Cold start problem

[petik]

My truck has quite some miles on it so it does tend to be a bit hard to start when it is cold. That being said, it's never been like this...

First, the things I have done in the past year or less while working on other maintenance items to help rule out what the problem isn't:
- replaced GPs and GPR as well as checked that GPR is actually providing voltage
- replaced the IDM (now carry an extra spare in the truck)
- replaced injectors (went to stg1 single shot) and fuel pump

Now for the problem. When it is cold, and only when it is cold (40F), the truck will not start. Regardless of whether it is plugged in or not. The truck turns over and batteries are fully charged, it just won't catch. The problem is somewhat intermittent, but worse the colder it is. Below 40F it is almost impossible to start. While trying to start and motor turning over, I can hear a relay clicking repeatedly behind the dash (where the radio is) - I think this is where the 5 light relays are. When I hear the relay clicking, I know for sure the truck isn't going to start. I can wait some time and try again and when the relay clicking doesn't happen, the truck always catches.

It happened to me again this morning and I had my laptop and AE handy, so I quickly ran the KOEO test and came back with two codes:

P0605 - Internal Control Module Read Only Memory (ROM) Error
P1668 - PCM/IDM Communications Error

I think I've had the P0605 error before since I got a chip, but I definitely haven't seen the P1668 error and it doesn't show when the truck starts.

Here's a youtube video of what it sounds like when it won't catch:

Powerstroke cold start problem - YouTube

Powerstroke cold start problem - YouTube

Do I have a bad IDM yet again or should I be looking at the ECU?

[wireman116]

unplug your chip then try to start it

[petik]

Truck won't start without a chip on single shot injectors.

That being said, putting the truck batteries on a charger while plugging in the heater at night seemed to help. I think this may be just the batteries running down a bit (I only drive the truck once every week or two). I'm going to permanently wire in a Battery Tender and T it off the heater plug and put a switch on the heater. That way I can charge whenever the batteries are low just by plugging in an extension cord.

[jermcd]

40 isnt really "cold"... when my batteries were going out last year the truck was hard to start even when plugged in and about 10 degrees but still fired up.

[AzPatMan]

Originally Posted by jermcd

40 isnt really "cold"... when my batteries were going out last year the truck was hard to start even when plugged in and about 10 degrees but still fired up.

Agreed with this!
40 Degrees, sitting over night - should fire right up.
When you're starting and your gauges start going nuts - I think you have a battery/charging issue.
Take your batteries in for a load test. Just because you have 12v fully charge - don't mean you have diddaly for AMPS...

[petik]

Batteries are fine. They're both optimas red tops about 10 months old. Just the same, I pulled them and tested them on a carbon pile tester - both tested like champs.

I have been a little skeptical of the battery wiring on the truck though. The exposed strands on terminals are dirty (not really corroded, just dirty-nasty). I got under the truck and ends where the grounds bolt up as well as the starter look equally filthy. I went ahead and ordered new 1/0 gauge copper wire as well as new heavy duty terminals for everything. I'll run all new ground and battery wiring and see if I have a poor connection on a ground or hot side. While I'm at it, i'll inspect the IDM ground connection as well. The code thrown seemed to suggest the IDM is not powering up when the condition is present.