mattyd

Hope you guys can help me get pointed in the right direction. My 93 SE won't start, but just barely. The starter turns well and there is even some ignition (sometimes) which takes the engine to 500rpm or so before stumbling and dying.

Starter: strong
Ignition: confirmed spark exists on all six coils
Compression: decent compression (130,130,120:150,150,160psi)
Spark plugs are covered in gasoline, perhaps a little oil on one or two bc of my leaky valve cover gaskets), but mostly gasoline.
I just bought a new set of plugs yesterday (the same that had been running for two months prior).

The ECM throws no codes which is frustrating.--
update:
Okay it appears I have multiple problems. I was having a hard time starting and read low voltage under load. Replaced the battery and now I can get the car to start, but only for 3-10 seconds before it dies. Touching the gas pedal causes an immediate stall. Unplugging the MAF does not change symptoms. I dont see any cracked vacuum tubes or hear any leaks. ECU still throws no codes.

If the IACV is not working properly will the car cease to idle? Am I barking up the wrong tree by investigating MAF/IACV/vacuum? I am replacing the PCV valve which is clogged as well.

asand1

iTrader: (1)

You could be flooded, try starting it with the gas pedal flat to the floor. This will usually disable the injectors, or at least allow enough air to get a decent AFR. Also check your fuel pressure, you may have low pressure and too lean an AFR to fire.

mattyd

WOT does not seem to help and the coil-over plugs all check out perfect on the voltmeter. I'll look in to a fuel pressure check.

Greeny

iTrader: (43)

Replace the coolant temp sensor, cheap and easy to replace..If that doesn't do it, clean or replace the mass air flow sensor...

mattyd

I've had MAF go out before in another Nissan. Those symptoms were "start cleanly" then "die suddenly". MAF shouldn't affect the initial ignition/start should it?

Greeny

iTrader: (43)

just unplug it, the engine wont rev over 2500rpm with it unplugged, buy it will tell the tale of weather its good or bad...

mattyd

Okay it appears I have multiple problems. I was having a hard time starting and read low voltage under load. Replaced the battery and now I can get the car to start, but only for 3-10 seconds before it dies. Touching the gas pedal causes an immediate stall. Unplugging the MAF does not change symptoms. I dont see any cracked vacuum tubes or hear any leaks. ECU still throws no codes.

If the IACV is not working properly will the car cease to idle? Am I barking up the wrong tree by investigating MAF/IACV/vacuum? I am replacing the PCV valve which is clogged as well.