Long crank

[fuzzman]

Having some problems and hoping to get pointed in the right direction.

I have had my truck about 6 months, and have an intermittent long cranking condition. Usually only the first start of the day, but sometimes it happens when warm, but not up to operating temp. If I stop cranking ant try again it always fires up.

I recently replaced the oil cooler, EGR cooler, IPR valve, batteries and rebuilt the FICM.

I have a dashboss monitoring system, so I can see most every parameter.

Here's what I usually see:

battery about 13.1 immediately after start and then climbs to 13.4 or 13.6
FICM Usually stays between 47and 48. Occasionally drops to 46 and peaks at 48. Never ever under 45
Fuel pressure around 68psi

Ipr% at idle around 25
ICP PSI at idle around 580-600

Any ideas?

By the way I just added AR9100 (like Rev-x) and it sounds great once lit now, but still long crank...

[mhatlen]

Is the alternator charging as soon as the truck starts?
Do you have a inductive amp gauge where you can check the glow plug drew for each bank?When you first start are you waiting for the fuel pump to come up to pressure before cranking?

I think there is something going on with your glow plug cycle, the alternator should not be kicking on for at least 1-1-1/2 minutes after it starts. Voltages should be in the 11-12 volt range right after it starts.
Do you have a fuel pressure gauge on it by any chance.

[fuzzman]

Man, I thought I caught that in my edit. Voltage was 12.1 at start, sorry bout that.

While driving it fell as low as 11.9 over next minute. Then I saw the voltage instantly jump to over 13 somewhere. Didn't know what was going on till you explained it.

I leave the key in about 30 seconds before starting. I hear vacuum pump building, but not fuel pump.

I do have a fuel pressure gauge, it I haven't watched it while starting. Seems to me I don't get a reading till its started, but I'll pay more attention. What should I be looking for?

Thanks Mark, I'm learning as I read through these forums that there are a few guys who really know what they are talking about. You are obviously one of them!

[mhatlen]

Ahh there are some really smart guys on these forums, much more savy than I am. I know the basic functions on things when they are doing what they should be,lol

The fuel pressure should be in the 60 psi range while cranking and idle as well. Fuel pressure should be 60-70 psi range and will drop as you throttle up especially under a load. At 45psi the injectors are starting to not like it and will damage them over time.
I am curious at the pressure with the BB Mod, I have no fuel pressure gauge but did put the new updated spring in and IIRC is around 65-70 psi. I do know that my truck really smoothed out right after I changed the regulator spring.

One other thing you might look at is the pigtail to your ICP, make sure there is no oil in it or on the wires themselves. The ICP is a pressure sensor that uses variable resistance depending on the pressure to control the IPR. If there is oil on the plug wiring it will alter the setting to the IPR and cause all kinds of running issues. Often when the ICP fails it does it by leaking oil through the sensor and into the plug assy as well. Must be cleaned completely or replaced if oil soaked.

[fuzzman]

I UPDATED INFO HERE. IN THE ORIGINAL POST I MISSREAD MY DATALOG, THOUGHT I HAD LOW PRESSURE WHILE CRANKING, BUT THAT WAS BEFORE CRANKING


So I ran a data log today while starting.

I had a terrible start, but was not logging. I had to crank several times before it finally lit, fuel psi was as low as 6 before cranking. The next start after a one mile drive I did data log. It lit right away, but fuel psi was 14.1 before starting then jumped to 68 while cranking and stayed there.

iPR % while cranking was 15
ICP jumped right away to 979 while cranking
FICM Was at 48 or 47.5 while cranking

When I changed my ICP valve (after cooler install it got ruined) there was no oil on the harness for the iPR.

Should my fuel pressure build to over 45 before cranking? Any recommendations?

[mhatlen]

Considering the fuel pump is in the hfcm and is cycled with the key I am sure the pressure should be 60 psi +or- before it's running.

I question your BB mod to get the spring pressure to a higher cracking pressure level. (your fuel may be returning to the hfcm or tank) until spring starts cycling from opening and closing.
The injectors need that pressure to fill. I bought my blue spring from RifRaff a few years ago for $38.00, not sure what they go for now but I would toss the bb and old weak spring and put in a good spring. My truck was noticeably smoother after the switch.
Hope this helps.......

[dhanna6powerstroke]

Fuel pressure should be at 48 psi + as soon as key is turned on. What kind of oil filters are you using?

[fuzzman]

I'm using Racor filters, I read here that they are identical to OEM.
Think they are really the same or was that a bad idea?

Sounds like its time to get rid of the BB and put the proper blue spring in. Ill get to work on that, hopefully by next weekend. Think I made thi Gs worse with the BB?

Thanks guys, I'll keep you posted.

[dhanna6powerstroke]

Originally Posted by fuzzman

I'm using Racor filters, I read here that they are identical to OEM.
Think they are really the same or was that a bad idea?

Sounds like its time to get rid of the BB and put the proper blue spring in. Ill get to work on that, hopefully by next weekend. Think I made thi Gs worse with the BB?

Thanks guys, I'll keep you posted.

You're good with Racor. I was just thinking maybe the canister was draining contributing to your issue but shouldn't be with that filter.

[dhanna6powerstroke]

Also, what are you considering a long crank in terms of seconds?