Engine/Transmission (1994 - 1998) Help!!! No start and burned wires.

[JSmith]

Went to start the cummins and got the low batt sound (uh,uh,uh). I tried to start her again and the same thing. On the third try I held the key to get her to start and burned wiring smell was present. Raised the hood and the grid heater wires were smoking, and the dip stick was melting to the intake. I disconnected the batteries. I, screwed up.



I had the truck towed home.



Guys, what is the problem with my truck?

I will be offline for 5-6 hours(sleep), when I get some free time at work I will be back on the TDR.

 

[Joe G.]

Check the heater grid relays. They are on the fender well just below the driver side battery.

 

[JSmith]

I just woke up, leaving for work.



Can someone explain what relationship the grid heaters have with the truck not starting? Is my starter OK?

 

[Joe G.]

The heater grids are not connected to the starter circuits. But they draw a lot of current. If something is wrong so they are shorted then they may draw enough to affect the starter. You might try disconnecting the heater grids and see what happens. I was thinking the if the grids are hot enough to smoke and melt the dipstick tube then they are drawing a lot more current than they should.

 

[Andy Redmond]

I saw a new 2001 almost catch on fire from relays that stuck. We disconnected the assoc. wiring and all was well as it was warrantied. They wanted to re-use the black and discolored air horn so we sent it out for polishing/buffing and a shot of clear coat.



Those guys pull many amps, but are cycled so a too much heat is not a concern. Has battery acid leaked down the inner fender onto the "dual relays" on the inner fender?



Good luck, Andy

 

[JSmith]

No Andy

The batteries do not leak, I use the Optima batteries.

There is no acid on the relays.

 

[Joe G.]

Easy to check. Disconnect the wires to the heater grids and see how it starts.

 

[JSmith]

Joe G. Easy to check. Disconnect the wires to the heater grids and see how it starts.





Joe G. I disconnected the two wires and the truck started. I spoke with the local Cummins West and they do not carry the relays. How much do the relays cost? I will also check the gris heater, with 12v.



Thanks Joe G.



I just renewed here on the TDR, the TDR has saved me quite a bit of time and money.

 

[Howard Durand]

The two heater grids are pretty much a dead short when first energized. The current will drop off as they heat up.

The relays are cycled on and off by the PCM so that they are only on for short periods of time but if one of them happens to get stuck closed you will have a real heavy draw on the batteries.

The grids are fed from the relays with two #6 copper wires but the feed wires from the battery to the relays is a couple of #12 fusible links.

If a relay failed I would think that it would be normal for it to fail open but if the contacts are shorted together you may have a short somewhere else or even a problem with the PCM.

 

[Joe G.]

I have no idea what the relays cost. So far, I have managed to avoid breaking one of them. Probably have to get them from Dodge (ouch!!). I would try NAPA or some other good parts store before buying them from a dealer.



Howard is right about it maybe being a CPM problem. I don't really know how the check for that.

 

[Andy Redmond]

The relays are available from DC as a pair on the bracket for 80+/-.



Some other gent posted an elec. supply on the left coast (web orders too) that offered similar relays w/mods to the brackets for 20 p. relay



Good luck

Andy

 

[JSmith]

Now I have no boost?

I have the wires from the heater grid removed. I need the truck to get to work. On the way to work I noticed the truck was gutless. I got on an open road and floored it at 25mph, then at 45mph. Boost only goes to 14psi, where before this electrical problem I could easily get 34psi. I looked around the intake, hoses, turbo, and intercooler and see nothing out of the ordinary. Before starting the truck this morning I tightened the intake horn.

Any ideas why I lost boost?

 

[Joe G.]

I would suspect that all that heat may have taken out some gaskets. Intake manifold maybe?

 

[JSmith]

Joe G. thats what I am thinking.

 

[Howard Durand]

There is a description on page 46 of the latest TDR on how to make an adapter to allow pressurization of the intake system to check for leaks.

This might be a good time to try it out.

 

[krs]

I think that those heaters are a trouble spot that most of us don't need. At least three engine fires or intake meltdowns have been described in here that seemed directly related to an intake air heater malfunction.

There have been several methods posted about how to control them or turn them off unless needed. Mine are switched by putting a switch in the cab(s) that interrupts the ground wires on both relays so that I can use the heaters if they're needed or keep them from working when I don't need them. Down to 20 degrees my trucks start fine without them although one of them runs rough for a few seconds after starting. That's as cold as I've tried it but I've seen people say that theirs started fine at much lower temps than that.

Some people have wired them to turn off as soon as the engine oil pressure has built up. On 24 valve trucks each relay will throw a code if it's been altered but it won't light the check engine light so it's no big deal.