ok my friend has a 1991 chevy 1500 that we took from TBI to carb. he had performed the Ultimate TBI mods to it and he said i could have it and put it on my car. so i didn. hooked everything back up. fired right up and everything. but when i go to drive it it holds in gear longer than it use to and shifter harder at part throttle. i adjusted the TV cable as per the instructions and it still acted the same. any help or is this the way its suppose to drive it just was out of wack before?

 

Did you change the mount for the throttle and detent cables? is there any difference in the locaction of the connections on the tbi for the cables? If the detent cable is being pulled to the point that it's being overextended than it could cause these problems. It could be that with the worked tbi helped your low end torque. A firmer shift reduces heat in a tranny too, but a detnent cable being maxed will burn the front pump. It sounds as though its the cable from the symptoms.. Good luck......

 

well i dont mind the harder shifts whatso ever. but its the fact that it holds in gear longer than what *I* think it should be. usually if i accelerate at 2k rpm it will shift now its gotten to the point where it will just stay in 1st gear and not go to second until i let off the gas. where the cables go on the TBI didnt change a single bit. didnt move anything other than replaced the TBI unit. any other ideas??

 

if nothing in the mounting or the motion of the cabel changed, then you need to change your tranny fluid and filter. The Only two problems that cause your symptoms are either the detent cable being overstrethed and maxing the throttle valve or the valve in your govener is starting to jam from dirty fluid.. If it was me I'd pull the pan, Have an assistant move throttle from closed to open and see what it's doing in the tranny and if it's maxing the valve out. then while i inspected and cleaned the pan i would pull the govener. check the valve in the govener for sticking or binding. (Brake parts cleaner is good to clean it with. In my opion I would say it sounds like the govener is giving you a fit. If it holds a gear untill you let off throttle, then shifts, it's more than likley the governer, but i would't abandon the detent cable/throttle valve because of when the problem started

 

yea the weird thing is it was like night and day. drove to my friends shop. acted normal and everything. pulled my tbi off and put the other one on started it up and headed out and it started to do this. so im thinking something wth the TBI unit is doing itn.

 

sounds like the throttle cable pull is not sychronized to engine torque.the cable adjustment should be re adjusted.some things we should keep in min are as follows:the throttle opens from 0 degrees closed throttle to 90 degrees wide open throttle.if the tv limit pressure is 90 psi, that is what the line pressure should be at idle .what this means is that modulated tv oil which is raised in relation to throttle opening and is 0 psi at idle and 90 psi at wide open throttle should enter the circuit and create shift delay resistance at the throttle upshift valves according to the following principles.if line psi is 90 psi at idle and then 235 psi at wot the pressure for a normally aspirated engine should rise 36.25 psi for every 22.5 degrees of throttle opening or 1/4 of total opening.

 

ive adjusted it and adjusted it per the tech article on this site and it still does it.

 

i can help you if you provide me with some information.what is the wide open throttle shift rpm you need?5500 etc.does the vehicle get passing gear too early with the setting you have now?what is the wot shift point now?what is the minimum throttle 1/2 at in mph and engine rpm?

 

it kicks down fine like it use to. normally it shifts at WOT at 4500 RPM which it still does. when im going down the highway it down shifts where it use to just stays in gear to long at part throttle. you want me to go and hold throttle half open and note the mph and engine rpm correct?

 

yes ,but judging from what youve stated the cable is on the tight side .try this,adjust the tv looser until you loose the 2/1 kickdown below 30mph.then tighten it 1 click at a time until it comes back and road test to verify late shifts are still there.

 

will it hurt anything letting it shift like this? i can get use to having to let off the gas to have it shift to the next gear.

 

it will burn excessive fuel and may even cause engine overspeeding if it kicksdown from 4th or 3rd to second or first when it should only backshift 1 gear.these functions are hydraulically calculated via tv cable tension and vehicle speed hydraulic signal fed to the valve body via the governor

 

could the TPS be outta wack and cause this???something i thought of seeing as we didnt adjust it and the TBI is off of a different motor.

 

tps wont effect this.tps provides information to the computer in reference to engine load/throttle position.