Need HELP diagnosing glow plug cicuit using the D.B.Predator

kawikid1425 · Post by **kawikid1425** » Tue Dec 23, 2008 3:13 am

Hello i am experiencing some severe hard starting with my 2003 dmax LB7. The glow plug light is staying on for 10-15 seconds before going out. If i don't plug the truck in it will barely even start. I have read a old forum where a member stated that he had checked his glow plug circuit using the predator. I was wondering how to do that as well? Any suggestions?

johan · Post by **johan** » Tue Dec 23, 2008 10:06 am

I personally do not know but maybe one of the other members will know.

rydnhi4x4 · Post by **rydnhi4x4** » Tue Dec 23, 2008 2:22 pm

Try going to one of the Diesel Forums like http://dieseltowingresource.com/ and ask around. Someone may know. If not they will find the answer for you.

03TBZ · Post by **03TBZ** » Wed Dec 24, 2008 11:39 am

The glow plug light being on for 10-15 seconds means that it is cold out side and the computer is activating the glow plugs to try and heat up the engine before you start it. Wait till the light goes out and then try to start it. Also if it is really hard to start try cycling the glow plugs multiple times before starting. The light being on is nothing bad, just the truck doin what its supposed to to make things easier for you.

kawikid1425 · Post by **kawikid1425** » Thu Dec 25, 2008 10:25 pm

thanks for all replies, i understand what is being said. But i would like to plug my predator in and do a diagnostics test on the truck, especially the glow plugs, i read a forum of a guy that used his predator and it actually displayed on the screen the voltage that each glowplug was getting! that way you will know if one is bad or not because there is a certain voltage that tells you bad. can you d.b. techs please tell me how to do this.

neonhomer · Post by **neonhomer** » Fri Dec 26, 2008 9:00 am

I don't know if the Predator does any diagnostic testing, but just reads error codes. If there was something wrong with the glow plug system, it should flag and error code in the PCM.

You might have a weak glow plug and it is taking an excessive amount of time to heat up. A friend of mine had a old 85 Mercedes Benz 300D and it would do the same thing. Come to find out, he had a bad glow plug, and the fuse that feeds them had a crack, and was not passing full voltage.

rydnhi4x4 · Post by **rydnhi4x4** » Fri Dec 26, 2008 7:20 pm

kawikid1425 wrote:thanks for all replies, i understand what is being said. But i would like to plug my predator in and do a diagnostics test on the truck, especially the glow plugs, i read a forum of a guy that used his predator and it actually displayed on the screen the voltage that each glowplug was getting! that way you will know if one is bad or not because there is a certain voltage that tells you bad. can you d.b. techs please tell me how to do this.

I think your talking about the real time data. I don't know if it shows anything about the glowplugs to be honest.

neonhomer · Post by **neonhomer** » Fri Dec 26, 2008 7:29 pm

That's what I was going to say. It might be in the Real Time Data screen. However, I don't think glow plugs stay on while the engine is running. If you want to see what the glow plugs are drawing, put a voltmeter on the glow plug power point in the underhood fuse block.

I don't have a Duramax in my truck, but I dream about one at night!

rydnhi4x4 · Post by **rydnhi4x4** » Fri Dec 26, 2008 7:46 pm

I just went outside in 30 degree weather to check my real time data and it does not show anything about the glow plugs, but do remember I have a LBZ.

rydnhi4x4 · Post by **rydnhi4x4** » Fri Dec 26, 2008 7:47 pm

neonhomer wrote:That's what I was going to say. It might be in the Real Time Data screen. However, I don't think glow plugs stay on while the engine is running. If you want to see what the glow plugs are drawing, put a voltmeter on the glow plug power point in the underhood fuse block.

I don't have a Duramax in my truck, but I dream about one at night!

Is the Duramax leaving smoke trails in your dreams?

Jackofalltrades03 · Post by **Jackofalltrades03** » Sat Dec 27, 2008 3:12 pm

rydnhi4x4 wrote:I just went outside in 30 degree weather to check my real time data and it does not show anything about the glow plugs, but do remember I have a LBZ.

It shows on LB7

rydnhi4x4 · Post by **rydnhi4x4** » Sun Dec 28, 2008 6:27 pm

Jackofalltrades03 wrote:
rydnhi4x4 wrote:I just went outside in 30 degree weather to check my real time data and it does not show anything about the glow plugs, but do remember I have a LBZ.
It shows on LB7

I would explain it to neonhomer on how you got to this data.

Jackofalltrades03 · Post by **Jackofalltrades03** » Sun Dec 28, 2008 10:22 pm

rydnhi4x4 wrote:
Jackofalltrades03 wrote:
rydnhi4x4 wrote:I just went outside in 30 degree weather to check my real time data and it does not show anything about the glow plugs, but do remember I have a LBZ.
It shows on LB7

I would explain it to neonhomer on how you got to this data.

All you have to do is to go to the Real Time data section and keep scrolling down....It's in there

Need HELP diagnosing glow plug cicuit using the D.B.Predator

Need HELP diagnosing glow plug cicuit using the D.B.Predator

RE: Need HELP diagnosing glow plug cicuit using the D.B.Pred

RE: Need HELP diagnosing glow plug cicuit using the D.B.Pred

RE: Need HELP diagnosing glow plug cicuit using the D.B.Pred