12v gp mod

dh100m · **Posted:** Thu Dec 04, 2014 5:54 pm

i used denso dg 176 plugs and mercedes modual from 4 cylinder 1984 2.2d as i own one
lots of other vehicals use this modual in europe hard part is finding push on plugs for modual
the modual has an starter connection that shut down modual 15 sec after starter engaged
just install bypass switch for cold start I ran the B+ for plugs thru a dual amp volt meter used
for car sterio system cost about 20$ this tells me whether all plugs are working as they draw
25 amps cold 100amp total settle down to 60 if one fails i would know right away
ps plug from 5cylder is th same 1 terminal note used bolted on bracket just behind battery
cables thru fire wall are short

thermorex · **Posted:** Thu Dec 04, 2014 6:39 pm

Just out of curiosity, why would you go on 12v? Better warming? Price? Or just hobby? It may be a very good mod for whoever may want hotter glow plugs, those of us who update to etecno and live in colder climate may like this idea.

Btw, I have a 300sd from 82. That engine starts when you just show it the key, lol, no matter how cold it is...

dh100m · **Posted:** Thu Dec 04, 2014 7:15 pm

yes to all i live in brockville ont gets nice and cold i also like the fact of being able to control
them

graycenphil · **Posted:** Thu Dec 04, 2014 9:38 pm

Nice mod. No problem with the Jeep computer? Does it think there is a glow plug problem? Do you even need the module - would a 100 amp relay work just the same?

diesel_guy86 · **Posted:** Fri Dec 05, 2014 2:44 pm

Could we go a step farther and see if kieth could reflash the computer to run 12v plugs? Every engine I've had with 5/7 volt gp has always had a mod to upgrade them to use 12v plugs. I do think there should be something better than these crappy plugs.

gmctd · **Posted:** Fri Dec 05, 2014 3:20 pm

The 7v plugs had specific purpose relevant to the method of energizing, which allowed almost instant cranking after key-on - intended customer-base had no experience with Diesel wait-to-start scenarios, which would be a poor selling-point - instant-start would be similar to those familiar with gasoline-fueled instant-start scenarios - a really good selling-point

I never see the wait-to-start lite, and have seen it only flicker while intently staring at the icon - according to the chart, it should be full-on for one (1) second at local ambients

diesel_guy86 · **Posted:** Fri Dec 05, 2014 7:36 pm

I understand there reasoning for choosing the 7v plugs and it makes sense, but to those of us who DO have diesel background, there downright pitiful. I have a mechanical 95 dt466 that has no glowplugs or intake heater, and it starts almost instantly down past 0°f. Have several other diesels from a yanmar .6L to a CAT 16L, and the crd is the second hardest starting engine with the c16 being #1.

If the plugs are capable of near instant 1,200°f+ temps, are they equally as likely to cool off just as fast? Especially when freezing cold fuel hits them?

Maybe instead of different plugs, could an "afterglow" procedure be created to keep the glowplugs up to temp while cranking and xx amount of seconds after the key is rotated back to run?

Weeks heated intake elbow is a great idea and i can't wait to get it, but let's look at what it really is, a band-aid fix for a piss-poor design.

minisub · **Posted:** Fri Dec 05, 2014 8:53 pm

gmctd wrote:

The 7v plugs had specific purpose relevant to the method of energizing, which allowed almost instant cranking after key-on - intended customer-base had no experience with Diesel wait-to-start scenarios, which would be a poor selling-point - instant-start would be similar to those familiar with gasoline-fueled instant-start scenarios - a really good selling-point

I never see the wait-to-start lite, and have seen it only flicker while intently staring at the icon - according to the chart, it should be full-on for one (1) second at local ambients

Well, apparently, the selling point purpose didn't exactly have the intended effect with what, 11k or so sold per year? :wink:

Personally, having spent so much time in a 6.5, my wife still asks me what I'm waiting for when I drive her Acura and turn the key one click and then sit there for 15 seconds.... :ROTFL:

A better plug with a significantly longer glow time would be welcome for me. I would guess that the vast majority of those dealing with these beasts would be of the same opinion as they've chosen to be in this game in spite of the foibles.

gmctd · **Posted:** Fri Dec 05, 2014 9:52 pm

diesel_guy86 wrote:

I understand there reasoning for choosing the 7v plugs and it makes sense, but to those of us who DO have diesel background, there downright pitiful. I have a mechanical 95 dt466 that has no glowplugs or intake heater, and it starts almost instantly down past 0°f. Have several other diesels from a yanmar .6L to a CAT 16L, and the crd is the second hardest starting engine with the c16 being #1.

If the plugs are capable of near instant 1,200°f+ temps, are they equally as likely to cool off just as fast? Especially when freezing cold fuel hits them?

Maybe instead of different plugs, could an "afterglow" procedure be created to keep the glowplugs up to temp while cranking and xx amount of seconds after the key is rotated back to run?
This from the FSM was previously posted in another thread -

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.

GDE posted that the chart is for the early export KJ 2.5L CRD, altered slightly for the US 2.8L version**

Weeks heated intake elbow is a great idea and i can't wait to get it, but let's look at what it really is, a band-aid fix for a piss-poor design.

Billwill · **Posted:** Sat Dec 06, 2014 8:01 am

The early Export CRDs such as I have use 11 volt glow plugs.

Very basic system, the ECU determines how long they should be switched ON for depending on ambient temperature, ECU powers up two large relays....each relay powers two of the four glow plugs. After the determined time the relays drop out. No such thing as a glow plug module fitted anywhere!

The reason they used 11 volt glow plugs is that they know that at least one volt will get dropped over the relay contacts and connector contacts.

