Truck troubles...EFI guys I need ya help

Topic: Truck troubles...EFI guys I need ya help (Read 1014 times) previous topic - next topic

Truck troubles...EFI guys I need ya help

January 29, 2006, 09:46:43 PM

The ol 300 I6 is giving me trouble...it "misfires/hesitates" on part throttle, 35-50 mph is the worst...you can hear/feel it sputter...I've changed plugs,wires,cap,rotor,HEO2 sensor, IAC, switched MAP sensors *used t-bird one...it sucked* when I switched map sensors it got a lil worse...but when I pulled the vacuum line off it still ran unlike the one that was in it...when I pulled it off it surged up and down. didn't find any vacuum leaks for that...someone mentioned to take off the T/B and clean it. also said sometimes they try to swallow the gasket? OUCH...I have a code reader...said Spout circuit was open, and the O2 was reading rich...has a new aircleaner....I'VE been chasing this for a month...so i'm discouraged

Truck troubles...EFI guys I need ya help

Reply #1 – January 29, 2006, 09:51:32 PM

Quote from: 86Tbuzzard

someone mentioned to take off the T/B and clean it. also said sometimes they try to swallow the gasket?

They do tend to suck in the gasket. Its definately worth cleaning the TB and replaceing that gasket.

In light of everything youve mentioned replacing, I can't think of anything else off the top of my head, but I'm digging around.

Truck troubles...EFI guys I need ya help

Reply #2 – January 29, 2006, 10:07:36 PM

Check the spout and make sure it is plugged in good. If so the ign pick up in the bottom of the dist is pobably going out. It will cause the timing to jump around.

Truck troubles...EFI guys I need ya help

Reply #3 – January 29, 2006, 10:29:07 PM

pickup? on the shaft or inside under the cap?

Truck troubles...EFI guys I need ya help

Reply #4 – January 30, 2006, 10:06:18 AM

Inside the dist you have to press off the gear and remove the shaft

Truck troubles...EFI guys I need ya help

Reply #5 – January 30, 2006, 10:36:07 AM

Might be something for you to check, I had a truck with similar symtoms after moths or replaceing and trouble shooting I was just cleaning the engins notice the wires for the O2 sensor had burnt slightly on the exhaust and was shorting on the block replaced the wires and problem was solved. Also hae you checked your fuel pressure.

Truck troubles...EFI guys I need ya help

Reply #6 – January 30, 2006, 10:49:09 AM

Our 91 EFI 300 did the exact same thing. Same symptoms and everything. Fuel pump was dieing. New pump and it is back to being a stump pulling 300. Its amazing what low fuel pressure will do to a vehicle.

Truck troubles...EFI guys I need ya help

Reply #7 – January 30, 2006, 06:27:30 PM

it has 2 tanks...does it with both

Truck troubles...EFI guys I need ya help

Reply #8 – January 31, 2006, 12:21:09 AM

Yeah but do you have a frame rail mounted pump? Your truck may have 3 pumps.

Truck troubles...EFI guys I need ya help

Reply #9 – January 31, 2006, 06:46:49 PM

Problem solved...only cost me a buck... the engine sucked in the T/B gasket, and the timing was too far advanced...I reset the T/B screw on top that acts like a stop for the throttle...so when I mash the loud pedal...the ol 300 I6 is there....