Cranks, then hesitates, has spark

JAKE JONES

MEMBER
1997 CHEVROLET TAHOE
5.7L
V8
4WD
AUTOMATIC
127,000 MILES

Replaced the cap, rotor, and wires for general maintenance a couple months ago. As well as injectors, duel pump regulator, and fuel pump. It was great, on my way to work I was just cruising doing about 60 mph and it just shut off. It cranks and has spark. When it cranks, it cranks then sounds like locks up and and starter can barely turn it overwhelm it does turn over it backfires through the intake. I had a 1997 k1500 with the same problem. Replaced the whole distributor as well as the finding gear and chains. Still couldn’t figure out the problem. Need help ASAP.

Saturday, February 9th, 2019 AT 6:01 AM

1 Reply

JACOBANDNICKOLAS

MECHANIC
110,182 POSTS

Hi and thanks for using 2CarPros.

Often times a backfire is caused by a very rich fuel mixture. Since you just replaced the injectors, confirm that the fuel pressure is within the manufacturer's specs. You may have a bad regulator causing a rich mixture.

Here is a link that discusses backfires. Take a look through it to see if it helps.

https://www.2carpros.com/articles/engine-backfires-while-running

As far as the slow crank, I'm concerned that one or more of the cylinders is filling with raw fuel and causing a hydro-static lock.

I would start with checking fuel pressure. Since everything was replaced, including the regulator, pay attention to pressure drop off which may indicate sticking injectors.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Here are the specs for fuel pressure:

Fuel Pressure Specifications

Cental SFI .................... 415-455 kPa (60-62 psi)
SFI .................... 385-430 kPa (56-62 psi)

Let me know if this helps, what you find, or if you have other questions.

Take care,
Joe

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Saturday, February 9th, 2019 AT 10:29 PM