1991 z34 twin cam v6 hard start.

[NEWTEC04]

Hello everyone ,I m new so cut me some slack or some cheese :-) but please help. I purchased a 91 z34 in good shape but working on the car i found everything good excepr for 1 fuel injector which measured in @ 4.0 ohms. .The problem I really have is that everything checks out good except when I put a fuel guage on the rail to measure pump volume the car has about 45 to 47 psi present at the rail but will not start. The strange thing is if I bleed the fuel pressure off to about 25 psi with a hose running in a gas container the engine starts and runs????? how wierd is that. If I regulate the pressure while the engine runs by closing off the bleed the car cuts out when the correct fuel pressure is given.....stumped. Does anyone have any suggestions?

[SappySE107]

RE: 1991 z34 twin cam v6 hard start.

Do an injector leak down test. Thats my only guess at the moment.

[NEWTEC04]

1991 z34 hard start problem

Thanks for the suggestion but the injectors don't seem to leak,the spark plugs nor the cylinders are wet and no rich fuel on starting.

[your_I.D.]

this car ever run right since you've owned it?

[NEWTEC04]

still no start

when I bought the car it was in this condition, I have been trying to troobleshoot it before i spend tons into it.

[your_I.D.]

If your bleeding off fuel pressure and it starts. It has to be overfueling it to make it die or not start. I'd do the injector leal down test, check fuel pressure regulator diaphram and do a compressiobn test to make sure theres no major mechanical problems.

[NEWTEC04]

3.4 POOR RUNNING ENGINE FIXED

It's been a whil but I did finally fix the car,the things I did find wrong were #1 Injector dead,and 2/5 coil pack dead also the O2 was dead,I guess this was all the things wrong with this car.
Sorry for the late post but I had a hard time getting back in.

Now the car runs really good and I am glad to have put the time into it to make it run.