Stock 4.0L Jeep IAC motor

For discussing injector selection, manifold modifications, throttle bodies, fuel supply system design and construction, and FIdle valves and IACs.
Forum rules
Read the manual to see if your question is answered there before posting. If you have questions about MS1/Extra or MS2/Extra or other non-B&G code configuration or tuning, please post them at http://www.msextra.com The full forum rules are here: Forum Rules, be sure to read them all regularly.
Post Reply
hippled
MegaSquirt Newbie
Posts: 30
Joined: Thu Dec 02, 2004 12:06 pm
Location: Beamsville, Canada

Stock 4.0L Jeep IAC motor

Post by hippled »

Hi.

I been Looking around these forums I can not find the answer to this question and does anyone know if the stock 1991 Jeep 4.0L IAC motor needs the power resistors on the MS-II board shorted? I know the IAC instruction page says that it might. Will Anythign be hurt if I short them and it is not needed? My IAC moter does crazy things. I have not yet started my engine, I am just doing some checks to make sure everything is good before I try to start it. When I turn my key on (power up MSII) the IAC moter does somethig differant evey time. Sometimes it goes in sometimes it goes out. Does this sound like a power resistor problem or should I be looking somewhere else for a fix?
I have a V2.2 board running MSII with V2.36 code adn using megatune 2.25 for tuning.
Thanks for any help
Dave
bleoh
Helpful Squirter
Posts: 43
Joined: Tue Aug 16, 2005 12:36 pm
Location: Maryland

Post by bleoh »

Mine seems to work okay. I get a slightly higher idle after warm startup vs. after a cold start and I let the engine warm up without any restarts.

Make sure you have it wired correctly. Not to long ago a typo was corrected in the manual.
MS2 v3.0 MT2.25 controlling 6 high z injectors and ignition
hippled
MegaSquirt Newbie
Posts: 30
Joined: Thu Dec 02, 2004 12:06 pm
Location: Beamsville, Canada

Post by hippled »

I will check my wiring tomorrow. Did you use the wireing as per the manual and the diagrams. So with the curve of the connector on the top, then left to right is 2B, 1A, 1B, 2A, is this correct?
Dave
1990 4.2L Jeep YJ Running MS Extra controlling fuel, ignition and a three wire PWM idle valve.
Running MS/extra, MT 2.25 ,hr_08 code, v2.2 board, HEI 7 Pin.
ae1969
Helpful Squirter
Posts: 43
Joined: Wed Nov 23, 2005 12:06 pm

Post by ae1969 »

That is exactly what mine is doing.

I am running the jeep one as well....... but I picked the GM one today.
Doing the same thing.

I started the car......and warmed it up.

I enter step values at the appropriate coolant temp just to test. And I get erratic behaviour.

I am just about to run the wire accross the resistor. Will let you know if it help.

I enter values of 100 sometimes it goes up. Enter 200 goes up.... enter20 a little blip. Sometimes it goes up and down... very eratic.
944 2.5 L Turbo EDIS 4 MS2
My Success Story
ae1969
Helpful Squirter
Posts: 43
Joined: Wed Nov 23, 2005 12:06 pm

Post by ae1969 »

hippled take a look at my post ..... near the bottom http://www.msefi.com/viewtopic.php?t=17742&start=170

I had the same thing happening you describe. On the bench it would exhibit some WACKY behavior.

I jumpered the resistor........ it did not help.

As I describe......I bought another Jeep IAC and GM one. I could not get the 2 Jeep IACS working no matter what settings or wiring combinations I tried.

The GM one did work on the first try.
944 2.5 L Turbo EDIS 4 MS2
My Success Story
hippled
MegaSquirt Newbie
Posts: 30
Joined: Thu Dec 02, 2004 12:06 pm
Location: Beamsville, Canada

Post by hippled »

thanks for the info ae1969. It seams that you and I are having the same problem indeed. I think I and going to forget about debugging my jeeps IAC and go buy a GM one. Can you help me with part number or car make/model/year for the GM IAC. Or did you just use the part numbers in and MSII IAC manual?
Thanks for all you help.

Just an update on my jeep project. I expect to have it running buy then end of this weekend(need to calibrate MAT and CLT and get a new IAC motor). I also just tacked together a new custion made skid plate for my gas tank tonight since the old one came out in 3 pieces. So once the skide plate is done and the gas tank is reinstalled and the new IAC is bought I will be ready to go.
Dave
Dave
1990 4.2L Jeep YJ Running MS Extra controlling fuel, ignition and a three wire PWM idle valve.
Running MS/extra, MT 2.25 ,hr_08 code, v2.2 board, HEI 7 Pin.
ae1969
Helpful Squirter
Posts: 43
Joined: Wed Nov 23, 2005 12:06 pm

Post by ae1969 »

hippled wrote:thanks for the info ae1969. It seams that you and I are having the same problem indeed. I think I and going to forget about debugging my jeeps IAC and go buy a GM one. Can you help me with part number or car make/model/year for the GM IAC. Or did you just use the part numbers in and MSII IAC manual?
Thanks for all you help.

Just an update on my jeep project. I expect to have it running buy then end of this weekend(need to calibrate MAT and CLT and get a new IAC motor). I also just tacked together a new custion made skid plate for my gas tank tonight since the old one came out in 3 pieces. So once the skide plate is done and the gas tank is reinstalled and the new IAC is bought I will be ready to go.
Dave
Dave,

I used the part # in the manual. I called NAPA and they cross referenced the part to a NAPA part #.

The pintle I believe does not extend out as far as the jeep one. I measured mine to come out to ~25 mm with 200 steps and ~14 mm at 10 steps.

I had to make a housing for the IAC for now.

I just realized you actually have a JEEP. :) Uhmm would be ideal to get the jeep one to work.... but for the life of me I could not get it two work.

It should look like the one in the pic I posted on the other thread. Silver and black.
944 2.5 L Turbo EDIS 4 MS2
My Success Story
Post Reply