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21:15:43 - 04/18/2024
General Dakota Board
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Bobby M
Dodge Dakota
JOIN HERE
3/29/2011
16:54:27
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 Subject: 4.7 troubleshoot rough running after low
IP: Logged
Message:
2000 Dakota 4.7, 5 speed. Just about to turn 70k miles. The only work I ever did on this engine was replacing OEM injectors with FMS 21 lb back at 45k miles because of a low power/bogging issue. Found most injector screens fouled with sediment/rust. I must buy crappy gas often.
Fast forward 8 years and 25k more miles, almost run the tank dry, pull into station and fill half the tank. Restart and it's a bit stumbly. I immediately suspect water picked up or sediment. Throw a can of drygas in the tank and give it a chance. A few days later I pull the fuel rail and injectors and sure enough, a few screens are a bit rusty and the fuel coming out of the #7 port on the rail is NASTY. I lay a few rags in there and just pulse the key to discharge. I tap the crap out by banging on the rail, etc. I sprayed all the injector baskets out and tap them upside down until clean. Reinstall and it didn't help.
There are actually two levels of poor running. One is just a barely noticeable stumble where the engine is making a bit of a lower pitch in the exhaust. The other is a full on hesitation and stumble at any speed. The latter is intermittent. Even at its worst, the truck will continue to run and even idle in neutral. I just don't get the sense driving it around every day is a great idea even though I have to.
Ruled out: fuel pump. Getting a good 45 pounds at the rail and I can actually get good acceleration and high RPM under load. Not starving.
Tested all the primary/secondary resistance on all the coil packs and all check out.
I pull all the plugs and regapped. Most were approaching .050" and one of them was a little wet. Not sure if oil or gas.
Vacuum test shows solid 20 psi at idle.
I cleared the PCM and now the only code it's pulling is P0203, injector control circuit malfuction.
Next steps:
I plan to swap the #3 injector to another port and see if the code follows it.
Noid light test all injector connections.
Pull all the plugs, rent a gauge and test compression for valve train problems, rocker/cracked springs, etc.
Replace spark plugs in the process.
If no compression problems, replace all the injectors and figure out how to install an inline filter.
Is there anything I missed and does my plan sound right?
Thanks a million, I'm going nuts.
Bobby
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