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Discussion Starter #1
Hello,
my van won't start when the engine is hot or even warm. for a while there it would not start at all, even when cold, then i found one bad glow plug by the #8, replaced it, and it started right up like never before, and it has been for the last few days as well.
however if i shut down when it is hot it will not start no matter how much i crank it until it cools down. Basically i have to wait until it is cool enough for the glow plugs to cycle for a while - when it is hot they don't cycle long enough for it to start.
could the problem be with the other glow plugs - they are only about a year old and are good ones - or could it be the sensor that determines how long they cycle for?
I know tigman will say "pull the IP pull the IP" but i don't want to pull the IP unless i know the IP is the problem - and this IP has less than 5K on it AND i have described the problems i have been having to two different IP techs who rebuild them and both say it is not the IP. The last time i pulled the IP (summer) i was convinced it was the IP even though the IP tech said it wasn't and, guess what? it wasn't the IP.

Has anyone had a similar problem and solved it? if so, how?
thanks,
Paul
 

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So you think that the glow plugs not coming on when the engine is hot is causing the hot start problems?

Try this:

With the engine hot, try and start it. It won't start? Good!

Turn the ignition on and short across the terminals on the glow plug relay with a screwdriver for about 8 seconds. Immediately try and start the engine.

If it starts, the glow plugs are causing the problem. If it doesn't start the problem is in the fuel system.

Let us know what you find...
 

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Discussion Starter #3
high sierra,
i tried something like that but must have done it wrong. Do you mean to remove the wiring harness and touch those 4 (or 5?) little silver terminals together? or do you connect the two large connections with the heavy wire that brings power to the relay and the other one that brings it to the plugs? i tried the second one and it did not do anything.
thanks,
Paul
 

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The early DB2-4911\equiv Inj Pump had a hot-start problem, from excessive head-rotor clearances - solution was upgraded head\rotor assembly.

If your DB2-4911\equiv has a black label, that is the problem - if it also has a green tag, it has been repaired and\or upgraded once.

Can also be slow cranking speed - starter, battery cables, batteries, not necessarily in that order
 

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high sierra,
i tried something like that but must have done it wrong. Do you mean to remove the wiring harness and touch those 4 (or 5?) little silver terminals together? or do you connect the two large connections with the heavy wire that brings power to the relay and the other one that brings it to the plugs? i tried the second one and it did not do anything.
thanks,
Paul
I mean the two large terminals with heavy wires (I should have made that clear). You should get a small spark when you do it. If nothing at all happens, first make sure the connections are clean and then use a voltmeter or test light to check for power at the relay. Touch the + lead on the voltmeter/test light to the terminal on the wire that brings power to the relay and the - lead to a good ground. You should have ~12V there... If you don't there is something wrong with the wiring to the glow plug relay (a broken wire or loose connection).

Let me know what you find...
 

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If the cranking speed of your engine is fast when the engine is warm,my bet is a bad injection pump.When the pump cools,the clearances between the head and rotor return to normal.On a hot engine,glow plugs should not be needed in my opinion.
 

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Discussion Starter #7
highsierra,
i know i have power coming to those terminals but i did not get a spark when i touched them together nor did the glow plug light go on at the dash. is the glow plug light supposed to go on when you do this? Or does it mean the glow plugs are on anyway even if the light was not on?
That sounds like a great trick (if i can get it to work) though because that way if the relay ever fails you could still start the engine - correct?
i will try it again.
thanks,
Paul
 

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Yes, if the relay fails you can start the engine using that method. Depending on how the controller is wired the glow plug light may or may not come on... In most stock systems the light will come on (it acts like a 9th glow plug, basically).

I can't really think of any reason this trick wouldn't work if the glow plugs function correctly with the engine cold other than dirty terminals on the relay...

Try disconnecting one of the glow plugs. Take a test light or a VOM and insert the + probe into the terminal on the wire you just disconnected. Ground the other lead. Then try shorting across the relay. If the glow plugs are turning on the light will light up (or if you are using a VOM it will show voltage).

If the cranking speed of your engine is fast when the engine is warm,my bet is a bad injection pump.When the pump cools,the clearances between the head and rotor return to normal.On a hot engine,glow plugs should not be needed in my opinion.
I agree, but I absolutely understand wanting to make absolutely certain there is nothing else wrong. I can say that if it were my truck I wouldn't condemn the injection pump without checking to see if the glow plugs made a difference first.
 

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Ronald Reagan fan
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Agreed.:) I just feel that if a 6.2 engine is up to operating temperature and it refuses to restart several minutes later i would suspect a bad IP.Thats just my opinion on the matter.Sometimes that little bit of extra preglow will allow a 6.2 engine to start hot with a weak IP.
 
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