The ECU does not test at all whether the glow plugs are actually doing anything....you could disconnect them and the ECU will not post a code.....just rough stating up! The ECU only detects that the relay coils are not shorted out or open circuit.

I do not believe that these glow plugs have an "afterglow" period as stated.....the relays are either ON or OFF and it is a straight connection from +12 volts, through the relays, to the glow plugs. I read a post somewhere where the poster had scoped the current 2.8 CRDs and saw that the "afterglow" on these plugs was actually a Pulse Width Modulation waveform!

I have had no problems with my glow plugs but then again I live in a very warm climate....even winters come nowhere near to freezing.

I have read some posts on one of the KJ forums from someone in Austria where it seems that converting the newer system back to the 11 volt system is pretty popular....usually using NGK plugs. There obviously must be some way of fooling the ECU to ignore any errors coming from the conversion.

dh100m · **Posted:** Sat Dec 06, 2014 9:28 am

I asked kieth @ gde if a 12v flash was probable he said not worth the engineering for so few
people My thought is that europe use the 11V gps in their 2.8crd then maybe some software guru could compare the two tunes for the difference
the mercedes modual has a built in temp sensor for glow plug on time Have used it now 12 months so far starts very well down to -15c I left the original modual in situ but still throws cel

graycenphil · **Posted:** Sat Dec 06, 2014 4:49 pm

How about using the 7 volts to the glow plug to trigger a relay, which supples the 12 volt plugs? Woul the computer know it is energizing a relay, not the plugs?

gmctd · **Posted:** Sat Dec 06, 2014 5:07 pm

Billwill wrote:

The early Export CRDs such as I have use 11 volt glow plugs.

Very basic system, the ECU determines how long they should be switched ON for depending on ambient temperature, ECU powers up two large relays....each relay powers two of the four glow plugs. After the determined time the relays drop out. No such thing as a glow plug module fitted anywhere!

The reason they used 11 volt glow plugs is that they know that at least one volt will get dropped over the relay contacts and connector contacts.

The ECU does not test at all whether the glow plugs are actually doing anything....you could disconnect them and the ECU will not post a code.....just rough stating up! The ECU only detects that the relay coils are not shorted out or open circuit.

I do not believe that these glow plugs have an "afterglow" period as stated.....the relays are either ON or OFF and it is a straight connection from +12 volts, through the relays, to the glow plugs. I read a post somewhere where the poster had scoped the current 2.8 CRDs and saw that the "afterglow" on these plugs was actually a Pulse Width Modulation waveform!

I have had no problems with my glow plugs but then again I live in a very warm climate....even winters come nowhere near to freezing.

I have read some posts on one of the KJ forums from someone in Austria where it seems that converting the newer system back to the 11 volt system is pretty popular....usually using NGK plugs. There obviously must be some way of fooling the ECU to ignore any errors coming from the conversion.

Problem being, comparing any of the export models to USA models is like comparing apples to apple pie - world of difference in the mix

Our US gp module is an electronic device, not a simple relay, and has some autonomy in the energization and maintenance of the glow cycle, reporting back any discrepancy in the glow plug driver system and the gp's

ECM will also post a code if there is any fault in the gp module

95Z28A4 · **Joined:** Sun Mar 30, 2014 9:53 am **Posts:** 297

graycenphil wrote:

How about using the 7 volts to the glow plug to trigger a relay, which supples the 12 volt plugs? Woul the computer know it is energizing a relay, not the plugs?

A 7 volt relay may be difficult to find, but 6 volt relays are readily available and could probably be used.

Billwill · **Posted:** Sun Dec 07, 2014 3:55 am

gmctd wrote:

Billwill wrote:

The early Export CRDs such as I have use 11 volt glow plugs.

Very basic system, the ECU determines how long they should be switched ON for depending on ambient temperature, ECU powers up two large relays....each relay powers two of the four glow plugs. After the determined time the relays drop out. No such thing as a glow plug module fitted anywhere!

The reason they used 11 volt glow plugs is that they know that at least one volt will get dropped over the relay contacts and connector contacts.

The ECU does not test at all whether the glow plugs are actually doing anything....you could disconnect them and the ECU will not post a code.....just rough stating up! The ECU only detects that the relay coils are not shorted out or open circuit.

I do not believe that these glow plugs have an "afterglow" period as stated.....the relays are either ON or OFF and it is a straight connection from +12 volts, through the relays, to the glow plugs. I read a post somewhere where the poster had scoped the current 2.8 CRDs and saw that the "afterglow" on these plugs was actually a Pulse Width Modulation waveform!

I have had no problems with my glow plugs but then again I live in a very warm climate....even winters come nowhere near to freezing.

I have read some posts on one of the KJ forums from someone in Austria where it seems that converting the newer system back to the 11 volt system is pretty popular....usually using NGK plugs. There obviously must be some way of fooling the ECU to ignore any errors coming from the conversion.

Problem being, comparing any of the export models to USA models is like comparing apples to apple pie - world of difference in the mix

Our US gp module is an electronic device, not a simple relay, and has some autonomy in the energization and maintenance of the glow cycle, reporting back any discrepancy in the glow plug driver system and the gp's

ECM will also post a code if there is any fault in the gp module

I agree with you fully....the newer CRDs, Export models included, with the glow plug module fitted will be very difficult to convert to 12 volt glow plugs and would really not achieve much....I do not know how or why these Austrians seemed to be obsessed with changing from the 7 volt/5 volt system to a 12 volt system.

My old system works well but it would actually be better for me to have some form of warning that one more glow plugs have failed! :shock:

12v gp mod

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