1999 5.7 Engine Stall

[gburg006]

I checked the fuel pressure today on cranking. Between 55 and 60 psi on crank.

So, new coil, new ignition module, fuel pressure with no leak down. Crank sensor??

 

[Schurkey]

1. Verify fuel pressure when it cranks but won't start.

2. Verify spark with a spark-tester calibrated for HEI when it cranks but won't start.

I checked the fuel pressure today on cranking. Between 55 and 60 psi on crank.

Could be a bit higher. I'm thinking that Vortecs with the poppet injectors should be 60+, a little less with the electronic injectors.

Probably good enough, though.

new coil, new ignition module... ...Crank sensor??

DO
YOU
HAVE
SPARK
when the vehicle won't start?

Does a scan tool show RPM when cranking, and the vehicle won't start?

Any chance the spark plugs have gotten fouled, so there's spark, but not across the plug gap?

 

[jjester6000]

1999 C2500 Suburban 5.7
106,000 miles

I had an issue one day where I came out of the store and went to start the truck. It would turn over but would not start. I know it had less than 1/4 tank but didn’t think I was out. Gas was my next stop on the way home. I ended up getting my dad to bring gas. Poured in maybe 3 gallons of gas and the truck started up. I went to the gas station and filled it up.

A few days later I head to work. The truck ran for 10 minutes and then died in the parking lot when I was getting coffee. After 20 minutes of sitting I was able to start it and rushed to get it back home.

I already had a new Delphi fuel pump so I figured it was time. Pulled the tank, replaced the pump, installed, and started the truck no problem. Drove home with no problems at all.

The next day I grabbed my trailer and was heading to my shop to do some work. I made it up a very gradual incline and over the hill. When I got to the bottom and applied more throttle I was pretty stumped when the truck didn’t make a noise. I coasted for maybe 1/2 mile and eventually pulled over. 10 minutes of waiting I was able to get it to start (stumbled and then started).

So what is the most logical option. I have gone from is it just a relay (have not done that yet), to fuel pressure regulator, to bad poppet injectors. What is the most logical reason for my issues and what should I be testing?

I was having a similar problem with my Suburban earlier this year, and a new distributor fixed it.

It had spark, but just wouldn't start.

 

[gburg006]

Could be a bit higher. I'm thinking that Vortecs with the poppet injectors should be 60+, a little less with the electronic injectors.

Probably good enough, though.


DO
YOU
HAVE
SPARK
when the vehicle won't start?

Does a scan tool show RPM when cranking, and the vehicle won't start?

Any chance the spark plugs have gotten fouled, so there's spark, but not across the plug gap?

No spark to the plugs. I haven’t checked to from the coil yet.

 

[gburg006]

No spark to the plugs. I haven’t checked to from the coil yet.

And no spark from coil

 

[Schurkey]

If your scan tool shows RPM when cranking, the crankshaft position sensor and wiring harness is good. The problem is farther upstream. You'd want to verify that the ECM fuses; the coil, and the module all have "12 volt" power. If the ECM fuses, the coil, and module have power, the computer, or the wire harness between module and computer is suspect.

If there's no RPM signal when cranking, you have problems somewhere in the CPS circuit--the reluctor, the sensor, the wire harness, or the computer.