Modifying ambient air temp sensor to extend glowplug time

gmctd · **Posted:** Fri Dec 05, 2014 1:41 am

dsmart705 wrote:

Great responses guys, there are certainly afew ways to deal with this problem. Im guessing from the lack of response to my specific question about using a resistor to mimic the "max cold" glowplug time hasn't been done so im going to do some testing and see if it helps. Jumping the connector with the appropriate resistor is likely to cost less than $1 which is alittle cheaper than any other method mentioned. I realize its not a permanent fix when the temp gets really low but I dont have much interest in buying an intake heater and all the other stuff that goes along with it if it can be avoided.
You're correct, this hasn't been tried, prolly because the ECM and GP Module monitors all facets of gp operation, DTC resulting - the glow-time is resulted by monitoring the voltage-feed into the plugs, voltage rising as the gp heats up, killing the feed when timer times out - the timer is digital - we don' need no steenkin' resistor, eh.....

5/7 volt glowplugs work in other engines....what is so special about the VM that makes it so cantankerous when the temperature gets low?
Can't speak for northern climes, but down here the wait-to-start lite just blips, and very seldom at that
- my indirect-injection GM 6.5LTD gets a good long wait-to-start glow even on warm mornings
- my direct-injection 5.9L 24v Cummins gets a good wait-to-start pre-heat
- but the direct-injection KJ puffer 'go-ahead-and-start, dipstick' lite seldom even blinks
- cycling the IGN switch alters nothing - crank it and it lites off

dsmart705 · **Joined:** Thu Nov 27, 2014 5:40 pm **Posts:** 13

Temp Lamp Pre-Glow Post-Glow
-30C 10 SEC. 35 SEC. 200 SEC.
-10C 10 SEC. 23 SEC. 180 SEC.
+10C 1 SEC. 21 SEC. 160 SEC.
+30C 1 SEC. 20 SEC. 140 SEC.
+40C 1 SEC. 19 SEC. 70 SEC.
+70C 1 SEC. 16 SEC. 20 SEC.

OPERATION

**CAUTION: The glow plug system is a 7 volt system.DO NOT ATTEMPT to test the glow plug system with a 12V power source or damage will occur. When the ignition (key) switch is placed in the ON position, a signal is sent from the sensors to the ECM relaying current engine coolant temperature and ambient air temperature (Fig. 21). After receiving this signal, the ECM will determine if, when and for how long of a period the glow plugs should be activated. This is done before, during and after the engine is started. Whenever the glow plug module is activated, it will control the 7 volt high amperage circuit for the operation of the four glow plugs. The Glow Plug lamp is tied to this circuit. Lamp operation is also controlled by the ECM. With a cold engine, the glow plug module and glow plugs may be activated for a maximum time of 200 seconds. Refer to the following Glow Plug Control chart for a temperature/time comparison of the glow plug relay operation. In this chart, Pre-Heat and Post-Heat times are mentioned. Pre-Heat is the amount of time the glow plug control circuit is activated when the ignition (key) is switched ON, without the engine running. Post-Heat is the amount of time the glow-plug control circuit is activated after the engine is operated. The Glow Plug lamp will not be activated during the post-heat cycle.** (This is directly from the service manual)

So there it is, if one were to wire up a dummy circuit for the coolant sensor and ambient air sensor which would simulate a -30 degree situation you could get max glowplug time whenever you wanted (circuit would be activated manually during startup by a button). This would be more work than just installing an intake heater and would likely not help startup much in really cold situations....it would however be pretty cheap if time was plentiful. I think this is as far as I will take this idea but if anybody else is interested in wiring it up and trying it out please report back.

ArmyChief · **Posted:** Fri Dec 05, 2014 10:26 am

Since you also have to use the coolant sensor..there may be ramifications in fuel and timing control. I would not do it

dsmart705 · **Joined:** Thu Nov 27, 2014 5:40 pm **Posts:** 13

ArmyChief wrote:

Since you also have to use the coolant sensor..there may be ramifications in fuel and timing control. I would not do it

The idea here is for a circuit that would only be activated during startup in cold weather condition....say 0 to -30 degree's celcius (below -30 it would have no affect on glowplug operation). Im my opinion any changes in fuel and timing it might have during startup would likely assist in getting the engine running.

That being said this is just an idea, after studying the system I dont think my idea is worth the effort but somebody else might see a value in experimenting.

gmctd · **Posted:** Fri Dec 05, 2014 4:00 pm

dsmart705 wrote:

Temp Lamp Pre-Glow Post-Glow
-30C 10 SEC. 35 SEC. 200 SEC.
-10C 10 SEC. 23 SEC. 180 SEC.
+10C 1 SEC. 21 SEC. 160 SEC.
+30C 1 SEC. 20 SEC. 140 SEC.
+40C 1 SEC. 19 SEC. 70 SEC.
+70C 1 SEC. 16 SEC. 20 SEC.

OPERATION

**CAUTION: The glow plug system is a 7 volt system.DO NOT ATTEMPT to test the glow plug system with a 12V power source or damage will occur. When the ignition (key) switch is placed in the ON position, a signal is sent from the sensors to the ECM relaying current engine coolant temperature and ambient air temperature (Fig. 21). After receiving this signal, the ECM will determine if, when and for how long of a period the glow plugs should be activated. This is done before, during and after the engine is started. Whenever the glow plug module is activated, it will control the 7 volt high amperage circuit for the operation of the four glow plugs. The Glow Plug lamp is tied to this circuit. Lamp operation is also controlled by the ECM. With a cold engine, the glow plug module and glow plugs may be activated for a maximum time of 200 seconds. Refer to the following Glow Plug Control chart for a temperature/time comparison of the glow plug relay operation. In this chart, Pre-Heat and Post-Heat times are mentioned. Pre-Heat is the amount of time the glow plug control circuit is activated when the ignition (key) is switched ON, without the engine running. Post-Heat is the amount of time the glow-plug control circuit is activated after the engine is operated. The Glow Plug lamp will not be activated during the post-heat cycle.** (This is directly from the service manual)

Good input - brings back a flood of data I had forgotten after the KJ was tasered by the mighty flying fickle finger of Jehova back in ought 10 - explains why it always lites off - still, no explanation why the WTS icon only flickers once in a while - one (1) second is way longer than flicker, eh

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

The chart for glow light on time is for the 2000-2004 KJ export market. Chrysler forgot to update the chart when writing the 2005-2006 service manuals. In North America 2005-2006 KJ CRD, the glow light should be on for a maximum of 2-3 seconds unless it has been modified.

