eventually start, but has a really bad idle

[maverick_26]

I'm new to dsm tuners and have been having problems with my 94 awd turbo laser. The engine is completely rebuilt, thanks to a snapped timing belt (from the previous owner). I got the engine in about 2 months ago and it has been hell ever since. It will eventually start, but has a really bad idle. When I drive it it has absolutely no power at all, at 1/4, 1/2 and full throttle it will hesitate, bog, and buck and will not make any power past 2000 rpm, it just revs and gets louder but no difference. Its extremely hard to even get to 15mph. I've replaced the injectors, plugs, wires, fuel regulator, fuel pump and coil pack. I'm tired of wasting money on this thing and am about to get rid of it. I've tested the tps and idle sensor, they checked out good. What could really be the problem with this? I've heard it could be the computer, but the caps all look good and nothing smells. The cam timing is perfect and I did a boost leak check and there are none at all. I'm COMPLETELY stumped. Please help dsm gods!!

 

[tommy260]

Are you running a stock fuel pump? You NEED to list your mods so others can see what you're working with.

 

[maverick_26]

Its completely stock, I replaced the fuel pump (oem) and I resurfaced the flywheel and intalled a new oem clutch when the engine was out. This thing is cursed.

 

[Calan]

Have you checked:

1. Plug gaps, wiring order
2. Fuel Filter
3. Base timing
4. All sensor/wiring connections

 

[maverick_26]

The fuel filter is also new, the wires are on the correct order, i'll have to recheck the plugs but i'm fairly sure they're at factory spec. All connectors are hooked up, and timing is perfect, I've checked and rechecked a million times. Its wierd, once it warms up, it just starts bogging really bad, and its barely driveable. Is there a way to clean the mass air sensors on these cars or is it basically "if its bad, replace it"?

I'm using autolite copper plugs. They have always worked on my other cars but could this be the problem?

 

[Calan]

I'm using autolite copper plugs. They have always worked on my other cars but could this be the problem?

I'm not familiar with them, but anything's possible.

Spend $6-$8 for a set of NGKs and find out. (I wouldn't run anything else anyway )

How are you monitoring/logging the car? How do fuel trims look?

 

[FatalDreams]

When you had the motor done did they touch the head? If so check all the gaskets, also check the intake tubes by the maf, and by the tb. oh does it smell like its running rich when its on?

 

[maverick_26]

The head wasn't touched at all, except for them checking to make sure it wasn't warped or anything.

This is real weird, i've never had so many problems with a car like this. Unfortunately I have mostly experience with ford so this is a mystery to me, .

 

[tqmx1]

Has the ECU been gone through?

 

[snox135]

It seems really strange that they had to rebuild the motor from a snapped T-belt, but they didn't touch the head. The valves are the weak link and bend or break before anything else.

 

[kenamond]

If the previous owner snapped a timing belt, the valves could be bent from hitting the pistons. What work was done while the motor was out? If they didn't touch the head, I'd do a compression test to see if the valves are sealing. If compression is low, do a wet test to rule out rings. If compression still sucks on a wet test, do a leakdown test.

And you shouldn't run anything other than NGK BPR6ES plugs (NAPA has them for $2/ea) and gap them to 0.028". That's easy and cheap enough to try, but I'd be more worried about the head.

A good webpage for compression and leakdown testing on our cars as well as specs is below:
Compression test: http://www.geocities.com/dsmgrrrl/FAQs/compression.htm
Leakdown test: http://www.geocities.com/dsmgrrrl/FAQs/leakdown.htm

Good luck and don't give up (yet).

 

[maverick_26]

I'm not worried about the head, I had to replace it because half of the valves bent on the original head and the other half broke and lodged themselves into the pistons making huge holes so you could see through the pistons.

I haven't really thought about the ecu much. Is there a way to test capacitors or is it just by smelling it and seeing if their leaking or not?

 

[Diplomat]

Have you already tried retrieving the diagnostic trouble codes (DTC's) from the ECU? This can be done with a basic analog style multimeter on 1G's. Aside from that, or borrowing a Pocketlogger from someone, there's not a whole lot you can do at home to diagnose ECU health. Well, not that I'm aware of at least.

By the way, have you checked the Power Transistor yet? They've been known to go bad. Also, you might want to check the Cam Angle Sensor (CAS).

 

[mitch26753]

have you checked for boost leaks? also when you put the motor in did you make sure all the vaccum lines where connected in the proper places? my buddies car had a problem similar to this. The guy he bought it off of didn't have the boost lines in the right order. also he had a blowoff valve that was VTA.

 

[maverick_26]

Can a transistor pack cause these problems? Maybe i'll give it a shot and buy the ngk plugs gapped right and a transistor pack? Can just plugs cause all of these problems? I give it gas and it either bucks HORRIBLY, or it keeps revving. All you hear is it getting louder, power stops at like 2000 rpm and the rpm raises without any more power. Anyone out there with similar problems?

Thanks, Jesse

 

[kenamond]

Can a transistor pack cause these problems? Maybe i'll give it a shot and buy the ngk plugs gapped right and a transistor pack? Can just plugs cause all of these problems? I give it gas and it either bucks HORRIBLY, or it keeps revving. All you hear is it getting louder, power stops at like 2000 rpm and the rpm raises without any more power. Anyone out there with similar problems?

Thanks, Jesse

I've read some pretty bad horror stories that were due 100% to plugs, so it *might* have something to do with it. It's cheap enough ($2 per plug at NAPA) that I'd do it anyway. NGK BPR6ES gapped to 0.028". If it doesn't help, go to the next idea.

And you never said whether or not you did a boost leak test. Heck, a coupler could have popped off the intercooler or something. It's something you need to do. If you find leaks, you obviously need to fix them.

And please fill out your profile. If your car is stock, it takes even less time to fill out. Your original post is the only info we have about what car you even have.