yes ctubutis i meant "close" the relay and complete the circuit, sorry for the confusion.

UPDATE-
I haven't checked my ign. wire yet...but I did a quick test today while my truck was acting up. I let it sit in gear in the driveway while the idle was stumbling...it seems like it eventually smoothened out and had no problems. So then i tried to get it to act up again...by turning on the a/c. The truck acted up again, but soon fixed itself. after that, i could not get it to act up again.

I checked to make sure the alternator could keep up, I maxed the a/c, but my highbeams on, as well as my interior lights, and played my stereo really loud, and it is a fairly good sized system. I then checked voltage at the battery, it was around 13V when the radiator fan was off, and when the ac cycled and turned on the fan, voltage dropped to around 12.8V. With no load on the electrical the voltage is just over 14V, like it should be.

Also to clear things up a little bit, the truck did this very occasionally before i got the fan, it just seems like having the extra electrical load likes to make the problem happen more often.

The truck seems to run rich, especially at startup. I know the main sensor associated with this are the o2, ect, and MAP. And i know that the MAP is associated with engine load, could it possibly be my problem??

I wouldn't be too happy if it was of course, i've replaced that sensor before...and the last time i code checked my truck, nothing came up to show that the map isn't working.

thanks for the help

 

Hello again,
I brought this thread back so that you guys have a reference to my problem. In short, when my electric fan comes on, my engine stumbles and has a "surging idle".

It was asked before about where my ign. positive wire was hooked up, as well as my ground. I have changed the ground, directly to the battery.

Here is a picture of where my ign. wire is hooked up to...my truck still has this problem and with warmer weather coming, I need to figure this out soon...thanks guys!!

 

any thoughts....I really need some help guys!!!! where is a better place to hook up this wire?? I need a ign switched 12v source.

 

You have EFI which I don't have, so I obviously don't recognize any of the wiring or tubing in that picture.

In general, the question you should be asking yourself is, what had been recently changed when the problem began? Locate that change and revert it back to the way it was. Undo it, then proceed forward again taking a different route having learned something about the past one.

But you probably don't want to do that here as it'd be a big hassle.

I think autozone.com has wiring diagrams available online, you could find the ones for your truck and locate an ignition-on circuit and tap into it in place of that yellow wire (with a black hash?) you're currently using. I don't know the URL to the autozone.com stuff but you could go searching around that site.

This might be a place to start:

http://www.autozone.com/az/cds/en_us...rInfoPages.htm

I re-read the entire thread, did you mention that you were having these problems *before* the installation of this fan, but now they're just getting worse? If that's the case, the fan installation is merely exacerbating an already-existing issue. Finding it is the hard part.

I would guess the ignition module gets 12V at the key-on position, I don't *think* it ever gets its voltage reduced but then again I've never had to go there...

--ct

 

thanks for the reply, yes it did have the problem, but not much, hardly ever. It now has the problem whenever the fan comes on.

For guys that do have EFI, any input?

I was leaning towards the IAC, because sometimes my engine likes to die when i'm doing heavy-duty turning, like lock to lock kind of things.

If the problem is happening, and i hold the brake and give it a quick jolt of gas, the idle will come down to a perfectly smooth 600ish idle. but as soon as I accelerate and come to a stop again, the problem will "reappear".