The corrections for glow duty cycle are weighted much heavier based on coolant temp vs. ambient temp. Ambient corrections are more in play with warm coolant and very cold air. GDE

gmctd · **Posted:** Fri Dec 05, 2014 8:56 pm

GreenDieselEngineering wrote:

The chart for glow light on time is for the 2000-2004 KJ export market. Chrysler forgot to update the chart when writing the 2005-2006 service manuals. In North America 2005-2006 KJ CRD, the glow light should be on for a maximum of 2-3 seconds unless it has been modified.
I upgraded to IN-MOTION's ECM Hot tune shortly after acquiring the li'l puffer for my son, so have no reference for previous interval - then the lightning-strike wasted the electrical system and the computer went from IN-MOTION to NO-MOTION ECM - I acquired a replacement ECM for your GDE Hot tune in 2011, replaced the damaged GP module, and have done nothing since - I see a barely-visible flash, at best - it does have a gp DTC for hi volts sense, IIRC, but the oem gp's all measure ~0.7 ohms - hi volts would indicate an open or hi resistance gp element - know how to test for quick-glow, just have not done so, yet
The corrections for glow duty cycle are weighted much heavier based on coolant temp vs. ambient temp. Ambient corrections are more in play with warm coolant and very cold air. GDE
We seldom see 20*F down here - can be 85*F\sunny on T-giving, Xmas, and N-Y days - FEB is usually our coldest month, 40's - 30's
Appreciate the updated input

dsmart705 · **Joined:** Thu Nov 27, 2014 5:40 pm **Posts:** 13

GreenDieselEngineering wrote:

The chart for glow light on time is for the 2000-2004 KJ export market. Chrysler forgot to update the chart when writing the 2005-2006 service manuals. In North America 2005-2006 KJ CRD, the glow light should be on for a maximum of 2-3 seconds unless it has been modified.

The corrections for glow duty cycle are weighted much heavier based on coolant temp vs. ambient temp. Ambient corrections are more in play with warm coolant and very cold air. GDE

Do you offer a new glowplug strategy with your eco-tune? If so then I would be very interested in sending out my ecu....all the other stuff would just be a bonus!

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

dsmart705 wrote:

GreenDieselEngineering wrote:

The chart for glow light on time is for the 2000-2004 KJ export market. Chrysler forgot to update the chart when writing the 2005-2006 service manuals. In North America 2005-2006 KJ CRD, the glow light should be on for a maximum of 2-3 seconds unless it has been modified.

The corrections for glow duty cycle are weighted much heavier based on coolant temp vs. ambient temp. Ambient corrections are more in play with warm coolant and very cold air. GDE

Do you offer a new glowplug strategy with your eco-tune? If so then I would be very interested in sending out my ecu....all the other stuff would just be a bonus!

If you take the risk of the glow plugs failing we can set the duty cycle to whatever you want. To do this properly requires an instrumented glow plug and one these is very expensive and fragile.

CATCRD · **Posted:** Sun Dec 07, 2014 11:29 pm

dsmart705 wrote:

ArmyChief wrote:

Since you also have to use the coolant sensor..there may be ramifications in fuel and timing control. I would not do it

The idea here is for a circuit that would only be activated during startup in cold weather condition....say 0 to -30 degree's celcius (below -30 it would have no affect on glowplug operation). Im my opinion any changes in fuel and timing it might have during startup would likely assist in getting the engine running.

That being said this is just an idea, after studying the system I dont think my idea is worth the effort but somebody else might see a value in experimenting.

viewtopic.php?f=5&t=78102&p=822130b#p822130

dsmart705 · **Joined:** Thu Nov 27, 2014 5:40 pm **Posts:** 13

Thanks for the link. I read through alot of" "cold weather" post before I made my post but I must missed that one. At any rate there still seems to be no easy solution to the problem.

I went through this same issue on my 2004 TDI. The TDI came with 7 volt ceramic plugs which, after afew years, were starting to become a liability issue for VW dealers. They issued a recall and installed 5 volt steel ones. This recall also included a ECU reflash which initially didnt work. I went through an entire winter with a car that would barely start. The following year they came up with a new reflash that solved the problem and the car has no problem starting even on the coldest mornings without being plugged in. All of this was done at no cost to the customer

What is disappointing to me is that not only has Chrysler done the same thing here with the CRD, they charged people for the update. I went and priced out the parts just for fun and was quoted

$68 for the controller
$155 for each glowplug
2 hours @ $110/hour

When I asked about a reflash they told me that it wasnt need??? At any rate its pretty clear that Chrysler does not really care much about the 05/06 CRD's. There are so few of them out there that even if we all yelled out loud nobody would here us. Makes a forum like this all the more valuable!

ArmyChief · **Posted:** Mon Dec 08, 2014 10:22 am

If you live in an area that has potential for cold starting issues...I would follow the Sasquatch Motorsports thread about possie intake air heater add-on kit.

Modifying ambient air temp sensor to extend glowplug time

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