Good morning everyone,
I've been working on an issue i started having over the winter thinking it was the ficm. no starts rough idles and running on half the cylinders.
I would get very little and weak injector clatter, it would start, run rough and then jump back to normal after i hit the road, ive replaced the ficm and it cleared the problem up for a week then came back replaced the ficm again and same thing expect this time around it lasted just a few days before i was hit with the same symptoms. running rough, running on half or so cylinders and no start scenarios. Having just a scan gauge made my diagnosis ability extremely limited. but what i can tell you is i have no codes at all. freshly charged battery's, Fresh ficm out of a running truck, Brand new injector harness ficm sync is good while cranking, ficm main power is at 48-49 volts, i have good icp at 500+ while cranking my ipr is between 22-35 while cranking. Im pretty stumped at this point on where i should look next. any advise would be greatly appreciated! You guys have not let me down yet!
Its been a long time since I've posted here, hope everyone is well!
Thanks in advance,
Adam

 

Sounds like a fuel issue to me.

Fuel filters
Fuel pressure

Also check your batteries and alternator. If either are bad they could be frying your ficms...they're very sensitive

 

changing the filters right now!

 

A fuel pressure gauge is a necessity on these trucks.

 

would i still show good voltage and sync if they are fried?

 

I haven't dug into the FICMs very much but there is a logic side that can be bad while still showing sync and good voltages I'm pretty sure

Check your voltages while cranking...how low do they go..

Voltage at initial startup

How long until it climbs to 13.2+?

 

I may have a similar issue, just started a thread for it.
When the engine has been sitting, try a Key On No Crank, let the glow plug indicator go dark, Key off. Then repeat. Then crank it. Mine will start immediately, but even if I crank it, will not start during the first two.

 

im getting no injector clatter what so ever. how about you?

 

Main voltage 48.5+ with sync while cranking all look good accept the FLP is at 11.5 before crank and while cranking it drops to 9.5. both batteries are fully charged! could this be the logic side of the ficm going bad? Ive been through 3 ficms total and all show good voltages accept the FLP remaining below 12v

 

Well, took a shower in diesel.. changed the filters and still no clatter which i had a feeling was gonna be the case anyway. at least it has new ones now!
on to the next step!

 

dosent seem to be a fuel supply issue the system had pressure when i changed the filters. Granted I dont have a pressure gauge i purposely cranked then imeidiatly loosened the engine side filter to check if i had pressure and it sure was there.

 

That test can not differentiate between 30 psi and 50 psi.

 

I gotcha. mad respect! thank you for your comment! you are the king! What can give a no clatter situation then? it idled rough and then ran great after i got on the road. got home shut it off an got no clatter what so ever. thoughts?

 

Look at my no-start sticky in the Tech Folder
https://www.ford-trucks.com/forums/8...condition.html

The point was that low fuel pressure will ruin expensive injectors and MANY times you don't get injector codes even when they are bad. Fuel pressure can be a very good clue.

Scangauge is a very poor code reader. ForScan is a MUCH better troubleshooting tool. It will pick up codes when other scan tools don't. It will run an injector solenoid test (which also will test to see if the FICM will issue the signal to operate the solenoid). It is all in the sticky thread.

There are a lot of cheap FICMs out there that I wouldn't want to install in my truck. 9.5 volts is getting low enough to perhaps damage them. Should still start at 9.5 volts when cranking though (would probably be a hard start).

As posted above - have you checked your alternator yet? Checked the grounds?

 

There's a lot of ineffectual data here.

First, if you have poor running and inconsistent or no clatter, you've typically got FICM problems, it's not a fuel issue.

If when cranking your down to 9.5v your not "fully charged!". Define your fully charged.

You need to have the batteries tested for capacity. If the batteries are compromised, you can achieve a good voltage level after a charger or run, but without good capacity, they will quickly fall into the area where the FICM gets damaged, including the replacement FICM. Did the running truck that the FICM came out of have clatter or not? If you have poor voltage, you may have just hurt a second FICM.

As Mark stated, declaring no codes with a poor code reading isn't a declaration of no codes.