Hard starts still!!

[mcdaniel1991]

Alright I have 2 new optima yellow tops, BPD 58v 6 phase, rev x , and winter fuel additive!! All was good for about 1 month until it started getting colder out 30*F and now it will start then die like 4 times before it will stay running but it clears up and idles smooth as soon as it starts ! I put a new oil pressure regulator in it about 2 months ago when I had a no start problem

 

[Stroker#66]

Gpcm

 

[mcdaniel1991]

^ sorry can u elaborate

 

[CCRICE]

Gpcm= glow plug control module


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[mcdaniel1991]

Ok that makes sense, I'm also throwing icp circuit voltage low, glow plug # 6 code and FICM performance(58v FICM)

 

[Mdub707]

I'd inspect that ICP low first. Can you monitor ICP actual and desired? Do you have a way to do that?

Don't just go throwing more parts at it, diagnose, verify, repair...

You can certainly test the GPCM and the glow plugs, very easy to do with a multi-meter.

Disconnect the 4 pin connector at the valve cover. Measure each glow plug resistance to battery ground, the glow plugs should fall between .1 and 2 ohms. Then measure the engine harness resistance to the GPCM, those should fall between 0 and 1 ohms.

 

[mcdaniel1991]

I have an edge Cts and SCT x3. Last time I did a date log my actual was below my desired that's about all I remember at idle my icp is right a 870

 

[Mdub707]

at idle icp is at 870... is that actual or desired? What's IPR % duty doing when you're monitoring. If you had actual lower than desired, that means the system isn't' building the right pressure. Which could certainly get worse over time and cause hard/no starts. Sounds like you should try monitoring this stuff again. Can't the CTS monitor that?

Watch ICP actual, ICP desired, IPR %. Let us know what you find. Monitor it while you're cranking to get it going and once it's running give us idle numbers and maybe take it out for a romp and see what it does under WOT.

 

[mcdaniel1991]

870 is actual I will hook it up in the morning and try to get some data logged

 

[Mdub707]

Ok, let us know what you find. It needs 500 or 525psi (I can't remember which) to actually fire.

 

[mcdaniel1991]

Well I monitored it during start up but since I plugged the truck in last night it started right up. The livelink software only displayed 11.xxxxx for my icp? Is the volts or what cause my Cts displays psi but not desired

 

[mcdaniel1991]

So far all I know is idle is 870psi and wot is 1740psi

 

[Stroker#66]

So when it is hard starting does it build icp slow? Crank slow?

 

[Mdub707]

1740 under WOT is way too low, it should be closer to 4000psi.

Next time you go to start it, try a cold start and try unplugging the ICP sensor, see if it starts easier.

 

[mcdaniel1991]

Ok thanks for ur help

 

[mcdaniel1991]

It started good this morning with the icp unplugged. . But it was only 40* instead of 30* this morning

 

[Mdub707]

It may be a faulty ICP sensor bud. Next time it's acting up like that, unplug that sensor and see if it starts up easier. You can drive it with it unplugged, but it's going to be a slug. Unplugging it basically defaults the PCM into a 2000psi desired ICP. So it should start smooth and run ok, but obviously if go full throttle it's not going to go very fast. It's kind of a way to test the sensor or limp you home if the sensor fails.

 

[mcdaniel1991]

That's crazy that its supposed to be 4000 and mines only at 1740 because my truck by no means feels like a slug it will break the back tired loose and kick sideways when I punch it. But I think I will order a new icp

 

[mcdaniel1991]

I think it's my edge Cts reading it wrong I just looked it up and it looks like it won't read icp correctly once the truck has been tuned... I think I'll untune the truck and go drive it again to see

 

[Mdub707]

Ah yes, I was just thinking of that when I was reading your post over again, you need to be trying this with stock tuning on. My bad, should have mentioned that before.