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View Full Version : Idle @ 600 then instantly dies...?



blkbird95
01-12-2003, 03:45 AM
I just got this SC last month. When I idle in gear it is usually @600 or so, higher when in park or neutral. However, it will die all of sudden, no real hestitation or rough idle before it dies. It does seam to search for idle a little bit. Very strange, I can't think of what it could be. Possible vacuum leak? I build about 12lbs of boost and normal idle is around 15 vac. Any one have an idea?
Just point me in the right direction so I can start checking things!
Thanks,
Brad

GooeyGus2
01-12-2003, 06:40 AM
15 vac sounds like a leak to me, but shouldn't be enough to mek it stall out really quick. also, the vac gauge could be wrong, does it center back onto 0? also, on the rear intake (on the end of the lower I/C tube) there will be a vac nipple with a hard line on it. this goes to the boost gauge. suck on it then use your finger or somthing to see if it holds vac pressure. that might be why it says 15 vac.

does it throw any codes?

my bet is on vac leak somwhere.

mn12sc35th
01-12-2003, 02:13 PM
15lbs of vac at idle should be normal. If you're building 12 lbs of boost, it's not as likely you have a vacuum leak. Try cleaning your IAC my Base V6 did the same thing and it turned out to be that. It's easy to check so try thaht and see if it helps.

Mike8675309
01-12-2003, 02:32 PM
Do you notice the tach drop to zero before the engine quits, or does the engine die and the tach drops with it? Start with pulling any codes that might be present.

The key is to puzzle out of this is electrical or fuel. It doesn't sound like an intake leak so the only other thinks that could stop the engine would be loss of spark or loss of fuel pressure.

If the tach drops first, then the engine, I would say there is an electrical problem somewhere.

but if that isn't what happens, then it is still either electrical or fuel. You should think about picking up a diagnostic fuel pressure gauge. Hook it up on the fuel rail and see if you can see the engine quit and monitor fuel pressure. Fuel pressure should maintain even if the engine quits. The fuel pump should maintain pressure as long as the ignition is turned on.

If fuel pressure drops, you could have a failing regulator, or a wiring problem with the fuel pump, or a failed fuel pump. Or maybe even a plugged fuel filter.

Has this only happened at idle? Never while going down the road have you felt a hic-up in the power delivery or noticed the engine try to die?

Electrical problem could be more complex. It could be anything from a bad battery connection to the harmonic balancer failing.

blkbird95
01-12-2003, 11:28 PM
I'll look into getting the codes. Tach drop and stall occur at the same time, and only at idle or a stop light, never when moving. I notice that if I rev it hard in park or neutral, it will stall or have a hard time finding idle, but not every time.

The car is used with no maintenance history. It has good power with no hestitation when moving 5 mph+. However right from a start it almost wants to die, hic-up.

I am going to do some home work regarding codes and other special features of this car. Is it true that all SC's came with keyless entry key chain remotes? Mine is a 94 and it also has the keypad on the door. Thanks,
Brad

pdennis93
01-12-2003, 11:32 PM
it could in fact be a vac leak, the hose on the back of my inlet plenum (pcv valve hose) fell off and made my car stall randomly, and my vac gauge would read between 10-15 when at idle, now that its plugged back in it reads 20 all the time.

curse
01-13-2003, 12:05 AM
blkbird95,
My 94 came with the remote. Just thought I'd let u know it is true.

blkbird95
01-14-2003, 02:11 AM
Thank you guys,

I took the panel in the trunk out last night and it does have the grey connector which means I am supposed to have remotes. There seems to be a lot more "good" participation in this club then I remember. (it's been at least a year since I really followed this board). Thanks for all the help,
Brad