Glow plug relay problems........

[JW-VW]

I bought a 6 sec glow plug relay and plugged in and with a stop watch took almost a minute to switch off This is my 3rd new relay and same problem. Im at a lost all new fast glow glow plugs installed cleaned all conections etc. I hooked up a meter to the glow plug rail and almost a full minute till power is shut off. Anyone have any ideas? Tired off replacing glow plugs twice a year and spending $48 a pop on relays. -Jacob-

[Vincent Waldon]

Your problem is very likely the temp sensor (or the wiring in between) rather than the relay... which is why replacing the relay several times has not solved the issue.

The relay will go for the full 30-60 seconds if if it thinks it's really cold out *or* the coolant temp sensor is defective *or* the wiring to the coolant sensor is broken.

More troubleshooting info and pictures here:

http://www.vincewaldon.com/index.php...d=41&Itemid=28

[JW-VW]

Big thank you!!!! It turned out to be a corroded temp sender conection. I wish I would have known to check that before blowing $150 on 3 glow plug relays haha. -Jacob-

[dsl_lvr]

I am going to append to this thread even though it is quite old. But... so am I.

'91 Jetta: Intermittent problem 2 or 3 times in January, no problem in Feb-Mar. Continuious problem since mid-Apr. I can't drive the car now.

Cold-cranking: Glow-off the plugs, hit the starter, engine fires immediately but not quite enough to run and then no fire just like the glow plugs turned off. If I keep re-glowing and cranking for a really long time, -like 2-3 minutes, engine will start but only continue running with the starter engaged. After about 10-sec, you can drop out the starter but the engine is barely able to keep going. The engine continues to get stronger as it warms a little and finally is running at full strength after maybe 4-5 minutes. Note: this is ALL cylinders, not a "skipping" condition where one or more cylinders aren't firing while the others are firing normally.

What I have done: I bought a chinese-made glow plug relay off the internet for $8 and it won't even respond normally on the initial glow-off. Wasted money. I have performed EVERY test of the glow plug circuit and original relay as prescribed by the Bentley manual, Passes every one except te one with the temperature sensor wire grounded and you are supposed to get voltage on the glow plugs with the switch in the cranking position. I get 0.0002-volt. But, I really DO have voltage when I crank with the sensor plugged-in and really cranking. I changed the glow plug fuse just for the heck of it. I have not done the current-flow test on the glow plugs because it was running on all cylinders even when this was an intermittent problem so I don't suspect a single bad glow-plug.

This just has me buffaloed. Could it be a shorted glow plug instead of thenormal failure that is an open glow plug? A shorted plug might sink all the current through it and keep them all from getting hot.

Any "out of the box" ideas? Please advise.....

[Glegor]

I am going to append to this thread even though it is quite old. But... so am I.

'91 Jetta: Intermittent problem 2 or 3 times in January, no problem in Feb-Mar. Continuious problem since mid-Apr. I can't drive the car now.

Cold-cranking: Glow-off the plugs, hit the starter, engine fires immediately but not quite enough to run and then no fire just like the glow plugs turned off. If I keep re-glowing and cranking for a really long time, -like 2-3 minutes, engine will start but only continue running with the starter engaged. After about 10-sec, you can drop out the starter but the engine is barely able to keep going. The engine continues to get stronger as it warms a little and finally is running at full strength after maybe 4-5 minutes. Note: this is ALL cylinders, not a "skipping" condition where one or more cylinders aren't firing while the others are firing normally.

What I have done: I bought a chinese-made glow plug relay off the internet for $8 and it won't even respond normally on the initial glow-off. Wasted money. I have performed EVERY test of the glow plug circuit and original relay as prescribed by the Bentley manual, Passes every one except te one with the temperature sensor wire grounded and you are supposed to get voltage on the glow plugs with the switch in the cranking position. I get 0.0002-volt. But, I really DO have voltage when I crank with the sensor plugged-in and really cranking. I changed the glow plug fuse just for the heck of it. I have not done the current-flow test on the glow plugs because it was running on all cylinders even when this was an intermittent problem so I don't suspect a single bad glow-plug.

This just has me buffaloed. Could it be a shorted glow plug instead of thenormal failure that is an open glow plug? A shorted plug might sink all the current through it and keep them all from getting hot.

Any "out of the box" ideas? Please advise.....

most of us hardcore VW junkies get rid of the stock VW glow plug system..

a ford starter relay, and a momentary switch take care of the duty alot better than the stock system..

hit the button, count to 8, fire engine..

if its warm, dont worry about the glow plugs.

if its half ways cold, half ways warm, then glow it for like 3-5 seconds..

i dont run a stock VW glow plug system in my diesels..

CLICK HERE, FOLLOW THESE DIRECTIONS, AND BE FOREVER HAPPY WITH YOUR MAINTENANCE FREE WIRING!

[dsl_lvr]

I have had 3 of these little Mk-II diesels, plus a Rabbit, and logged over 450,000 collective miles with them. This is the first "fast-glow" issue I have ever had. But, maybe not....

I think I need to look elseware. A buddy reminded me today that my symptoms are conspicuously fuel-ish. I did have a similar problem on this very car whan I first got it with 235,000-miles and it hadn't run in 3 years. It did not want to crank because the leaking pump seal would let the pump lose its prime if it sat overnight. re-sealed the pump and all was good. Makes sense that it is doing it again, -or something similar. I can test easily by pouring fuel in the pump.

More later......