truck won't start

[TCluff]

My, my! They just KNOW its an injector causing hard starts and rough idle, huh?



Kinda like every one KNOWS BFG's cause DW... . hmmmmmmm??? :-laf:-laf





Injectors are definitely one source, but, there are others that are just as common or more so. A search here and on about any board will show that if you dig deep enough. In fact, there is a thread over on the Cumminsforum with the exact same symptoms on 3 different trucks. Two have what is obviously bad rail pressure reliefs and the 3rd is looking that way also.



Don't shoot the messenger here, but, before I would even think about injectors there other items that will cause the SAME symptoms and have been proven so.

if you read what i wrote, hard start (but runs great after started) most expierienced technicians would already know there is one or more injector failing on the return side, a weak rail relief could cause hard start, but would come with low top end power,a bad fca, no hard start, just surging and wrong rail pressures at given throttle position and load ie not running fine after started, a bad crank or cam position sensor can cause hard start but will usually but not always come with a code and usually doesnt run great, the deal with the injector return failure is it wont build enough rail pressure at cranking speed to fire the injector, ether or pull start will speed the pump enough to maintain rail pressure and in most cases the pump will outflow the leakage causing the injector to run normal because pressures are in check during low idle rpm and normal operation, not shooting the messenger but just a few key points and this has been happening on a regular basis...

 

[AllianceDiesel]

I don't know how you could of hit the nail on the head any better, great points.

 

[cerberusiam]

if you read what i wrote, hard start (but runs great after started) most expierienced technicians would already know there is one or more injector failing on the return side, a weak rail relief could cause hard start, but would come with low top end power,a bad fca, no hard start, just surging and wrong rail pressures at given throttle position and load ie not running fine after started, a bad crank or cam position sensor can cause hard start but will usually but not always come with a code and usually doesnt run great, the deal with the injector return failure is it wont build enough rail pressure at cranking speed to fire the injector, ether or pull start will speed the pump enough to maintain rail pressure and in most cases the pump will outflow the leakage causing the injector to run normal because pressures are in check during low idle rpm and normal operation, not shooting the messenger but just a few key points and this has been happening on a regular basis...

Exactly!! Now you have articulated just exactly what I am pointing out. You cannot make a snap decision that its injectors without a LOT more supporting information. A 2 sentence answer will not convey what you just said. If one knew what he was looking for and the implications, one could glean the info from the whole thread and MAYBE infer the same as above, MAYBE.



Not disagreeing at all, just pointing out there is a process and other things that can contribute to the final diagnosis. You would be surprsied just how many threads touch this very subject without ever coming close to the info in your 1 post.



Thank you for clarifying and summing it up very well.

 

[AllianceDiesel]

Ya your way is probably the right way, but when your on commission and you have seen probably at least 30 trucks with the same problem your gonna test the injector return or cut-out an injector before you try testing the rest of the stuff, once you find the bad injector you replace them, if that doesn't fix it your continue the other tests, I would rather spend 20 mins. on each truck testing the injectors and getting it right 99% of the time than spending 45 mins testing all the trucks and only fixing the FCA or fuel rail pop-off !% of the time, its all about making money.

 

[cerberusiam]

Ya your way is probably the right way, but when your on commission and you have seen probably at least 30 trucks with the same problem your gonna test the injector return or cut-out an injector before you try testing the rest of the stuff, once you find the bad injector you replace them, if that doesn't fix it your continue the other tests, I would rather spend 20 mins. on each truck testing the injectors and getting it right 99% of the time than spending 45 mins testing all the trucks and only fixing the FCA or fuel rail pop-off !% of the time, its all about making money.

You are exactly right, considerably more accurate at diagnosis than most of us, and you make a living at it. That is the real worth here. There is no "right" and "wrong" when its your job, only results and how you get compensated.



Most people are going to read the first part to see the problem, jump to the last page for the solution. Go out and fix it, THEN read the content. If they did not know there is some intrinsic knowledge avaialble to reach the "bad injector" conclusion it could be an expensive lesson.

 

[fourwheel1]

I had 03 that would not start except on either. Turned out to be rail pressure relief valve. I thought too it may be injectors but they are fine. Take out relief valve and put in a bolt to, if it starts like mine did then thats your problem. Very simple to test.

 

[fourwheel1]

Mine also ran fine after starting on either. Even towed gooseneck just fine but it would not start until i blocked off relief valve. changed it and has run fine for several months now

 

[AllianceDiesel]

and thats the funny thing, I have not replaced one relief valve or fca, I have tested many because its one of the tests for when you have to order injector through the star center but never seen one bad, but I hear about them all the time, but there are some dealerships that replace many of them but no injectors, I guess it just depends on what part of the country you live in.

 

[cerberusiam]

I would pull the tank sending unit and pickup and check everything very closely. If the pump is good, its new but you never know, I wonder if your previous fuel contamination has not plugged a screen, fouled a line, caused a breakdown in the material, or ??? Either way, if the gauge is right thats not enough fuel pressure. If this has been going on for a while the pump may very well have been eating itself up over a period of time.



Twas me, I'd make sure the fuel pressure problem at the CP-3 is solved then go from there.

