Another Z with a cold start issue!

[rcb280z]

I have spent a lot of time researching this issue both on this site and my car.

I have a 5/77 280Z. It is running really good. Fuel pressure is correct (just leaks down over several hrs) I can live with that for now. I just prime the pump in the morning (when I do drive it) before starting it. I checked engine vacuum and it's at 19. The issue is after priming fuel lines for about 5 seconds (i have a pressure gauge in line) it doesn't start right away like it used to. It cranks probably 5-7 times and then fires. The idle is around 700 rpm. I have to throttle it around 1300 rpms for a couple of minutes before it will hold there until warmed up. After that it idles at 800. Cold start valve, thermotime, coolant temp sensor, air regulator are new. All connectors except TPS are new. All vacuum lines are new. Replaced them about 2 yrs ago while getting this car ready to pass CA smog. Got 3 k-ohms at pin 13 and ground today. Temp outside was about 59 degrees when I checked. Everything that I can tell checks out good or good enough. I know the check valve is bad and will add an in-line one later. That's why I prime the fuel lines before starting it cold. Before I forget it doesn't matter if the engine is warm or hot. However it does start better (less cranking) when warm. I used to brag about how fast it would start. I have checked so many things. I spent a lot of time searching for vacuum leaks. I found one small one and it didn't change anything. I did notice something the other day when I was changing out the last of the connectors. It was the air regulator one and I forgot to plug it in and started the engine and it rose to 1500-1600 rpms. I plugged the connector back into the air regulator and it gradually dropped to 800 rpms. That was like it was when the Z was new. I guess I'm picky when it comes to my Z but I know something isn't right because it was better. And the battery is good. Holds charge, and good cranking amps. Timing is somewhere between 12 and 13. Seems to run best there. Just trying to supply everyone with as much info as I can. Hopefully someone has had the same or similar issue. Any ideas? Thanks.

Bob

Merry Christmas!

[esmit208]

RCB

I don't know if that particular model has a COLD START VALVE or not. My 82ZX did have one. I lived there in Ventura for a couple years and know the area well. Sun West Motor Sports (805) 644-9644 2113 Palma Dr, #B, Ventura, CA 93003 ...................TRY THIS GUY. He replaced the harmonic balancer on my 82ZX back in 1994 and did a good job. Good Luck

[rcb280z]

Oh yes, know Michael all to well at Sun West Motorsports. Visit with him a couple times a month. Don't take my car to him because I like the trouble shooting aspect of it myself and the satisfaction of fixing the problem. The cold start valve is good according to the FSM test's. It's at 3 k-ohms when cold. So I think that is good unless I'm not understanding something.

[rotorgoat]

Try pulling the cold start valve and check it for flow. Easy to do (2 screws I think). You'll need someone to crank the engine for a few seconds while you aim it into a jar to collect the fuel. They are solenoid operated and can hang up even with the proper resistance.