3 codes at once!

[Mephisto]

Just hooked up datamaster and these 3 are on from start to finish...

33-MAP High
35-IAC Error
42-EST Monitor Error

I'm guessing I didn't hook up something properly when I put the motor back in?? No idea what'd be causing the "MAP high code" unless it's related to the other 2?... i put all new vacuum lines in, and just double checked all the connections.

Truck runs pretty good for the most part though... knock retard is supposed to go up 1* for every psi of boost right??:rotf: Definitely gotta burn off the old gas that's been sitting in the tank for 6+ years, before I try to do any tuning or real testing.

 

[SY2932]

Re: 3 codes at once!

Check out possible causes of the codes here.

 

[Mephisto]

Re: 3 codes at once!

Check out possible causes of the codes here.

good call! Thanks Mike!

Gotta call the smog shop tomorrow and see what's up... the CEL is not on with any of these codes, just wondering if I can still pass smog with failure codes even if the CEL isn't on??? Or is it automatic fail if you have any failure codes?

 

[Jimmy]

Re: 3 codes at once!

DaveP is basically your neighbor,couple minutes down the PCH....

Give him a holler.

Trust me.

 

[Mephisto]

Re: 3 codes at once!

man... 7 years out of the game and I'm full of rookie mistakes! :roll:

throwin all the codes because I unhooked to tan wire to check timing, and the vacuum line for to check fuel psi...

unhooked the battery, cleared the codes and all is good.

 

[Mephisto]

Re: 3 codes at once!

well not so fast... the IAC error came back again and of course it's right before I have to bring the truck in for inspection. I've unplugged the battery and reset the ecm a few times, and the second I start up the truck the CEL light comes on. I tried the paperclip trick in the ALDL and I can hear the IAC motor working so it's not entirely dead.

When I hook up DM I get 0 on IAC Pos, but the truck idles fine between 800-850. Should it be higher??? Do i need to mess with the TPS adjustment on the front of the TB???

I read the how to clean the IAC thread on thirdgen, but if i'm gonna pull the IAC out, i'm just gonna replace it and not eff around with trying to clean it.

I'm just a lil hesitant as I'm thinkin it might be something electrical since the CEL comes on right away... if it was a bad IAC wouldn't it take the computer a little bit of time to determine this?

 

[Quickstop [UK]]

Re: 3 codes at once!

0 IAC count means the IAC is as closed as it can go. normally due to extra air from somewhere like a vac leak. So you may have a vac leak from somewhere but the fact you are idling at 850-900 is encouraging

High IAC means that the engine is trying to open it and let more in. .

Your IAC should read 25-35 ish at idle. I would start the engine, connect DM and adjust the little screw and see if the IAC changes. Counter clockwise = throttle closed so the IAC should open up slightly. If Idle drops/bogs, IAC in't working. It's a 3 minute check.

Did you have problems with the truck before? If not, it's unlikely that screw has come loose and may indeed be something electrical.

Swapping the IAC isn't too bad. It's not amazing fun but you could swap one and see if that makes a difference. HTH.

:dunno:

 

[Mephisto]

Re: 3 codes at once!

0 IAC count means the IAC is as closed as it can go. normally due to extra air from somewhere like a vac leak. So you may have a vac leak from somewhere but the fact you are idling at 850-900 is encouraging

High IAC means that the engine is trying to open it and let more in. .

Your IAC should read 25-35 ish at idle. I would start the engine, connect DM and adjust the little screw and see if the IAC changes. Counter clockwise = throttle closed so the IAC should open up slightly. If Idle drops/bogs, IAC in't working. It's a 3 minute check.

Did you have problems with the truck before? If not, it's unlikely that screw has come loose and may indeed be something electrical.

Swapping the IAC isn't too bad. It's not amazing fun but you could swap one and see if that makes a difference. HTH.

:dunno:

thanks for the tip! I'll try messing with the screw when I get home and see what happens there. Not a ton of room around the IAC to get that thing out even if I take off the upper IC... probably easier to just remove the TB? I already have a TB gasket set sitting in my garage so that's no issue.

 

[dgoodhue]

Re: 3 codes at once!

If you have a stock chip 850rpm is way to high. Idle is closer to 600. I wonder if some has 'adjusted' the throttle body stop to raise the idle and the ECM is trying to lower the idle speed.

 

[Mephisto]

Re: 3 codes at once!

that little cover over the throttle position screw is still there... so no one has messed with it... I ordered a new IAC (just to be safe) and I'm going to check everything out when I get home, starting with the vac lines. I just installed the sportmachines vac line kit and everything is hooked up properly so i don't think there's a leak anywhere...

 

[Mephisto]

Re: 3 codes at once!

PROBLEM SOLVED!!!

turned out to be both... a bad IAC and the idle screw.

I pulled the cover off the screw and turned it all the way out... reset the ecm and still got code 35. pulled the upper IC off, swapped the IAC, and set the idle screw back to where it was... reset the ecm... 30 seconds later... code 35 again! wtf!?! sprayed electrical cleaner on the connectors, reset the ecm... code 35 again... turned the idle screw all the way out, reset the ecm... and good to go! :tup:

kinda weird the screw needs to be backed all the way out. Idles a lil rougher now between 650 and 725. As long as the CEL doesn't come on and I can get this POS smogged and registered then I don't care.