[Fine 5.9]

looked everywhere on here for other threads with my symptoms with no luck. so here it is... just switched from h and s to efi live from fleece about 3 weeks ago. ran great till a few days ago. was driving to work at a steady speed and it had a little hiccup miss. Didn't think much of it. prior to this (night before) i got a map sensor code two times in a row after deleting them. when i went to leave work i had to give it a little bit of heavy throttle to keep up started missing/ popping. any time i would put a load on the motor as in heavy throttle or go up a hill it would have what i call a little hiccup miss or cut out got a split sec and you can feel the truck jerk back. when i made it home it had the a slight miss at idle but it would happen a random and just barely feel the truck jerk slightly. so i drove back to work and switched out both the sensors on the air intake and that seemed to help it.didnt notice a miss at idle and it feels like i have to really try to get it to miss under a load maybe once you get the revved up to 2800-3000 and get the boost around 40 it will really miss and jerk its worse. rail psi stays between 23-25kpsi. i think its electrical but what do i know. lol doubtful its an injector cause they just got tested a year ago and 5 rebuild by area diesel. has no smoke white at all on start up. any help is much appreciated!!

 

[Farmerbrown]

You had just 5 of the injectors rebuilt? I'd start with the one that wasn't rebuilt.

 

[Fine 5.9]

I done a cylinder balance test with a snap on scanner and it all came back good all cylinders were 100% equal even when i would drive it and get it to miss. on my way home again today i got P0107(map sensor) i forgot all about the map sensor on the back side of the pusher intake. So i gave a little tug on the plug and it slid off the sensor!! I put it all the way back on and went for a drive. I got it out on the high way going up a big hill in 5th and let her have it. Of course started missing but not as bad i don't think. It didn't jerk as bad when it missed and i have to really lay into it. No more missing at idle tho. i did notice rail psi was around 22k going up the hill. i don't think that's low enough to make it pop like the rail is going dry do you? Also after i got into it hard another time it through the p1507. crank case restriction. I have about a four foot hose coming off the valve cover venting into the atmosphere. crank case filter has less than 15k miles on it. any more ideas where to look? I wanna look over everything before i take the injectors out and get them tested. Thanks for the help!!

 

[Fine 5.9]

I also have a mechanical fuel pressure gauge from the fass to the cp3 and it drops from 16 to 15 psi under wot. I cant decided if its a fuel issue or electrical...???

 

[Fine 5.9]

what more information do you guys need? Give me stuff to try and ill do it! would a connecting tube cause this? I'm going look under valve cover tonight and check over injector harness. I have reused the tubes about 4 or 5 times but I don't know what a bad one looks like. Any help would be great!

 

[rjp]

Hows crank time?
Watch rail pressure as you crank and take note?
Got a temp gun? Shoot manifold at each cylinder and note temp differences.
Bad connection at harness plug and are loose connection at injector.

A few things to look at and report back.

 

[Fine 5.9]

Thanks for the replay! Crank time is normal. I know it idles around 5-6kpsi. I will shoot the manifold tonight and record the rail when i crank. I did remove the valve cover last night. Checked all the injector wires and Ithink the connecting tubes are fine casusethere is no fuel in the oil. i checked over all the sensors and grounds making sure they were all plugged in. so after all of this itook it for a drive just to see. It had one slight miss to it when i slammed into it going up a hill. which is much better than what it has been. drove for another 5 miles and tested it again on a hill. NO miss at all. stopped at a buddys places and stayed for 15 mins. on the way home it missed just like it did a few days before. you get it under a load and it has a few hiccups. its not a dead miss at all and the truck still has great power

 

[Fine 5.9]

When I start it the rail spikes to 16kspi then levels to 5.1-4.9kpsi. I didn't have much time to shoot the manifold temp but here is what I got. cold they were all 56-57 deg. after I few sec I got CYL#1-60 CYL#2-62 #3-62 #4-60 #5-66 #6-65 after a min or so.. CYL #1-65 #2-70 #3-73 #4-67 #5-76 #6-70. had to leave for work after that. I can get a better one tonight if needed. so now I know #1 is little cooler and #5 is a little warmer but I don't think its that much of a difference do you?

 

[rjp]

No that seems normal. Obviously if its running fine at the time you checked the temps, they will show to be within reason.

To completely rule it out I would try to catch it when its running bad.

Does it do this under light throttle as well as wide open? Sorry if noted already, my mind is tied up remembering a bunch of other things at the moment.

