ECM controls Grids cycling?

[gsnick]

When its cold outside, 5-0 Celcius (not F) my truck will cycle the grids on every start even if the coolant temp is 195 (which it is all day) I have replaced the IAT sensor and there is no change, I think its unnecessary alternator load, and wondering if anyone else has this issue.

My choices are instal a switch either on the signal wire to the Grids relays (which will trip a code no biggie) or leave a hi-amp switch under hood and use it to sever the connection on the ground or the hot side

My truck is a courior rig and gets started and stopped likely 50-100 times a day, on a normal DD I dont think its an issue, but in my case that is unnecessary load, and also runs the risk of having the grid relay stick and placing a 200amp load on the alt and batterys, not to mention electrical fire risk

 

[gmctd]

When cold outside, the fuel is cold and the air is cold, reducing cylinder temps towards threshold of combustion temperature - doesn't hurt for the grids to cycle until ECM thinks everything is copasetic - you can try inserting a dpst switch in the control circuit of the two contactors, but it's not damaging anything to let it function as designed.

As an example, look around you at all the tens of millions of Dodge Cummins Rams, noting all the burned hoods, fenders, smoke trails up the windshields on all the ones that caught fire due that circuitry - mine's a well-traveled '96 and the power wires are not even browned from excessive heat, which heat would be normal if the circuit was over-stressed

No, if you want to worry about something, worry about the Inj Pump, which uses the pumped fuel as the sole lubricant, just like on the 6.5 - is ULSD providing enuff lube to protect the internals?

 

[THEFERMANATOR]

The grid heaters are supposed to cycle like that, every other CUMMINS out there does it as well. The CUMMINS ECM controls the grid's on an 01. I'm sure you don't want to start burning excess fuel or have raw fuel start coming out the tail pipe from low combustion temps do you? And there are 2 fusible links at the battery that will prevent them from shorting out. If the solonoids stick on for to long then the fusible link will burn through. And your alternator is many times dropped off line when the grids come on to prevet alternator damage.

 

[gsnick]

Thanks, my concern was more that they cycle on EVERY HOT start, I get what you are saying about the emmissions/cold start issue, and dont have a problem with that. so ferm your saying the ecm turns the alt off during grid cycling. gonna have to dig out the multi-meter to do a couple of tests to see if mine does that. if it does then I wont have an issue with it. just seems like unnecessary electrical load on a hot start

JD,
your right I should worry more about my poor old VP, I do feed it a regular diet of 2 stroke or Amsoil Diesel Concetrate, and I fill up every 2 days (last yrs fuel bill was 11,000$). I just installed an Edge J/A and have not tried a hard run on level 5 yet, so I'll do that close to home...just incase. the VP was new in May 08 but I have estimated it has seen 1100hrs of use in 7 months...wanna place a bet to see if it'll last? I've pretty much budgeted for a VP failure, with the money this truck has made me its not a big deal to buy another VP, its not the cost of the VP that worrys me its being stranded in the middle of now where that makes me nervous ,(hwy 63 in Alberta on the way to Frt MacMurry is a long cold road) if it could be so simple as having a spare PMD in the glove box I'd be a happy camper.
Now that you mention it I have not seen many(none) trucks all burned up from the grids, so I guess I was a little dramatic with the "risk of fire comment" huh? point taken.

 

[gmctd]

Ashless 2-stroke is fine for lube, but won't help a bit if fuel supply press drops below ~15psi - the Bosch VP44 is very similar to the Stanadyne DS4, but the Bosh PMD is built-in, part of the IP - most VP44 failures are due to the PMD overheating\failing caused by insufficient fuel flow-thru as the Carter lift pump begins failing: burn the PMD, replace the VP44 - Carter spec'ed that lift pump for pusher-type service, not draw-type - 'nuther words, that lp is to be mounted near the fuel tank, not on the side of the engine - to fix, remote-mount the lp, run 2-stroke motor oil, and yer VP44 should survive indefinitely.

 

[gsnick]

I replaced my LP with an Airdog(FASS) within 2wks of the new IP, 1/2 fuel line with a draw straw. even with the Edge J/A on 5x5 a WOT run does not drop below 14psi I have the alert (data log) set for 10psi but I'll move it higher to see if the pressure ever drops when I'm not looking.

 

[gmctd]

Yeah, I noticed that in your sig, so yer good to go - my response also addresses those who have not corrected the factory error: relocate the lift pump or kill yer VP44 - and the lift pump: that is the prime cause of so many Carter pump failures in the Dodge platform - how did Dodge respond? - a new all-plastic sealed lift pump, securely attached to the fuel filter\manager head - result: continued failures of lift pump and VP44, continued lp failure and starvation in the '03^ CRD trucks.

