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91ScOwner
03-10-2003, 08:14 PM
Hello all,I recently bought a 91 SC from a friend and I have been having problems that I hope you can help me with.My car will start fine in the morning,and run for awhile.If I turn it off however it will not restart for anything,even if you floor it.So far the cam and crank sensor has been changed,the fuel pressure regulator was replaced,the fuel pressure is reading around 35 PSI,the fuel filter is ok and the fuel pump seems to be working fine.I even went as far as to blow out the backflow hose just in case it was clogged.The interesting thing is that when I unplug the line going from the fuel tank to the fuel filter,it will start up and run the gas out of it.then dies without restarting.It is throwing no codes,and everything else seems to be working.Any advice? I really want to get it running good for spring.

J57ltr
03-10-2003, 08:43 PM
do you have spark when it won't start?

Jeff

IGot6UGot8
03-10-2003, 11:46 PM
Hey, I'm Jake, AKA the friend that sold him the car. The car has spark. We only checked one plug, as hard as they are to get to. It seems to be flooding the car out. It used to start when the accelerator was floored, but now it will just hit for a second and that's it. Cranks fine (until the battery dies). Are there any sensors that would cause this?

Jake

J57ltr
03-10-2003, 11:48 PM
Not really, unplug the regulator and see if fuel comes out the nipple.

Jeff

When it won't start check the spark.

IGot6UGot8
03-10-2003, 11:52 PM
I didn't feel any coming out. We disconnected the return line thinking maybe it was clogged, but still no start. Fuel was coming out that line just fine. Fuel pressure went up as normal when the regulator was disconnected. So all of the fuel system SEEMS to be working right.

The car has spark at the time that it won't start.

Jake

J57ltr
03-11-2003, 12:17 AM
Maybe an injector is stuck open or is being held open. Hook up a noid light or use a meter. One or more of the drivers might be toast holding the injector open.

Jeff

scbird1
03-11-2003, 12:19 AM
Maybe the DIS. they tend to not work right when hot.
Anyone else?

J57ltr
03-11-2003, 12:25 AM
If it was ignition related you wouldn't have spark.

Jeff

IGot6UGot8
03-11-2003, 12:29 AM
Right, and it will do this when the car isn't even hot. Yesterday, it wasn't even running for a minute... we shut it off, and it wouldn't start again.

Jake

cudaz101
03-11-2003, 08:03 AM
Have yet to see any mention of codes CE light etc. If there are none then this would narrow the possablities...

From what I have read so far, looks like you need to run codes on the initial start, monitor the data while running, try a wiggle test and try clearing codes even if it shows something insignificant.

It does sound like you gotta challenge there...

Good Luck

Brad

TbirdSCFan
03-11-2003, 11:36 AM
Originally posted by IGot6UGot8
Right, and it will do this when the car isn't even hot. Yesterday, it wasn't even running for a minute... we shut it off, and it wouldn't start again.

Jake Jake, you have checked your crankshaft main bolt, right? There is the slimest of chances (like <10%) that its the harmonic balancer, but its easy enough to check.

Also, next time try this. When you have a no-start, key-off (all the way to the lock position), wait 5 seconds, try again.. Do this 5 or more times and see if it makes a difference.. What this does is to try and get the DIS to guess at the firing order in the case of a missing CID.

Oh, and 1 more thing, you can test for spark with a timing light or by pulling a cable off at the coil pack and checking it there. I recommend thick gloves and/or insulated pliers to keep from zapping yourself. Check all 3 rows on either side.

IGot6UGot8
03-11-2003, 09:44 PM
The check engine light does not come on. Would it still throw codes even though the light isn't coming on?

Thanks for the suggestions, I'll try those next time I got over to work on it.

Jake

cudaz101
03-12-2003, 05:34 AM
Yea you can have codes and have no CE light...I had a intermitten Crank sensor and had no light, no codes leading to it until it finally rared its head high enough to pop a code...Then I finally got enough information to change a part that made some sense, and lead to the fixing of the intermitten senseless problem that I had been having...

You get the idea...

Run Codes...If you get a System pass and no memory codes then you may need to take it in for a diagnostic monitor...It sounds like you have covered alotta bases with no results, so it may be time for a new approach.

Brad

darriantbird
03-28-2003, 03:10 AM
I am having the same problem no spark have gone through the usual sensors coil pack harness module pcm etc ... still no spark cranks fine but ..... let me know if you find anything iI got a mechanic checking it out he is baffled so far too. I'll let you know if I come up with any thing too.

pastera
03-28-2003, 11:05 AM
Originally posted by darriantbird
I am having the same problem no spark have gone through the usual sensors coil pack harness module pcm etc ... still no spark cranks fine but ..... let me know if you find anything iI got a mechanic checking it out he is baffled so far too. I'll let you know if I come up with any thing too.

Do you get a shift light while cranking?
I know you said you checked the usual sensors but did you check all the fuses. How about power at the sensors?

Where are you in Mass?

Aaron

darriantbird
03-28-2003, 01:44 PM
Yup, check fuses main ones under the hood as well as the harness leading to it and the fuse under the dash band straps (well my mech told me he did) I don,t know if I trust him too much-but I don't have time to do this working full time and all.BTW I'm in the Brookfield's 20 minutes west of worcester. this mech is not my regular but his shop is right down the street so it was convenient ,and I have not signed a consent form for the work so if he tries to screw me I'll do some screwing of my own!

IGot6UGot8
03-29-2003, 05:47 PM
Well we found out that the temperature sensor was bad. This sent the computer into "limp" mode, and wouldn't let it run for any period of time.


Jake

himylo
03-30-2003, 12:15 AM
CHECK THROTTLE BODY AND POSITIONING SENSORS.

Mike8675309
03-30-2003, 07:57 PM
Originally posted by 91ScOwner
My car will start fine in the morning,and run for awhile.If I turn it off however it will not restart for anything,even if you floor it. It is throwing no codes,and everything else seems to be working.Any advice? I really want to get it running good for spring.

I think your thread has become hijacked.

Need to clarify. Starts in the morning, shut off, won't come back on. How long does it have to run for it to not start after you shut it off? Seconds?Minutes?Hours?

When does it restart? Seconds? Minutes? Hours? Days?

When it starts, does it run fine? Good power, all seems just right with the world?

When this happens, you have spark but no fire? I'd due a pressure leak down test to start with. Hook a fuel pressure gauge to the fuel rail and see how long fuel pressure is maintained. It shouldn't drop off significantly for hours.

If you're in an area that carries winter blended fuel (most of the north and midwest states) you could also be having problems with vapor lock. The fuel blended with alcohol to decrease winter emissions decreased the boiling point of the mixture causing vapor lock issues at times where it didn't exist before.

So, check the leak down. And maybe try throwing some ice on the fuel rail to see if it speeds up the ability to start the vehicle.

If neither of those seem likely you need to start thinking about an ignition problem. Spark is good, but you also need spark at the right time.

cudaz101
03-31-2003, 07:48 AM
I am pretty sure that Jake "Igot6Ugot8" is helping the origional thread starter out...Pretty sure that Jake sold the car to him...Sounds like they may have a foothold on the problem...

Brad