 

[Fine 5.9]

Is any time its under a load or heavy throttle. Right around 55% throttle and up. The more rpms it goes the more it misses and pops. Sometimes a little puff of black will come out when it does it. It runs pretty clean other wise. Also no boost leaks or blow by. Motor was fully rebuilt under 10k ago. It hasn't missed at idle since that one day It all started.

 

[Fine 5.9]

i just noticed something.. if you roll into the throttle really slow the rail stays around 26-27kpsi. if you keep it up there it dont pop or miss. but if you really slam into it and keep it on the floor when the turbo is trying to spool it will start to jerk and do its normal thing. but the rail is still around 23kpsi. never below 22k. to explain the pop it is almost like a back fire maybe? this really makes me think fuel prob but after i got into it fast and made it jerk a few times i went to go around a turn and was like 15-205 throttle and it did 2 little light jerk and misses.. im really at a loss on this

 

[rjp]

What size cp3 are you running?

If its an actual popping kind of noise my guess would be an electrical connection of some sort. Check your wiring, specifically the fuel rail sensor wires. Move all wires and plugs that have something to do with that circuit while the engine is running.

It could still be a fueling issue if it feels more like your turning the key off and on while under WOT. Have you monitored lift pump pressure while this is happening? How about a full tank of fuel versus 1/4 tank?

Happen to notice if its boost specific? Note the psi when it happens, is it consistent? 36psi?

Process of elimination, you'll:thumbsup: find it!

 

[Fine 5.9]

Stock cp3. I have 60% exergy nozzles in it but they tuned the injector duration down so it would hold rail. Fass stays at 15-16psi. Its not boost activated. I'll see if a full tank helps tonight. It doesn't sound or feel like you turn the key off at all. Its def more like a pop or backfire.. I'll check all the plugs on the cp3 and the fuel fail sensor tonight and let you know what I come up with. I did put a beans fuel sump in it the night before it started doing this but I don't think it has anything to do with it. I really appreciate all the help!!

 

[rjp]

You wouldn't think so. I am a firm believer on if it didn't do this before and now it does it may be the issue.

I would definitely look over your work to make sure all is good on the sump.

 

[rjp]

The pop backfire noise definitely sounds like electrical though. I chased this on mine back when i built this motor.

Brand new wiring harness had a broke wire in the plug at the fuel rail sensor. every time the engine would torque over under heavy load it would pull on the harness and make the connection issue.

 

[Fine 5.9]

All is well on the sump. Got the fuel level down to an 8th and filled it all the way up. Still the same. I have some more info for you that's odd. Driving home in the rain tonight it was popping/missing happened more often than it was. It would do it just normal driving. It wasn't as violent in the lower rpms tho. If you hold the brake and give it a good amount of fuel it seems to do it more. Also any time it pops louder a small amount of black smoke comes out the stack, just a quick puff.

I noticed something else very odd on the drive home. I looked at my edge cts insight and thought i seen the rail pressure drop then come back up. So i watched it really close with the truck set on cruise control. Rail was around 8k and would all of a sudden drop to like 3.2k and shoot back up to 8k. I caught it doing it around 4 times on the way home but it never missed or popped when it would drop. CTS messed up or think its accurate? Its only a mo old.

After i got home i checked all plugs and wiring on the back of the rail and cp3. All looked well but couldn't check out the wires that well cause they are all wrapped up. ! followed them as much as i could. I hope this helps!!

 

[Fine 5.9]

I done a free rev to 3k and it is smooth the whole way. I revved it up slow and got into it fast still no miss or pop.

 

[rjp]

Have you noticed it worse with lights on or lights off. Another scenario to look at is your alternator. Lack of amperage will play havoc with injectors.

Voltage may show ok but running amps may be diminishing. How old is the alternator?

Lots of things could cause this, just have to narrow it down.

Do things like crank and turn all power draining sources off. How does it idle, does it miss when you try to brake boost, at what RPM, whats rail pressure doing.

Do same thing with lights on. Anything change?

 

[rjp]

At least youve determined you have a rail pressure issue. Now just need to find out whats causing it.

If you've moved all wires and connections while the truck is running and it doesn't act up, it may be an injector acting up.

It would be great if you could get it to act up and isolate the potential bad injector or connector tube leak with temp gun. It would save you the next step of process of elimination.

 

[rjp]

If you have any doubt about the connector tubes being tight enough, I would start there.

The popping still gets me though. I've had bad injectors and leaking connector tubes and it normally just white smokes, misses and runs bad.

I guess it could still be an issue in the solenoid part of the injector.