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Idle problems with the SPG

1K views 10 replies 8 participants last post by  Tweek's Turbos 
#1 ·
So, the SPG is having some weird warmpu/idle problems and I'm looking for help on troubleshooting before blindly replacing components.

When the car is cold, it starts immediately, but within seconds, the idle will dip very low - usually resulting in a stall. If I feather the throttle, I can keep it alive. Once the engine has a bit of heat, this stops happening. After a minute or so, it'll stay running, but still swing up and down every 20 seconds or so. After 4 or 5 minutes, it'll have a stable idle, but a little high (1200 RPM or so).

Here's what I've tried to troubleshoot:

1) No vacuum leaks. All hoses were new from the PO and I double-checked them.
2) No vacuum leak through the turbo bypass valve. Took it off and checked it.
3) Took off the AIC valve and cleaned it, just in case. No change in behavior.
4) Unplugged the AMM and tried running the car like that. Ran like crap, idled at about 400 rpm really roughly.
5) Unplugged the o2 sensor. Car idled much more smoothly, even when cold. Still not perfect, but much nicer, no swinging, and it didn't stall. Car seemed to run OK w/o o2 sensor.

Another thing I should mention - for the last few days, the check engine light has been coming on every so often. It'll come on for a minute or two, then go out for a minute or two. The cycle repeats until I shut the car off.

Anyone have thoughts? Seems like the o2 sensor is the culprit, but at $120 for an OEM replacement I hate to replace it without knowing. I have to admit that I'm far too used to just plugging in an OBDII reader on newer cars, so I have no idea how to read the CEL code on this car. Anyone know how?

Even though the car ran like crap w/o the AMM plugged in, could this be a sign that it is on the way out?

Last and not least. Could this be a sign from above that I am supposed to just rip LH off the car and megasquirt it? :D
 
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#5 · (Edited)
You should get a bentley manual.

It has all the info you need!

If you have a steady blinking CEL, it's igniton related.

If it's solid, you have a LH/fuel issue.



As far as reading the codes, you would need to make a "test lead" and hook it a connector.

Depending on the year of your car:

88: the connector is in the engine compartment by the intake.

89 and later: under the rear seat.


A test lead is a wire with a spade end, a on/off switch, and an end you can ground.


To test:

Turn the car off.

You plug the spade into the connector.

Then you turn the key to "on"

When the CEL comes on, turn the lead on.

Then read the pattern.

There are long blinks at the beginning and end of the pattern.

2 blinks=the number 2.
 
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