Keith Browning Posted October 22, 2009 Share Posted October 22, 2009 Do you think it is possible for a failed fuel injector with no obvious physical damage to cause a no start condition by affecting ICP? Quote Link to comment Share on other sites More sharing options...
Fredsvt Posted October 22, 2009 Share Posted October 22, 2009 Not sure on a 6.0. Seen it on a 7.3. Only once, I had a truck with 1 injector pouring oil out the spill spout and out the bolts of the solenoid while cranking, with ICP around 350psi. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted October 22, 2009 Share Posted October 22, 2009 IN THEORY, anything is possible. Quote Link to comment Share on other sites More sharing options...
mchan68 Posted October 22, 2009 Share Posted October 22, 2009 Do you think it is possible for a failed fuel injector with no obvious physical damage to cause a no start condition by affecting ICP?Not to be a pain in the ass, but is there a point to this question? I've only had two 6.0Ls that were no-starts due to one failed injector that I can recall. But both those injector failures were not due to low ICP issues, and were in conjunction with EGR valves stuck open causing the no-starts. Quote Link to comment Share on other sites More sharing options...
Mikill Posted October 22, 2009 Share Posted October 22, 2009 I would believe that the only way it would affect ICP is if the clip on top of the injector was missing or damaged causing the loss of high pressure oil. Seen a few of those. I don't see any other way but there is always that crazy problem truck that comes thru the door. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted October 22, 2009 Author Share Posted October 22, 2009 Not to be a pain in the ass, but is there a point to this question? Why yes, there is a point. To satisfy my curiosity. You see, I worked on a truck today with a 6.0L that was towed in (?) for running rough. I discover a truck that has slightly run down batteries yet still cranked but wouldn't start... till I gave it a sniff of an "alternate fuel." It runs and has a heavy misfire. I got IDS hooked up and retrieved DTC's for cylinder #6 and low ICP/cranking... long story short, all diagnostics pass so before even looking at the STC fitting and inspecting all of the high pressure seals I decided to replace the two injectors on bank 2 that I determined were useless and inspect the seals on that bank first while I was there. I did shut it down and tried to restart it but I only got 45 PSI... I decided to see if the engine would start and low and behold it fired up after a little cranking as usual, but it started, on it's own. I let it get warm. Still starts. tried 5 or 6 more times, still starts. So unless this is a giant coincidence and I have one of those STC fittings that is playing games with me I wanted to know if it was even possible for a 6.0L injector to do that. I personally have never seen it and was wondering if anyone else had. The truck as it sits in my bay is "good" at the moment. Do I let it fly if I can't duplicate the no start or do I continue on with my ICP diagnosis? See my point Mike? Since I don't want to screw the customer I will do the intelligent thing and find out for sure. I just wanted to ask. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted October 22, 2009 Share Posted October 22, 2009 On a 7.3.... yes.... on a 6.0, I think you'll need more than one OR a relatively obvious physical concern(that weep hole isn't all that big, right?). Of course one would have to temper that with what may or may not be wrong with other components. So... you have a no start with low ICP.... you could conceivably change a faulty injector and have it "push you over the top"... enough ICP to start the motor - but it still may not be right because of other leaks or a weak pump or a leaking IPR or.... Look at the high pressure oil system like it was a bucket.... it might have one big leak.... or it might have a bunch of small ones.... If it's small ones... the more of them we plug, the more oil we can get to the destination... Curious question... "Curiouser and curiouser" - Alice in Wonderland. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted October 22, 2009 Author Share Posted October 22, 2009 On a 7.3.... yes.... on a 6.0, I think you'll need more than one OR a relatively obvious physical concern(that weep hole isn't all that big, right?). Exactly my point so when this truck started and all I had done was replace two injectors I was a little surprised. I was just studying the injector section in the Coffee Table book and I suppose it is possible for a spool valve to hang right in the middle but I doubt enough oil could flow through to drop ICP down to 45 PSI in a cold engine. I am sure I will find something else. This was just weird and caught me off guard. Now if you will excuse men, I am late for my un-birthday party! Quote Link to comment Share on other sites More sharing options...
