HELP Rough idle/start no codes ever.

[spaceace77]

Recenty purchased with 129,000k. New batteries, FICM tests okay 48vdc, so I unplugged GPRM and no change or codes. Does not want to start in the 40s when cold and unplugged from house. Fuel ok and oil change is good. Running Stanadyne in fuel and Prolong in oil. GPRM is my target but not sure. Runs fine/starts fine when warm. Am I missing anything?

I had to post as I always see that codes are always present on the obvious.

[najaf4life]

glow plug relay working?

[spaceace77]

I just checked it, power everywhere to the glow plugs and they all ring out at less than 3 ohms. Since the FICM voltage seems fine... maybe I just need a new flash for the stiction issue? I dread the thought of new injectors.....but no codes... I almost wish I had a code.

[Heathrm]

I would not be too quick to get the latest flash from ford, as you will probably see a drop in MPG's. If it is doing it with the GPM connected and un-connected, that might be the culprit. I would try to swap out with a known good one if you have the ablilty to do so. I know this doesn't help much, but don't want you to be banking on the updated flash to fix your problems.

[spaceace77]

What should be swapping out? The FICM or the GPRM? I am going to try an amp test on the glow plug harness. I am half tempted to get a rebuilt FICM even though my voltages are correct. I could spend that kind of cash just hooking up the scanner at the dealership.

[Fishermedic]

Before you throw money at it I'd have the batteries load tested even though they are new. You never know.

Did you test the FICM engine off, cranking or started? Cranking or just after starting will show the lowest voltage.

[spaceace77]

I wish it were the batteries. The starter cranks over like lightning. The FICM was checked at both KOEO, KOER and with all blowers and accessories on high.

[Heathrm]

Spaceace,

I agree with fishermedic, check the batts, the easy things that can be checked with no charge. Is it cranking over just not firing up? What exactly is it doing. Does it sound like the batts are charged? Is is just cranking for a long time with no light off?

I was talking about swapping out the GPM with a known good one, from a friend, etc. If the FICM is good, I don't think that is your problem. I think it has something to do with the glow plug harness or the GPM itself. At the same time you don't have a code or anything, I think the GPM throws a code? Do you have an insight or are you waiting for a CEL to come on? If you don't have a monitor, I would try to check for soft codes, that might lead you in the right direction.

[spaceace77]

The batteries are less than 30 days old. The are fully charged. They are 13.2v with the engine off. 14.5v charging. After it sits day or so...it cranks, tries, but does not run long. Runs like it is only on 5 cylinders. On like the 6th attempt it finally stays running Then smooths out. It does not like to start when cold. The warmer, the less noticable. Block heater on...purrs like a kitty. I checked the glow plug resistance through the harness and buss. I use a new Innova scanner and it has no pending codes or a CEL. CEL light comes on during dash test.

[FSS Diesel]

change the GPM .......... borrow a friends its cheaper that way...... but thats your problem......