 

[AllianceDiesel]

Let me tell you something about the lift pumps in the tank, they actually test them using flow not pressure, they really don't care about the pressure but I think the spec is 540ml in 30 seconds at the lift pump, but I would have to double check it



Andres, I will do some looking on your problem tomorrow like I said I would, hopefully I can think of something.

 

[Coalsmoke]

if you read what i wrote, hard start (but runs great after started) most expierienced technicians would already know there is one or more injector failing on the return side, a weak rail relief could cause hard start, but would come with low top end power,a bad fca, no hard start, just surging and wrong rail pressures at given throttle position and load ie not running fine after started, a bad crank or cam position sensor can cause hard start but will usually but not always come with a code and usually doesnt run great, the deal with the injector return failure is it wont build enough rail pressure at cranking speed to fire the injector, ether or pull start will speed the pump enough to maintain rail pressure and in most cases the pump will outflow the leakage causing the injector to run normal because pressures are in check during low idle rpm and normal operation, not shooting the messenger but just a few key points and this has been happening on a regular basis...

Thank you for taking the time to post that

 

[betterthanstock]

There are caps you can put on each injector line.



Another place for leaks is the connector tubes into the injector body. Very sensitive to torque, and easily damaged (cracked injector body if too much). A real weak spot of the Cummins design. You could loosen and retorque each connector tube (the internal ones, after you remove the external lines).



Cummins should learn from Isuzu on that D-max injector design, all external, outside the valve cover.

 

[PLaFrombois]

I've had my truck to the dealer because of this problem. They've checked crank and camshaft sensor. They tightened the transfer tube, and replaced the grid heater gasket. It started every time they tried while it was in the shop. I came to pick it up, and wouldn't start. I raised the question about a bad injector, and was told that wouldn't be the case unless you had black smoke on start up from excess fuel in the cylinder. They ordered and installed a new CP3 and tested the lift pump. That was yesterday. I didn't get a phone call today as to what else they tried.



Paul

 

[cerberusiam]

What I don't understand is how a tiny shot of ether (I mean tiny) starts it up, and it idles with a rail pressure around 5K and runs to 7 or 8K with a light touch of the gas (in the garage). So apparently the bad injector(s) seem to work?

The injectors do not fire right at that low off pressure. Consequently there is not enough fuel injected to get a combustion event going. The ether provides that, irregardless of what the injector does.



You either have an injector that is bypassing too much fuel and not letting rail presure build with just the starter spinning it, or, there is a problem in the CP-3. I have seen both cause the same problems.



A transfer tube leaking will generally cause it too make oil as it leaks into the engine. If you have not touched the injectors since this started and it has gotten worse since the bad fuel I would not suspect the transfer tubes.



As I said before, the contamination can cause the pump or injectors to start having problems. I think I would pull the injectors and send them to somebody that will examine them closely for problems. If the CP-3 is causing it its a good bet there will be metal in the injector bodies and you will know you need a pump.





Good luck, hope you get it figured out.

 

[EDaigneault]

I have exactly the same problem and i have a #6 bad injector.



03, 305, h. o. , 4x4, qc, lb, dark slate met, nv5600, 3:73

2" lift, banks 6gun-speedloader-pyro-boost, 4" magnaflow, bd short shift, k-n fipk, 33" toyo, pml diff. cover, hellwig swaybar, amsoiled, reccaro seat, modified suncoast creation ram air hood .

 

[icman95]

depending on miles accumulated it is some times cheaper in the long run to put in a 6pack. it is less expensive than one at a time.

I gotta agree with this. I paid $700 for a 6 pack of performance injectors and then a few hundred more to have a guy install them. Total cost was way less than what you paid for 2 injectors. I realize that you were in a bind and once the dealer opened it up to diagnos it, you didn't have much choice, but in the future you might look into aftermarket stuff.

 

[cerberusiam]

I gotta agree with this. I paid $700 for a 6 pack of performance injectors and then a few hundred more to have a guy install them. Total cost was way less than what you paid for 2 injectors. I realize that you were in a bind and once the dealer opened it up to diagnos it, you didn't have much choice, but in the future you might look into aftermarket stuff.

Ummm..... CR injectors are $1100 to $1300 APIECE. If you don't have to replace bodies and a lot of other pieces, a refresh on 6 injectors with new tips is around $1200.



One generally does not go out and just buy a 6 pack of CR injectors. :-laf

 

[HCanales]

I gotta agree with this. I paid $700 for a 6 pack of performance injectors and then a few hundred more to have a guy install them. Total cost was way less than what you paid for 2 injectors. I realize that you were in a bind and once the dealer opened it up to diagnos it, you didn't have much choice, but in the future you might look into aftermarket stuff.

Wow! That's a really good price. I wish I would have known. I just hope my other injectors don't poop out though. Also, I thank every one of you guys for your inputs and I'm very greatful for TDR!



Thanks a millon guys

HCanales

 

[icman95]

Sorry, my bad. Didn't realize CR injectors were THAT much more than the older ones. Good luck.

 

[AHolt]

There are brand new injectors on ebay for CR for between $300+ $400 each.
I bought a set of used ones for my 05 for $350 sent them to Don and
had new tips put on.