Defuel under load.

Nootch

Nootch

nosprkreqrd
Joined
Jan 13, 2013
Messages
1,360
Been chasing a code problem and it ended up being the MAP sensor in the air box as well as the one in the intake manifold. during that time, rail pressure was spiking to 29k. put maybe 120km on the truck with it like that, and always under low load until I could figure it out.

Now that there are no codes and rail pressures are acting proper when I ask for the power it just falls flat on its face. if im under 20psi boost all it well, but as soon as i try to make more than 20psi (rail pressure at 24k) it falls flat to 5k or less and then build up, but falls again with in a second. Thinking it was a fuel feed problem i replaced both the filters on the FASS to no avail.

First problem i figure is that the FASS is failing to give me good fuel flow to the CP3.

Second could be the CP3 was hurt when it was running rough under spiked pressures.

third injectors got hurt. This is least likely for me to believe as my experience says injectors go bad to open up and just pour fuel, not defuel and close up.

I am going to gauge the fuel feed right at the CP3 tomorrow and see what i get under the conditions it fails.


Truck specs are as follows.

FASS Titan 150
Bag-o-parts CP3 200K (15k on bag-o-parts)
66mm Industrial Injection
90HP DDP nozzles on year old new bosch injectors.

Before the sensor problems the truck was running perfectly fine and was making 45+psi boost.
 
I don't think so. Pressure was at 29k driving around and it dueled under load. Now my code is gone im sitting at 24k, same problem.
 
So after some reading i thought it might be the FCA, even though its relatively new from the Bag-o-parts. Checked flow and thumb over pressure from the FASS. good volume and makes good pressure. swapped out the spare FCA and put the last known good tune on the smarty. Fired up, and no codes present. Took it for a boot and same thing. soon as i hit 20psi, total loss of power and bunch of white smoke. rial pressure is now down to 23k when it happens, but that is from the tune. There is no popping or noises other than the regular turbo spooling down.

I don't think it is the gear pump on the CP3' but i have the spare of that still, and might swap that in.

Anyone have any other ideas?
 
Did you have the CP3 tested before the bag of parts?

Although I don't think it's the internals causing such issues, 200K is a pretty good amount of miles on it. Depending on how hard it was having to work before the upgrade to it.

Also if you want to test to see if it's the relief I believe I still have my stock one laying around somewhere that I could ship up to you to test with if you cover the ride. It'll be about a week before I could, but it's something if you're in no huge rush.
 
its an 05.


haven't driven it in a week. taking my service truck home cus its convenient.

Thanks for the offer AdamsMarshall for the offer, but i should be ok.

When i was driving up from edmonton it was performing very well so long as i was under 20lb boost. Being snowy/icy i was at 10psi the whole way and no noises or rail pressure fluctuations. stayed at 20-22k. Got to the shop where it was -25C and say for an hour and cooled off. when i left i got to 10psi boost and it defueld until it got warmed up and then it was back at 20.

with this information, i am thinking i might have an issue with the transfer pump on the back of the CP3. I have lots of fuel at the pump. i couldn't hold back the pump with a mechanics thumb, and lots of volume. once the temp comes above -25C i will take the tools to it again and pull the gear pump off of it. i have the stock one back in edmonton i can ship up and scavenge off of.

I know i won't get warranty off of the bag-of-parts gear pump, and thats fine. The CP3 wasn't tested before i put the BoP into it, but 200k km isn't a whole bunch. The pump didn't even have its gloss coat paint faded or heat cracked.
 
So i am getting nowhere with my issue. This weekend I took it down to my parents place after it was doing the same thing at 10PSI boost or less. i could hear an injector going south on me. Replaced the injectors and transferred over my tips. Tips looked fine. bout the same amount of carbon on each one. noticed the end play on my turbo was not happy, and there was some oil coming from the compressor side. So I put a kit into it to tighten things up and re-worked a new oil return line incase it was getting too hot and coked up the line.

Got it all back together and its doing the same thing. Hit 25PSI the first time, 20PSI the second. no codes just as soon as it makes power it dumps all the fuel out the stack as white and falls on its face. I don't think its my CP3 still, as in 3rd i can tack it up to 3000rpm and low boost and it makes 27K fuel pressure. with no defuelling. Before just before i swapped the injectors i couldn't even get it up past 2500 rpm without it farting and banging around
 
JUST cleaned and re-oiled it. Was one of the thoughts on why my turbo was leaking oil.
 
If its pouring white smoke out when it falls on its face i doesn't sound like its defueling, that"s raw fuel being dumped. The only time i had something similar happen is when the turbo would suck the pleats together on my stock air filter. Only did it on wide open throttle runs though
 
thats a possibility. I have digging to page 3 and 4 of google searches and seen that other people had the same issue and had the IAT sensor at the air box going south. after 3k on injectors and such, I can justify a new set of sensors and air filter to see if it helps. I will pull the filter and run it for a quick boot.
 
Auto trans?

If so might look at your valve body solenoids for trash.. I just recently had the issue your describing. Lockup solenoid had debris in it causing lockup at random while trying to load the truck on boost at the staging line.
 
Well, it looks like I am a Dumb Dumb Salad. Fixed the issue today after I went back to square one again. New filter went on, put the dust cover/bag on top and ran it. I got slightly better results. So I took the dust bag off, and bam, full power again. The black dust bag didn't look dirty or clogged, but I guess it was. For the ammount of time and money it just cost me, I will clean and replace filters as needed more often and not use the dust bag. FFS. Cleaning the old filter and re-installing it I didn't even think to check the bag for clogging.
 
I try to stay away from salad at all cost, good to hear you got it fixed. As I was reading through I was gonna suggest a short romp without the filter. I had a tandem do similar things to me when snow plowing a few years back, real dry powder snow, plugged the air box and truck was running just as you describe.
 
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It didn't even occur to me until it was the last thing i didn't change yet. ohh well, i am very glad the problem is fixed. just cost alot to get there. I originally put the bag on to keep the debris out of the pleats in the filter, but after this, i will just spend the extra time cleaning the bastard.

thank you to all who helped with suggestions and advice though this process.
 
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