don't know exact year, I can find out.

starts but will not idle, I can keep it running with my foot on the gas, smooths out above 3000 rpm. Code came up for map sensor (low voltage I think). I've got what I believe is reference voltage at sensor, but no return voltage. Swapped out the map sensor, same problem.

7/7/2007 8:31:52 PM

iac

7/7/2007 8:32:34 PM

Why do you say that? Will the Iac cause it to cut off?

7/7/2007 8:33:51 PM

yep. as a result of the no idling/low rpm performance, it can cause some odd map readings and throw a code.

which engine is this?

[Edited on July 7, 2007 at 8:38 PM. Reason : .]

7/7/2007 8:37:15 PM

2001 3.3L "G" motor

7/7/2007 8:44:44 PM

clean IAC with carb cleaner.

7/8/2007 1:51:10 AM

^ don't listen to this dumbass, just replace it, and clean the ports well with a fishtank type brush and some carb cleaner, if you get any of that on the iac, it will destroy it, even if it were worth messing with, exactly what code number was it?

7/9/2007 11:10:52 AM

I don't know the exact code number, my buddy has it written down I was just giving him a hand with it.
He will probably mess with it again today, I told him to swap out the iac. Thanks guys.

7/9/2007 11:36:01 AM

^ make sure he cleans the ports well, especially the seat, but does it run rough at idle and cuts off too low, or does it just not run worth a shit period below 3000? sounds like it could be a few things, but i would start with the iac

7/9/2007 11:37:41 AM

will not run AT ALL below 2500. Cam and crank sensor look like seem to be working correctly, according to the scope.

7/9/2007 11:46:55 AM

You could have a major mechanical problem then, but that doesnt explain why it smooths out over 3000, unless it is just dumpin fuel for some reason, what is the long term fuel trim and the difference between bank 1 and 2 on the intantaneous trim, and what are the O2 sensor crosscounts?

7/9/2007 11:49:45 AM

I will be sure to look at those things when I get back to it.

7/9/2007 11:51:58 AM

the biggest thing you would be lookin for would be a rich condition on one bank with low crosscounts and a low or negative fuel trim, also check your fuel pressure

7/9/2007 11:57:22 AM

Why is no one testing the MAP sensor circuitry? These things are speed density, so if the MAP sensor is not responding correctly, or if there is a discontinuity between the sensor and the computer, it makes perfect sense that it won't run worth a shit at lower rpms. I'm not saying that the sensor itself is bad, but I'd make damn sure that the sensor is performing correctly, and that the signal is reaching the engine computer. I know that older vehicles can have some codes set by a different problem, but I would think that by 2001, the trouble codes have gotten a little more accurate.

7/9/2007 12:32:30 PM

^ if it shows an open circuit or short in the reference voltage, or signal voltage, or out of range of the map, it will go into open loop, if you don't belive me, go start your car, and unlug the map sensor, it will continue to run, just off a defualt map slightly less effeciently, how many of the 3.3's have you worked on? none? thats what I thought.

3 most common problems I've seen with these engines:

bad iac
bad egr valve
bad fuel pressure regulator

any one of these can cause the problem he is describing and set a map sensor code, the scan tool is not a crutch for diagnosing, its a source of information, like pulling a spark plug, you can tell its been running rich, but the plug isnt going to tell you why, that takes diagnostic work

[Edited on July 9, 2007 at 12:38 PM. Reason : dumbass]

7/9/2007 12:37:25 PM

Quote :

"the scan tool is not a crutch for diagnosing, its a source of information, like pulling a spark plug,"

I agree completely, but remember this:

Quote :

"I believe is reference voltage at sensor, but no return voltage."

Looks like there's something that should be checked at the least.

Open loop just means that the O2 sensor feedback is ignored. Not sure what Dodge uses, but Fords have their "Limp Home mode" like what you're talking about. So this van still runs, but very shitty, below 3000 rpm. Could it have a MAP sensor problem? Maybe, but like you said, it needs to be properly diagnosed first before just throwing parts at the problem.

I have worked on a couple of these 3.3's, thanks (1996 and 2001). I do have a good amount of experience with fuel injection in general, and can learn various OEM's methodologies pretty quickly. My point is not that the MAP sensor is for certain the source of the problem, but to not check the circuitry first off to rule it out completely before taking another direction in diagnosing the problem to me seems foolish.

I'm not new to diagnosing fuel injection problems, and I'm certainly not the dumbass you think I am.

7/9/2007 12:51:30 PM

well from the way he was talking, i'm assuming he checked the return voltage on the plug with it unplugged, and that would explain why there is no signal, i also ingored this fact because he said he swapped map sensors and it didnt change anything

7/9/2007 12:55:10 PM

It was the damn computer, if you care.

9/20/2007 11:07:44 PM

my dad had a caravan that i used to drive to college and then to work for him

shit caught on fire one day after a quick dash to wendy's for lunch between classes

wasnt worth 500 bucks but insurance gave him 4500

he thanked me later

9/21/2007 12:46:01 AM

Quote :

"^ don't listen to this dumbass, just replace it, and clean the ports well with a fishtank type brush and some carb cleaner, if you get any of that on the iac, it will destroy it, even if it were worth messing with, exactly what code number was it?"

what ever dummy.
clean with brake/carb cleaner. if it works then you know what to replace..

just in case you do clean it and it just hapens not to solve the problem. that is better than throwing parts at it. it gives you a good starting point.
good luck with fix

Quote :

"It was the damn computer, if you care"

just goes to show its better to clean parts first that replace it saved your self anywhere from 30-90 bucx on an iac

[Edited on September 21, 2007 at 3:47 AM. Reason : good thing he didnt just go buy an IAC]

9/21/2007 3:44:07 AM

seriously, just stick to changing oil. if you can even do that right.

cleaning an iac is generally useless because:

1.) 9 times out of 10 it doesn't do shit. occasionally it will help a rough idle, but almost never for any other driveability issues.

2.) cleaning with chemicals can ruin the sensor. if it was good before spraying it, it's probably not going to be after.

9/21/2007 3:51:36 AM

the IAC is not a sensor

9/21/2007 5:42:13 AM

pwnt. valve, sorry... it's early morning.

9/21/2007 5:50:28 AM

what in the hell are you doin up at 4am and 6am.. lol

[Edited on September 21, 2007 at 9:00 AM. Reason : asdf]

9/21/2007 9:00:24 AM

Quote :

"iac "

eaither way your were way off so it doesnt matter now

9/27/2007 2:49:14 AM

either way, you're still a dumbass. point?

9/27/2007 4:15:55 PM