Is there a "normal" glow plug cycle time?

[rjinga]

Long story short: Mechanic says all the glow plugs, and their connections, are good. Mechanic repaired a broken wire to, and replaced a defective, relay. Mechanic says the wait light, and therefore the glow plugs, stay on too long the first cycle of the day and I should replaced the GPM.

My brother and I performed the Electrical Troubleshooting malfunction #15 out of the TM and, except for the wait light not turning on when we jumped the dark blue wire to ground, everything checked out OK.

It was 58 degrees this morning and the wait light light stayed on about 25 seconds before the initial cranking. Right after it cranked, the wait light came on for another 3-5 seconds and then went off.

Is that normal? Is it cycling too long? Is there a "normal" cycle time? Why do hotdogs come in packs of 10, but the buns come in packs of eight?

 

[SGT Estum]

Didn't the TM tell you what action steps to take as a result of your malfunction?

 

[rjinga]

When you say "malfunction" are you talking about the wait light not coming on when the wired is jumped to ground?

 

[Warthog]

Here is a troubleshooting guide from GM. It covers the civvy model but it does make a reference to the CUCV.

The "normal" GP time for the civvy unit is ON for 4-6 seconds, OFF for 4.5 seconds and then cycle on and off for 20 more seconds.


Have you read the CUCV Sticky for the Glow Plug Operation?

 

[rjinga]

Have you read the CUCV Sticky for the Glow Plug Operation?

Yes I have.

 

[wallew]

Yeah, after reading this, I went out and cycled my wait light (7 sec) and then it started right up.

My M1028A2 has always started up quickly. I just love them.

It seems your extended wait time IS probably due to ambient temp.

If you get any warmer days (or have recently) does it still take 25 sec of wait light time?

 

[1stSarge]

No normal, too many variables.

Most likely target;

Bad, loose, or dirty connection to the temp sensor.

 

[Shrapnel]

I had a similar problem on mine. The wait light would stay on too long and it was really hard to start cold. I replaced the relay/module thingy on the firewall and the glow plugs now only run a few seconds before the light goes out. Fires up really good on the first try now. They are not very expensive.