Interesting starting issue, fuel pump? FPR?

[nigel34]

So I have recently replaced my injectors because the seals on two were leaking pretty bad and flooding the cylinder. So I just replaced them all. I'm not sure if that has anything to do with my issue but I believe it's fuel related. When I turn the key the motor turns over for about 3-6 seconds depending on how long it sits. If I just shut if off and start it right back up it starts fine. It starts eventually overtime; I can smell gas occasionally. Someone said FPR, some one said fuel pump... any ideas?

[PyR0NiAk]

If you are smelling gas, it's not the fuel pump... Smelling gas is a sign of TOO much fuel, but here's an easy way to check to make sure your fuel pump is WORKING for sure. (For future reference, at least.) When you turn the key on, you should here a mild whining sound coming from the back of the car. That's your pump priming.. If you hear that, the fuel pump is working. This doesn't guarantee it's at it's full potential, but it IS working. The only way you can know if it's the FPR is either by putting a known good one on it, and seeing if that fixes the issue, or getting a gauge. I recommend you confirm you're getting spark on all cylinders. The smelling of fuel could be fuel not burning.

[nigel34]

Well, i know its getting spark for sure. Ive somewhat tried to hear the fuel pump with no luck, but i cant say i was really listening for it... Is it possible its the FPR? its like all the fuel is going back to the tank or something, and the lines are empty.

[PyR0NiAk]

If the lines are empty and you can't hear the pump, your pump is dead. Here's something I did to test my pump when I first did my walbro install... (I was working at a hobby shop and s*** was too loud to hear the pump priming, but I was 95% sure it was working.)

WARNING: DO THIS AT YOUR OWN RISK

1) Remove feed line from fuel rail. (It's the one with the filter on it) Note: Fuel may still be under pressure in the line, and if so some will spray out when you remove the fuel line.
2) Insert this line into a jug that is approved for gasoline. (A 5 gallon gas can is plenty)
3) Have someone turn the key on, count to 3, then turn key off. (They need to turn it all of the way to the ON position, as if they were going to start the engine. Not accessory mode. Just don't actually crank it.)

If the pump works, there'll now be gasoline in your gas can. If it doesn't there won't. You could also try and see if your filter is clogged by doing the same thing with the filter off.

LIKE I SAID BEFORE. TRY THIS AT YOUR OWN RISK. GASOLINE IS HARMFUL TO THE BODY.

[nigel34]

Ok, thanks! i will give that a shot. wouldnt the car not run at all if the pump is bad? Because after about 6 seconds tops, it starts and runs fine. Seems to have a rough idle though.

[PyR0NiAk]

pump could be failing and not building up enough pressure initially... This could also prove to be a simple filter issue. Go to autozone, and pick up a fuel filter for a 95 300zx. If your filter is mildly clogged it could be hurting your pump's ability to get the fuel there. But after a while is able to get ENOUGH to get the car to run..

[nigel34]

Awesome, ill get a new fuel filter, im sure its been a while >.<

[PyR0NiAk]

I hope this fixes the problem... Let me know, and if not, hopefully I can be of further assistance.

[sr20671]

One thing. About the pumps also, they're really sensitive. Check the wiring for the pump and see if the pump didn't shift cause if you hit a hard bump or accidentally move the pump if it's not seated right it will not work either... Sometimes shutting off while the cars running

[PyR0NiAk]

One thing. About the pumps also, they're really sensitive. Check the wiring for the pump and see if the pump didn't shift cause if you hit a hard bump or accidentally move the pump if it's not seated right it will not work either... Sometimes shutting off while the cars running

I've NEVER seen an issue with the pump not being "seated" correctly. I could be wrong, I guess.. Just seems highly unlikely.

[shiro_neko]

retard your timing and try to start. no change, check canister purge hose. if ok remove vacuum hose from FPR and start. improves, check fuel pressure

[nigel34]

Ok, ill try retarding the timing and removing the vacuum hose from the fpr. The fuel filter defiantly needed replacing, but did not solve the issue. Im not sure if this info helps. but this issue started right after replacing the injectors. all 4 were replaced, had new seals and everything.

[nigel34]

No difference on retarding the timing or hose from fpr. The problem is defiantly getting worse. taking longer to start, runs really rough for about 10 seconds when it does start now, and a rougher idle. But, still it seems to cruise fine and accelerates just fine. not sure if the higher rpms are just covering up the rough running >.<

[PyR0NiAk]

How about plug wires? It sounds like you have a small miss and it could very easily be a bad plug wire... We can sit and name parts all day for you to change and you might get lucky, but if not, it's going to nickel and dime you to death.

[nigel34]

The problem ended up being a bad injector seal... My guess is that when i shut the car off the fuel pressure pushed some fuel in the cylinder, so it was running rough due to it being flooded for the first couple seconds. also kinda explains the miss/rough moments at idle. It was a new injector... i put grease on the o-rings and placed the injector in its spot, and used the bracket as a press to get it in all the way. is that correct? Just wondering why the o-ring got torn up.

[PyR0NiAk]

It should've popped in all the way with just your hand... Using the bracket probably shoved on one side more than the other and caused it to tear.