Engine/Transmission (1998.5 - 2002) Really hard cold starts

[bigbrassmonkey]

I have had diesels fro 10+ yrs, and never had to use the heater (block) , now it just starts really hard, and runs on 2-4 cyl for about 30 sec. s , I have 130K and original batteries, but they still crank hard, what are your thoughts, light is and stays on longer than normal

 

[LSMITH]

Adjust the valves.

 

[CstlEng]

is it your 2000 you have the problem with or a 93?

 

[bigbrassmonkey]

2000, no I dont the the valve adj is the answer, that wouldn't give such a dramatic change

 

[CstlEng]

Are you ever getting the "low fuel pressure" reading on the FMS? I used to get it for just a sec when I still had the carter lift, and similar symptoms to yours. but you are running big injectors and should see low pressure often if there was a problem.



Trust your fuel isn't gelling? it was real cold for a while. or is it hard to start all the time?

 

[bigbrassmonkey]

never seen the LPF signal since I changed to the twin carters, even a WOT at kill, it runs like it it's only firing on 2-3 then 4 then 5 cyl, then it runs like a champ , I 've had fuel jell before, but not in this truck, and it wouldnt just be AFU on start up, it would usually die on the road also

 

[LSMITH]

The valves being out of adjustment will cause EXACTLY what you are having. Adjust them, it will only take an hour and eliminate one possible cause. It needs to be done at 75K miles at the latest on an ISB, you are about double that.



One grid heater not working will cause it too, check the resistance of the heater grids. If they are drastically different replace the one with the lower resistance reading.

 

[bigbrassmonkey]

the lash was set at 80K, but my apoligies, I'll see if its the problem, I'll make an appointment

 

[LSMITH]

OK, should have been clearer on the first one.



I need to add too that if you check the resistance on the grids and one is infinity or VERY high that is an indication of a bad one as well.

 

[jbone]

BBM, I think LS is probably onto something with that suggestion about the heater grids--could be the relay also... If you got a meter around the house should only take couple of minutes to check those out... ... . R, J. B.

 

[bigbrassmonkey]

thanx, I was thinkin the heater grid also,, torqemech, doesn't feel the valves are the thing , it doesn't fit fully into the puzzle like the grid does, I'lll try that, does any one know how much the grid is??

 

[bigbrassmonkey]

I just checked the resistance of the grids, they both show . 3 ohms, so I think thats about right??

 

[LSMITH]

That is about right, the FSM does not list a value though. I would make sure both relays are operating properly, and if so move on.

 

[CstlEng]

BBM,



just so we all have this clear: this only happens at cold start up, and only when cold outside. If you immediatly turn off and then restart, no problem? If warm out, no problem? No, big clouds of somke until it catches? And then it runs 100% once it catches. I just had a problem with some of the same symptoms (and others) and found the solution in a lose/ wet ECM plug (the 50 pin with the allen screw holding it in under the fuel filter). I chased it for a long time before MCummings set me straight.



Oh, even though LFP never showed, have you changed the fuel filter yet, just to rule it out? I realize you haven't seen LFP on FMS, but...

 

[bigbrassmonkey]

yes the way you are describing the problem, is basically what is going on, I put a meter on both grids this morning and they both read 10. 4 VDC, but once it's going, it runs like a corvette, and always restatrs, it's just 1st thing in the morning when it's cold, where are the ecm plugs??

 

[LSMITH]

ECM is just below and a couple inches forward of the fuel filter housing. It is under the intake manifold and bolts right on the side of the block. There is a screw in the center of the plug. UNHOOK BOTH BATTERIES before unplugging it if you decide it needs unplugged. If the screw is tight the connector is tight and sealed.

 

[CstlEng]

LSMITH is absolutely correct, make sure the batteries are disconnected first, to be safe. ECM is right below the fuel filter and is a LOT easier to get to with the filter bowl removed (this is a great chance to change the filter if you haven't in a few thousand miles). Other connections to check while in the neighborhood are MAP (in back of filter on block) and IAT (behind MAP on block). Can you find out if you are setting any codes?

 

[bigbrassmonkey]

yes i can see about codes, after removeing the grid wires and testing every thing, the next morning it was 4 degrees out , and it started fine, no problems, I dont know

 

[Sh8ryn]

We are experiencing basically the same problems in cold weather as you folks are talking about. Unfortunately, our dealer does not seem to be able to remedy the situation even though he has had the truck since the week before Christmas. While it has been there, they have replaced the ecm module, the lift pump and are now waiting for an injector pump, which they seem to be having a problem finding. I hope they have it back before summer.

Once the temperature dropped below freezing, we could not get the truck to start at all. This poses areal problem up here in Canada, but I guess that is one way to keep the mileage down on the vehicle. Wish we could find a competent garage to solve the problem.