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Weird Cranking Spark Issue
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Post Weird Cranking Spark Issue 
Hopefully someone else has come across this issue. I have a problem with the PCM commanding ~80 degrees timing while cranking (verified with a timing light and the fuel shut off). Engine is very hard to start and does give my mini starter a workout. After the engine does start, it runs great! Timing is dead on to what the PCM is commanding (verified with a timing light as well). Cam/Crank correlation is withing limits. I have played with B5909 & B5915 with no luck. I have triple checked the wiring as well with no ideas.

2001 S10 with 0411 PCM
383 internal balance L31 Vortec
Mercruiser MPFI ported, 27lb injectors, ported throttle body
Iron 64cc vortec ported and polished
Comp Cams Beehive springs for 0.550 lift, Crane gold rockers 1.5 Camshaft:Comp Cams XFI 280 hydraulic roller, Comp Cams Magnum hydraulic rollers

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You may have some cranking spark tables in the that are off or another variable multiplying the cranking spark and messing t up. Add another ground wire to the engine for cranking/ voltage drop purposes and put another IC module on the IGN module with heat transfer compound for another trouble shooting purposes.
Also make sure the battery cables are not routed near the crank position sensor

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What tables would affect Cranking Spark?

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Checking a few tolerances out on the crank sensor. The block was line bored before assembling so I want to see if this could be a factor.

I measured a good working donor truck and measured the depth to the lobe of the reluctor.
Working engine: .756" from housing edge to lobe. CKP Sensor is .721" reach leaving .035" air gap
Problematic engine: .759" from housing to lobe. CKP sensor is .709" reach leaving .050" air gap

I filed the timing cover down a bit until the depth was .740". This reduced the air gap, but made no improvements.

Do i focus on the tune? Anything that could stand out causing a bunch of timing to be added when trying to start?

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I don't have my laptop with me but with Efilive from memory, there are a few specific tables for cranking timing in park/neural
As soon as I get it back I can try to look. But if you are using efilive it's easy to find in your tune

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I took a look at the tables and changed all values that would be in the startup-idle area. These are all now nearly same as factory, but no difference on startup.
I logged EST PIDs and could only acquire data when the engine was running. The only PIDs that affected the timing when idling was the following:
EST - Base Spark
EST - Idle Spark
EST - Run Spark

Is there any way to log these while cranking? I can never obtain data for EST PIDs during the startup procedure.
Any ideas what i could log that would show the timing being added during startup?

This is a stock Vortec distributor with MSD wires. Any chance the distributor could be the issue? I have no misfires when the engine is running.

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Little more troubleshooting here, the engine startup routine is nearly the same with the Camshaft position sensor unhooked. It still has way too much advance in timing (like before) with the sensor unhooked. I did the basic testing out of the CMP sensor, 12.7 V in and 10.8 V signal to the PCM. This does drop to 0 V and back up to 10.8 V when the engine it turning.

Ideas?

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RESOLVED:
NEVER TRUST reman distributors from local parts houses. This distributor has less than 1000 miles on it and is shot.
Luckily i had a donor vehicle to trade parts on and compare. Pulled the distributor out and noticed a good 1/2" or more vertical slop in the shaft. I swapped it out for one that had less than 1/16" vertical play. SUCCESS!! Starts perfectly!

For anyone having an issue with Vortec engines adding a crap ton of advance timing on starting, this is most likely your issue. All the slop allows the distributor to climb of the helical gears on the cam and change the timing. This most likely was attributed to the reluctor window not passing through the Camshaft Position sensor correctly.

The PCM definitely references the CPS while cranking for proper timing. This acts like an old pickup coil.

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Good job man!
That aluminum ebay distributor worked well for me on a few motors (new)
Cheap and better quality than a stock plastic one.,

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Wow! I wonder if it jumped out of the oil pump too? If it climbed that much would it disengage from the pump drive?

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No issues on oil pressure

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