Z34 - Black Smoke

[shakerharley]

!992 Z34:
Bought brand new in 1992 and put 165,000 on it before parking it. It gets driven every few months and that's it. Yesterday the car started fine and warmed up then cut itself off. Upon restarting the car studdered and began to exhaust thick black smoke. The more gas I gave it the more it smoked. After sitting for 20 minutes it cranked back up fine and ran for a while but proceeded to repeat the process over. The car sits in storage without being driven much so what could be the problem? Please help.
Don

[richtazz]

Start with simple things like tune-up parts. Since it sets a lot, you could have an injector hanging up too.

[shakerharley]

If it is an injector how would I go about determining if that is the problem?

[richtazz]

do an ohm test across the terminals and see if it's within spec from repair manual.

[jeffcoslacker]

He might wanna see if the fuel pressure reg blew up or something, too, maybe?

Make sure the vacuum line to the MAP sensor didn't break or fall off...

[tblake]

or do an injector balence test to completly rule out a leaking injector

[Supergumby]

Is the Service Engine Soon light on?

[Blue Bowtie]

If an injector has gone static (stuck open) a solenoid coil resistance test will reveal nothing. It's a good start, just to be certain the injectors are electrically viable, but a running and standing fuel pressure test will reveal a static injector or blown FPR diaphragm.

There is a good chance that old, stale fuel, accumulated water, and the sediment in the tank have stuck and injector or done some other damage. A new fuel filter is probably a good idea, as well as a fill with the lowest (NOT highest) octane fuel you can get to help dilute any stale fuel that may now be in the tank. Lower octane fuel is more volatile, and is more pure gasoline than additive, so it can help dilute and flush through any varnish, gum, and deposits caused by aged, stale fuel.

[shakerharley]

I appreciate all the input. I have yet to get back to the car due to my sons baseball tournaments. I tend to think if it were a fuel injector why would it start cold and run fine each time until it shuts off. Wouldn't it be stuck all the time and constantly burn black even on cold starts?

[tblake]

hmmm lets recap here, you start the car cold, it starts/runs fine wih no black smoke, but then dies and upon restarting it, it exhausts thick black smoke? Black smoke is usually the product of running way too rich. IE, incorrect air fuel mixture, more fuel than air. If it runs fine with no black smoke then dies out and then smokes black upon restart its very odd. If it smoked black straight from the get go, i'd guess a lazy o2 sensor. But maybe like jeff said, bull the vacuum line off of the Fuel pressue regulator and turn the key to on, but dont crank, and watch to see if you have Ol' Faithful coming from the FPR. The diaphram in these will crack and cause raw fuel to be sucked into the intake manufold through the vacuum line.