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Old 06-10-2021, 05:02 PM
Dave Jeeper Dave Jeeper is offline
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Location: Denver, CO
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Won't start, timing chain slip?????

Is there a simple way to check for a slipped timing chain?

Whole, long story:



1989 G Wag, 95k miles. Howell fuel injection. My GW sat for 15 years before being restored. I did not run the engine before draining the tank, installing a Howell 50 state and putting on a lift, brakes, tires, etc. The reason that it stopped running 18 years ago was a bad duraspark ignition module on the fender. New plugs, module and distributor cap/rotor got the engine working with the newly installed Howell 50 state TBI. It did not have enough power.



I installed a cheap HEI distributor/ignition but made a mistake by powering it off the yellow 12v/6v wire from the original coil. After installing the HEI I did not have more power. I later found (last 12 months) that the throttle plate was not fully opening at WOT and my fuel hose from the tank to the hard line on the frame was kinking, reducing fuel pressure and flow.


About a month after installing the HEI I had occasional loss of power while driving as if the engine was starved of fuel. The Howell won't give gas unless there is a tach signal, so if no spark, then no fuel. This began happening more frequently and for longer periods. This was at the same time that there was a problem with the throttle plate not fully opening and intermittently kinking fuel line.


15 months ago I took the vehicle way up into the mountains and it did great. It sat for an hour and then barely made it home. I believe that was a kinked fuel line. I repaired the throttle linkage and fixed the kinked fuel line but did not drive the vehicle due to a terrible tranny leak. Recently repaired the tranny leak. Pulled a lot on my wiring harnesses while doing the tranny job.


After the tranny job I would take the vehicle around the block, it would run rough and then it would stall and it would have to sit a long time before restarting. I believe that the HEI coil and maybe module have gone bad.


I reinstalled the duarspark ignition, but I have not been able to get the engine to start (run without the starter spinning it). I had just installed an HEI relay and diode, so I bypassed the HEI diode on the alternator emitter wire, but no change. It sounds like it wants to start but won't catch. There is fuel spraying into the throttle body. The #1 piston is at TDC when the harmonic balancer mark is at 0 degrees. I attached the #1 spark plug wire to a spare plug and laid it on the block and we had a yellow spark while trying to start. I could not fit a camera into the #1 cylinder to see the valves when it is at TDC.



My Buddy thinks that the timing chain has probably slipped a tooth or two. I am not sure how to check it without removing the timing chain cover or a valve cover.



Last year I checked compression and it varied from 117 to 130 psi with 10 cranks. I did not do leak down or wet testing.


Is there a simple way to check for a slipped timing chain? Do I need to run another compression check?



I am considering ordering another cheap HEI ($75) to see if it will run with a new coil and module. I don't want to spend tons more money now if the engine won't run. If it runs on a new HEI then I can buy a better one later if need be.


Later I will try moving the plug wires 180 degrees around the cap to be sure that I am not 180 degrees off on the distributor install.


Thanks for any help.


Dave
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Old 06-10-2021, 05:44 PM
Dave Jeeper Dave Jeeper is offline
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Join Date: Sep 08, 2019
Location: Denver, CO
Posts: 111
I swapped each wire for the one on the opposite side of the cap to rotate 180 degrees. Engine would not start, even with rotating distributor back and forth to alter timing.
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Old 06-10-2021, 06:00 PM
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babywag babywag is online now
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yellow spark is no bueno. need to figure out why...
bad module/coil/wiring/etc.

timing chain extremely unlikely to "slip"

my guess would be weak spark+very bad fuel
or above+wiped out cam gear due to hei
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Old 06-10-2021, 06:08 PM
Dave Jeeper Dave Jeeper is offline
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Location: Denver, CO
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New fuel, fully charged battery, been using the original gear on the bottom of the distributors (OEM and HEI).
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Old 06-10-2021, 06:20 PM
Dave Jeeper Dave Jeeper is offline
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Location: Denver, CO
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The only electrical connector that is not in great shape is the three wire connector on the wiring harness that connects to the distributor's reluctor pickup and carries that signal to the ignition module on the fender.


I am getting a spark, so I figure that this must be making a connection.
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Old 06-11-2021, 08:45 AM
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tgreese tgreese is offline
 
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Location: Medford MA USA
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Duraspark is sensitive to connector contact quality. BTDT. Suggest you use electrical contact cleaner and a flux brush and clean the contacts between the module and the harness, and the distributor and harness (reluctor connector). I suggest a thin coat of dielectric grease on the contacts at assembly.

May not solve your problem, but you'll want to eliminate the possibility.
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Old 06-11-2021, 09:20 AM
Dave Jeeper Dave Jeeper is offline
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Join Date: Sep 08, 2019
Location: Denver, CO
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Thanks, I will check on the contacts. I went ahead and ordered another HEI to see if that will work. If not then I need to check for slipped timing. Is there any way to do this without pulling the timing cover?


Dave
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