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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Diesel Engine Discussion => Topic started by: rockygryphon on February 27, 2014, 04:08:52 pm

Title: turns but won't start
Post by: rockygryphon on February 27, 2014, 04:08:52 pm

so I drove in the morning, afternoon wouldn't start.  Cranking fine, glow plugs cycled (wipers came on!), turned on manual glow switch, nothing.

Pink wire to IP solenoid makes noise when dis/re-connected.
Fuel squirts out of the square fuel filter bleed port.
0.02v or no voltage between one glow plug and wire during cycling.

In the past few years at least, in the cold, I've had to hold the manual glowing switch (that I installed) and hold the pedal slightly down to keep the engine running until warmed up and white smoke went away after driving a half block with the glow on.  Maybe I need new plugs?

This is a 1985 K10 Silverado 6.2L Diesel.

Title: Re: turns but won't start
Post by: rockygryphon on February 27, 2014, 07:22:20 pm

With a multimeter, I found:
Infinity resistance on front right two plugs between the prong and ground (engine and battery negative pole).
No voltage between the 2nd to front right glow plug and the battery's positive terminal.
12 volts between  the front right glow plug and the battery's positive terminal.

I also noticed what looked like liquid under the lift pump.  Maybe the pump sprung a leak and isn't putting enough pressure to the IP?

I haven't tested the relay with a multimeter or 12v continuity light.
I also haven't tested resistance (to check continuity) between glow plug wire connectors and end at the relay connector.

I guess if the wires are ok, it's time to change the plugs and check to see if the lift pump really has a leak.

Title: Re: turns but won't start
Post by: gildardo01 on February 27, 2014, 08:30:41 pm

hey there.. just a thought.. you said you found a minor leak near the small manual pump.. could it be that it sucked in air and emptied the lines of fuel back to the tank and now you have an empty filter and pump... just a thought..

Title: Re: turns but won't start
Post by: rockygryphon on February 27, 2014, 09:30:18 pm

Well, I saw liquid that could be diesel on the crossmember under the lift pump. When I cranked, fuel came out of the filter bleed port.  I didn't crank enough to make sure the filter wasn't being emptied.  Right now I'm thinking the plugs need to be changed and there may be something wrong with the wiring that needs to be checked.  Of course, I need to check that puddle on the crossmember under the lift pump too.

Title: Re: turns but won't start
Post by: rockygryphon on February 28, 2014, 09:34:10 pm

checked wiring today.  glow plug wires seem ok.  ordered plugs.   may check compression, crank out air, observe fuel misting from plug holes, install plugs, if still no start, check out lift pump.

Title: Re: turns but won't start
Post by: rockygryphon on March 10, 2014, 11:03:30 am

Well, it was the glow plugs.  Changed, started right up. 

Title: Re: turns but won't start
Post by: bd on March 10, 2014, 04:29:56 pm

FYI - Bypassing the glow plug controller with a manual override switch will burn the glow plugs out prematurely.

You might also want to check the condition of the return line check valve in the pump.