Problem with losing fire or fuel during crank...

C

Curt2199

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Aug 2, 2011
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It's kinda hard to explain but when I first start it, no matter if it's cold or warm, it will fire and then die or hesitate for a split second and then take off again... almost like it's losing fuel for a second. I took a video clip of it happening and put it on youtube.. This is a very mild occurrence, sometimes it will die completely and and I have to crank it over again to start it. It does have a T&C Diesel 30% over CP3 and an AirDog 150. I called you a month or so back Todd but had to leave and I know you called me back and I haven't had a chance to get back to you with some troubleshooting, just wanted to throw this out in case someone has had a similar experience and it was not CP3 related.

Video of hesitation during start... http://youtu.be/O7Ze-6_PIj4

Also, I am getting a lot of foam coming up from the tank... enough that it will kick the fuel nozzle out at first when filling the tank. The AD fuel pressure is always between 20-25psi and rail pressure is always good at idle and hits around 25k during full throttle.

Also, I am not ruling out maybe the modded FCA or injectors as a cause of the starting problem. If I hold the pedal at a certain RPM while running, there seems to be a variation in the rpm... not by a lot but you can hear it. And it also idles a little rough. Also high idle is not smooth, it's a bit up and down... not the lope though... I know what that sounds like. It's inconsistent.

Again no complaints about T&C or their products as customer service has been top notch. I'm gonna try and get outside tonight and do some more troubleshooting, just been cold, rainy, and dark after work.

Curtis
 
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I have a very serious nasal infection I can barely talk, I lose my voice in less then 1 minute,as soon as I can speak I will call You, If its urgent call, I got 1 minutes to fix.......
 
Thanks Todd, it's not an emergency. Just give me a call when you're feeling up to it or if you want to message me that's fine if it's some sort of quick fix type deal. In the meantime, I'm gonna see if I can figured out the foaming issue.
 
Also, just doing some more reading and I've read that a high lift pump pressure and Modded FCA don't mix well.. being that my AD 150 seems to be putting out around 22-25 psi which is a bit high from what I've heard, I'd guess this may be why. I may try pulling the AD spring out tonight and cutting it down a bit to see if it lowers my running lift pump fuel pressure.
 
I dropped the tank tonight and found my fuel lines were getting pinched a bit which I believe is what was causing the higher than normal fuel pressure from the air dog. I also found the return line piece which taps into the fuel fill rubber house was upside down causing the return fuel to be pushed up resulting in the foaming below the fuel cap so that's fixed. PSI is back down to around 17-20 psi range.

Now I moved on to the starting problem... I hooked up my Diablo Predator and set it to watch the rail pressure. It does build up enough pressure to fire and the idles 7k psi. As soon as I shut down the truck the rail pressure dropped down to 80-100psi within up 20-30 seconds. Is it normal for the rail to bleed off pressure that quickly?
 
Curt2199 said:
I dropped the tank tonight and found my fuel lines were getting pinched a bit which I believe is what was causing the higher than normal fuel pressure from the air dog. I also found the return line piece which taps into the fuel fill rubber house was upside down causing the return fuel to be pushed up resulting in the foaming below the fuel cap so that's fixed. PSI is back down to around 17-20 psi range.

Now I moved on to the starting problem... I hooked up my Diablo Predator and set it to watch the rail pressure. It does build up enough pressure to fire and the idles 7k psi. As soon as I shut down the truck the rail pressure dropped down to 80-100psi within up 20-30 seconds. Is it normal for the rail to bleed off pressure that quickly?
Click to expand...

Yes...
 
ok, I'm trying to find someone with a stock FCA locally or nearby that I can swap out to see if the modded one is what's been causing the problems. If there's any other parameters I should check with my parameter that'd help with diagnosing, let me know.

