My dad just recently purchased a 99 f550, story on it can be found here, has only had the a short while and this morning i got a call saying that it started up fine, he went to take off and it seemed a little sluggish but he thought that it just wasnt warmed up yet on a cold morning. He got a few blocks from the house and the CEL came on and he said it had no power. Sounded like it running on only half the cylinders, no throttle response, wasnt sure that he would make it back home. He limped home, parked it, and said in park it had some throttle response but still ran like dog poo. At that time he called me after he jumped into his 6.0 to make it work. Now thats a reversal of fortune, 6.0 coming to resuce of 7.3, haha. Anyway, I got on here this morning to do a quick search of what i could find and came across this thread that seems to be a very similar problem to what was decribed to me and it seems he determined his problem was IDM. Would the UCVH give these same symptoms? Ive been lucky, mine runs like a top and Ive never had to actually troubleshoot these type of issues. Where to start? Tips or pointers? Anyone available in the Orange, TX area with AE want to assist in troubleshooting, heck for that matter AE not required only the want to assist part, haha. We will try to find a used IDM to swap out and see if that improves anything to try and eliminate that as a cause. Will keep informed as I go. As always, any and all information is appreciated. Thanks.

 

Usually a bad idm will cause a no start. Sounds a problem with the 9 pin plug under the valve cover. I would grab a meter and ohm out the glow plugs and injectors on the outside of the valve cover. Rick and Bulla live down there so maybe one of them could scan the truck for you.

 

Hey Damon.

I would check UVCH on both sides and do the Chris-50 mod. Check to make sure the WH on top of the VC are not chaffed and grounding.

You can use your IDM to check to see if that is his problem.

 

Chris posted some good info in this thread: https://www.ford-trucks.com/forums/8...ck-shakes.html

 

Here is a thread I had earlier this year where the problem was both a loose UVCH and a bad IDM. Some good diagnostics in here if your dad can use a multimeter:

https://www.ford-trucks.com/forums/1...need-help.html

 

All good info guys. Thanks. Ill be doing this tomorrow and let yall know how it turns out.

 

I have IDM codes on my 02 a few months back
IDM was checked out/cleared as Good-Turns out I had a bad UVCH/ wire harness was messed up. Replaced with NEW and I have no problems! new UVCH/wire harness for both sides(if need be) is not too expensive-just takes time to remove and reinstall

 

Ok, got around to testing the harness connection and got the following:

Passenger Side I got no readings at all or infinity on the meter, nothing registered. So that told me that this side was disconnected for sure. Took the cover over and sure nuff, it was damn near unplugged all the way. So I snapped it back on am about to do my $0.25 fix for that side.

Driver side I got a 0 reading on all pins. The same reading i would get if i just touched the two leads of the meter together. The meter I am using is an analog meter with an adjustment for ohms. I touched the two leads together, adjust that so that it reads 0. Then when i touch all the pins on the driver side i get this same reading, 0. I havent taken the cover off of this side yet to look at the harness but since this was the opposite of the passenger side (no reading) does this still indicate the harness being loose? Im gonna take the cover off and do it anyway but was just curious incase it means something else.

taking a break now to type this but will get back at it again shortly. Thanks for the help.

 

Ok. The 25c shim in place. Check again with meter. Same as driver side on all pins with a reading of 0, same just touching leads together. Pluggedd harnesses back up to try and start. Nothing. Just spins. No start. Taking drivers sidw off now to do 25c shim on that side. Thoughts?

 

I don't thionk 0 ohms is right. I think each injector should ohm out to about 3.4 plus or minus. And they should all be within .5 ohms of each other. Do you have your truck there? Can you swap the IDMs to see if the 550 will start?

 

Most analog meters aren't sufficiently accurate at the very-small resistance readings that injector solenoids and glow plugs have. Especially cheap meters.

If you are reading zero, you likely have both glow plugs and solenoids that draw current, and are probably operational. It's about the best you can determine with the test equipment you have.

With a more-accurate DVM, you can make better determinations. Got a friend with one?

Pop

 

Have you changed the battery it that d'Arsanvol meter. They are very inaccurate with a weak battery.

 

Brand new battery in meter. Puttin driver side back together now. Will know something shortly.

 

It's important that you get a good reading for the solenoids. One bad solenoid can knock out the whole bank but still buzz test ok. Best time to ohm out the solenoids is when the valve covers are off and you can unplug each solenoid and check their resistance.

You should also check for burned pins or plugs. LINK

 

Well. Ill have to check that another time. Got things back together. It starts easily. Sounds better than before. Going for test drive now. Thanks for the help guys.