86 shutting off
Thread Starter
6th Gear
Joined: Sep 2011
Posts: 6
Likes: 0
86 shutting off
My 86 shuts off for no reason, it shuts off while ideling or driving down the road. It will start right back up with no problem. I have new dist cap, coil,wires, plugs, new MAF sensor, rebuilt alternator, new battery. The dash cluster does not go out when it shuts off or the radio die. I get no trouble codes from the ECM. Help any suggestions??
Drifting
Joined: Nov 2009
Posts: 1,341
Likes: 2
From: Perth Western Australia
St. Jude Donor '10
It has to be either fuel or ignition.
Suggest you screw a fuel pressure gauge on and watch that at idle. If the fuel pressure drops and the engine cuts out then you know where to look.
Otherwise it is an ignition related problem.
Suggest you screw a fuel pressure gauge on and watch that at idle. If the fuel pressure drops and the engine cuts out then you know where to look.
Otherwise it is an ignition related problem.
Thread Starter
6th Gear
Joined: Sep 2011
Posts: 6
Likes: 0
Thanks for quick response, fuel pump is new as is also the fuel filter, however I will try guage to see if the pressure does drop for some reason, could it be the oil pressure switch dropping out in the fuel pump circuit? I guess the guage will tell. Otherwise I am not sure how to proceed with checking out the ignition citcuits, any suggestions
Drifting
Joined: Nov 2009
Posts: 1,341
Likes: 2
From: Perth Western Australia
St. Jude Donor '10
Thanks for quick response, fuel pump is new as is also the fuel filter, however I will try guage to see if the pressure does drop for some reason, could it be the oil pressure switch dropping out in the fuel pump circuit? I guess the guage will tell. Otherwise I am not sure how to proceed with checking out the ignition citcuits, any suggestions
Is the cutting out linked to engine temperature at all?
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
Thanks for quick response, fuel pump is new as is also the fuel filter, however I will try guage to see if the pressure does drop for some reason, could it be the oil pressure switch dropping out in the fuel pump circuit? I guess the guage will tell. Otherwise I am not sure how to proceed with checking out the ignition citcuits, any suggestions
ricky, read some of the recent posts concerning this. far as we know, unless the FP relay is out of the circuit -at which time you would be seeing long crank times, THEN if the oil switch failed, the pump would shut off.
otherwise, you are chasing wrong information.
"shuts off" and "suffocating, chugging and dying" are different. if it is like key off, prob ignition related. icm comes to mind. also loose connections on any of the many wires on the distributor.
since it restarts, probably not the pickup coil.
if you have access to fsm or even a Haynes, that's where you need to go. more history would help.
joe
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
One of the things you can do to check the ignition is to disconnect the ignition bypass connector (next to the brake booster with the tan wire with a black stripe).
This will hold your advance at 6 degrees (so the engine won't run the best) but it also eliminates the wiring between the distributor and the ECM and the ECM itself from the equation.
This will hold your advance at 6 degrees (so the engine won't run the best) but it also eliminates the wiring between the distributor and the ECM and the ECM itself from the equation.
Thread Starter
6th Gear
Joined: Sep 2011
Posts: 6
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Thanks for info on ignition, I will try eliminating ECM first. It did finally shut off again after I connected pressure guage, the pressure didn't drop one bit so fuel is definately not the problem, At least now I know where not to look
Thread Starter
6th Gear
Joined: Sep 2011
Posts: 6
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P.S. This is definately not a sputter shutoff, it shuts off just like the key was turned off. This does happen alot more when car is cold but does happen sometimes when it is at operating temp but not as often.
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Thread Starter
6th Gear
Joined: Sep 2011
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Okay I changed the ICM and it made no difference. Strange thing is it will sometimes run for twenty miles with no trouble then shut off twice within a couple minutes,new coil new wires plugs ICM bypassed the ECM still it shuts off on ocassion when either hot or cold, does seem to like to do this when slowing down if that means anything
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
Okay I changed the ICM and it made no difference. Strange thing is it will sometimes run for twenty miles with no trouble then shut off twice within a couple minutes,new coil new wires plugs ICM bypassed the ECM still it shuts off on ocassion when either hot or cold, does seem to like to do this when slowing down if that means anything
some possibilities: IAC, egr not closed, tps circuit. ck that carbon is not affecting throttle closing -would have to be extremely heavy. also ck PCV system, if it happens with throttle closed.
any codes? intermittents are usually connections, don't follow predictability.
you should ck resistance on pickup coil, esp harness connector, per fsm or Haynes. also connection of bat terminal on dist cap, can be loose due to terminal spread.
Racer
Joined: Sep 2011
Posts: 352
Likes: 6
From: Centreville Maryland
Okay I changed the ICM and it made no difference. Strange thing is it will sometimes run for twenty miles with no trouble then shut off twice within a couple minutes,new coil new wires plugs ICM bypassed the ECM still it shuts off on ocassion when either hot or cold, does seem to like to do this when slowing down if that means anything
