Flooding ... Leaking Fuel Pump Replaced ... Won't Start

[RonK]

75 280Z with 114K miles.

Took my z in to have the rear tranny seal changed and my mechanic asked if I had been smelling gas in my car .... Yes, I have been for several days. Turns out the fuel pump was leaking.

That may answer the other problem I have been having ... in the am the car would start up right away but run rough until warmed up. If It died before being warmed up, I would have to crank the car for long period of time (40+ secs, 2 or 3 times) before it would eventually start, acting like it was flooded, but got through it and ran well. Would have no problems for the rest of the entire day, stop and go, starting fine.

Forgot to tell my mechanic about the morning ritual when I left it at his shop the night before to get the tranny seal fixed and sure enough, in the morning he started it, didn't make sure it keep running and it died ... after cranking it for a little bit, he concluded it ran out of gas and called me for the gas cap key. After me explaining the morning ritual, he said that he had gone ahead and just pushed the car on the rack and got to work on the tranny.

After fixing the tranny, he changed the leaking fuel pump, but now can't get the car to start. He says the fuel pressure is good, has spark and is getting so much fuel it's "washing out the cylinders and the oil smells like gas".

Suggestions?

[grantf]

Thinking...... could be many things, bad cold start injector, bad FPR, bad temp sensor. sounds like to much fuel is being dumped. Is there any black smoke when it does run?

[grantf]

or a major fuel leak.

[RonK]

Update.... my mechanic has discovered there is an "overflow line" from the fuel pressure regulator that goes to the gas tank...and that line apparently is not allowing the gas that exceeds the amount regulated by the regulator to return to the tank, rather it is being forced into the chambers via injectors .. HENCE, Flooding.

We suspect there is a problem associated with the evap system.

[Zed Head]

There's a diagram of how the fuel system works on page EF-5 of the FSM. You should find a new mechanic. And have the new one measure your fuel pressure.

[Zed Head]

No editing allowed. Weird.

Didn't mean to sound harsh above, but a good mechanic should know about the return line on a pressure regulation system. "Discovering" the return line is a bad sign.

[RonK]

My mechanic noted that if they pinched the fuel line coming from the FPR the engine would run well....let it go and ran terrible = too much fuel. He decided to pull the fuel line running from the FPR that goes back to the tank, let it hang to the ground and see what it does...and, sure enough, it ran well = line back to the tank has some blockage?? Blew "shop air" into line returning to tank, hooked all lines back up and is running great!

[SteveJ]

No editing allowed. Weird.

Didn't mean to sound harsh above, but a good mechanic should know about the return line on a pressure regulation system. "Discovering" the return line is a bad sign.

It wasn't harsh. It was spot-on.

Edit: Oh, and there is only a short window to edit the post.