New Glow Plugs Installed; Starts Worse Than Ever

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gottaluvit

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It was 14.5°F here this morning at sunrise. I went out to test the GPs and it started the same as when it was 35°F. Only thing is, as I was about to walk away from it, she stalled. Then I restarted it the same way (that I have recently been taught), and it started fine but needed a little throttle to run right and then the GPs kicked back on and off twice, really making my belts squeal as I tried to keep 900+- rpms. Then once GPs stayed off I could give it a little throttle to 1100 rpms or so and then it leveled out and idled nice. Maybe I am supposed to start it and then just drive off once the GPs initially kick off. Or maybe a little water the Stanadyne missed?20151123_072021.jpg
 

cucvrus

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I disconnected my fast idle solenoid yesterday on the Mule. It wanted to idle fast all day. What tells it to stay on fast idle? I am thinking the 2 prong sensor on the right rear passengers side head. I never had one fail. I replaced them as a misdiagnosed glow plug issue years back. It is nice to have that fast idle. Without it it wants to just shut off at cold start ups.
 

Hasdrubal

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You got it, the coolant temp sender on the right rear passenger head controls the high idle/cold advance circuits. I had mine fail, so wired a manual illuminated rocker switch on the dash into the circuit. Now its fully manual, nice to be able to use it when the motor has cooled down a little but the coolant temp is still above what the sensor would trigger at.
 

gottaluvit

New member
You got it, the coolant temp sender on the right rear passenger head controls the high idle/cold advance circuits. I had mine fail, so wired a manual illuminated rocker switch on the dash into the circuit. Now its fully manual, nice to be able to use it when the motor has cooled down a little but the coolant temp is still above what the sensor would trigger at.
That brings up another forgotten fact. The wire that goes to that on mine looks as if it had gotten really hot/short circuited. It had some bare copper showing but I routed it in a way to be impossible to touch ground. I only saw one prong on the srnsor though.
 

rsh4364

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You got it, the coolant temp sender on the right rear passenger head controls the high idle/cold advance circuits. I had mine fail, so wired a manual illuminated rocker switch on the dash into the circuit. Now its fully manual, nice to be able to use it when the motor has cooled down a little but the coolant temp is still above what the sensor would trigger at.
I like your idea on the manual switch.Have you posted a how-to on this that I could read?
 
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Hasdrubal

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Sensor should have two prongs. Sorry, I have not posted a how-to. It was 10 years ago. I can check and see how I wired it. I believe..I ran a wire from the always hot power that feeds the temp sensor around the front of the IP, then back through a rubber grommet on the firewall somewhere below the wiper motor to the switch. I installed it horizontally, just to the right of the headlight switch on flat vertical part of dash panel. Then another wire runs from switch through same grommet and delivers power to high idle and cold advance solenoid when switch is on. The switch is an Illuminated rocker (not toggle type) about 1 1/2" long. Lights up really bright when its on.
 

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tim292stro

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From my studying, there are several sensors on the cylinder heads.

The cold start switch is a 100°F switch that closes (complete circuit) below 100°F and opens above (broken circuit). This switch should have a pink/black wire that is ignition switched power, and a green wire that goes first to the cold advance solenoid on the passenger side of the IP, then continues as a green wire to the fast idle solenoid on the top/front of the IP next to the throttle linkage. When the passenger head and coolant is cool (below 100°F) the switch closes (completes the circuit) so that when you turn the ignition on the IP can advance the timing (allow a longer time for fuel to burn in the cylinder by injecting earlier), and the fast idle solenoid will activate. I personally expect a fast idle solenoid to kick-up the throttle, but everything I've read in the last day suggests that the fast idle solenoid is not strong enough to actually do that - the driver must do the old carburetor cold start trick - stomp the accelerator to the floor, then let go and then try to start. The solenoid is apparently just strong enough to keep if from returning all the way to low idle this way. Again, it's my belief that it should just add throttle if it's needed - I'm inclined to make that happen...
IP_Cold_Start.jpg
Both solenoids ground to through the case into the IP, so if you touch +12V to the terminals on them you should hear a "click" from each.

As you see in the picture above the sensing element is a wax slug in a copper cap - these have a tendency to corrode over years and leak into your coolant rather than push the switch in (so they fail non-functional, which is safe). These do have to be serviced after a while. If your block is cold to the touch there are two terminals insulated from the engine ground that should measure 0-Ohms or no resistance (like a piece of wire). With the pink/black wire on one terminal, the green wire on the other terminal and the ignition switch turned to run, you should have +12V at the green terminals by the front of the injection pump (one for the advance, one for high idle).

[EDIT:] Late add - because the 6.2/6.5 uses a timing chain to drive the cam and Injection Pump, you do need to watch out for chain stretch as it wears out too. The chain stretching will cause the IP timing to change - and this in itself can retard the timing enough to make it difficult to start. With the cold start advance fighting against a stretched chain, the IP function will lose... [/EDIT]
 
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joshuak

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... I personally expect a fast idle solenoid to kick-up the throttle, but everything I've read in the last day suggests that the fast idle solenoid is not strong enough to actually do that - the driver must do the old carburetor cold start trick - stomp the accelerator to the floor, then let go and then try to start. The solenoid is apparently just strong enough to keep if from returning all the way to low idle this way. Again, it's my belief that it should just add throttle if it's needed - I'm inclined to make that happen...
Step two of the diesel engine starting procedure sticker on my sun visor seconds your thoughts.