Curtis
 
Hey Todd, I tried the battery charger on it and it made no difference. I don't think it's a electrical load problem or it wouldn't just be during starting or grid heater vs no grid heater should make a difference. The hesitation happens every time I crank it over no matter if it's warm or cold. I took another video and boosted audio on it so you can hear it happening pretty clearly. Also did a walk around while it was running so you can see it's idling normal once started. I'm still working on tracking down a local that'd help me with an FCA swap out and see if that cures it. It just seems like it has to be fuel related like the CP3 is getting a small air pocket in it or a hesitation in fuel pressure like it's losing prime somewhere in the system after it's shut down. Most of the time it just acts like it's going to die but sometimes it just flat out dies.. yesterday it died on me twice trying to start it before it stayed going on the 3rd crank. Let me know what you think, I'm still doing some guess and check here. I know injectors could have something to do with it but I'd think my rail pressure would be affected a little more if I had a bad injector or two. I'm gonna try unplugging the FCA so RP goes max and see if it fires right over.

In the vid you can hear it do it twice in a row with the first start being a little more pronounced.

[ame="http://www.youtube.com/watch?v=IXU2wrvcOUM"]http://www.youtube.com/watch?v=IXU2wrvcOUM[/ame]
 
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I hear the hesitation too but that sounds normal to me. I guess I never thought anything of it and am running dual modded pumps. Mine never dies or even stumbles though.

Jake
 
Yeah, other than that it runs great. I'm just more worried that sometimes it does completely die during that hesitation and I have to crank it again and also, I'm worried about what it may be doing to other parts of the engine if it is losing fuel or getting air and it's causing the momentary loss.
 
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If the CP3 gets any air when running it will Die, Even in most cases you just remove the COV to look at it the Small amount (What Maybe 1/8oz) will cause the Pump to lose prime,99% of all fuel once it enters the Manifold is under Pressure.No vacuum allowed.if you starve the pump it will stop pumping Liquid and Pump air,If the CP3 is feed adequately it has NO choice but to pump.if the signal to the FCA is wrong or interrupted the truck will die,in most cases it will re-start.No need to worry you are Not causing any damage.. call Me when You get some free Time.
 
Ok, i'll give you a call tomorrow night when I'll be home and around the truck.
 
Hey Todd, I just got in and it's pretty late so I don't really want to call and risk waking you up. After getting some things done and getting hunting stuff ready for the weekend it ended up getting pretty late on me. I did manage to check one thing... I fire the truck up twice and it had the hesitation twice in a row so I pulled the FCA connector and then cranked it over and it fired right up, no hesitation whatsoever, did this twice in a row too and no hesitation either time... although it sounded like sh*t once it was running and rail maxed around 27k or at least that's all the rail sensor could read. I only let it run like that for 2-3 seconds each time. Hooked the FCA back up and it was back to nearly dying and stumbling during crank.

So my next question... sounds to me like this has to be the modded FCA. I also noticed that once it went into high idle tonight around 1krpm (not 3 cyl) (it's cold as hell out) the rail pressure was fluctuating almost 1k psi between 10k-11k. So would you wanna send me a stock FCA and if it fixes the problem, I'll ship the modded one back to you and just call it quits with modded FCAs for now? I can't have more than 1k miles on this thing because the truck has been sitting so much with diesel prices being $4.20/gal out here. And to be honest, being this is the second one and it appears it's still having problems, I'd just assume go back to stock and be done with it. If that doesn't fix the problem, I'd be more than happy to paypal you enough to cover your shipping costs for the stock one to me and ship it back to you as well.
 
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I will send New Modded FCA...But even at High idle you should only be seeing 6800/7500 with No load.I will send factory used FCA also (tired & working),You can try them Both.I do wish you would just call, to much info is lost in typing, Also it takes xx time longer.
 
Thanks todd, I can call tonight, it'd be around 7 cst, not sure what time that is your time. Or if you want to give me a call around that time is fine. I've just been crazy busy until pretty late at night normally and don't want to keep putting it off. Thanks for the help though... Any chance I get, I'm throwing out the T&C name.
 
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