Hello all,

I am currently running a DX block 350 with the later injection system and intake but I am still running the very early glow plug system with 8G (I think) plugs. Everything was working fine (IE: waiting 30-40 seconds) until recently the pass. side stopped getting power to the plugs. And, of course, because it is winter she will not start.

My question is: does anyone know where to get another relay? I've attached a photo. Nobody seems to carry this specific relay and I ordered one from rockauto.com but they sent me the later one that looks like a f*rd starter relay.

I am big fan of having things work as per factory and do not want to install a manual switch.

Any help is greatly appreciated. The pic below is of the factory relay, one box for each side of the engine.

-Cort
http://i234.photobucket.com/albums/ee278/Corts76/Tomsbrowntruck1/SDC16277.jpg

What I would I do and I highly recommend this,is to use the 6.2 diesel electronic glow plug controller from 1985-1993 if you want a factory setup.It's a white controller(some aftermarket brands are black but be sure to count 4 pins before purchasing)that has two large studs and 4 small pins.You will need that controller and the electrical connector that plugs into it.The acdelco part number for the connector is PT262 but i will check for another part number.

You can keep your "wait" light fully operational and once you turn the key to run mode,after 7 seconds,the light will go out and will function better than your old system.

I've retrofitted that system upon two of my 5.7 diesel powered trucks and i'm about to do the same with my '98 silverado that now has the 6.2 diesel.

Never had a problem in 11 years since retrofitting the 6.2 glow plug system to my '93 chevy.Works perfect,could not ask for anything better.

The 8G glow plugs in your 5.7 are the fast glow type and will work perfect with the 6.2 controller.I'm using 8G plugs in our 5.7 diesels and had one glow plug burn out in 11 years.Those plugs take 5-7 seconds to fully heat up but if your system takes 45-60 seconds,you must either have the older 7G plug or the PTC 12G plug.8G plugs would burn out instantly beyond 8 seconds.

I'm guessing I have the 7G's then, as they are not burnt out. Will the newer controller still work with them?

7G's won't work with the 6.2 controller as the 7G takes almost forever to heat up.The preglow period on the 6.2 controller will end at around 7 seconds.Not nearly enough time for those 7G plugs to do the job properly.You'll need 8G plugs for things to be effective if your going with the 6.2 controller.

OK, I have another question: Will the later relay that I received from rockauto do the job that my early relay did? I am trying to go cheap right now and I can't afford to replace all of the glow plugs to use the later 6.2 controller.

I noticed that my current temp sensor for the glow plug system only has two prongs and the later sensors have 5 prongs or so. Should I just buy the later one and wire in the f*rd looking relay? Or will this not work at all? Do you have any schematics?

Thanks again for the help.

You can use the relay you got from rock auto and use a push button to activate the plugs.Basically,that relay resembles the ford starter solenoid found on the fenderwell of older ford cars and trucks.

I used to have the relays your looking for.I may still have them but I will have to check.If I do have them,you are welcomed to them.I'll get back to you tommorrow on that.

I do have schematics of the different glow plug systems but will need to take a picture of them and will send them to you.

Well, here's my new plan. I am going to take the later relay that I received from rockauto and wire it into my current system. The old style was basically two relays mounted together so one ran the left bank and one ran the right bank. It seems to me that I should just be able to use the new relay and just double up the wires from the old two...make sense?

I am going to check everything out first before I start cutting wires to see if this is a possible solution. I'll post what I find out.

Well, I got the new relay wired in. It works great but for some reason after the engine starts the power is still going to the glowplugs. I am guessing it has something to do with the controller card underneath the dash. So, my fix just involved running the negative wire from my relay to a switch under my dash for now so I can control them manually. But the good part about the controller still being hooked up to the temp sensor, is the "wait to start" light is still ran by the controller and so when I press the switch manually (which makes the "glow plugs" light come on), I just wait for the "wait to start" light to go out and then let go of the switch.

It is not the way I want it to run but it seems to be reliable and I'll fix it the right way later with the 85-93 glow plug system.

I hope this thread helps some of you '78 Chevy Diesel owners since it seems we are the only year that had the different relay and controller for the 5.7's.