I am having a cold start problem. I checked the gpr and it is working fine. I pulled the connectors off of the valve covers and tried to check the terminals to the glow plugs and i get 0 ohms on 6 of them and .1 on two of them. First off, i am not that handy with a meter. :icon_rolleyes: But does this mean the glow plugs are bad? Also took the meter and did a continuity test from ground to the terminals in the valve cover and it appears they are all going to ground. It does not get very cold around here and the truck is not my daily driver. It has 149,000 on it and i am pretty sure the previous owners did not take great care of it. Thanks for any help.
Glow plug question
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The pins will be arranged like this:
G - G - I - I - C - I - I - G - G
G = glow plug
I = Injector return
C = Injector common feed
Good glow plugs should read around .6 ohms. If not the uvc may be partiallly unplugged, the glow plug is bad or they are not plugged in/wiring issue.
Follow this procedure: http://www.thedieselstop.com/forums/f47/hard-no-start-check-here-first-75094/
G - G - I - I - C - I - I - G - G
G = glow plug
I = Injector return
C = Injector common feed
Good glow plugs should read around .6 ohms. If not the uvc may be partiallly unplugged, the glow plug is bad or they are not plugged in/wiring issue.
Follow this procedure: http://www.thedieselstop.com/forums/f47/hard-no-start-check-here-first-75094/
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How's the quality of your meter? Is it a digital one, or a cheapy? If the latter, you may not have enough accuracy. A good GP should show between 0.5 to 1.2 ohms, and a bad one will generally show infinite ohms (meaning an open circuit). I don't think they will fail by shorting out (showing zero ohms), but I could be wrong. If they did, though, I think that youwould burn out a fusible link from overcurrent.
The injector feed and return terminals should show infinite resistance when measured to ground, so either you're doing something wrong in measuring, or it wouldn't run because the injector circuits are shorted. The GP's are "self grounded" where they screw into the head, so the terminals there are only isolated from ground by the resistance of the GP element.
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The meter may of read 0 M ohms which is infinite or open. That's what mine read when I had a UVC partially disconnected.
I have a digital meter, its a craftsman was like $80 some years back. I had it set to ohms and i touched the front terminal with red lead and black lead to battery ground and it read 0. Then the next terminal, then the back two. Same on other side. I hope it is the meter cause i can't believe that all 8 would show zero. The truck runs fine after i get it started, like i said it don't get too cold here but earlier this week it got down to the teens and it took me about 15 minutes to get the thing to start so i do believe that something is wrong just not sure what. Will have to go out and mess around again.
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Unless the meter is autoranging (sets itself to the appropriate range for the measured value), it may be set to too high a range to read accurately enough to tell the difference between 0 and 1 ohm.
Check your GPR a number of times to make sure you get voltage thru it every time. If not, it may have burnt contacts that only work when they feel like it. GPR replacements are around $25 from International and take about 15 min to change out. If it's never been changed, I'll bet it's time.
Check your GPR a number of times to make sure you get voltage thru it every time. If not, it may have burnt contacts that only work when they feel like it. GPR replacements are around $25 from International and take about 15 min to change out. If it's never been changed, I'll bet it's time.
So when i turn the key on, it sends the 12 volts from the relay to the electrical connector on the valve cover and then into the glow plugs, correct? Should there be 12 volts at the glow plug terminals on the valve cover plug that goes to the relay? not the side that goes into the valve cover but the other side.
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There should always be 12V on the large terminal with the rubber boot on it (black/orange stripe wire). There should be 12 V on the small terminal with the red wire with key on. There should also be 12V or so on the small terminal with pink/orange wire with key on (when the PCM isn't grounding the circuit to activate the GPR - both sides of the coil will be floating at 12V without ground, it'll be a bit less when the relay is pulled in). On the large terminal with the brown and yellow wires connected, there should be 12V minus the voltage drop across the contacts when the relay is pulled in. If ALL the GP's are bad, then there won't be any current flowing thru the relay contacts and they won't have any measurable resistance, in which case the voltage will be the same on both large terminals.
Hope that helps.
when the relay is pulled in, i have about 11 volts on the constant side and around 10volts on the glow plug side. I know thats low but i have been screwing with this thing for like two days. I didn't know if there was a way to check that the current is making it to the valve cover harness or if the wiring is messed up along the line somewhere.
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If you're getting a 1 V drop across the GPR, then there's current flowing. If you're down to 11 V, you should charge the batteries before trying any serious cranking.
I have access to a DC clamp-on ammeter, and have measured the current on my GP circuits. I see about 75 amps/bank IIRC. It's really quite a bit. I'd think if it were going somewhere else than the GP's you'd be seeing sparks.
I have access to a DC clamp-on ammeter, and have measured the current on my GP circuits. I see about 75 amps/bank IIRC. It's really quite a bit. I'd think if it were going somewhere else than the GP's you'd be seeing sparks.
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Zero ohms isn't necessarily bad. It means there's a complete circuit. I doubt that there's a problem with your GP's.
Open between ground and inner 5 pins is good too. Means your injector circuits aren't grounded.
If you do pull the VCs, you might consider doing a compression check (using the GP holes). You may find low compression, which will also cause hard starting. It takes compression to build heat in the cylinders and ignite the fuel.
Good luck with it.
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If your open up the valve covers make sure to check the injector hold down bolt are torqued to 120inch/lbs. Also make sure the rocker pedastal bolts are 20ft/lbs. Glow plugs are 124inch/lbs. Valve cover bolts are 97 inch/lbs. The injector hold down bolt is know to come loose so make sure to check while you have it open.
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Also if under the valve covers, I suggest when engine is cold have someone crank over engine and see if oil spouts are all spitting out oil. If you have bad poppet seats on any injectors it will not spit out correctly and it also causes a cold start problem. There is a way to measure the armature plate clearance if you decide you would like to check this. It involves removing the injector solenoid and using a feeler guage
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I would check the HPOP reservoir to make sure it is full. Also check for hpop lines and pump for leaks. Also, does it start after the engine block heater has been plugged in for several hours?
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