1986 z24 no power

bowhunter723 · Jul 3rd, 2009, 09:08 AM

Hey guys. i have a 1986 z24i. Sometimes when you try and take off from a stop it will bog down and back fire and then be fine. And when you are going down the highway and mash the gas, you can hear the tbi sucking but it feels like you are hitting a wall or pulling a heavy load and not going anywhere. and sometimes it will pull on through. i have replaced the dist. plugs, no vacc leak, MAF sensor. any ideas or anyone had similar problem with any suggestions. thanks

zanegrey · Jul 3rd, 2009, 09:11 AM

read the codes..

and check for exhaust coil for spark...

bowhunter723 · Jul 4th, 2009, 09:45 AM

i pulled the codes and got a 23 and a 24

zanegrey · Jul 4th, 2009, 10:09 AM

pull the bat cable for five minutes or so..

then re attach bat cable and start engine.
let run for a few minutes and then re read codes..

as you read the codes hit the gas pedal a couple of times and move the shifter around the pattern ..

those codes should go away...

repost what codes you get..

also while it is idleing pull the exhaust coil wire and see if you are getting spark..

bowhunter723 · Jul 5th, 2009, 10:38 AM

alright, i cleared the codes and started it up. checked the exhaust coil, good spark., test drove and pulled codes again. pulled a 11, 23, 24, and a 42. still acting up

zanegrey · Jul 5th, 2009, 10:58 AM

do not worry about the 23 and 24 (right now).

the 11 is in the dizzy and 42 is the fuel temp sensor

the first thinfg is to remove the cover plate for the dizzy to get tothe opti sensor and clean it..

the 42 will most likely go away when you fix the 11..

the opti sensor is positioned over and around the opti plate ..it has 360 slots in it and as the dizzy shaft turns it turns and deternmines engine timing..

the opti reader is dirty (or bad ) or the opti plate is dirty(or bad)

clean then..

bowhunter723 · Jul 6th, 2009, 04:53 PM

tore the dist apart and the opti sensor and plate were clean and good. any other input

zanegrey · Jul 6th, 2009, 04:57 PM

did you start the engine again and re reread codes after cleaning dizzy ??

bowhunter723 · Jul 6th, 2009, 04:59 PM

yeah, same codes as previous

zanegrey · Jul 6th, 2009, 05:01 PM

you are reading the codes wrong...

bowhunter723 · Jul 6th, 2009, 05:03 PM

how is that

zanegrey · Jul 6th, 2009, 05:04 PM

you have to sart the engine and let it warm up..

turn off engine but leave key in the run position.

flip the switch to on ..on the ecm

at ecm the lights will flash 1 time then 2 times then three times then four and then 5 times..

these are modes..
you need the 3 rd mode

so just after the lights flash three times turn the switch off and then record the codes...

bowhunter723 · Jul 6th, 2009, 05:07 PM

gonna try again

zanegrey · Jul 6th, 2009, 05:10 PM

take ball peen hammer and knock urself inthe middle of head 4 or 5 times ..

this cures most ailments...

cal40299 · Jul 16th, 2009, 04:19 PM

I have the same truck that you have and had similar symptoms. My problem was a blown head gasket and coolant was getting in the oil and a cylinder. Easy enough to check to see if coolant is getting in. Take the valve cover off and see if you see any discoloration in the oil on the inside of the cover (coffee with a lot of cream). If you don't see the discoloration, then it could be blown differently. Compression check maybe?

This is the second head gasket that has blown on me, but the last time (about 10 years ago) it was just between the 3 and 4 cylinders where the wall seems quite a bit thinner than between the other cylinders. The engine made a ton of noise then and a dealership service center actually diagnosed the problem as bad connecting rod bearings. They wouldn't do the work and tried to get me to buy an engine. I said no thanks, checked it out myself and discovered the head gasket was blown.

Not sure this is it, but I messed around looking at a bunch of other stuff before I took the valve cover off and saw the coolant in the oil.