Starting issue making me crazy!!!

[jman]

I have a weird starting condition that is driving me crazy. If I turn the key on and start right away it fires right up. If I turn the key on for say 5 seconds like I'm waiting for the WTS light it stumbles and chokes and gags to a start. What ever is causing this seems to be related to how long the lift pump runs. I have the flash that makes my lift pump run for 30 or so seconds when I turn the key on. It's almost like it is getting too much fuel if I let the pump run to long.



I have the original lift pump on the filter canister and it has 109K on it and I replaced the FCA. Fuel mileage is 19-21 mpg and it runs great. Hopefully someone has some insight on this one. I would love to get this fixed someday.

 

[rbattelle]

Wow, that's a tough one. Very strange symptoms.

But I wonder if it's the LP going bad on you. Like it's not really putting out enough flow. Initially, when it first starts up, it gives a nice surge of fuel to the CP-3, allowing an immediate start.

After a second or 2, the surge peters out, and the flow rate drops off. This makes it harder to start.

A fuel pressure gauge might tell you what's going on for certain. I'm just taking a guess.

Ryan

 

[jman]

It is weird that is for sure!!! I can start it and shut it down. Then turn the key on and let the pump run and re-start it and it will do the same thing. It doesn't matter if it is the first start of the day or the tenth. It can be fully warmed up and if I turn the key on and wait a few seconds it will stumble on itself. Its been doing this for a while and when I changed my fuel filter last time I figure that would be the moment of truth if it didn't refill the filter canister, but it did and fired up. When it does stumble it does give a little puff of smoke, but nothing too extreme.



The thing that bothers me the most is if I have to wait for the WTS light to cycle it starts just as poorly as just hitting the switch without waiting for the grids.



Maybe I should just grab a new lift pump and change it out and see what happens.



I've thought maybe air in the system, but I have no long crank issues or anything else that would lead me to getting air in the system.

 

[rbattelle]

Maybe I should just grab a new lift pump and change it out and see what happens.

Unless you can get a fuel pressure gauge hooked up, I'd say that's a good idea.



Ryan

 

[jman]

If the lift pump turns out to be the problem then it has had a slow death because I have been fighting this for quite a while. I will order one from Geno's tomorrow. I was thinking of getting an Air Dog, but I would prefer to solve the problem in stock form, before I start throwing another iron in the fire.



I took it to the dealer before the warranty ran out and of course it started "normally" in there eyes. #@$%!

 

[jman]

Is there some sort of pressure check valve in the lift pump that can go bad and open to return fuel to the tank as the pump is running so excess pressure isn't created??? I guess I am just baffled on how letting the pump run longer would cause a more difficult start.



Didn't someone say you could buy the canister mounted lift pumps at NAPA now? I know Geno's has them, but didn't want to wait for it to ship.



Please chime in if any of you have any other ideas on what is causing this.



Thanks rbattelle for your insight. I haven't ruled out the LP yet just don't want to start throwing parts at it, although a new LP is probably a good idea with 109K miles!!!

 

[rbattelle]

Is there some sort of pressure check valve in the lift pump that can go bad and open to return fuel to the tank as the pump is running so excess pressure isn't created???

I don't think the pump has an internal bypass as you describe. But I'm not sure.



Even if it did, and that bypass went bad, there's no way I know of to open the pump and change it. I believe the pumps are factory sealed.



Ryan

 

[jman]

Well today I dropped my daughter off at school and when I got back in to restart I turned the key on and got sidetracked for a few seconds. Sure enough it stumbles to a start and is idling rough. Get on the highway and travel toward home and everything seems normal. I have a downhill grade before my turn and when the tach hits about 1100 it starts knocking a little. I get to the house and into the garage and the idle is still rough. I increase the idle speed and of course my idle sticks at 1000 rpm (a whole different issue). I get it idled back down and it is back to idling smooth again.



When I took her to school I went from key off to start and it fires right up like new. Maybe I should take the lift pump off and roll like the D-Max.



This thing is making me crazy lately.



I have to go pick her up later today, so we'll see what happens.

 

[jman]

I'm bringing this post back to the surface again. I talked to Laser Bob in Greeley (Great Guy!!!) and he was stumped as well. He thought maybe I should change the Crank and Cam position sensors and see if that helps. Do you guys think going from key off to start without waiting isn't letting it "think" and I'm just lucking out?



I talked to a guy at Cummins about my idle sticking and he thought maybe I had some injectors going south. He said he had heard of some doing this, but they all ended up in Dodge shops and he hadn't heard what the cause was.



I did notice that when it sticks it doesn't sound to smooth at the tailpipe so maybe a couple of injectors are causing this because of the ball and seat problems. He suggested a heat gun to see if I had a couple cylinders hotter than the rest. This has been going on since 80K and I would like to find a cure.



Sorry so long, just want to give you guys as much info as possible to see if we can work it out.



Thanks!!!!

 

[MMeier]

Well today I dropped my daughter off at school and when I got back in to restart I turned the key on and got sidetracked for a few seconds. Sure enough it stumbles to a start and is idling rough. Get on the highway and travel toward home and everything seems normal. I have a downhill grade before my turn and when the tach hits about 1100 it starts knocking a little. I get to the house and into the garage and the idle is still rough. I increase the idle speed and of course my idle sticks at 1000 rpm (a whole different issue). I get it idled back down and it is back to idling smooth again.



When I took her to school I went from key off to start and it fires right up like new. Maybe I should take the lift pump off and roll like the D-Max.



This thing is making me crazy lately.



I have to go pick her up later today, so we'll see what happens.

That almost sounds like an FCA issue.

 

[jman]

I replaced the FCA and it did nothing for this. It did quiet the acceration knock down a lot.

 

[BGlidewell]

batteries??

 

[rbattelle]

I don't understand replacing the FCA and NOT the old-style canister-mount lift pump.

You said "I don't want to throw parts at it", but that's what you're about to do (FCA, crank position, cam position).

Ryan

 

[MoparDave]

I'm just throwing this out there but maybe an injector that's leaking, not fully seated/ closed. not sure if that possible or not

 

[WKruger]

Might be a shorted wire. I believe there is a thread on it.

 

[Slow Six]

I had a starting problem with mine last month. I took it to a good diesel shop where they went directly to the crossover tubes and injectors. Three of the crossover tubes were loose and showed signs of erosion (leaking). After a lengthy conversation with the tech I opted for new crossover tubes and injectors. The results were great as this engine has never started as well or ran as quiet as it does now. Also improved driveability. Tech explained to me that the rail pressure has to be at a minimum pressure before the ECM will let the engine start and that the leakage at the crossover tubes can cause hard starting. This may not be a solution to your problem but it solved mine. I had it to a dealer before this and I don't think they really knew where to start looking, but they were talking mega $$$. My fix was expensive but reasonable and I was treated fairly and it only took one visit.

 

[jman]

I'm not going to throw parts at it, I was simply trying to brainstorm some ideas. I got a name of a shop in my area from another member that seems to be very knowledgeable of the CR engines. I'm taking it to him the first week in February to troubleshoot the problem, rebuild the injectors, install upgraded nozzles and install a FASS setup. I figured I would rather put some money into this one than deal with a new 08 and the emmisions junk. I decided to take it to someone that had the knowledge and equipment to repair it. It is pretty sad that after 2 visits to the dealer they kept telling me it is "operating as designed". I almost wish you could buy a new vehicle at a discount and opt out of the warranty, because it is usually more of a headache than it is worth. The only things I got repaired under warranty were 2 u-joints and ball joints. Chump change compared to what this is going to cost me.