Hard starting at only 20F

So i get an engine light intermittently. Last time it was scanned at dodge it was a glow plug code.

I ordered a couple plugs thinking i had one out. It was starting hard a 0F a coulple years ago.

Today i go to test the plugs and i get .8 .7 .8 .8

didtn check the last one as this seems like they are all good. The new bosch measures .9 not installed just laying on the bench.

Now my leads themselves read .3, not sure if anyone elses meter does that but always has. I also used this same meter to diagnose chevy 6.5 glow plugs and it told me exactly what was going on.

So next step ya i can try checking number 5 but i have a feeling they are all good. So you think its possible someone replaced them but left the controller in bad shape (blown fuses)

Basically wanting to know to leave glow plugs alone and check out the controller instead.

189k miles 2004 unknown history other than last 10k miles over the last 3 years

I read what i thought was every glow plug thread but must have missed something. Most of them are just replacing them. Only thread i found that had ohm readings was on newer 3.0L

HELP!!!

thx

Joe

Yeah we got a code for gp4 in our 2006,it read about 10, and the other read 0 on the ohm meter.

Since you have a 2004, you probably have the "old" (original, internal fused-links) glow plug controller.
It can blow some or all of the links, which would (probably) cause the coil to stay illuminated on the instrument display.

During the glow plug "on" time, are you getting voltage (with adequate current) at the plugs?

The replacement glow controller no longer blows its internal fuses. It's smarter.

Here are two threads on self-repair of the old module: https://sprinter-source.com/forum/showthread.php?t=6935
and https://sprinter-source.com/forum/showthread.php?t=12150

--dick
p.s. it's fairly common for inexpensive ohmmeters to have problems giving accurate readings below one ohm.
Even making a zero-ohm connection with a hand-held probe is pretty difficult

Ohm readings are not always conclusive for testing T1N Sprinter glow plugs. There is a control winding and a heating winding involved.

That said, use the threads that Autostaretx Dick provided to check the glow plug module.

A 12 volt "Spark Test" courtesy of Doktor A is a very conclusive test for the glow plugs.

vic

ahah..... i have voltage on number 1 only lol im surprised it starts at all!!

i might try the fuse hack, see if any blow, then think about changing glow plugs, seems like they are all good yet.

I stopped making the fused GP modules because the new style is so much better. I recommend saving your time and money and just getting the new style module that has breakers instead of fuses.

I was able to start my van after a night in the low to mid teens with only 3 glowplugs, but it took a while and I thought I was going to run out of battery. One technique others have used is to cycle the glowplugs a few times without attempting to start the van in order to heat the area better.

Or even better, do the mod to make your ESPAR run without having to start the engine. That heats up everything nicely before attempting to start.

I got my fuse mod done, tried the key, blew fuses 2 - 5 ..... 1 is still good

I replaced 4 and 5 with new bosch glow plugs (this had the same silver coating as the beru that came out btw) and again blew fuses 4 and 5

Now what??

Jodean said:

I got my fuse mod done, tried the key, blew fuses 2 - 5 ..... 1 is still good

I replaced 4 and 5 with new bosch glow plugs (this had the same silver coating as the beru that came out btw) and again blew fuses 4 and 5

Now what??

Click to expand...

Throw a few more fuses at it. Renew the 20 amp individual fuses. (25 amp work fine too.)

Disconnect all of the glow plug caps at the glow plugs. Energize the glow plug controller (turn the ignition key on). If the fuses open again aka "blow" you either have a harness issue OR you wired something incorrectly when doing the modification. If no fuses open with the caps off you still have glow plug issues.

vic

oh i forgot, i had all wires off when i first tried, had power at all 5 connectors, fuses blew when i put connector back on glow plugs.....doesnt make sense, so theres no harness issues.

https://imgur.com/KMN4tXB

https://imgur.com/C9Nv2yu

https://imgur.com/l8TRy4v

https://imgur.com/DoMxLX1

If the harness is good.

And the glow plugs are good.

Maybe the modification has a problem.

I'm guessin' from a distance.

Have you tried the Doktor A fuse test on the glow plugs?

Good luck. vic

I was going to say look at the wire harness; mine had worn through and grounded out on the steel brake lines, but if the fuses only blow when the GPs are connected, it seems like it must be the GPs. Maybe try it on a spare GP that is just sitting free and not screwed into the block and see what happens? and BEWARE, the tip gets hot, so make sure it's not touching anything or close to anything that could get damaged by heat. And don't let it run like that very long.

ok so the diagrams were unclear or i read them wrong......here is what i believe is true and didn't find anywhere for pin-out on the module

https://imgur.com/NnQtaJy

I have no clue why 4 blew during 1st test, but i tried 25 amp fuses on 4 and 5 and now they stay good. Ordering 2 more glow plugs now.

Aqua Puttana said:

Have you tried the Doktor A fuse test on the glow plugs?

Good luck. vic

Click to expand...

Ha! i read that all over and didnt see what the test actually was, thats what i thought i was doing LOL They must mean fused straight from battery i take it, still cant find Doctor A procedure and i read ALOT of glow plug threads before i started.

The Doktor A testing is included in the first post of my fuse mod.

https://sprinter-source.com/forum/showthread.php?t=51543

vic

If a "good" GP is only a half-ohm, then it's going to draw (A=V/R ... 12/0.5=24 amps ) when cold.
So a 20 amp fuse is definitely undersized.

--dick

autostaretx said:

If a "good" GP is only a half-ohm, then it's going to draw (A=V/R ... 12/0.5=24 amps ) when cold.
So a 20 amp fuse is definitely undersized.

--dick

Click to expand...

My 2004 has been running DIY added 20 amp fuses for 6+ years now. Not one problem. (knock/touch wood)

The glow plug control winding comes in to play to limit current. That may be a factor.

To be clear, I'm not against using a 25 amp fuse. I used that size in my 2006 module modification. The fuse is there for short protection. It doesn't really need to protect the wiring.

vic