GM 3800 crank, but no start

[benzrider85]

Hey guys. I’d appreciate some advice on this one. Hopefully this won’t be information overload. 🙂

I’m working on a 1998 Buick Regal for a family member that cranks, but does not start. The driver said it lost power while driving close to her destination and once there it restarted once.

Car has about 150-160k on it (don’t know for sure due to the odometer not displaying)
Code present is
P0300 misfire (misfire counter shows 1- 1614; 4 – 2253; 6- 1243)

I’m getting spark on all coil towers.
It has fuel pressure at the rail and I know the injectors are firing due to noid light testing and the plugs being wet with gas.

It does not sound like an engine that has any compression issues while cranking, but it only actually fires every so often while cranking, most of time not. I beileve when it fires I’m hearing popping from the intake on occasion making me thing the chain jumped, but that seems to be very rare in this engine due to GM upgrading to metal timing gears in the early 90’s (instead of nylon).

I’d like to rule out the crank sensor at this point, due to the spark I can see, but I also noticed while cranking I do not have an RPM signal… I’m not sure if that is relevant on this engine.
Maybe an intermittent failure?

Not sure what the next step should be with this? I’m tempted to pull the timing cover and check timing marks, but I would like some expert advice before going further. Thanks!

Topic

[Bill]

First of all does it have anti-theft and is the light on or blinking? You stated that it has fuel pressure but how much? It has spark but will it jump a 1/2 in. gap? Is the fuel pressure regulator leaking into the vacuum hose and flooding out the engine? Does the scan tool show RPM while cranking? Do all of the input and output values look sensible on the scan tool? Do all sensors have a 5 v reference?

That said try disconnecting the MAF sensor electrical connector and try to start. You might get lucky.

Bill you missed your calling you should have worked for Hall mark. 🙂

[benzrider85]

Alright so I thought I posted back here, but even though I’m six months late I figured I’d post my findings on this. I did solve the problem which turned out to be an issue with the intake manifold. A metal tube from the EGR melted a hole in the intake manifold causing it to flood with coolant. Pretty happy it didn’t cause any damage to any other components. Car has been on the road since just a few days after my last post!

[Author]

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