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F14CRAZY

Just not making enough power

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Hey guys. I posted this at Bonneville Club. Something's up with my coupe...

Howdy. Pretend I'm dealing with a '95 SSEi, but it's actually the supercharged LN3.

The past couple days, it seems its just not making the power it should. It's like the Reatta's being pulled by a Tech 4 or something Sad . I can step it to the floor and its just not pulling like it should. It's not like a low boost issue, but like a smaller motor's been put in, or I'm towing A TON, as in 2k pounds. It's much slower than stock. I'm having to give it a lot more gas for just a little acceleration. The transmission seems to be shifting fine. I'll try to point out what I've tried.

-I had a power steering leak which was getting on the belt at the same time. I fixed it, replaced the belt (the longer one that runs the water pump, S/C, A/C) and cleaned the pulleys. I thought maybe the S/C belt was slipping. No change.

My AC Delco plugs have about 20k miles on them, maybe a little less. I pulled them all out and they all appear to be the same and look normal. No evidence of an injector stuck open, misfire, etc.

Plug wires are about the same age. I removed all of them and checked them out. All are within like 4k-6k ohms.

I spun all the serpentine acessories by hand, and all spin freely and without noise.

I swapped in a known good ECM while transfering my memcal. No change.

I'm running an Accel coil pack. Swapped in with a known good Magnavox. No change.

Oil pressure is high/good, no abornmal noises or knocks.

No CEL or hidden codes. TPS operation is good and not very old. Crankshaft PS was replaced not too long ago, though I will be visually inspecting it.

Put it in neutral while on the freeway and the car coasts freely/normally.

Checked the fuel pressure, 38 psi key on, 32 psi or so idle. Which seems to be good as far as I know. Spikes up and settles as it normally does when revved. No gas in the regulator vacuum line. Fuel pump, screen, and filter were replaced about 12k miles ago.

Have bought smaller amounts of gas while this has been happening, so I doubt its a bad batch of gas.

Starts and idles fine. No backfires, no missing.

Seems to rev fine in park, but this may info might not help any.

Air intake/filter is reasonably clean. Made a quick run with it off, infact. No change.

MAF wires appear to be clean.

TPS is fairly new and checks out good in Diagnostic Mode (slowly depressing the gas with the engine off and voltage increases like it should. You know what I mean. No dead spots)

Catalytic converter was replaced about 25 miles ago.

Seems to lack power everywhere in its RPM range.

What do you guys suppose is wrong? Thank you.

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Just guessing; did you test the ICM? How 'bout a streached throttle cable or a loose bracket or something? Did you test for full throtle movement to get WOT under load. Hope you find out what's wrong, Kenny

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I swapped in another good coil pack assembly, no change.

I can get to WOT, and I made sure the TPS readings are true in Diagnostic Mode. Nothing wrong there.

I'm posting on Bonneville Club. I'm thinking something either in the motor or the tranny crapped out. Even at idle in park/neutrel it "sounds" like its under load, like it's in gear with the brake pedal down. Idle RPMs seem a little slow to me as well.

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Just guessing here, but, you mentioned changing the cat about 25 miles ago. I'd look at that to see if there is any blockage. All the symptoms of a lot of back pressure.

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It does sound like a possible backpressure problem, especially since that is the most recent change. Any idea what your engine vacuum reading looks like?

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Sorry I don't have a vacuum reading. I still need to get around and tackle a boost/vacuum gauge.

Anyway, a Bonneville Club member said that a bad cat would only act up at high RPM, but my issue is at all RPM. You guys still think it could be the cat? If so, it's not too bad of a job for me to crawl under and sawzall it off for the time being.

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Have you ever checked the ttc silonoide.By brother's Century had the same problem. That made a world of difference when he changed it. If you are going to changed the cat, I would suggest CatBack

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ok I am back. I would unplug it. If your engine rins better, that was the problem. If you wonder where it is at, it is on the front of the tans. near the intake and the cruise control servo. If it continues, I would check you fuel pump or filter or run seafoam through the engine.

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You didn't tell us when it started acting up. Was it after the cat converter change, or did you do the cat converter as a trial fix? If you did, it could be the muffler stopped up.

I would consider removing the pipes before the cat converter and running it disconnected. If it runs good, that is the problem. This is many times the case when the mechanics cannot find the poor performance problem.

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Well, we did all wonder how long the tranny would hold up to the supercharger. Hope its an easy fix, Kenny.

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It lasted 20k miles under boost, ending at 172k miles. I don't think that's bad cuz its been through a lot. Obviously would have lasted longer if it had lower miles, or was rebuilt, or was "performance" rebuilt. I didn't and don't have much faith in 4T60s.

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I remember some of your comments in prior threads, too bad there is no really good direct replacement. and yes, you did very well with a hi-mile tranny to start with.

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The boost/bypass control actuator is working just like it should. As Bonneville Club pointed out, I'm building RPM just fine. I could redline it if I wanted to, but still not getting anywhere. I've driven it without boost before, and it is slower, but not nearly this slow.

If I decide to stay with the 4T60, the one to have would be an "F-7" from a Cadillac. They're built a little better for V8 power.

I'm still tossing stuff around in my head. Thrasher shoudl email me back on if there is a such thing as a 4T65-HD controller for the old ECM

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Guest imported_Fox W.

Will the F-7 or HD versions of the transmission work as a direct replacement on a 89 Reatta?

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Brian recently asked Ryan about that. It seems the F-7 is actually inferior to our current transaxles. A 4T60E could be used with a standalone controller.

The 4T60-E/HD really only has improvements to the differential for the most part, and isn't worth trying to use.

I still believe the best solution is the 6 speed manual

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Guest imported_Fox W.

Sounds good, how much $,$$$ do you want to convert mine? <img src="http://forums.aaca.org/images/graemlins/smile.gif" alt="" /> heh heh. The transmission has always been a scary thing for me because I hear that Buicks in general seem to be known for having 'weak' trannys. So far I have almost 130k and no problems, and its one of the smoothest transmissions i've ever felt. (except sometimes when I put it into reverse, it's always kinda been a bit hard when you first do that, is that normal? Mine has done it since I got it almost 4 years ago. Going into drive however can hardly be felt.)

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