97 Blazer won't start unless primed

[97explorersport]

I've changed the fuel pump,spider,fuel regulator,and checked all the relays and fuses. The only way this truck will start is to prime the engine with a shot of gas and then it will start and run great. Shut it off and NO Start. Really pissing me off. I figure it's something simple but it has be baffled. ANY IDEAS???

[Tech II]

Have you put a fuel pressure gage on the vehicle? What is the reading....has to be greater than 60 psi to start....

Usually, when it wont start and spraying carb cleaner into the intake, it will, means fuel pressure is marginal(just below 60).....

In the list of parts you replaced, I don't see a fuel filter listed.....that would have been the first thing I replaced....

[97explorersport]

Originally Posted by Tech II

Have you put a fuel pressure gage on the vehicle? What is the reading....has to be greater than 60 psi to start....

Usually, when it wont start and spraying carb cleaner into the intake, it will, means fuel pressure is marginal(just below 60).....

In the list of parts you replaced, I don't see a fuel filter listed.....that would have been the first thing I replaced....

Ya did the fuel filter also....was a biatch to get off but it was done also....so it needs a minium of 60psi to start? When I had the tank out I did notice a large amount of rust at the pump opening ....would that also cause a pressure drop ??? Tanks(lil pun on words)

[chcknugget]

You should check the fuel pressure, it sounds like your new pump is bad...

[Scrapper]

Originally Posted by 97explorersport

I've changed the fuel pump,spider,fuel regulator,and checked all the relays and fuses. The only way this truck will start is to prime the engine with a shot of gas and then it will start and run great. Shut it off and NO Start. Really pissing me off. I figure it's something simple but it has be baffled. ANY IDEAS???

have you checked spark to see if it's yellow or blue? yellow bad blue good also i would use eather rather than gas. but yeah look see what color of spark your getting?

[old_master]

The poppet valves, (one in each fuel nozzle) on your 97 CSFI engine require approximately 40psi of fuel pressure to open them and squirt fuel. If fuel pressure is below 40psi, the engine will not run, period! If it's between 40psi and 60psi, it will usually start with a shot of carb cleaner or gasoline, but most likely there will be driveability issues.

Ignition in RUN position, engine off, fuel pump running; Pressure must be 60psi to 66psi and must remain above 55psi for 3 to 5 minutes after the pump shuts off. Post your results.

Don't use starting fluid unless you want bigger problems. Once you see a rocker arm cover get blown clean off an engine, you'll understand

[Scrapper]

Originally Posted by old_master

The poppet valves, (one in each fuel nozzle) on your 97 CSFI engine require approximately 40psi of fuel pressure to open them and squirt fuel. If fuel pressure is below 40psi, the engine will not run, period! If it's between 40psi and 60psi, it will usually start with a shot of carb cleaner or gasoline, but most likely there will be driveability issues.

Ignition in RUN position, engine off, fuel pump running; Pressure must be 60psi to 66psi and must remain above 55psi for 3 to 5 minutes after the pump shuts off. Post your results.

Don't use starting fluid unless you want bigger problems. Once you see a rocker arm cover get blown clean off an engine, you'll understand

you would use gas instead of starting fluid? i know what he's talking about just a squirt and it will run. but you been around longer than i have so you must be rite.

[DeltaP]

I do believe he said Carb Cleaner! Not gas, Not ether,(aka starting fluid), unless ya want to drop a valve or blow yer face off!

[old_master]

Carb cleaner is the safest, easiest, and most convenient. If you put gasoline in a squirt bottle of some sort, or the old style oil can with a pumper, that will work too.



Starting fluid, (ether) is far too volatile and extremely dangerous. One little backfire, or a leaking spark from a plug wire or distributor cap, and you've got an instant fireball in your face. Or, if the engine is cranking, it sucks it in, and the engine backfires, it can blow the oil pan or rocker arm cover clean off with great force! Trust me, seen it happen, not a pretty sight, or sound. A friend of mine working a couple of stalls away from me, had it happen to him. He was damn lucky, all he had was ringing ears for a week.

[97explorersport]

Originally Posted by old_master

Carb cleaner is the safest, easiest, and most convenient. If you put gasoline in a squirt bottle of some sort, or the old style oil can with a pumper, that will work too.



Starting fluid, (ether) is far too volatile and extremely dangerous. One little backfire, or a leaking spark from a plug wire or distributor cap, and you've got an instant fireball in your face. Or, if the engine is cranking, it sucks it in, and the engine backfires, it can blow the oil pan or rocker arm cover clean off with great force! Trust me, seen it happen, not a pretty sight, or sound. A friend of mine working a couple of stalls away from me, had it happen to him. He was damn lucky, all he had was ringing ears for a week.

Oh NO either for me Just a minor squirt of Petrol from a viscosity tube.........don't need ringing I have 2 EX's that can do that if needed.

[g1smith]

I had a similar issue. Have you checked for injector pulses with a NOID Light? I wasn't getting injector pulses, had to swap the ECM / Computer.

[mixin]

As crazy as it sounds, try jump starting it. I had a bad battery and didn't know it. Because the battery was bad, the FP would not get enough power to make the psi to start the engine - although it sounded like the starter was cranking fine. If I shot carb cleaner in it or jumpstarted it with another vehicle, it would start fine.

[rplabat]

I have the same starting problem.

1. will start with a boost because it gives you more cranking time to build up fuel pressure.
2. hitting engine with gas, carburetor cleaner, or starting fluid, ( in that order)

Possible solutions:

1. possible leak in return fuel line. disturbed by changing a fuel fuel filter or repairing a fuel line. The return line could have a leak letting air onto line.
2. Bad check valve ( allows fuel to go in one direction, to keep pressure up. ( unfortunately its in the fuel pimp assembly so changing fuel pump corrects that) One person installed another check valve just past the fuel filter and it solved his problem). much cheaper and a lot less work than dropping the fuel tank.