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Can you diagnose this shebs a smoker

ritathebus

New member
"woo-hoo! first legit post

"woo-hoo! first legit post

so. rita is my bus. 1970 GMC suburban charter bus. 40ft with a detroit diesel 8v71 in the back. auto trans, she runs, brakes work, etc...

i will try to provide as much information as possible, so ask away, if you think it's going to help.

I recently got the bus and it had been basically unmoved for over a decade, and life before that owner is unknown. when i started her cold, she'd smoke while idling, but once the air pressure was high enough foe the air brakes to release and i could give her the pedal to the metal, she'd clear right up. as soon ass we could get somewhere where we could jam on the pedal there'd be no smoke, and minimal smoke while idling (stopped).

because it'd been so long, i decided to change the transmission oil, transmission oil filter, oil, oil filter, and the 2 fuel filters- one cartridge and one sock. i took all the filters off and put them in a bag so i could make sure the new ones were the correct size. all replacements fit except the sock, so i cleaned the minimal amount of oil out of the filthy old sock filter and put it in with the new ones so i could at least start her up. ran her for less than 10 minutes like this.

later i fixed the new sock filter bu banging one side down so it would fit in the casing. it still fit in really snug and i took out the old/oily/crappy sock, disccarded the fuel in the casing, and put in/on the new sock with fresh diesel in the casing.

at first she smoked a lot while in idle, then not so much. it wasn't until we were going fast, and shifted into gear (this trans has only 1 gear with hydraulics used to get up to speed to shift in) that she started kickin out dark smoke. drove her about 20 mi and everytime she got fuel from a dead stop, or when we shifted into gear (about 30-40mph) she kicks out smoke. dark grey smoke.

what is going on? before idle was smoke and driving was fine. change the filters and give her new fluids and and she's fine idling, and smokes while driving.

please help me cuz i love rita but i don't love her smoking like a chimney. it's gross. she needs to kick that bad habit. if you need more info or have questions or whatev ask em, i'll do my best to help you out

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"Is your exhaust wet? Do you

"Is your exhaust wet? Do you have a fuel pressure gauge installed? If so, what PSI is the fuel pressure running at idle and WOT?

Sounds like an injector problem to me...maybe blown tip. You can pressure up the fuel system and see if it's losing pressure. If it is, I'd pull the inspection covers and roll the engine over to look for fuel on top of each piston. If you find fuel on top of a piston, remove that injector and check the tip. If it's blown, replace it. That should help your problem."
 
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