Backfiring and erratic idle.

[s.u.p.r.a]

Hey all,

My '89 turbo backfires (fast popping) when I floor it in 3rd/4th. It also backfires when I get off the pedal without slowly letting it out.

If I let it sit and idle it will drop down to near death every few minutes and then spring back to life and idle fine.

Everything is stock and I'm running stock boost. Only thing missing is an exhaust, open downpipe at the moment.

Any ideas appreciated,
Thanks

EDIT: It's an automatic btw.

 

[Fletch124]

Boost leak?

 

[s.u.p.r.a]

I thought about that and checked for leaks on the IC piping -- everything is nice and tight.

 

[s383mmber1]

Codes?

 

[s.u.p.r.a]

No engine light + no codes.

 

[cordoba]

No engine light + no codes.

I had a problem similar to this, with no engine light or codes. I started looking at my wiring and noticed that a few of my cam position sensor wires were messed up and shorting to eachother and/or the sensor casing. The wires were probably vibrating and swaying as I accelerated and braked, causing the short to act erratically as the wires moved into and out of range of what they were shorting to.

I fixed the wires, making sure all insulation was handled properly and haven't had the problem since.

The only difference is that my car would actually end up dying and then I couldn't start it if the wires remained in a "shorted" position.

 

[Supra-Man18]

Could be the MAF or MAF wiring...

 

[s.u.p.r.a]

I'll check all my sensor wires today -- I have solid motor mounts so maybe the vibrations are shaking the wires.

Still trying to figure out my battery problemo though -- after about 1 hour after I turn the car off it brings the battery down from 12V to 9V. When I disconnect the (-) terminal it jumps back to 12V.