HELLP No start in cold. Appears to be GP's .. want to install Push Button GP glow - PeachParts Mercedes-Benz Forum

coachgeo · #1 01-26-2009, 10:03 PM

Life is really giving me the shiats right now.

First question, did I potentially ruin something? I was desperate.

Car (1985 300SD) would not start this morning again. Has been an issue that I "thought" got fixed when I found an air leak in rubber line running from steel fuel line to the lift/primer pump. Was warmer then. Today cold.... back to same problem I had before. In cold NO START, BUT this time the glow plug light went out. NO LIGHT at all. Could not hear a relay click either.

I live half hour from my work.... and since I had to be at work cause I have the keys and own the biz. I got desperate. I bypassed (I think) the glow plug relay.

Unplugged from the GP relay the heavier of the plugs on top of it. Wires seem to go from this toward the engine's GP's so I assumed these were power OUT of the relay to the plugs.

I put in 14gauge wire into each socket as a jumper. Wired them all together and clipped them to a jumper cable. Climped the Jumper cable to the battery Positive (for not more than sixty seconds.) Glow plug light now came on which I did not expect since I essentially thought I was bypassing the relay.

Car still would not start.

Desperatation calls for desperate measures. Thus I drove my uninsured, unregistered, me not liscenced to drive yet, big air braked International truck to my biz. Had not choice.

Soooo did I potentially fubar anything.?

Next question in next post.

coachgeo · #2 01-26-2009, 10:05 PM

This car is suppose to just be a parts car for my Unimog (that is dissasembled) but I HAVE to drive it cause my 2003 VW is FUBARED beyond the imagionable it appears (undetermined electrical faults causing havic with computers, fly by wire fuel pedal, radio, windows, etc.) 6 months of searching, replaced both computers... still cant find the problem.

Anyway..... I keep hoping we will find the VW's problem so Im not wanting to spend money on a whole new GP relay for the SD so I want to build a relay bypass, our should I say put in a push button glow plug arrangement.

Here is a photo of one. What is the clear plastic thing above the starter type solinoid? Is that a giant fuse (relay). I know the stock OEM fuse in the GP relay is 80amp.

anyone got a wiring digram on how to build one of these? Will put a push/hold in switch on the dash to opperate the GP's.

Thanx in Advance.

(PS- Brake parts are on the way for my grrrrinnnnnnding passenger front brake.)

kerry · #3 01-26-2009, 10:35 PM

Can't see the photo. You did exactly the right thing by hot wiring the glow plugs. Since it didn't start, my first guess would be that you have bad glowplugs. This would account for the lack of a glowlight. The system compares current draw between #2 and the others. If there is a difference, glow light does not glow. Ohm them out with a multimeter before taking any other steps.

coachgeo · #4 01-26-2009, 11:04 PM

ahhhhhhhh..... no picture showing up for you guys.... now that explains the other posters responce.

if its working here... then the one I put in the orginal post should be working now too.

does this pic work or can you not use [img] tags in here?

coachgeo · #5 01-26-2009, 11:22 PM

here is a thread on the topic I reviewed previously.

http://www.peachparts.com/shopforum/diesel-discussion/183583-manual-glow-plug-timer-switch-post1816093.html

appears to me that the post on the center of the body of the solinoid is the one you wire switch to. switch activates the solinoid allowing the large current to flow thru it, and out the other side where you have the glow plugs wired.

so is that

From Center Post Solinoid, switch(push button), battery.

grounded solinoid means no second (negative) wire needed in the switch circuit?

(Yes I will still check GP's Ohms and do relay testing first.) Im driving an illegal rig now so I want all my ducks in a row so I do not have to go to part place more than once.)

imagesinthewind · #6 01-26-2009, 11:52 PM

Which wire in the relay plug goes to the #2?
I have no GP light after switching all the GPs.
Maybe it's the wire to the GP. What color combo
is the #2 wire?
Sorry to hijack, but it seems pertinent to this thread.
Thanks

coachgeo · #7 01-26-2009, 11:57 PM

In reading the Diesel Giant info I think it said if you pop off the GP harness from the relay you will find them numbered on the harness or relay.. somewhere around there.

