chevy wont start

I have a 1997 chev silverado 5.7L vortec 350. We where having fuel problems cause it would studder when we excellerated hard. So we replaced the fuel pump and it ran fine untill one day when i crossed some tracks it stalled and would not start. So we replaced the fuel pump and filter and it still wouldnt start. We have replaced the distributer, distributer cap, starter, plugs and all sensors under the hood that we can find. The truck has good fuel pressure at the service line behind the engine. I have good spark and when i dump fuel down the intake it will run until the fuel runs out. i dont know wat else to do? :banghead: :runaround: Please any sugestions would help.

Did you check the FPR (fuel pressure regulator)?

Check all wiring harness connection points and make sure nothing shook loose. Any OBD codes (check engine light)?

Sounds like the fuel injectors aren't firing. Is the crank sensor one of the sensors that you could find? If not, check it to make sure it's bad. If it's good, check the wiring. Throwing parts at vehicles usually ends up costing more than paying to have it diagnosed.

There is no codes that have came up. We checked the regulator and it was clean.(im talkin about the one atached to the injector body) and all the attachments were Ok. When i go to start it my pressure gauge on the dash drops to zero but when i stop it goes half way up?

There is no codes that have came up. We checked the regulator and it was clean.(im talkin about the one atached to the injector body) and all the attachments were Ok. When i go to start it my pressure gauge on the dash drops to zero but when i stop it goes half way up?

A pressure gauge measures fuel pressure in PSI. You attach it to the Schrader valve on the diagnostic port, it's not on your dash. If you're referring to the fuel level gauge, the behavior you describe is normal.

I didn't even think about the crank sensor (CKP), but if that's the issue, you'd also have a check engine light.

Im talking about my Oil pressure gauge that does that. And the we replaced the crank sensor. And my sister replaced the deck a while back so i checked to see if any wires where short circuiting and when i went to remove the dash the rpms went up?? so there must be short in my dash or something?????

It won't start, but the RPMs went up?

If the oil pressure is 0, the engine won't start (at least on the older ones, can someone confirm that on a '97?). I would check the oil pressure with a screw-in guage to make sure the guage on the dash is accurate, if it is you may have a bad oil pump.

so how exactly would i test the guage if it is acurate

Have you replaced the ignition control module in the distributer?
Do you have fire to your fuel pump?

I have spark and the pump runs for 3 secs before turning over.
There is pressure at in the line at the engine but no fuel getting through the injectors and yes we replaced distributer and the sensor cause it was corroded last year

so how exactly would i test the guage if it is acurate

Get a test guage, the kind that screws into the test port (almost always very close to the oil filter). If it reads 0 PSI while cranking, there is a very good chance that your guage on the dash is correct. If it reads 10 PSI while cranking (or really anything), you know the guage on the dash is wrong. If the test guage does read some pressure (my '86 builds 10-15 PSI while cranking depending on the temperature, I'm sure a newer engine would be even higher) check the oil pressure sensor to make sure the computer is seeing oil pressure.

Thank you greatly for your time and help. I have a guage that i use for fuel pressure. Will it work for the oil as well? And i will update you with any info when i find it.

The guage should work, but you will need an adapter to use it for oil pressure.

I would also like to test my oil pressure at the sending unit location. What kind of adaptor are you referring too.

Thanks

I found in a book i own how to test it. :) Plus a guy told me that the oil pan can be sealed back on with just a cork or rubber seal. YEAH. And the pump comes off with two screws. so this should be easy...BUT how much would the pump cost??????

Rockauto.com has one for $36.79. This is one part I WOULD NOT go the cheap route on. Either go with a GM part, or a high performance aftermarket.

Thanx for the help i will try and get it running after work:)

sorry havent been by a computer in a while. Got the pump in but still my pressure drops when i turn it over... so i was thinking it could be the oil pressure switch/sensor. My dad bought one a while back but we cant find where it goes:crying: ive gone through a couple rebuild books but still nothing. Please anything will help...thanx for reading

I would check the ignition control module. Might be as simple as that . Like it was with my no start issue recently.

... we have replaced that and the coil that goes with it... Is their even a oil pressure regulator on a 97????? My oil pressure drops slowly when i go to turn it over so could their be a seal broken??????

It won't start, but the RPMs went up?

If the oil pressure is 0, the engine won't start (at least on the older ones, can someone confirm that on a '97?). I would check the oil pressure with a screw-in guage to make sure the guage on the dash is accurate, if it is you may have a bad oil pump.
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Hi,
The fuel pump runs for 3-4 seconds to have pressure to start it.
It doesn't need oil pressure to start. However to keep running after starting, it will need oil pressure then. Only around 5 lbs should keep it running. If for some reason the oil pressure goes away while running, it will shut off as a safety.
So for no start at all, get away from the oil pressure thoughts.
Bob B

AAAAhhhhhh :runaround: But thank you for the help... you saved me money:2cents: but what else could it be????????/