She's Possessed! Will not idle more than minute; loses vacuum, runs w/o key in ign!

Jonnymkiii

Jonnymkiii

High Altitude
Mar 31, 2005
140
0
16
50
Boulder, Co
I've got a strange problem I'm dealing with and am at a point I need help. The car will start and idle nicely for about 1-2 minutes, then the vacuum starts to drop; at first it holds around 14psi, then after a minute or so, it starts to drop. Once the vacuum drops, the care starts to idle rough, sputters as the rpms start to drop, then she will die. The car will not restart again for several more hours; it will turnover, but there is never any ignition. Wait a few hours and it will start back up fine and repeat the symptoms. The kicker is, now when I take the key out of the ignition, it keeps running. I have to pull the battery cable to kill the engine.

Its an '87 Turbo with the following mods:

T06 Turbo; Spearco intercooler; upper hard pipes; extrudehoned intake, heads, exhaust; 3" DP/Exhaust; high flow cat; MAP-ECU fuel computer, 550 injectors, Walbro 255 FP, Aeromotive FPR


Symptoms:
- Car idles nice for 1-2 minutes
- After 1-2 minutes, the care begins to sputter
- Dark smoke out of the exahust; not sure if related to having CAT off to replace gaskets
- Vacuum can hold at first around 14-15 PSI (5,000' Altitude) then it drops
- Car runs pig rich once vacuum drops
- Car sputters
- Car continues to run with key out of ignition


Problem Determination
- There are no codes; they have been checked several time
- The ISCV was cleaned and reinstalled. It clicks when the car is stopped.
- Unplugging the ISCV resulted in car idling high, as expected; however, after 1-2 minutes the vacuum dropped and car started sputtering
- Inspected all hoses, couplers, intercooler piping, etc for leaks; no issues detected
- Tried find leak with starter fluid trick; found no evidence of a leak


Anyone have any ideas or seen this before? Could my ECU be shot? I have had this car since 1992 and this is the worst she's ever been and I am out of ideas. If anyone has any suggestions, I am all ears. Thank you!


Jonny
 
Last edited:
Jonnymkiii

Jonnymkiii

High Altitude
Mar 31, 2005
140
0
16
50
Boulder, Co
Sagillman, Yes, the FP stays the same; I even gave it a few revs and you wouldn't have know the key was out of the ignition. Only way to kill it now is to pull the battery cable.
 
Jonnymkiii

Jonnymkiii

High Altitude
Mar 31, 2005
140
0
16
50
Boulder, Co
Bump.

Any ideas as to what the issue could be? I've had this car since 1992 and have put every bit of sweat and blood I have into it and I am a half step away from selling it off as a parts car, which makes me sad... this is my best cry for help. Yes, I am stooping to sympathy help at this point :icon_razz


Thanks!

Jonathan
 
GrimJack

GrimJack

Administrator
Dec 31, 1969
12,377
3
38
56
Richmond, BC, Canada
idriders.com
Pulling the battery cable shouldn't kill the car, either, as the alternator should make more than enough power to run it. Unless your alternator is also dead. I can't conceive of a way for power to make it to the engine from the alternator without also getting it from the battery.

To test the ignition switch, try firing it up and unplugging the switch under the steering column. If this kills the engine, and the key does not, it points to a dead ignition switch.

And get your alternator tested.
 
8

89supracrazy

New Member
Oct 31, 2009
317
0
0
wise
Pulling the battery cable shouldn't kill the car, either, as the alternator should make more than enough power to run it. Unless your alternator is also dead. I can't conceive of a way for power to make it to the engine from the alternator without also getting it from the battery
Click to expand...
.

It will if you pull the negative cable.:icon_bigg
 
You must log in or register to reply here.
Top Bottom