IAC motor symptoms.
 

O.K. guys here are the new symptoms. Hard start cold weather when it starts it stops 4-5 times. This morning (7F), started and was warming it up out of idle range. Engine settled out when I let it go to idle and then would surge couple hundred RPM, and back. Did the same thing the other day when the temps were in the 50's. Thinking because ive heard it in both very cold and mild weather has to be IAC motor. Also yesterday after warmed up drop it in drive and immediate stall out, which also reinforces my diagnosis. WHen it is warmed up and running various RPM never have a problem, thus I am eliminating fuel supply problems in my mind. Any concur or other ideas?

Exactly what are you working on? (year, engine, model)

do you have to give it a little throtle to get it started? if so that is a sign of IAC. Does it only do it on cold starts? Does it start like its flooded? black smoke? Does it start fine when warmed up?

When my IAC motor failed completely, it would start fine if you gave it throttle. You can adjust the little bolt on it to raise the base RPM a little, but it will idle high when warm. Makes for some awkward red-light waits when you are next to some sports car.

Sorry you asked exactly the question I ask all the time on the bike site,rofl. 94, 5.2, 4x4 all bone stock except for K&N kit.

It actually is so eratic on start it is getting funny. If the temp is above 28 to 30 it starts normal. If as its been for the last few days its a grab bag. No black smoke ever. I might add I have at this point checked fuel pressure at the rail, and have even put a heater under the hood. I know the CPU is seeing a bad input ftom the temp sender have been putting that off for a while pulled the A.C compressor to change it yesterday but with all my sockets I did not have a geep enough one. THats the project for today, socket. No advanced autos close and the Zone says nope they just sell the part, ( they don't sell the deep socket for the oil pressure sender either). One guy named Brian told me to go to the Dodge dealer for a socket.:icon_shrug:

IAC motors do go bad but rarely. Usually when the fail the fail completely and will not idle properly warm or cold. I would check the continuity of the wires while wiggling/manipulating them. Have you posted on the 2nd Gen site?

If your temp sensor is not reading right, it can cause problems starting, that why i asked if it was starting like it was flooded. they can also read the other way and not put enough fuel to the engine when cold, If you have a scanner or know someone who does see what its reading when its cold, I' not sure which way but i think when you unpug it the reading on scan tool goes to -40 and when you jump the wires it goes to 300 or something like that, anybody else remember for sure? havent had one read bad for a while. most problems with them are connections or wires. Let me know, thanks

It was rain today and I did not change the sensor yet. I do have a socket set that will do the job. The old sensor looks like yuck and my OBD tell's me there is a sensor problem, I have bought the part so whatever Ill change it when I dont have to take a frigid shower to do so. In the meantime Ill drive the 89 Dak.