Feels like it's hitting on 3 at idle

[MZahn]

Driving the 60 mile commute this AM and truck ran fine until 1st stop signal in city. It felt like and extreme miss & shook the truck. It smoothed out upon leaving the green light but kept occurring at in gear stops while brakes were applied. Neutral didn't help and it coughed once.

I put + 50 HP injectors in it at 275K or so miles. Have had no problems for 30K miles since.

It felt like it was idling on 3 cylinders. No check engine or Codes on my OBD2 reader. It's parked and driving the car tomorrow. I looked at the DR service manual and realized this could be a problem with way too many sensors or a delivery bank in the ECM. I'm a novice after 10 years and could use some advice.

 

[MZahn]

Sorry, Mods please move this down to where I should have posted....

 

[DonFitzwater]

First things first, make sure which cylinders it's NOT hitting on. Don't go chasing your tail with sensor or electrical problems right away. Usually a sensor or harness failure will show up as a dtc. Mechanical injector failure can be undetected by the PCM. One of my favorite tools to isolate which cylinders aren't firing is a hand held temp gun. Shoot each cylinder at the point where it dumps into the exhaust manifold.

Also, don't overlook fuel pressure from the lift pump as a basic check.

 

[cerberusiam]

It sounds like you got a bad load of fuel, might try heavy dosing with additives and a fill up. An electrical problem that would cause dropped cylinders will show as a DTC and CEL. A mechanical or fuel problem won't. It could be anything from bad fuel to injectors full of FOD. A filter change and housing drain would be worth the effort to see if there are any filings or junk in the filter.

 

[AH64ID]

When you did the +50 injectors it was new bodies and nozzles right? Not just nozzles?


I agree with cerberus and would check/change the easy things first.

 

[MZahn]

When you did the +50 injectors it was new bodies and nozzles right? Not just nozzles?



I agree with cerberus and would check/change the easy things first.

I used 6.7 nozzles at the recommendation of Injectors Direct. Rebuilt Injectors.

I agree that it seems like a fuel problem. I wish it would have thrown a code to give me a hint.

Could the harmonic balancer cause this?

 

[MZahn]

It only has an 1/8th of a tank now so I'll change the filter, give it a heavy dose of power clean and fill it to see what it does.

Thanks for all of the advice.

Cerb, hope that part I sold you years ago is still working in that truck...

 

[cerberusiam]

If you got remans from ID then I would suspect them. Dose it well with lube and cleaner and see if that helps, if not you might have to pull them and get them checked. Not positive but don't think the 6.7 nozzles will work on a 5.9 injector, the injectors are a bit different I do know. If you got 50 HP advertised injectors the nozzles were probably the BMS marine 50's.

The OD lockout box is the best mod hands down I ever made to this truck. Still working like a charm and making towing much better.

 

[AH64ID]

6.7 nozzles in a 5.9 seems odd. I do realize the difference is only 2° from the MY03 spray angle but I also thought there were other differences. I do know that 6.7 bodies don't like 5.9 ECM voltages and drivers.

 

[MZahn]

The tubes are 6.7....

 

[cerberusiam]

The 6.7 tubes on a NEW injector should not be an issue. On a used reman that is another story. The angles on the mating surface are the same form 5.9 to 6.7 but sometimes they just don't work right. Usually that result sin hard starts and long crank not misfires. They are probably fine but reman injectors are just a crap shoot.

 

[MZahn]

Changed the fuel filter, dosed it heavily with power clean on the 1/8th tank and when it started it smoothed out. I ran it up to 2000 rpm a few times and let it idle for a half hour. Seems to be solved. I kept the old filter for any advice of dissecting.....

 

[MMeier]

Did you take it out for a hard run ?

 

[MZahn]

Not yet, just did that ^ in the driveway. Fueling & romping in the AM.

 

[MZahn]

I'm 55 & a 70 year old neighbor that walks my road told me today that he likes the sound of my truck in the early AM. I'll need to have him tell me if he hears a difference next chance.

 

[MZahn]

It was rough again when started this AM. Drove 3 miles and it idled well at fuel pump. Smoke was black on the way there and grey when I drove home.

The smoke was black when I romped. Idled smooth once home... WTF

Look at all the money I saved on injectors.

 

[DonFitzwater]

Sounds like an injector hanging open or closed. My injector failures would almost always show up at idle and at cylinder would cut out. Used the temp gun on the manifold trick to find the culprit.

And you'd best be careful romping on it with possible injector problems. Many engines have been torched by this, especially if the injector is hanging open. It burn the hell out of the piston like a blow torch. Oh the joys of common rail!!

 

[MZahn]

Thanks Don. It's parked for now & destined for my friends shop before any damage will occur. Kind of a bummer as it has been a great truck. Only 304K miles.

Just needs a little T.ime L.abor & C.ash.

 

[MZahn]

No codes on the truck at friends shop today on his Snap-On Solus scanner. He said ask you guys if 14# of boost is normal at idle. His 2001 is zero psi at idle. He is not as familiar with HPCR.

Thanks

 

[cerberusiam]

No codes on the truck at friends shop today on his Snap-On Solus scanner. He said ask you guys if 14# of boost is normal at idle. His 2001 is zero psi at idle. He is not as familiar with HPCR.

Thanks

No, 0 psi at boost is normal not 14. That said, if it is being read from the data bus the reader is probably not correcting for ambient pressure like it should. A hanging injector will show no codes and destroy the engine in short order. If it is rolling out black smoke at low throttle then there are some serious issues.