1992 D250

Truck is hard starting. I hear the click (I would assume the relay) for the grid heater and the "Wait to start" comes on but the voltage meter on the dash doesn't move. I would like information on trouble shooting the problem to figure out if it is:
1. The heater itself
or
2. The relay
or
3. Some other wiring problem.


Any advice would be greatly appreciated.


Thanks for the help

 

Is it real cold where you are located?

Has the truck ben sitting for a long time? if so it could have gotten some air in the line, crack injector lines and turn it over until fuel shoots out of them, then tighten them back up.

 

Don't know where you are at but if it isn't REAL cold, the inoperative grids won't cause a hard start. I start mine regularly without the grids down to 0*.

I think (?)there is an article in the sticky that details how to clean the grid heater relay contacts.

Here it is:

http://dens-site.net/Dodge_CTD/Grid_Heater_Relays/


Hope this helps.

 

I agree with the posts above. It's probably more than just your grid heaters, but should start there anyhow since it would seem they're inoperative.

A voltmeter or light tester works wonders. Check to see if power is going to the heaters. If not, work your way backward. Could easily be your air intake thermoswitch (the one for the grid heaters #5 in the second picture to the link, not the one for the KSB (#6)). Make sure there is power across the switch when the engine is cold.

https://www.dieseltruckresource.com/...d.php?t=128911

Let us know what you find.

 

2nt all the above^
look to see if there is any sigh of corrosion on the nuts of the relay(s) and on the heater grid.

These cable carry ton's of amprage.......any Resistance would cause bad performance of the heat grid.


Flash.

 

Thanks for all the great information from you guys especially the pictures and step by step instructions.

One more question for you guys: in the 91-ServiceManualSup-14-4.jpg link from ofcmarc I see it says
"do not to energize the air intak heater relays more than once per 15 minutes. If the relays are cycled, the key turned off, and then turned back on, the engine could be damaged. Wait 15 minutes before turning the key back to the ON position."
I don't see how it could hurt the engine and I have often turned the key to the off position after a failed start in really cold weather (near zero) to get another cycle from the heater without harm. Am I mistunderstanding what they are saying? I don't want to hurt my engine but if I have to wait 15 minutes between checking each spot on the circuit it is going to take me quite a while and doesn't make much sense. What do you think?


To the questions from you guys:
No it isn't real cold probably about 20-25 degrees F. And it isn't so hard starting that it is a battle to get it going I can just tell it isn't starting like before. Runs somewhat rough for the first 30 seconds or so and seems like more smoke than it used to.

Sitting a long time? No, for the last few months it has been run every day so the longest it sits is probably 10 hours.

Again thanks for all the help. I'll go armed with an electrical tester and see what I come up with. Also will bleed the injectors incase it got some air in there as prior to the last six months it did set sometimes for a couple months at a time without running.

 

When was the last time you changed your fuel filter? Any chance you have a fuel pressure gauge between the filter and IP? If so whats the pressure. The little extra it takes to start these days could be a sign if fuel pressure problems. Could be as simple as a filter change or maybe a LP on the way south.


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If you are checking when it's real cold out I wouldn't worry about it. It sounds to me like the contacts in the relays are cooked so the grid probably isn't getting hot anyway.

Check around the fuel heater/fuel filter for leaks. That would explain the hard starting and rough idle.

 

Thanks for all the advice from everyone. Turned out to be a bad connection on the lines feeding the grid heater. It sure is helpful to get information from others rather than just jumping into it blind or worse yet an expensive trip to the dealership. Thanks again.