IMG_0871.jpg
 

cucvrus

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I must agree when you follow them instructions on a cold morning and the engine does start. You panic and release the pedal and it shuts off again. Then you start it all over again. i have been starting them with just an idle and once they start slowly accelerating. It makes me and the engine feel a little better. That rude flat out ignition start-up is hard on cold engines in my opinion. GM wrote that as an absolute instruction because they had to. If you can't get it started with out instructions. You probably need instructions on how to drive it. It should just say fire up engine by any means available or walk. Cold starting by holding the throttle flat out is just as hard as starting fluid being misused. I said misused on purpose. Everything is useful and safe when properly used. Ether don't kill engines people do.
 

Assel

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when its below 0 I start it this way: make sure every switch is in "off" position (radio, heater, lights) , then put key in and turn on, shortly before the "wait" light goes off, I floor the pedal, then release it about half-way and hold, when the "wait" light finally is off I turn the key over and as soon as I hear the engine runs I release key & pedal. then the CUCV goes "Vroom rattle rattle rattle rattle" and everythings fine. I think its not meant that you keep the pedal pushed down until the engine reaches its deadline rpm :whistle:...from the feel I say my engine does not go over 1300rpm during this process and idles betwenn 800 -900 rpm when cold, when warm its a bit lower.(I dont have a tach added) Also all check lights go out immediately as soon as the idle is reached..when starting without pressing the pedal my gen & oil lights stay on for few seconds more.

Is there anything bad about this method? I think I followed every step on my sun visor^^
 

cucvrus

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A+ if that is what it takes. Do as you must. i am not doubting that works for you. I just scare easy on any RPM above idle when the engine is cold. I like the heavy knock knock rattle rattle rattle and the Vroom. It sounds the same in English as in German.
 

gottaluvit

New member
when its below 0 I start it this way: make sure every switch is in "off" position (radio, heater, lights) , then put key in and turn on, shortly before the "wait" light goes off, I floor the pedal, then release it about half-way and hold, when the "wait" light finally is off I turn the key over and as soon as I hear the engine runs I release key & pedal. then the CUCV goes "Vroom rattle rattle rattle rattle" and everythings fine. I think its not meant that you keep the pedal pushed down until the engine reaches its deadline rpm :whistle:...from the feel I say my engine does not go over 1300rpm during this process and idles betwenn 800 -900 rpm when cold, when warm its a bit lower.(I dont have a tach added) Also all check lights go out immediately as soon as the idle is reached..when starting without pressing the pedal my gen & oil lights stay on for few seconds more.

Is there anything bad about this method? I think I followed every step on my sun visor^^
I like the sound of this best. You threw common sense in with the General's sense!
 

gottaluvit

New member
Well, I have since figured out the best way to get this started without burning up glow plugs or over revving the engine. I just barely push the throttle and turn the key on until wait light goes out and turn it over for 2-3 seconds and if it don't fire up I LEAVE THE KEY ON and wait a couple seconds and turn it over and it fires every time on the second turn of the starter, if it didn't on the first attempt. This has been working every time since cold weather and even this morning at 2.7 degrees F.

I believe I burned up the glow plugs before from a habit I picked up driving VWs for so long. A VW ignition has a mechanical blocker in it so you cannot turn the key to the start position without shutting the key off once you have turned it to the start position. They had this even in the late 70s front wheel drive units. This prevents turning the starter into a running flywheel gear. I just reverted the off after start attempt to all vehicles as it was a good practice, until having this glow plug diesel. Just not a good thing to do, making the glow plugs cycle over again when they were already in a cycle.

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Assel

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thats just what a sticker in my 98 6.5td says to do, in extreme cold weather "if it fails to start within 15 seconds of cranking let starter rest for a minute then try again, it should start now"
 
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View attachment 594435View attachment 594434View attachment 594433View attachment 594436View attachment 594437View attachment 594438Either way it is an easy fix if you choose to do so. Just remove the resistors with the 3 1/4" 3/8" headed hex bolts. and it the wire is missing replace it if you choose. it is 10 gauge wire. I used red and crimped new eye ends on each end. Hooked it all back up and it starts and runs as designed. I like the cycling in the morning. if your belts squeal tighten them or replace them. If you let them squeal the squeals will only get worse as winter rolls around. Good Luck.
Rick,

In your experience is it actually necessary to replace a resistor(s), or just simply make sure wires/connections are in good shape?

I've been having an intermittent cold start issue on my '84 M1028 - sometimes hard to start in colder weather with extended cranking and/or cycling of the glow system - and so have replaced glow plug controller card, glow plug relay, and glow plugs (AC60G's), which helped a bunch, but thinking the resistors are the last point in the system to the intermittent cold start issue.

Brad
 
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