98 C1500 5.7L Fuel Pressure (Won't start)

[BajaScout]

Still no start. Cranks over nicely but acts like it is out of gas. I tested the spark at each plug. A couple seemed to spark stronger than others. I am going to change out the distributor cap and rotor just for good measure. I have had problems with the caps in the past (known issue on these engines) and would like to order a cap with brass or copper contacts. Not the aluminum ones. Any recommendations on a good cap and rotor? The only one I found that states brass/copper is the AIRTEX 5D1079A http://www.rockauto.com/catalog/more...344&cc=1303366.

My spark tester is a cheapy, but it at least gives me some indication.

http://s285.photobucket.com/user/Baj...tml?sort=3&o=0

Does the HEI spark tester work on the Enhanced Distributor Ignition (EDI) system on my 1998 5.7L? Also interested in recommendations for fuel pressure testers.

It looks like the OTC 6589 may be the one to get. Good recommendations:

http://www.amazon.com/OTC-6589-Elect.../dp/B0050SFVO2

[BajaScout]

Received the AIRTEX 5D1079A Distributor cap and new rotor. The distributor cap had the aluminum contacts and not the brass/copper I read about on the Rock Auto web site. Installed cap and rotor but still did not start. Seemed to want to fire a little more though. Double checked the fuel pressure. 63 PSI when the pump is pumping. The fuel pump is a brand new Delphi. Haven't received the new spark tester yet. Once that comes in, I will check spark to see if it is strong enough to fire the plugs. I have spark at all cylinders but it looks rather weak to me on my cheapy spark tester that just gives a light indication.

If anyone has any other suggestions, I am all ears! Thanks.

[j cAT]

Originally Posted by BajaScout

Received the AIRTEX 5D1079A Distributor cap and new rotor. The distributor cap had the aluminum contacts and not the brass/copper I read about on the Rock Auto web site. Installed cap and rotor but still did not start. Seemed to want to fire a little more though. Double checked the fuel pressure. 63 PSI when the pump is pumping. The fuel pump is a brand new Delphi. Haven't received the new spark tester yet. Once that comes in, I will check spark to see if it is strong enough to fire the plugs. I have spark at all cylinders but it looks rather weak to me on my cheapy spark tester that just gives a light indication.

If anyone has any other suggestions, I am all ears! Thanks.

if the spark is weak and intermittent then you get into the ignition module and the coil . at this age I would replace all this along with the distributor. make sure all the plug wires are good . if the wires/cap has any arcing this damages the ignition module.

[BajaScout]

Using my new HEI spark tester (the one Schurkey recommended) I tested all 8 cylinders. I did not have spark in number 1. The rest had spark. Swapped wires 1 and 3 and then 3 did not spark. I think at a minimum I need a new set of spark plug wires. I also did the meter check on the coil as per the manual. These all checked good.

Should the spark be blue or white? Mine was white.

Not sure how to test the ignition module. Will research that. Hopefully the plug wires will solve the problem. I do haver a new cap and rotor.

Any recommendations or advice on spark plug wires? I see on NAPA that some a specific to certain engine codes.

[Schurkey]

Originally Posted by BajaScout

Using my new HEI spark tester (the one Schurkey recommended) I tested all 8 cylinders. I did not have spark in number 1. The rest had spark. Swapped wires 1 and 3 and then 3 did not spark. I think at a minimum I need a new set of spark plug wires. I also did the meter check on the coil as per the manual. These all checked good.

You have a dead or shorted plug wire. First guess: The rest are also bad, just not bad enough to prevent a spark.

Originally Posted by BajaScout

Should the spark be blue or white? Mine was white.

Unimportant, if you have an HEI spark-tester. If the spark jumps that gap...it's fine.

Originally Posted by BajaScout

Not sure how to test the ignition module. Will research that.

Very unlikely to be an ignition module since you have spark.

Originally Posted by BajaScout

Any recommendations or advice on spark plug wires? I see on NAPA that some a specific to certain engine codes.

I install CUT-YO-FIT helical-wound plug wires on every application I have a reason to replace the plug wires on. I don't remove functioning carbon-core plug wires, but if they're defective, I install the helical-wound units. There are many different brands.

[BajaScout]

Installed the new spark plug wires. Spark looks much better on all eight. I was also able to get the engine to fire up by putting some gas down the throttle body. but will not fire up on its own. Checked the injector signal with a noid tester. All injectors have the pulse signal.

Rechecked my fuel pressure:

Key on not cranking 56 psi. Is this too low?
Cranking the motor it goes up to 62 psi
After cranking the motor drops to 59 psi
Turn the key off it stays at 59 psi and hold that pressure for more than 10 minutes
Pinched off the return line with key on (not cranking) and pressure jumped to 84 psi and then dropped to 59 psi several seconds later.

The pump is capable of pumping at higher psi, so I assume it is good. I am thinking I may have a bad fuel pressure regulator. Fuel pump is a new AC Delco.

Would appreciate any opinions or other items to check.