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Engine Troubles - idles rough on clutch push and slow to start

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Old 04-23-13, 10:02 AM
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Engine Troubles - idles rough on clutch push and slow to start

I just bought a '94 FD that I plan to rebuild and fix up. Now, I am kinda thinking that I might have to rebuild the motor. Which scares me since this is a single turbo and there are wires and sensors unplugged all over the place. That'll be hard to figure out what is supposed to be plugged in and what's not.

Now, here's my problem:

It takes about 4 tries before it starts up. Once it does start, it actually idles alright. relatively smooth. Now, once I push the clutch in (not in gear or anything). The idle drops and sounds rough. I put her in gear and start moving, it revs a little slow to me. Then, once I hit zero vacuum or just before any boost, it falls on it's face and wont go into boost at all. I was checking around for sensors unplugged or vacuum lines unplugged, but couldn't really see anything at first.

I'm considering picking up an Apexi Power FC. Since I feel like that'll help me diagnose this and get her running right. But, I also don't want to start wasting money on things I don't really need yet... especially if i'm about to have to spend a few weeks/months (I don't work fast) rebuilding this motor.

Any Ideas?
Old 04-23-13, 03:12 PM
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Well, I called the 'Shop' that did the work. He said it is probably the check valve that is on the MAP sensor, since the MAP sensor is supposed to only read boost.

I did a quick search on here, and that is actually a filter and not a check valve. So, I guess that shows the knowledge of the guy that put this engine together
Old 04-24-13, 01:39 AM
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ok, so MY first question would be...how in the living hell do you have a single turbo even running with less than a power fc? there will definitely be ZERO money wasted if you get a standalone...
Old 04-24-13, 02:01 AM
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First, 4 tries to start the engine is an indication of not building compression,check if your engine is healthy, second you said bunch of wires not connected hanging around. If you have the wiring diagram of the power fc trace the wires that suposed be connected to sensors + injectors ect.. That will give you an idea where to start. Rot005
Old 04-24-13, 08:54 AM
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Originally Posted by Integral
ok, so MY first question would be...how in the living hell do you have a single turbo even running with less than a power fc? there will definitely be ZERO money wasted if you get a standalone...
Yeah, that's what I was wondering. The guy i bought it from paid a shop to fix it up 'to run 11's' It isn't running very far right now. I have a Power FC, Wideband and GM Map sensor all on order.

Also, I am kinda guessing that maybe the compression is bad bc of the slow to start issue. I guess I should check that. However, I spoke with the guy that built the engine and he said it was built and ran fine. He told the owner to be easy on it to break it in. Then, the owner started tinkering around with the electronics, came back to them 2 weeks later saying it was running like crap. Apparently an argument ensued, I ended up with the car for cheap and probably only a couple hundred miles from a rebuild.
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