I believe my GP Module is bad...

Question -- if I park in garage ... and do NOT fix this issue this year...
Will I be doing any harm/damage to the motor/injectors/etc. --starting car w/o
the GP Controller working?

Car seems-- to start fine in the am... and after sitting for couple hours outside in the Chicago winter so far.

thx

What year and model?

Probably won't do any damage. Have a strong battery and use synthetic oil in order to have a good cranking speed.

Good luck!!!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

I'm not familiar with the failure mode of these GP controllers. If they fail on, obviously that's going to burn out your glow plugs rather soon. If they fail off, yes you're likely putting additional stress on your starting and charging systems and batteries. If the engine takes two revolutions to fire instead of one revolution, it won't be any big deal. If you're having to crank for an extended period every time you start, then yes you're going to have issues.

I agree, what year and model? They appear to be under $100 from several online sources for the common model here on the forum, and another forum member may have a good used part they'd sell you for less than that. Last resort, a large relay and a button inside the car.

__________________
617 swapped Toyota Pickup, 22-24 MPG, 50k miles on swap

2005 e320cdi
GP Module -- is around $230 part + PITA location/ job to get to it- labor

Did you test the GP controller?

__________________
92 e300d2.5t
01 e320
05 cdi
85 chev c10

I tested the GPs-- they were good...

How do u test the GP controller?

Looks like it's under the intake?

$230 part plus under the intake isn't a huge deal, I'd confirm it was the problem and then replace it. If this is a known and recurrent issue with that item, I'd consider relocating it to an easier to replace location.

Might start fine in your garage, what about parking elsewhere? I'd be so pissed at myself if I got stranded somewhere because of a problem I could prevent, and didn't.

__________________
617 swapped Toyota Pickup, 22-24 MPG, 50k miles on swap

See if voltage is getting to the glowplugs. Test light or dvm at the glow plugs.

__________________
92 e300d2.5t
01 e320
05 cdi
85 chev c10

Need more information before testing or assuming the system is bad. Above a certain temperature the glow plug circuit does not come on.

All I get is a flash of the glow plug on indicator on two of our more modern type diesels. I read the thresh hold temperature somewhere but it has slipped my mind. Plus was on Volkswagons not Mercedes.

I thought probably a good ideal as the glow plugs are probably far more expensive than the older glow plugs. They will possibly last much longer.

At about 20F degrees above. Glow plug indicator lights for about 3-5 seconds on one of those engines.

Invest some money on an ODB II to read the fault code. If the GP controller is bad it will give a communication with ecu code. The controller can also identify which cyl GP is faulty. It is very clever. The GP controller is underneath the inlet manifold. Controller going bad is a known common fault with the CDI. It is expensive and pita place to get to. The GP is either 5 or 4.5v, not 12v like the old diesel. Measure good doesn't mean it is good. Btdt.

__________________
Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.

You will be fine, all you'll have is an engine fault code. Glowplugs on CDI engines are only for emissions reduction on cold start, they aren't needed or used by the ECM as a starting aid except in severe cold conditions.


Contrast to old IDI diesels which DO require glowplugs to start due to the high metal surface area in the combustion chamber and very poor fuel atomization.