Ideas? My car won't run right. 87 930
#1
Ideas? My car won't run right. 87 930
Car is stock a 1987 930 except for 1 bar spring and Zork tube. Went to the track and under full throttle and some boost, car would miss and cut out. It was a hard cut out, but it would come right back on. It was only off for a fraction of a second, but it was almost undrivable. Also it had a strong odor of gasoline. After 15 minutes or so, the problem would go away somewhat, but then it seemed down on power.
Ideas? Thanks for your help, the car is new to me, has 50k on a engine / turbo rebuild.
Ideas? Thanks for your help, the car is new to me, has 50k on a engine / turbo rebuild.
#2
Drifting
Originally Posted by zoomie
Car is stock a 1987 930 except for 1 bar spring and Zork tube. Went to the track and under full throttle and some boost, car would miss and cut out. It was a hard cut out, but it would come right back on. It was only off for a fraction of a second, but it was almost undrivable. Also it had a strong odor of gasoline. After 15 minutes or so, the problem would go away somewhat, but then it seemed down on power.
Ideas? Thanks for your help, the car is new to me, has 50k on a engine / turbo rebuild.
Ideas? Thanks for your help, the car is new to me, has 50k on a engine / turbo rebuild.
#5
hi guys,
What would cause the over boost switch to cut out? Could it be the recirculating valve not holding the boost or air leak? Is there anyway to elininate the switch by bypassing the system? Thanks.
What would cause the over boost switch to cut out? Could it be the recirculating valve not holding the boost or air leak? Is there anyway to elininate the switch by bypassing the system? Thanks.
#7
Originally Posted by InC
hi guys,
What would cause the over boost switch to cut out? Could it be the recirculating valve not holding the boost or air leak? Is there anyway to elininate the switch by bypassing the system? Thanks.
What would cause the over boost switch to cut out? Could it be the recirculating valve not holding the boost or air leak? Is there anyway to elininate the switch by bypassing the system? Thanks.
To bypass it just connect the single wire to a good earth. When testing make sure you don't overboost the car, watch the gauge and be careful with your right foot. I have an additional boost gauge in my ebc so I know how much boost my engine is getting after the intercooler. Overboosting your car will melt the engine so make sure you don't go over 1 bar of boost.
Jammed or not connected wastegate could cause overboost.
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#8
Originally Posted by InC
hi guys,
What would cause the over boost switch to cut out? Could it be the recirculating valve not holding the boost or air leak? Is there anyway to elininate the switch by bypassing the system? Thanks.
What would cause the over boost switch to cut out? Could it be the recirculating valve not holding the boost or air leak? Is there anyway to elininate the switch by bypassing the system? Thanks.
Don't disconnect it! If you're over boosting you need to address the reason you're doing so, not the result- overboost switch engaging. Without a knock sensor this is one of the most important engine safety items on your car.
#9
Check your fuel pressures in the CIS system and the CO output. Dont overlook the O2 sensor either. If all is good, I would look into the ignition system including spark plugs as mentioned too. It doesnt sound like an overboost switch although you can test it easily by grounding it out and seeing if the motor still cuts out. Just make sure you dont overboost consistently. Unground the switch and install a new one if it is malfunctioning.
#10
Thanks guys. Was trying to find out more about the car and symtoms when things go wrong. What about fuel? Would it have similar effect? I was told that the recirculating valve which comprises of two plastic diaphragms, some O rings and a spring. When the Diaphragm tears, the car will not boost correctly. Any idea?
#12
Ignition box ? I've rarely heard of one of those going bad that wasn't a hard failure...in other words the car wouldn't even start and run. Anything's possible I'm sure. I would believe it to be plug wires breaking down, especially if they are OEM or old and that, of course, could have fouled a plug. I'd also look at your distributor and rotor to see if there's any cracks or carbon tracking in there. Again, most of the time I find a coil goes to a hard failure. It won't run well at low or high-speeds. Good luck and let us know what you find.
#14
Burning Brakes
Join Date: Apr 2006
Location: Central Washington State
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If it turns out to be related to the overboost cutout, when that happens (the cutout at full boost), all the presssure suddenly has nowhere to go, and usually finds it's way out through one of the orange o-rings on your air intake (intercooler). Once dislodged, it will play havvock on your mixture as the air is leaked out. Will cause rough running and poor performance.
Check them out while you're looking around the engine bay.
Check them out while you're looking around the engine bay.