tinner73

my son's 1994 Olds 88 (65k miles)runs great until it randomly decides to die out. it has the standard 3.8l engine. it has the dreaded OBD 1.5 so pulling codes is a PITA. what happens is the engine just shuts down while driving. it will restart but does take a few tries. it did throw a few codes..

intermittent cam signal
est line not toggling (icm)
mass airflow sensor failure
cam sensor failure

fuel pressure is good. the mechanic suggested changing the icm which i did to no avail...and i changed the crank position sensor prior.

don't want to throw parts at it..any ideas anyone?? tia

bob guzzy

It could be a fuel filter back in 94 they still used them.

By the time you started checking for fuel it might let enough fuel flow by to have fuel pressure, yet running it might be starving for it.

It's a cheap item worth changing just to make sure.

tinner73

thanks for the response!!

fuel filter is new..fuel pressure is 36psi when running.

after running perfectly for about 30 minutes in the garage..we watched it sputter and die out. fuel pressure was fine..i pulled a spark plug and have good spark..i don't like throwing parts at it but i will be swapping out the cam sensor this weekend.

i am at a loss!!

runutzzzzz

Fuel pump?

I have a 97' Express Van, I know not even remotely the same engine, that would sputter and try to die with anything over 1/4 throttle. Fuel Pressure read fine, fluctuated a tad but, even right up to the point where it sputters.

Replaced it and has run great since.

Really sounds like a fuel issue of some sort. Especially since you say after a few trys to start it starts up. But could be electronic issues.

tinner73

actually my first thought was a fuel pump..so i put my gauge on it and it seems fine. i wish it would just give up it's ghost (whatever it is)..this random $hit is killing me.

the codes the mechanic pulled don't point to a fuel problem either. this is why i am changing out the cam sensor.

i was hoping that someone on this board went through something similar.

Dave68

When this happened to my 89 Mazda MX 6 GT, it was the coil that was intermittently faulty. The dealerships would typically monitor the coil while the car was driven to try to "catch" it failing. I felt that the symptoms were close enough to warrant changing the coil. The problem never occurred, again.

tinner73

that's what the mechanic was thinking changing the ignition control module(icm) as it sits under the 3 coil packs on this car.

tinner73

i changed the cam position sensor this morning. i let the car run for about 1 hour and 45 minutes. ran great but the check engine did come on. my son took it to the store about 4 miles away and it wound up dying out again as he turned onto our street. after being parked for about 10 minutes it wouldn't start again (in my driveway). fuel pressure was good..spark too. as he was turning over the engine i disconnected the MAF sensor and it started right up. i plugged it back in and all seems fine for now. i didn't think a MAF sensor would kill the engine? any ideas??

bob guzzy

Without the MAF the engine doesn't know how much air is coming into the engine, without it the computer doesn't know what to do.

My brother bought an old ford ranger it would run fine if you caught it in gear but it wouldn't start on it's own.

While the engine was turning over on the starter he tapped on the MAF the truck started and ran fine, changed the MAF never had another problem.

Your problem might not be the MAF but the wires running it I would start by checking all the pins are clean and the plug is tight.

I would get a cheap mulitimeter at harbor freight for 5 bucks, then get the test procedure off line for your year car and do a little checking.

While your at it check the TPS for the correct values if a TPS is off it can throw the whole computer off.

Cybermind

Sounds like a bad crank position sensor to me. GM cars are notorious for bad CKP sensors. A bad cam position sensor or MAF should not cause an engine shutdown. A bad CKP will.

tinner73

well..because of the codes i wound up changing the MAF sensor to get rid of that code.

upon further research on the web this is not unheard of with people having success in eliminating the grounding blocks located by the rocker panels which i did yesterday. i drove it on the highway for around 30 miles and i died out 3 times. on the last time it would not restart and was towed to a local shop. i'm kind of relieved it finally gave up and died. now it should be fairly obvious whats wrong.
thanks to all who replied.

tinner73

the first thing i changed.

Cybermind

Sorry, I missed that. I am assuming you replaced it with an OEM CKP sensor? Aftermarket CKP sensors are sometimes hit or miss.

Have you looked at the ignition switch? Any drop in voltage across a faulty ignition switch (bad/dirty contacts) can cause an engine shutdown.

tinner73

all done.

changed the pcm ($115) today and all is better.

explains all the crazy $hit it was doing.

thanks to all who helped.

tail_lights

Interesting!