Question : 95 3100 tries but wont start

[gnuiver]

I have a 1995 Acheiva 3100, 140,000 mile. It started to ramdomly stall a week ago and thought it was time for a tune up. It finally quite while running down the road on my daughter. I Checked fuel pressure (38 PSI) and spark, they are both good. the engine will try to start and pops when turning over if you pump the gas. Crank sensor is showing the proper resistance. and there is power on the ignition Module. Sound like bad timing?
Any Ideas????

[robertisaar]

achieva would be a N-body, so i would take a look at the MAF sensor.

[gnuiver]

MAF is in the inlet hose to the throttle body right?

[robertisaar]

yes. should be directly in front of the throttle. might want to try unplugging it and seeing if it will run that way to have the PCM go into failure mode.

[gnuiver]

forgive my ignorance please,

I have one sensor in the hose from the air cleaner box to the throttle body. I always believed it was the air temp sensor. Online parts show it as that. I still can't find a Mass air flow sensor.

[robertisaar]

and you're right actually.... for some reason, i was associating the N-body as having the MAF system in 94-95. the A-bodies did. the N-bodies use the same system as the W and L bodies.

[gnuiver]

Ok I changes the Ignition module and checked every vacuum line. I still have the issue, The engine will only attempt to start if I pump the gas peddle, and it will not stay running. Is there a Crank position senson on the flywheel? and what does it control? Its the only sensor I haven't messed with yet. Help

[pocket-rocket]

There are two crank position sensors. One behind the crank pulley that is in charge of Sequential Fuel Injection (SFI) mode (known as the 24x sensor). SFI mode runs the injectors individually until 1.2k-1.5k rpm, I forgot which. After that rpm it switches back over to batch fire mode like the older engines. The other crank position sensor is in the back of the block (7x sensor) and the PCM bases all of your spark and injector timing off of it. I wouldn't bother changing either since the engine will run with a bad 24x sensor and if the 7x was shot, it wouldn't even try to fire over.

[gnuiver]

Replaced Engine Cam Broken

[pocket-rocket]

Replaced Engine Cam Broken

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