From this you should be able to find out the wire color that corresponds. Might have to cut back a little of the outer plastic sheeth around all the 5 wires... buttt... my memory from this morning says you won't have too.

coachgeo · #8 01-27-2009, 01:17 AM

ok...... read about using a 1/4" drill bit BY HAND to ream out the GP holes if I pull any of them. Then blow out the crud by spinning the engine.

Anyone got a specific Anti Sieze compound the recommend?

toomany MBZ · #9 01-27-2009, 06:03 AM

Quote:

Originally Posted by coachgeo

ok...... read about using a 1/4" drill bit BY HAND to ream out the GP holes if I pull any of them. Then blow out the crud by spinning the engine.

Anyone got a specific Anti Sieze compound the recommend?

If possible, vacuum out the crud instead of sending it through your engine.

Check the GP's with an ohm meter, as per diesel giant.

coachgeo · #10 01-27-2009, 10:11 AM

Quote:

Originally Posted by toomany MBZ

If possible, vacuum out the crud instead of sending it through your engine.

Check the GP's with an ohm meter, as per diesel giant.

I thought about vaccume. Have not read it to be reccomened anywhere thus far so I was hesitant. I do have a battery powered computer vac. but do not think it will suck enough. I'll try to remember to take the shop vac. from here at my biz to my home where the car is.

I have 5 new plugs so I'll just replace them all. Not sure I will get them all in one day... matters if I have to do it between work task. If there are bad ones found from test thru the harness I'll hit those first and try to get the rest while Im in there.

SD Blue · #11 01-27-2009, 10:21 AM

Replace the 5 glow plugs, as you mentioned. When you ream the holes, apply grease to the reamer beforehand and you will not need to do the vacuum chore.

I replaced my glow plugs last winter and the resistance showed no problems. However, just as what you are seeing, it wouldn't start. I believe it's best to just change them and be done with it. Eliminating all of the frustration.

#12 01-27-2009, 06:46 PM

That glowplug relay is mine.

Its a 100amp continuous duty rated relay from NAPA. Cost about $30.
Left is the 5 stock glowplug wires modified with normal loop connectors.
Center post is the switched power signal. I use a normal SPST switch on my knee panel to control it.
Ground is through the body.
The plastic box above it is an 80amp maxifuse. (link)

coachgeo · #13 01-27-2009, 09:39 PM

Mucho thanx FI

coachgeo · #14 02-05-2009, 03:27 PM

Relay seems to be fine.

about 7 hours of work getting tiny tools and med sized hands snaked in around the fuel injector lines to replace 4 glow plugs not showing any ohm measurments (aka- dead plugs)..... I got them replaced. Finished around midnight working outside in the middle of the woods. I live in the middle of the woods.

CAR STARTED RIGHT UP

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next morning it was 10 degrees colder (40F?).... Back to no start; right back to where I started:crybaby2:

All plugs showed normal resistance marking that they should be working fine. All where hot tested prior to being installed. (hook to 12v to see if they glow).
Can hear the GP relay clicking off at the normal time.

Some things that were different between start at midnight and start failure at 9am.

. 10 degF colder outside
. battery was on charge most the time I worked on the GP's. No charging overnight. Really didn't sound any different in starter speed on both occasions though. Battery does drain quick though in no start situation
. Aux. fuel pump accidently left on for about 10min circulating fuel about half hour prior to starting that night. Use the pump to prime the system is why it is there. Tried running it for a while after the no start next morning to see if it helped. Even primed the system just in case. Still no start.

. Going to try to replace battery so I can have higher crank speeds to see if that helps.
. Considering installing a 110v coolant heater and turning it on hour before needing to head into work. Wont be till next week till I can get to it.

rrgrassi · #15 02-05-2009, 04:14 PM

That would be best. You need a really strong battery, and it's weakness shows up in either really cold or really hot weather. You do need a block or coolant heater and it is a good idea to put the battery on a charger to keep it warm.