Glow plugs

[Yellowdog]

New here, I just bought a 94 2500 GMC with the 6.5 turbo diesel. Having issues with cold start. I did a search and it looks like the most common advice here is to replace the glow plugs. I was told not long after I bought it to put a toggle switch on the glow plugs to help with the cold start. This truck will be parked a week or longer at a time without being able to plug in the block heater.

I did some testing and there is 10 volts at the glow plug can I just wire them direct? Or is there a better way?

[a5150nut]

Might want to test the Glow Plug Relay first.

[Yellowdog]

Is there a how to somewhere I can read? Where is the relay? This is my first diesel.

[trbankii]

The post four below yours - no start/hard start - has instructions for testing the glow plugs.

[a5150nut]

Is there a how to somewhere I can read? Where is the relay? This is my first diesel.

There is a search feature near the top of screen

Should be located in the middle of the valley just in front of the firewall. Black molded object with wires connected. Just follow glow wires back to it. Don't remember exact volts and resistances but again Search feature will lead you to the answers.

You can add more info about your truck to your signature and it will help us here to help you better.

Welcome to the best 6.5/Duramax forum there is

[Yellowdog]

Thanks guys I'm going out of town Tomorrow so I will look at that when I get back I'll keep you in the loop.

[tractorwilly]

I was told not long after I bought it to put a toggle switch on the glow plugs to help with the cold start

Welcome. I am also new here and would like to share my glow plug experience.

I opted to replace glow plugs with the Bosch Duraterms. The left side is a breeze to replace once you remove the wheel. I removed wheel, inner fender and turbo downpipe on the right side and just had to use long forceps to remove and replace plug wires on 6&7.
A good ohm meter to test plugs resulted in 6 of the eight being dead or low resistance (below 1.0) resulting in my poor cold starts. Now my cold starts are perfect and relay holds for adequate time and cycles according to outside temp. Best move made for Canadian winters.. I dowsed plugs with PB Blaster every night for a few days in advance to allow penetration and the plugs came out with little to no effort.

Good luck and keep us posted

Willy

[jrsavoie]

USe only Bosch duraterms or AC Delco 60G glow plugs. If you have something else in there take it out and throw it in the steel scrap.

If you go with the Ac Delco 60G glow plugs, do not let anybody tell you it is the wrong glow plug for the vehicle.

I had a diesel injection shop try to sell me some old 7Gs or something. They were insisting the 60G glow plugs could be messing up the way my vehicles run.

None of the other glow plugs have matched these 2 for performance or longevity

If you have to replace the lift pump, and you stay with an OEM style, use only an AC Delco lift pump for a 1993. There is a 2000 model or something that is also supposed to be higher flow but I can not confirm that.

On 1995 and older 6.5's do the dual lift pump relay upgrade. There is a schematic online someplace.
If you make your own, get a plug from an old lift pump to run wires back from the lift pump plug to trigger the relay. Do the prime feature also.

leroydiesel.com sells a good harness. The only thing I do not like about his is that he uses mountable relays instead of the mountable relay sockets that I prefer.

There are a couple of people that will make custom harnesses for you. Google headlight harness and 6.5 diesel engine harness or message me and I will try to send you a link

[a5150nut]

John Kennedy is a member and vendor here and he has a harness for 6.5 lift pumps.

[jrsavoie]

John Kennedy is a member and vendor here and he has a harness for 6.5 lift pumps.

Do you have a link to his harness?

Price?

Wire gauges?

What type of relay does he use?

Does he use mountable relay sockets or mountable relays?

Is it plug and play with no splicing?

http://www.kennedydiesel.com/detail.cfm?ID=402

I'd really like to know more about this kit. There isn't much info there, or I didn't see it. It looks different from the home made and others I've seen

[a5150nut]

Johns phone number is right there on his sight. He would be by far your best resource. He's not a bad guy and contributes here quite often.

[Yellowdog]

Sorry guys I'm a truck driver been out of town the last 3 weeks.

Update: it sat for 3 weeks tried to start it battery was slow turning, the shop let me use the power pack they use on the kw's hit the starter after the glow plug light went off and it fired real easy and fast. I bought new batteries a month ago 700cca each I'm now wondering if I should of went with stronger batteries. I have done anything to it yet. Thanks guys for your help.

[jrsavoie]

Sorry guys I'm a truck driver been out of town the last 3 weeks.

Update: it sat for 3 weeks tried to start it battery was slow turning, the shop let me use the power pack they use on the kw's hit the starter after the glow plug light went off and it fired real easy and fast. I bought new batteries a month ago 700cca each I'm now wondering if I should of went with stronger batteries. I have done anything to it yet. Thanks guys for your help.

I always buy the biggest batteries I can buy. At least 800 CCA

I've seen boosters take out PMD's on these 6.5's. Sometimes it takes a few weeks for it to show up.

[Yellowdog]

Thank you.

[Yellowdog]

Problem solved. Thanks guys. Batteries were too small.