Diagnosing a Intermittant Start Condition
Thread Starter
Instructor
Joined: Jan 2005
Posts: 236
Likes: 0
From: Hudson FL
Diagnosing a Intermittant Start Condition
Does anyone know the proper diagnostic proceedure for determining the cause of an intermitant start / hard start condition.
1994 6 spd, cranks fine but doesnt turn over, then other times will start right up.
I've checked the fuel at the schrader valve, and I've got gas but not sure at what pressure, dont have guage although pressure increases during crank.
I suspect it could be opti, but I would like to know proper diagnostic proceedure to isolate the problem for sure. I really dont want to undertake replacing an opti unless Im sure its the opti.
I cleared old codes and checked them again after quite a few no start and then start conditions and Im only getting C12 code at beginning of sequence and --- on all subsequent sequences. No trouble codes are poping up !!!
Anyone who knows the proper diagnostic proceedure please advise !!!!
I dont have an FSM .
Thanks
Frank
1994 6 spd, cranks fine but doesnt turn over, then other times will start right up.
I've checked the fuel at the schrader valve, and I've got gas but not sure at what pressure, dont have guage although pressure increases during crank.
I suspect it could be opti, but I would like to know proper diagnostic proceedure to isolate the problem for sure. I really dont want to undertake replacing an opti unless Im sure its the opti.
I cleared old codes and checked them again after quite a few no start and then start conditions and Im only getting C12 code at beginning of sequence and --- on all subsequent sequences. No trouble codes are poping up !!!
Anyone who knows the proper diagnostic proceedure please advise !!!!
I dont have an FSM .
Thanks
Frank
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
Get a fuel pressure guage and see what the pressure is...key on, cranking, at idle, driving, and WOT. This will tell you if the fuel system is working correctly. Have you checked for spark when cranking? I bought a tool from Sears that is a spark indicator. Looks like a pen and you just place the grooved edge on the wire when cranking or running to see if there is spark (there are other ways also). Have you looked at the spark plugs?
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
With all so far. Check for spark at the coil. Take the wire out, you can check it there, a spare wire would help if you had one, check for ark to ground. If no spark, could be the ICM (high failure rate). Also check to see if your coil wire is arking at the water pump area on top of were it connects to the opti.This does not sound like a opti or fuel filter at this time. But the fuel pump could be a cause, that why you need an gauge. I think the coils are pretty reliable and for most people who change them, it doesn’t seem to be their problem, but you can’t forget about it. I actually had a similar problem and it was defective insulation on the coil wire.
If you are going to do your own work on these cars, some of the systems and wiring are specific to the year. I think you know you need a good road map like a Helms to get thru some of these problems. A couple of special tools (ie: fuel gauge) for you car and you will have the ammunition to fight with. Not all the repair answers are in the books but without them your at a big disadvantage.
Last edited by pcolt94; Aug 24, 2006 at 07:57 AM.
