89 closer to perfect but not yet

[ftjew@uaf.edu]

jerry helped me a lot a few months ago but still have two major problems after complete engine rebuild,new computer,new injector and fuel pump on my 89 sidekick.

1.when starting fast idle goes clear to 2000rpm and stays there wont come off and settle down.

2. feels like it shifts through 3 gears (its an auto) fine but at about 50 mph it is showing 3000+ rpm and doesnt want to shift into overdrive. does this tranny have an overdrive?

any help would be appreciated.
thanks

[jtgh]

so this car is a old right.and as such you need to tell what parts
in the engine EFI domain, are non OEM.
any parts missing, and Catconv missing or rodded out?

hi idle.
Ok too fast idle ( assuming timing Ign and cam are spot on spec)
first off there are no less than 5 sources of air on this motor and any 6th source is illegal.
and any air from any source will cause a fast idle.
Speed density system it is.
just pull the EVAP hose off the nipple , note the rise in RPM.
see ? the 8v with its MAP based EFI , just mixes the perfect amount of fuel to match any air leaks from any source.. nice huh?

so (i have a huge page for this called racing ) but here is the gist.
89s are a PITA: (iSC sux)

the 5 normal paths.
Butterfly plate. (aka, throttle plate)
IAC (in base of TB (throttle body)
ISC (idle speed controller.
Air bleed screw on TB 91+ ( you dont have this)
Dash Pot.


any time idle is too high here are some tests.
1 pinch all vac tubes see if idle drops, it shouldnt.
2 pinch the ISC input hose, ahh, but the 89 dont have it.
so you unplug the connector to it? oops that kills the TPS , dang.
if it was mine (id shoot it) but id pull the isc off and block all its passages.
then start car see if i can get idle below 800 hot.

3: make sure dash pot retracts after 30 seconds max.
if not it is bad. (or its controls are bad)
4: make sure the IAC closes hot. (not sure how on car)
it can be viewed hot but that wrecks its gasket as you take off cover.

http://carfix.stufftoread.com/fresh-air/cold-air2w.jpg

here is mine , tested in hot water , at such.



5: illegal sources of air.

i seen many gaskets in the middle and bottom of TB crank and missing hole chunks after baking on a motor for 20 years.
intake manifold gasket bad?

if all else fails,just unscrew the butterfly plate HOT , unit idle is 800.
if that dont work you really have some air leak.


i am unsure of how to test a ISC on a 89/90
it is a real pain to work with it.

but i can tell you, if it were mine , id have a new inline set of new
connectors for it pronto.

that way i can:
unplug it and see what happens. (it will close) and idle will drop below 800)
and put 12vdc on it and see what happens, idle will go way over 800.

one can remove it and check air flow thur it by blowing thru the ports.
and then put 12vdc to it and see if it opens and closes smartly.

Hard working on 89's

cheers.














i dont think it has OD AND 3K IS NUTTN.
ARE AXLES ORIGINAL RATIO?

Originally Posted by ftjew@uaf.edu

jerry helped me a lot a few months ago but still have two major problems after complete engine rebuild,new computer,new injector and fuel pump on my 89 sidekick.

1.when starting fast idle goes clear to 2000rpm and stays there wont come off and settle down.

2. feels like it shifts through 3 gears (its an auto) fine but at about 50 mph it is showing 3000+ rpm and doesnt want to shift into overdrive. does this tranny have an overdrive?

any help would be appreciated.
thanks