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99 vert. 41k mi. At various times, recently running or cold start, I'll have to cycle the key as the first turn doesn't yield the engine firing. Usually no more than two key cycles. I have replaced the fuel filter about 1500mi ago and recently replaced the evaporator purge valve(picturebelow). Now, after replacing the purge valve the car did fire right up for about 150 minutes but then went back to its old habit.
Does anyone have any ideas? I've considered the fuel pump but no codes are thrown and fuel rail pressure seems adequate.
Any advice, ideas, questions are welcomewelcomed. Thank you all.
What does your fuel pressure do when you turn the key off...does it quickly drop to zero or hold pressure ???
I'll look into this. I do recall when I changed the fuel filter and went to drain the rail, it seemed like there should have been more pressure to relief. I thought about a bleeding injector but wouldn't that throw a code?
A leaking injector will not throw a code…the PCM has no idea what the fuel rail pressure is…the only things that will illuminate the MIL (check engine light) are things that will affect the cars emissions…a “better” scan tool will show other codes such as ABS, Body, and Chassis…or checking through the DIC.
Well, you have two ways to approach this...shot gun a bunch of parts or try to diagnose it and only change one part...if you want to change parts it can be an injector, fuel pump, supply line check valve...you have already changed the fuel filter/pressure regulator and purge valve but new parts can be defective...I have this special tooling from Kent Moore who is GM's tooling supplier but you can make this yourself to diagnose the injectors, fuel pump, and filter...all you need is some rubber fuel line hose, a shutoff valve and a male and female fuel line adapters...to diagnose the check valve you'd need a Mityvac pressure/vacuum gauge with a fuel line adapter...pics below.
Well, you have two ways to approach this...shot gun a bunch of parts or try to diagnose it and only change one part...if you want to change parts it can be an injector, fuel pump, supply line check valve...you have already changed the fuel filter/pressure regulator and purge valve but new parts can be defective...I have this special tooling from Kent Moore who is GM's tooling supplier but you can make this yourself to diagnose the injectors, fuel pump, and filter...all you need is some rubber fuel line hose, a shutoff valve and a male and female fuel line adapters...to diagnose the check valve you'd need a Mityvac pressure/vacuum gauge with a fuel line adapter...pics below.
Well I have thy mityvac so I'll try looking at the check valve. I have near 60 psi running so I'll lean towards the check valve first. What is the end you have on the mityvac?
Well I have thy mityvac so I'll try looking at the check valve. I have near 60 psi running so I'll lean towards the check valve first. What is the end you have on the mityvac?
You need to attach the Mityvac (pressure setting) to the fuel inlet line at the fuel rail that goes back to the pump (male fitting) and apply 15 psi…the pressure should hold for one minute…if it leaks down the one way check valve is leaking…you will need the 3/8 inch fitting which you can purchase from Amazon.
You need to attach the Mityvac (pressure setting) to the fuel inlet line at the fuel rail that goes back to the pump (male fitting) and apply 15 psi…the pressure should hold for one minute…if it leaks down the one way check valve is leaking…you will need the 3/8 inch fitting which you can purchase from Amazon.
I'll order that and give that a try before I crawl underneath the ol girl. I'm hoping it's the check valve. If not I'll move on to the rails. I appreciate the input and help. Thank you.
I'll order that and give that a try before I crawl underneath the ol girl. I'm hoping it's the check valve. If not I'll move on to the rails. I appreciate the input and help. Thank you.
You don’t have to crawl underneath to get to the fuel line…just open the hood and disconnect the fuel line going to the fuel rail. If it is the check valve you’ll have to get underneath and drop the fuel tank to change that line.
You don’t have to crawl underneath to get to the fuel line…just open the hood and disconnect the fuel line going to the fuel rail.
I'm sorry I mean I'll do this before I crawl under to replace the check valve. (In a way I hope it's the check valve as other areas are probably more spendy lol)
I'm sorry I mean I'll do this before I crawl under to replace the check valve. (In a way I hope it's the check valve as other areas are probably more spendy lol)
I guess you can also connect the Mityvac to the fuel rail and apply pressure on that end…if the pressure drops an injector is leaking.
Normal KOEO (key on engine off) value should be 55-62 psi.
So I'm not seeing an increase in pressure when i cycle the key to "on". In fact it only shows pressure when i start the car and Im definitely seeing 58 psi when it's running, but of course that quickly drops when I shut the car off.
So I'm not seeing an increase in pressure when i cycle the key to "on". In fact it only shows pressure when i start the car and Im definitely seeing 58 psi when it's running, but of course that quickly drops when I shut the car off.
When you turn the key ON the fuel pump will run for 2 seconds and then shut off unless the car is started…when the PCM receives an RPM signal the pump continues to run…I’d worry about the pressure drop when it shuts off…it should not drop more than 5 psi in a minute.
Cycling 2x to start.