BTW: did you see my solution for the 1/4-tank fuel starvation fiasco with the draw-straw? Use the '05^ Jeep Liberty CRD fuel tank module, modified to take the draw straw - it's identical to the Dodge module, incl the level-sensor and electrical connector and fuel supply and return lines - direct drop-in, and the lift pump can empty the tank - some have even modified the Dodge module, but it's not as easy as the Jeep version - check it out..................
http://dieseltowingresource.com/showthread.php?t=409

 

[gsnick]

JD
I ran my drawstraw into the fuel tank module (after removing the orginal pick up tube and filter) even drilled a couple 3/8 holes around the outside of the "basket" I still have 1/4 fuel pressure fluxiations,(does not run out of fuel, just drops to 0 ) mind you I seldom if ever let it go that low, I think the Airdog moves so much fuel that it emptys the basket quicker than fuel can get in there, I have not seen any posts with a sure fire fix, although some have said theirs does not act up, I did read your post, and noticed that my module is much more different than yours, mine is more encased....I'm going to help a friend instal an AD in an 02, his has the intank pump so this might be what the doctor ordered...I'll keep ya posted on the outcome

 

[gmctd]

Depending on how you have the pressure set and the return-line setup will determine the amount of return-fuel foaming - your symptom sounds like a foaming problem, a critical area when hi-volume fuel systems are installed in a vehicle used mostly in on-road traffic - the volume needed for FWOT events is magnitudes of overkill at traffic speeds, and that excess is returned to the tank in huge volume - that constant-volume pump is really thrashing the fuel at 30mph - the fuel in the tank prolly looks like meringue at\below 1/4 levels - those systems were originally developed for 900~1500cuin 18-wheeler motors with 100's gallons fuel tanks, overkill for 360cuin medium-duty engines with a 36gal tank - put a short length of clear vinyl tubing in the return line, watch for bubbles\foaming\frothing at idle - that's what your tank contains at low levels - return-line cooler will help, but excess-return volume thru a bypass-pressure regulator will always result in Diesel fuel aeration - just simple sloshing around will aerate warm Diesel fuel, and the fuel returned from the IP\injectors is ~180* hot, not just warm - also, fyi, those pump systems are pusher-type, intended for mounting as near the fuel pickup module as possible, on the frame close to the tank

 

[gsnick]

Well it had to happen... last night on the way home the check gauges lite came on. the Volt gauge was reading very low, so I switched the Juice to read Volts and sure enough I was down to 10.8 to 11.2, I only had a few miles to go, so home I went, parked the truck, fiqured I'd look at it in the morning. The next morning I went to do a couple of quick checks. went to check for power at the field and surprise surprise I had none, actually I had NO voltage anywhere the batteries were stone dead!! when I shut the truck off last night the batteries were low but not dead. they were so bad my battery charger kept popping off when I tried to charge them in the morning. so off to costco for 2 new batteries. on a whim I tested for continuity across the Grid relays and with no batteries in the truck I had continuity....the relay(s) were stuck on!! After installing new batteries and leaving the grid leads off at the battery my truck is charging fine and I have no issues with it. Just to confirm my relays were stuck/fused closed I touched the leads back on the battery and get a arc, so I guess I'll be wiring in a set of Frd starter relays and I will include a way of turning them off unless they are needed for a cold start. as I stated above I thought it was too much unnecessary electrical load when the engine is at 90F and on EVERY hot restart it would cycle the glows. For a normal daily driver maybe there would not be much of an issue but my truck sees more run time and on-off starts in one day than a normal DD would see in 1 week, heck maybe even in two weeks. I have also come to the conclusion that the ECM does NOT take the ALT off-line during glow loads, unless its looking for a load prior to turning the grids on. I say this because when the leads are off (grids dissabled) there is no voltage drop measured at the batteries.
My grids were stuck on all night and of course the truck never burned down but it still hurt to toss another 240$ in batteries that could have been saved

 

[gmctd]

Make sure the starter solenoid is not shorted, and the engine shut-off solenoid is not damaged - the heater-grid relays, starter solenoid, and shut-off solenoid go hand-in-hand at failure event, making the failure very difficult to troubleshoot

 

[gsnick]

All the above is good...new starter contacts/ don't have a shut off solenoid (24v) on an off note just before the grids stuck, I noticed when I used my mechanical hand throttle and set the hi-idle when I turned the key off, the truck stayed running! At first I thought that the remote had been turned on but it was not(confirmed by steping on brake, and engine did not turn off) the ABS and Airbag warning lights will come on and the truck cannot be shut off UNTIL the engine returns to idle.
to add to the problem tonight I was doing the mod to power the windows from the power seat breaker, soon as I hooked it up the headlights and the heater fan came on

I'm thinking I got a ground issue (seat/window mod) and possible that the alt is self fielding and back feeding keeping the engine running (shooting blanks here)