79 280zx engine problems.

[danielsheehan]

having an erratic idle, running rich.

ok so i cleaned out intake manifold, put new gaskets on intake manifold/exhaust manifold, all the way down to the cat, throttle body gasket, torqued down to spec. refurbished afm, new fuel pressure regulator, new distributer, wires, plugs, fuel filter, cleaned egr, new air pressure regulator,new pcv, new injector because one was cracked. Tested coil, spark is good, it actually went arced up to 40.

set static timing to top dead center and timing to 10 degrees btd.

so heres the bad, im having an erratic idle, it stumbles and doesnt hold steady, lack of power, and after i take it around the block once it shuts off and has problems staying on.

Also the fuel pressure at idle is 35 psi, the book says its supposed to be at 30, and when throttlke is fully open it jumps to 40 psi, the book states its suppposed to be at 37 psi.

Also, i did a vacuum test and intake vacuum is really low on the gauge, it says late valve timing but i think thats wrong.

its running super rich, gas is dripping out of the exhaust and carbon is getting sprayed all over the cement.

I really need help on this.

p.s. also if you guys have pictures of the vacuum lines and the electrical hook ups in the engine bay that would be really nice. just to make sure everything is hooked up properly, pretty sure it is though, but just want to double check. Fixing 11 previous owners mistakes.

Edited December 13, 2011 by danielsheehan

[garretthes]

I had the same problem and it ended up being the short wiring harness that runs from the injector harness to the coolant temp sensor/thermotime switch. There are three wires altogether. They tested OK with a meter but there was an intermittent short. A local Z car mechanic told me he always recommends replacing this short cable whenever the coolant temp sensor is replaced.

Have you checked the coolant temp sensor? If it is dead it will tell the ECU the engine is cold and cause a rich mixture.

Also make sure the cold start valve is working properly. It's a separate injector that leads right to the fuel rail. If it's leaking that could cause your problem.

[danielsheehan]

well i replaced the number 4 injector, since it was cracked, and leaking, making it run rich, replaced it and its still running rich. so i pulled the wire conenctors on the injectors one by one, only the 4th injector showing no change. I used the bulb tester to check for current and pulse of the injecotr cables, all of them light up. Could they have sold me a faulty injector?

[garretthes]

When you check with the test light be sure and wiggle the wire around. These old wires can have intermittent shorts. Is the plug good? If the plug is fouled it wouldn't make much difference if you unplugged the injector.

[danielsheehan]

wies are good, just for some reason its not making a connection with the 4th injector, I removed the vlave cover today to check the timimng chain,. its good, valve clearence is also ok, maybe a thousands of but thats ok, wont effect performance, was quite alot of sledge build up, some the size of base balls, and hard as a rock, going to do a flush, but still trying to fiugure out the running rich and erratic idle. what else should i check. also replaced the coolent temp sensor.

[danielsheehan]

just replaced ecm, no change

[danielsheehan]

ok so i got the engine to run good, no more erratic shaky-ness.

only issues, on cold start, like sitting for more then an hour or two, when i start it, the engine idles up to 3500 rpm which is bad and dangerous.

also, it stalled out a few times. it has new fuel in it and a fuel system cleaner as well. Also, i can start the car in drive, which i've heard means somethings not right.

[danielsheehan]

what do you guys think vcv or bcdd?

[zbane]

Do you have a copy of the Factory Service Manual? If not, PM me your email and I'll forward you a PDF copy.

You'll be able to find all the routing for the vacuum lines, as well as electrical connections...

Edited January 7, 2012 by zbane

[danielsheehan]

traced out ecu, no shorts, everything is connected. I also went ahead and replaced all of the connectors on the sensors, and all the injectors. still no change.

Timing is set at 10 degrees btdc, also put iridium ix spark plugs in.

[CEgg11]

CEgg11@aol.com