothing got better or worse. To be honest I don't know what the correct setting would even be.

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Re: 91 stealth rt/tt

Post by trplc21 » Fri Mar 27, 2015 6:05 pm

Oh, with the setting all at zero it should be running rich with the bigger injectors but it still is running very lean.

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Re: 91 stealth rt/tt

Post by apickle » Fri Mar 27, 2015 9:12 pm

That's why I'd check fuel pressure first. Could also just check voltage at the pump when it's running, if it's undervolted it'll have issues keeping the pressure up. A failed FPR would cause a similar issue.
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Re: 91 stealth rt/tt

Post by mjannusch » Sat Mar 28, 2015 2:33 am

Yes, check the fuel pressure. If there aren't leaks anywhere, it could be a bad O-ring where the pump fits into the sleeve of the hard line. Those are easy to find at the parts store. I have a part number if you need it that I could dig up. Failing fuel pump would react similarly as well.

Having the SAFC set to zero with 550s and it still running lean would seem to indicate a major fuel delivery problem. I'd start there.
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Re: 91 stealth rt/tt

Post by niterydr » Fri Apr 03, 2015 8:22 pm

What kind of air fuel gauge are we talking here? Could be lean, could be picking up a miss rich fire and showing lean, could be a blinky gauge that is worthless.
How old are the plugs?
How old are the wires?
Does the ECU have a "fish" smell to it?
What are the S-AFC settings?
You'll need to verify fuel pressure as well (as noted above)

I can most likely fix it or diagnosis it on the spot, but I am out of town this weekend and pretty busy the next few weeks. I can be available the evening of the 9th, and then starting the 19th thru the 24th.

PM me if you want me to make a service call and we can talk $.
-Josh
-(blue) 93 rt/tt --sold -720awhp, 11'[email protected]
-(white) 92 rt/tt --SOLD
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