Truck cranks but doesnt start

[SUBURBAN5]

Ok jw because when my fuel pump died. It literally died. Driving fine normal one minute next minute dead. Lights on radio on no start. Cranked but no start. I've never changed my crank sensor or camshaft. Mine has 470k.. I better knock on wood. Keep us posted though I curious the cause

 

[alpinecrick]

You say your distributor cap has play in it?

Every fuel pump on TBI's and Vortecs that quit on me just quit--and it quit when I shut the engine off and went to start it again. I have heard of pumps not producing enough pressure and the engine running poorly.

 

[obsguy124]

That pressure is too low for the original poppet valve injector setup.

Richard

How much should it be at?

 

[obsguy124]

You say your distributor cap has play in it?

Every fuel pump on TBI's and Vortecs that quit on me just quit--and it quit when I shut the engine off and went to start it again. I have heard of pumps not producing enough pressure and the engine running poorly.

The rotor had a bit of play when I took the cap off. Even if the pressure is a bit low it still holds at a reasonable number, you would think the engine would ATLEAST run poorly instead of not running at all.

 

[obsguy124]

Ok jw because when my fuel pump died. It literally died. Driving fine normal one minute next minute dead. Lights on radio on no start. Cranked but no start. I've never changed my crank sensor or camshaft. Mine has 470k.. I better knock on wood. Keep us posted though I curious the cause

470K WOW thats alot haha, ive done some research and found that people that were driving and their car died out of nowhere had issues with their crank sensor. Ill keep you posted I have plans on working on this thing all weekend and next week.

 

[obsguy124]

Ok jw because when my fuel pump died. It literally died. Driving fine normal one minute next minute dead. Lights on radio on no start. Cranked but no start. I've never changed my crank sensor or camshaft. Mine has 470k.. I better knock on wood. Keep us posted though I curious the cause

Also did your fuel pump make the startup noise when you turn the key to ON position after it died?

 

[stutaeng]

Only way to check for injectors is an "injector balance test," which requires a special gadget or a more advanced scan tool: https://www.amazon.com/OTC-3398-Inj...ocphy=9026913&hvtargid=pla-490383844056&psc=1

Does your distributer rotor spins? I thought sometimes the gear on these can break? Also, have you checked spark on all plugs? If you are getting spark on some plugs, then you can rule out the crank sensor.

If you are getting spark only on some plugs, look into distributer/ICM.

But also confirm on the fuel pressure. Don't know the minimum pressure required to start off the top of my head...

 

[someotherguy]

I kinda feel like a broken record on this one. A Vortec small block (with the original poppet valve injector setup) fuel pressure spec is 58-62 psi. Once they start getting down around the mid 50's, this will vary from truck to truck, there's not enough pressure to open the poppet valves and the truck will not start. If the pressure is marginal you may get it to start by cycling the key enough times for the system to prime and the pressure to just barely crack the "good" mark, it may run OK but stall unexpectedly, etc.

Chasing other scenarios is kind of pointless until the fuel pressure issue is dealt with. If the filter is old, try replacing that first.

Those with the injector upgrade to the MPFI setup find that their pressure runs consistently a little lower than spec, that is fine; those are real injectors with no poppet valve setup and they are far less finicky about fuel pressure.

Richard

 

[SUBURBAN5]

I kinda feel like a broken record on this one. A Vortec small block (with the original poppet valve injector setup) fuel pressure spec is 58-62 psi. Once they start getting down around the mid 50's, this will vary from truck to truck, there's not enough pressure to open the poppet valves and the truck will not start. If the pressure is marginal you may get it to start by cycling the key enough times for the system to prime and the pressure to just barely crack the "good" mark, it may run OK but stall unexpectedly, etc.

Chasing other scenarios is kind of pointless until the fuel pressure issue is dealt with. If the filter is old, try replacing that first.

Those with the injector upgrade to the MPFI setup find that their pressure runs consistently a little lower than spec, that is fine; those are real injectors with no poppet valve setup and they are far less finicky about fuel pressure.

Richard

I agree pressure sounded low

 

[obsguy124]

Only way to check for injectors is an "injector balance test," which requires a special gadget or a more advanced scan tool: https://www.amazon.com/OTC-3398-Inj...ocphy=9026913&hvtargid=pla-490383844056&psc=1

Does your distributer rotor spins? I thought sometimes the gear on these can break? Also, have you checked spark on all plugs? If you are getting spark on some plugs, then you can rule out the crank sensor.

If you are getting spark only on some plugs, look into distributer/ICM.

But also confirm on the fuel pressure. Don't know the minimum pressure required to start off the top of my head...

I only checked one of the plugs, ill check the rest today and let you guys know if they are good or bad, as far as the rotor yes it does spin. Ill take a look at that tool I think autozone or oreillys might rent it out, thanks for the info.