Rough Idle Problem!

[ACerf]

Applying the brake may put a little load on the engine through the hydroboost system. This will add a little more fuel which may smooth the engine.



When you are in neutral, do you have your foot on the brake to keep it from rolling? May explain the smoother idle in neutral.



I agree with JHardwick--injectors.



Randy

I did not have my foot on the brake when it was in neutral. I was parked on level ground, but I was prepared to apply the brake if necessary :-laf

I left the truck at the dealer this morning, and told them to keep it until they can fix it. They gave he a rental car in the meantime.

I mentioned to the tech that maybe he missed something when checking the injectors. It just is one of those problems that is not easy to find.



I got jumped on about the 2nd FCA. The tech told me that it is not an FCA but it is fuel control item near the back of the engine. He did not give me the offical name of the control or its exact location. I think he was trying to confuse me!

The EFC in TSB 14-004-05 is a Electronic Fuel Control. I don't think that is the problem with my truck, the TSB mentions Surging. I don't have this problem.

And the comment I made about the TSB being a TC. The correct term is TCC has it is called, is for information from STAR and is not replacing the TSB. But is does provide info that a tech can use to trouble shoot a problem. So I stand corrected! I must have misunderstood him.

 

[Missouri Mule]

On the second fuel control your tech mite be talking about the pressure relief valve. I beliveve it is on the rail but not sure. I have read it is very expensive.

 

[DerekW]

All right here is the puzzle; Since the FCA was changed the truck idle is okay in Neutral. However, if it is Park it starts to idle rough, but not as bad as it did before changing the FCA. If you apply the brake pedal when it starts to idle rough in Park, it smooths out for the most part. Why?

my truck used to do this when it went into highidle mode. if i recall it only used to do this while in park. it sounded like crap and was rough. when i went with new injectors from bosch with industrial injection 90 hp nozzles installed all from industrial injection it all went away and i forgot about when my truck used to do this until reading this thread this far along. injectors are good for about 100k with sotck fuel filter setup after that they are pretty wore out in the injector tips bodies and all. new injectors will bring your mileage back to life. we on our 2nd 04. 5 we held out as long as we could then spent the 3k injectors we made our money back in two weeks worth of fuel savings and saw less of our buddies that run our fav fuel station. talk to cody at industrial injection he is realy good. i deal with him alot. this month i bought new fass pump as old one died, sent in my old one to him, new 90hp injectors, and now dual cp3 with 2 new injector pumps as stock one is near death. cody is a tough one to get ahold of there but worth being on hold to talk to him out of all the other employees.

 

[ACerf]

FCA did not correct the problem. Tech did extensive testing and it appears that the problem maybe the In-tank transfer fuel pump. I had the pump replaced a year ago under warranty (TSB; engine mounted pump to in-tank). Tech told me that the pumps that were supplied in kits were giving problems. STAR told him that the problem was with me idle the truck to long and causing carbon build-up. While I wait for the pump to come in they are having me put some Centane Booster in fuel to clean it out. We will see more up dates to come.

 

[AllianceDiesel]

yep idleing a common rail is probably the hardest thing you can do to it, ill put money on it that you probably have injectors going bad, seen it many times.

 

[ACerf]

yep idleing a common rail is probably the hardest thing you can do to it, ill put money on it that you probably have injectors going bad, seen it many times.

I personally don't think I idled it that much. Injectors were checked out and found no problem with them. And this was done 3 times before deciding to replace the Transfer Pump. We will see if that corrects the problem.

 

[AllianceDiesel]

if that doesn't fix it, ask the tech what your injector return was.

 

[steved]

My vote still goes on injectors.

I agree... mine idled rough right before the injectors failed.

There really is no way to test worn nozzles...

 

[ACerf]

I agree... mine idled rough right before the injectors failed.



There really is no way to test worn nozzles...

I guess what is checked is; flow, or spray pattern. You will have to ask Mopartech. What doesn't make any sense to me is that you would think that I would have poor acceleration or reduced MPG. And that it would idle rough even in Drive.



Mine was idling rough just before the Transfer Pump fail, and has ever since. That was about a year ago and 15,000 miles of driving.

 

[ACerf]

Mopartech: question; how many quarts does the Power Steering system hold? I want to replace the fluid. Any easy way to do it?

 

[AllianceDiesel]

honestly, I don't know because we had bulk atf+4 and I would just add it until it got full. The best thing to do is, drain the system, then fill the resevoir, start the truck up just for a second than shut it off and fill it again until the fluid doesn't drop, then start the truck and turn the tires lock to lock and check your fluid when its running, most likely you will have lots of bubbles so you will need to let it sit for a while until it gets all the air out and check it again. I couldn't find a spec on how much it holds, guess it just depends on how much you get out of the system

 

[steved]

I guess what is checked is; flow, or spray pattern. You will have to ask Mopartech. What doesn't make any sense to me is that you would think that I would have poor acceleration or reduced MPG. And that it would idle rough even in Drive.



Mine was idling rough just before the Transfer Pump fail, and has ever since. That was about a year ago and 15,000 miles of driving.

Its how well they seal... not flow or spray.



I had no other signs they were worn other than a little more than normal smoke under hard pulls... mileage was fine and power was fine.



Depends on the load on the engine...

 

[ACerf]

After having two dealers trying to fiqure out the rough idle problem. It came down to a bad CP3 pump. The FCA did not do anything to correct the problem. The changing of In-tank-transfer pump did help for a while, but was back to doing the same thing. I did however notice that the performance was better with the new pump. It was however not any of the injectors causing the problem. I thought if it was I would have had other problems with performance or fuel mileage. In fact my fuel mileage has been better than ever since I have been using the Centane additive. I just glad that this problem has been put to rest!

 

[Dbonzi]

your truck still running fine?

I am fighting the same issues.

don't know what to throw at it.

how can you tell if the injection pump is bad?

Dennis

 

[JimB1]

My '07, 20k miles, began just a touch of rough idle with first cold start, when driving cross country this summer on straight #2. Cleared up soon as I rolled away.



I always fuel up at Seaport Petroleum here in Seattle, with B50.



Sales rep at their desk recomended Power Service, Diesel Fuel Supplement +Cetane Boost with Slick Diesel, part # 1025, 32 oz bottle, additive for which they are also distributor.



Costs about $8 per 32 oz bottle, case price.



I use the 100 gal treatment ratio.



Drove about 50 miles right after treating first tank and never had rough idle since.



Sales rep seemed pretty knowledgeable talking about current ULSD API refining process and allowable lower cetane rating contained within ULSD standard.



Don't even get the briefest small smoke puff, light or dark, on cold start, where before I did and before the rough idle issue on straight #2.



Also with freeway on-ramp near full throttle roll-on, can't see any haze where before I could.



Bone stock everything.



This is the least expensive first thing to try when troubleshooting rough idle issue.



From now on I'll always treat all my fuel.

 

[Dbonzi]

I have tried this

It helps alot but doesn't take the miss away

I make my own bio diesel, can only burn it in the summer,

all summer there is not a miss but when switching to ulsd it has a bad miss

or rough idle. Just thinking that the bio with better lubrication is masking the problem.

I would like to get this resolved

 

[ACerf]

The CP3 pump did in fact help, but in the end they replaced the injectors. The Centane additive did not do anything for correcting problem. But I wrote it did help the fuel mileage. I am still using the Centane booster, I buy it by the gallon for $17. 99 at Auto Zone.