I have spent hours on here and other forums reading about the issues I am having. So many things contradict one another that when I get to the point that I think I may be on to something I read something that tells me I'm not.

So quick rundown... My main issue of concern is that it is hard to start when cold and when its really cold out, even with the block heater, it sometimes almost doesn't start. I have always managed to get it going but sometimes I get concerned. Then of course when it does start it runs rough for several minutes. It doesn't make any difference if I use REV-X or not. I tried that out when it was just doing this every now and again.Once warmed up all seems well. I have a Autoenginuity scanner for the truck and I have been checking some things. Here is what I am getting:

Ran a buzz test cold. Got codes on all cylinders saying " Injector Circuit Low"

Checked FICM Voltage with a voltmeter as directed in another thread on here... I got 48.5 volts with the key on. With the engine running it bounces between 46 and 48.5. However when i checked it when the key is first turned on and the injectors buzz i get only 21.6 volts. I assume that this is why I got the error during the buzz test.

Next i started up the truck, which although cold, had been started earlier in the day. It had a miss when running like it usually does when I start it. I used the computer to cycle through the injectors to see which one was missing. When i turn off any injector the miss gets worse except #2. When I turn it off there is no difference. Leads me to believe I may have an issue with that injector as well as whatever else is going on.

After warming up I ran a buzz test again on the injectors and it passed the test.

Question is... what am I looking at here. I am pretty good when it comes to mechanical things but I am a bit rusty when it is electrical. Any help would be appreciated.

 

Your FICM needs repaired. Send it to ficmrepair.com to get it all fixed up.

 

Sounds like the FICM is toast.

At first koeo, and being cold, a bad FICM will do just what you described. Once a FICM gets warmed up, it can read normal all day.

Mine did the same thing. I used the Scangauge II and found mine dropping as low as 30v on first KOEO. That was first start in the morning. The rest of the day, My FICM read normal.

My FICM would go from 30v to 48v in a matter of 10-12 seconds. I wouldn't turn the key to start until it rose to 48v.

Time for a new FICM, or, send it in to FICMRepair.com, and Ed will fix it right.

 

^^^^^^^^^^^^^^^^^

What he said, all of it. Your cold starts will be much better by waiting for the voltage to come back up before starting, and after it's replaced you'll see night and day difference.

 

I, too, believe your ficm needs repair.
A trick I learned on here to help isolate the film is to hear it up with a great gin out hair dryer for a bit, then try starting the truck and see if there's any difference. Ed with ficmrepair is top notch!

 

Another thing you should do is have a charging system and battery check run. A good charging system will ensure that your FICM stays healthy and help your truck run to peak performance.

 

Thank you all for the replies. I will have more questions as time goes on. As far as the voltage drop goes it is only low until the injectors finish "buzzing" when the key is turned on. It immediately jumps to 48 volts as soon as that is done. But after reading about the heating that the unit does on startup it makes sense to me why low voltage at that point would cause an issue. This is just step one in a list of things I want to get straightened out on this truck. More to come later. Thank you all again!!!

 

Anything under 45V at anytime indicates a failed FICM, not just when it's starting. You definitely need to send it to Ed before further damage to the FICM or injectors occurs or it just plain leaves you stranded.

 

I agree with the others, FICM voltage should never drop below 45 from KOEO, cranking, idling and WOT. And X2 with sending your FICM to Ed at www.FICMrepair.com . Npccpartsman also made a good point that you need to check out your batteries and alternator as low system voltage is the leading cause of FICM failure.

 

The trick is to use a hairdryer or heat gun and heat up the FICM.

Josh

 

Thanks, Josh. Now I remember that as you are the one who suggested that originally I believe. I've corrected my post. However, all I had at the time was a light and it worked as well, but hair dryer or heat gun would be much faster!

 

Hope you don't mind if I tag on to your post.......I have the same issues and I'm glad you posted your scenario. To the other posters, what would we be looking at as far as the repair cost from Ed as well as turn around time?

Besides the annoyance of long, smoke filled cold starts and probable mpg decreases, is there any damage that occurs if you hold off on the repair/replacement?

 

Not sure on cost nowadays but he has a swap program where he will send you a repaired FICM and you send yours back once you swap them out, it's like an extra 50 bucks.
The real danger in putting it off is that it could leave you stranded.

 

Everything you need is right here http://ficmrepair.com/

 

For obvious reasons get your ficm done as soon as possible, and after make sure you revisit your charging system to make sure that everything is a okay. The problems you're having can also affect you're ICP and IPR in a very negative way.