mchan68 Posted October 22, 2009 Share Posted October 22, 2009 Originally Posted By: mchan68 Not to be a pain in the ass, but is there a point to this question? Why yes, there is a point. To satisfy my curiosity. You see, I worked on a truck today with a 6.0L that was towed in (?) for running rough. I discover a truck that has slightly run down batteries yet still cranked but wouldn't start... till I gave it a sniff of an "alternate fuel." It runs and has a heavy misfire. I got IDS hooked up and retrieved DTC's for cylinder #6 and low ICP/cranking... long story short, all diagnostics pass so before even looking at the STC fitting and inspecting all of the high pressure seals I decided to replace the two injectors on bank 2 that I determined were useless and inspect the seals on that bank first while I was there. I did shut it down and tried to restart it but I only got 45 PSI... Which two injectors? I'm assuming #6 was one of them. Did you shut the truck down shortly after replacement of the faulty injectors, and then try to restart the engine before the high pressure oil system was fully primed, and thus getting the low 45 psi? Sorry if it sounds like a stupid question, but I'm just trying to get a picture of what happened. Obviously this is an '05+ truck since you mention STC fitting. What is the mileage and maintenance history like on this vehicle? I decided to see if the engine would start and low and behold it fired up after a little cranking as usual, but it started, on it's own. I let it get warm. Still starts. tried 5 or 6 more times, still starts. So unless this is a giant coincidence and I have one of those STC fittings that is playing games with me I wanted to know if it was even possible for a 6.0L injector to do that. I personally have never seen it and was wondering if anyone else had. Did you check OASIS on this truck? Has an STC fitting ever been replaced before? Has this truck had other repairs done due to low ICP issues before? Like already mentioned above, the ONLY injector failure issue imagineable, that can cause a low ICP issue is when they "blow their tops", at least that I'm aware of so far. The truck as it sits in my bay is "good" at the moment. Do I let it fly if I can't duplicate the no start or do I continue on with my ICP diagnosis? See my point Mike? Since I don't want to screw the customer I will do the intelligent thing and find out for sure. If you can't recreate the no-start symptom, I guess the best course of action for now IS to just let it fly. I know you don't want to screw the customer, but you also have to make a living too, like the rest of us. One last thing you can do, is ask if you (or someone else, if you feel uncomfortable) can drive the truck home and back to work to see if any further symptoms arise. I just wanted to ask. How is everything else otherwise (base lube oil pressure, IPR, ICP bias, etc.)? Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted October 22, 2009 Share Posted October 22, 2009 Happy unbirthday!!!! Just remember... there will come a day when I cease to get older... At that point, you will begin to catch up with me.... in a hurry.... Now... whats going on with your IPR when you crank? If the duty cycle higher than what you'd expect? Guys will disable the injectors to try and test high pressure oil but this skews the IPR since the injectors aren't spilling.... Maybe we need to come up with an easy way to allow the injectors to spill, yet deny the cylinder any fuel.... My big hiccup???? Sometimes we can turn a no start into a cream puff simply by pushing the frickin' thing into the shop... DAMHIKT!!!!! Quote Link to comment Share on other sites More sharing options...
DamageINC Posted October 22, 2009 Share Posted October 22, 2009 I remember once on an E-van I had an injector that wouldn't seal to the nipple on the oil rail and it caused a no-start. It was very easily found via an air test through the ICP hole (it was an '04 model I think) but my cranking ICP was around 300psi if I remember correctly. Dave Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted October 22, 2009 Author Share Posted October 22, 2009 Well I found nothing out of sorts. Since it was apart I installed the new HPOP fitting. Runs perfectly starts really quick hot or cold. Quote Link to comment Share on other sites More sharing options...
GregKneupper Posted October 22, 2009 Share Posted October 22, 2009 Good question. I had a 2004 6.0 one time that came in for a no start. Low icp was the cause. While air testing it with the valve covers off there was a very large leak on the rh side of the engine. Tear down revealed no problems. Could not find a blown oring on any of the injectors. Put the rail back on and retested. Leak was now gone and truck fired up after that. I could never find what happened to it but I think that it had a stuck injector on it. Vehicle never came back after that. Quote Link to comment Share on other sites More sharing options...
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