Well I dragged yet another Jimmy home today. Beautiful body - looks brand new inside with 140k miles. I bought it from a guy, who bought it from a guy....... Who knows when the engine was last started.

I've got the "Engine Cranks But Does Not Run" thread and am working my way through it right now. Previous owner had replaced fuel pump, spider, distributor, wires, coil and ignition module. The fuel pressure gauge is on its way to the garage so I don't know about fuel pressure other than the pump runs and the line is pressurized.

I hooked up the scan tool and no powertrain or transmission codes. Passlock and and BCM modules report B1480 Battery Rundown Circuit Malfunction and the 4Wal says C0222 Right Front Wheel Sensor Missing. I can also see a crank signal. The starter is turning the engine over (150 RPM) and the battery is on a charger (12.7v). There is fuel in the tank, but I don't know how old.

Spraying some carb cleaner in the throttle doesn't seem to make a difference. The engine cranks and when I let off the key tries to start - almost like dieseling for a revolution or two - but never starts.

TPS checks out okay (0.63v), the ECT is fine at 32 degrees and I cannot find the VTD Fuel Disable parameter with my scan tool (does anyone know what module it is in?).

For a spark test can I simply hold a plug wire near the block and check for an arc?

UPDATE: Fuel pressure looks good. 62 PSI while cranking. Drops to 59 with the pump off and drops to 56 and holds after 10 minutes.

Kevin

 

Could be a problem with the ignition switch or ignition module.

At the ignition coil, the pink wire should show battery voltage with the ignition in RUN and START positions.

At the ignition module:

The pink wire should show constant battery voltage when the ignition is in the RUN and START positions.

With the ignition module connector unplugged, the black with white trace wire should show less than 5 ohms resistance to ground.

The white with black trace wire at the ignition module, and at the ignition coil, as well as the white wire at the ignition module, should all pulse ground when the ignition is in the START position. Connect the test light ground clip to battery positive and probe the wires while cranking, the test light should blink.

Post your results.

 

Battery voltage is 12.02.
Pink wire at the ignition coil reads 11.85
Pink wire at the IGM reads 11.80
Black wire with white trace at IGM reads 157 ohms [ voltage reds 11.5 so about 0.3volt drop)

White with black trace at coil pulses
White with black trace at IGM (IGM Disconnected)- constant on with KeyOFF - does NOT pulse <<--- CORRECTION
white wire at IGM does NOT pulse

 

With the ignition module connector unplugged, the black with white trace wire should show less than 5 ohms resistance to ground, (you're checking resistance here, not voltage). If you're showing 157 ohms to ground, resistance is too high and may have damaged the ignition module, if it hasn't already. Follow the black wire back to ground, it connects at the rear of the left cylinder head. If you can't find the poor connection, splice on a new wire and attach it to a clean engine ground. Then see if you have spark, if not, it may be a faulty module or coil, or both.

The white wire at the ignition module comes from the PCM and it tells the ignition module to fire the ignition coil. The white with black trace wire runs from the module to the coil to fire it. If the white with black trace is pulsing at the coil, and the coil does not produce a spark, the coil is faulty.

 

Captain Hook -

I see your a neighbor, thanks for the help.

Reading your post I want to clear up a point. I do have spark, the engine will not start. I checked for spark early on by removing a plug wire and checking for a spark to jump the gap to the engine block.

In the garage tonight I did notice a spark jumping from the plug connector on the tower to the body of the coil.

I'll check the ground point tomorrow. I am checking resistance (157 ohms). I just mentioned the voltage drop as the spec I've seen says a minimum of 10v at the IGM and I have 11.5.

I'm leaning towards a timing problem. The scan tools shows RPM so the crank sensor is working and talking to the PCM. Any easy way to check the timing chain?

Thanks, Kevin

 

Kevin, yes we're only a few miles apart. Spark jumping as you found at the coil, is an indication of high resistance in secondary ignition: Spark plugs, spark plug wires, distributor cap and rotor, or the coil itself. These things are very picky, use AC Delco parts only.


Yes, and if necessary I can explain it. At 140K miles I doubt there's a problem though. Get the secondary ignition problem diagnosed and repaired first

 

An additional question before I get into the garage this week. What is an adequate cranking speed? My scan tool shows 138 RPM.

 

Can't say that I've ever seen a spec for it, but that sounds adequate.

 

Well she is running. I fixed the resistance in the ground circuit. A loose connection, but that did not fix my no-start problem. I found the distributor 180 degrees out of alignment. Fixed the timing and she is running.

CMP Retard is -26 degrees. So it looks like I am off a tooth. The question is in which direction?

#1 plug was gapped at .070 instead of .060. Still need to continue to go through the entire vehicle to see what else might be wrong.

Thanks for the help.

Kevin

 

It is nice to get a clean vehicle with all those new parts. Could be a cheap ride for a long long time. Until buying the second one that would still run after 524K miles and hearing stories yesterday of some 4.3's making it to 700-800K.

Makes my 2002 with 193K miles seem like NEW.

You have great trouble shooting skills.