Morning, I have a 94, 6 speed that wont start, well it has spark from coil, no codes and had icm tested, checked relays for f uel pump and still no fuel pressure, I am at a loss of what next. It will start intermittantly but dies out of the blue. Any other ideas on the trouble shooting. I would like to get this fixed before I head back to Afghanistan. Thanks Jeff

 

Some reading

http://www.mainstreamtopics.com/foru...p?showtopic=78

 

Rodj, thanks looks like it should give me my answers.

 

The read is good, just cant find the jumper for the fuel pump under the ecm

 

You indicate no fuel pressure. Are you using a fuel pressure gauge to check for that?

Do you hear the fuel pump for 2 seconds when you turn the key to ON (no crank). If you don’t hear anything, check the fuse for the fuel pump #14.

If the pump is running then it could be any number of items and further investigation is needed. Post your information and results.

 

Is there a wright up like that for a 86 ?
Would the LT1 be close to a L98 !

 

Ok spent half the day running the tests to fig out the issue. Here it is in a nut shell, couldnt find the small prime wire so i ran a wire back to the sending unit along with a ground wire, the pump ran. Started checking fuses with the test light and there is no power to fuses 1,5,9,10,11,12,13,14,15. This just keeps getting better. There is a humming noise, high pitched from the front center of motor. When i disconnect the opti spart connector, there is a motor of some type that comes on front left side, think it is for emissions. Plenty of spark from coil and 4 plugs used test light on them(kinda looks like a spark plug but clear). Im at a loss. Also on the right side of the car under the ac pump, there is a corroded circuit board. Oh and i am using a fuel pressure guage, still reading 0 and the fuel dribbles out from the schrader. Jeff

 

Did you burn a fusebile link!
Start at the battery floler the hot wires comming off the battery
With a test ligjt befor and after every conection
All them fuses should not be dead

 

Any ideas where they might be. I can build one nice house but not so good with motors, yet.

 

I am assuming by running external power to the FP you then had fuel pressure so assuming the fuel system is OK.

I have separated your post. The first part post looks good based readings taken hopefully with your key ON. The second part sounds like you're going off on a tangent and complicating the problem. Unplugging stuff and hearing motor noises means nothing and not good symptoms to chase. Stick with the facts, no power to your fuses. Connect everything back to where it should be and troubleshoot the problem.

FYI - you won't have voltage on the fuel pump fuse unless the pump is running. It is the last link in the circuit before the pump. If the pump is not running, then there is no voltage to either side of fuse #14 (10A). The fuse is after the relay, oil pressure switch and main 12 volt power.

So I ask again. Does the pump run (2 seconds) when the key is turned to ON.

As said in another post, check the fusible links and the MAXIFUSEs also. Both items are in the small boxes around the battery.

Having said all, all fuses (the ones in the door you measured) might not have power on them at all times. It depends on what systems you call up to operate on car like A/C. Fuse 15 is for a LT5 which has a second fuel pump which yours does not have (I assume). So I am having a little bit of a problem chasing power on all these fuses. Feel like we might be missing something, not sure what.

But start somewhere and do the checks anyway on the links and MAXIFUSEs, you will hopefully find something. Fuse block 1, MAXIFUSE 2, is for fuel pump and should power at all times. Fuse 1 feeds PCM but also feeds fuel pump thru oil pressure switch (when engine running). Both are 20A MAXIFUSEs in block 1.

 

When i turn the ignition on, it is not cycling the fuel pump, there is noise from the emissions front left but nothing from the fuel pump. No pressure is generated at all. When i seperate the Opti connector, right side of fuel rail the emissions also cycles.

Thanks for the advice from the fuses. I dont have a second fuel pump. so i guess i have a spare fuse.

This happened three times so far. Once when i went to work on base and the second time with the wife xmas shopping. One hot day one cold day and most recent drove it for about 30 miles and backed into a parking spot and then it was kaput.

 

No disrespect, but do you know where the opti is? I am not sure what you are unplugging when you say right side of fuel rail. The opti is below the water pump on front of engine down below where it can be hardly seen. You can see the 4 pin connector on it on right side of engine down about half way. The front noise you hear on left is the air pump that runs for about 2 minutes during warm up. Don’t be concerned with that for now.

Was wondering if you ran external power to the fuel pump, does the engine start and run? Just a thought.

 

Well this morning i went out to the car and looked at the fuse pannel. Pulled the FP2 fuse and then looked at the relays. There was a relay for FP2. Pulled the relay and hear the pump prime and she fired right up. Is this luck or did i have something conflicting.

 

When you find out tell me!
I would change all the FP relay
Mabey one was stuck and ECM was lost?
Gland to here it runs
Good luck

 

I was thinking the FP2 was only used on ZR1's, and just a spare for us LT1 guys. Anyone else have info on this fuse?

 

My 94 LT1 has no fuse or even contacts in that spot #15 for FP2. So with no contacts, you can't even put a fuse in there because there is nothing to hold it and will just fall out.

These fuse positions are not designed for relays. However there are circuit breakers to the right of the fuses for the power seat and power window (position K and M).

Just for clarity for all. FP2 fuse is in the fuse box inside of the car near passenger door is what I am speaking of.




Were you under the hood in a fuse box or inside the car in the fuse panel. Do have an LT1 and not a ZR1. If you were in the car and at fuse #15, there should not be anything in that position as I indicted above.

If you were in the car at the fuse box you could have jarred fuse #14 for the basic fuel pump and now it's working. You might want to clean the contacts for that fuse. Also could have a bad connection at the fuse box, hopefully not.

 

Inside the passenger side fuse pannel there are connections for the FP2, i cant get the photos i took to upload, also there is a connector to the relays but cant get that photo to upload either. It is an LT1 94 Late model. http://forums.corvetteforum.com/album.php?albumid=15328

 

My 94 has a fuse and contacts in the FP2 spot.

 

So be it, there are differences. Must be a production change during that model year. Looks like I have an early 94 with having a production date of November 1993.

Mine is different that the pix in SEABEEVETTEs photos.

 

Mine is May 94 build.