'04 3500 no start issue fixed after injectors replaced
07-17-2008, 11:19 AM
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'04 3500 no start issue fixed after injectors replaced
This may not be the right forum area to post this so I hope it gets to some who are having problems with this issue.
We recently installed an engine in a '04 3500. The old engine was running but had high mileage and extremely high oil consumption. After replacing the injection system from the old engine to the new, reinstalled the engine in the truck, it wouldn't start. Turn over great, nothing else. Ether, start right up with a small shot then die. ( AIr box heater disconnected of course).
The problem after 3 days of diagnosing was a simple but critical error. The injectors were tightened before aligning the tubes to the injector. The injector is actually able to move a minor amount when it is installed into the cylinder head. If you don't properly align the tube to the injector,it will leak.
We were not getting enough rail pressure build up (close to 3000 psi) needed to tell the computer it was 'ok' to start firing the injectors. A quick test to confirm this without a scan tool is simple. Unplug a connector to a set of injectors at the cylinder head and probe it with a standard test light. Turn the ignition on and check for a possible pulsing on each wire to the injectors. This is a 'normal' state the computer puts the injectors through I imagine to purge air out of the injectors. They will only pulse for a short while then quit. Now, in the normal state (all connectors except the injector plug connected),crank the engine and check for a STRONG pulse at 2 of the connector pins. If you have none, stop cranking and do the following. Unplug the high pressure rail sensor and crank the engine again. If you have a MILD pulse on 2 of the pins at the injector plug, the pressure is not high enough to activate the computer to fire the injectors. I.E. a bad connection at the injector tubes or another type of injector system leak that is causing the rail pressure to stay LOW. This is one of the ways I found that the mechanic who installed the engine didn't properly seat the injectors. I'm a master tech who found his way to a position that I don't have to turn wrenches for a living any more. I try to teach others what I know and have learned over the last 35 years. I'm no expert in everything, but I feel as though I have good 'common sense'. It's gotten me out of alot of difficult situations over the years.
BTW, I have started using the AutoEnginuity software and with the updated connector, it's really sweet for the money! Get a laptop!
I was able to confirm my findings with the laptop scantool.
We loosened the injectors after removing the tubes. Then we reinstalled the tubes after checking the tips for damage and properly torqued the tubes. I believe it's 37 ft. lbs. ( book not in front of me.) Then we tightened the injectors in an alternating pattern from left to right bolt per injector to ensure the injectors were being drawn down evenly. (The book that we have doesn't state this procedure.) Once they snugged up, we torqued them to specs. Reinstalled everything and on the second crank the engine ran great. Rail pressure was up in a matter of seconds while cranking!
We didn't notice any fuel in the oil, though I had them change it anyway,or leaking from the top of the injector. When we did get it started though, there was a HUGE cloud of white smoke for a long time until the exhaust cleared out the raw fuel in the pipe! I guess with the computer trying to purge out the air it was steadily dumping raw fuel into the cylinders due to the computer seeing such low fuel rail pressure. (This is a theory I had,I could be wrong.)
Cam sensor, fuel filter, banjo bolts,relief valves, all seemed ok, just couldn't get the rail pressure up. It would max out even with the engine running on ether at around 750 psi.
I may have typed all this and someone else may have already posted an in- depth review for us all but danged if I could find it!. I did however find ALOT of posts with folks having an issue with changing their injectors and then they had a no-start situation and couldn't figure out why. I know I did.
I hope this helps someone.
dmtcm
If it's difficult,do it immediately. If it's impossible,it takes a little longer!
We recently installed an engine in a '04 3500. The old engine was running but had high mileage and extremely high oil consumption. After replacing the injection system from the old engine to the new, reinstalled the engine in the truck, it wouldn't start. Turn over great, nothing else. Ether, start right up with a small shot then die. ( AIr box heater disconnected of course).
The problem after 3 days of diagnosing was a simple but critical error. The injectors were tightened before aligning the tubes to the injector. The injector is actually able to move a minor amount when it is installed into the cylinder head. If you don't properly align the tube to the injector,it will leak.
We were not getting enough rail pressure build up (close to 3000 psi) needed to tell the computer it was 'ok' to start firing the injectors. A quick test to confirm this without a scan tool is simple. Unplug a connector to a set of injectors at the cylinder head and probe it with a standard test light. Turn the ignition on and check for a possible pulsing on each wire to the injectors. This is a 'normal' state the computer puts the injectors through I imagine to purge air out of the injectors. They will only pulse for a short while then quit. Now, in the normal state (all connectors except the injector plug connected),crank the engine and check for a STRONG pulse at 2 of the connector pins. If you have none, stop cranking and do the following. Unplug the high pressure rail sensor and crank the engine again. If you have a MILD pulse on 2 of the pins at the injector plug, the pressure is not high enough to activate the computer to fire the injectors. I.E. a bad connection at the injector tubes or another type of injector system leak that is causing the rail pressure to stay LOW. This is one of the ways I found that the mechanic who installed the engine didn't properly seat the injectors. I'm a master tech who found his way to a position that I don't have to turn wrenches for a living any more. I try to teach others what I know and have learned over the last 35 years. I'm no expert in everything, but I feel as though I have good 'common sense'. It's gotten me out of alot of difficult situations over the years.
BTW, I have started using the AutoEnginuity software and with the updated connector, it's really sweet for the money! Get a laptop!
I was able to confirm my findings with the laptop scantool.
We loosened the injectors after removing the tubes. Then we reinstalled the tubes after checking the tips for damage and properly torqued the tubes. I believe it's 37 ft. lbs. ( book not in front of me.) Then we tightened the injectors in an alternating pattern from left to right bolt per injector to ensure the injectors were being drawn down evenly. (The book that we have doesn't state this procedure.) Once they snugged up, we torqued them to specs. Reinstalled everything and on the second crank the engine ran great. Rail pressure was up in a matter of seconds while cranking!
We didn't notice any fuel in the oil, though I had them change it anyway,or leaking from the top of the injector. When we did get it started though, there was a HUGE cloud of white smoke for a long time until the exhaust cleared out the raw fuel in the pipe! I guess with the computer trying to purge out the air it was steadily dumping raw fuel into the cylinders due to the computer seeing such low fuel rail pressure. (This is a theory I had,I could be wrong.)
Cam sensor, fuel filter, banjo bolts,relief valves, all seemed ok, just couldn't get the rail pressure up. It would max out even with the engine running on ether at around 750 psi.
I may have typed all this and someone else may have already posted an in- depth review for us all but danged if I could find it!. I did however find ALOT of posts with folks having an issue with changing their injectors and then they had a no-start situation and couldn't figure out why. I know I did.
I hope this helps someone.
dmtcm
If it's difficult,do it immediately. If it's impossible,it takes a little longer!
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