The Chrysler Minivan Fan Club Forums banner

1 - 20 of 27 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter #1
So my moms van is sputtering, started out of the blue. Rough idle but runs, little power - I don't feel safe taking it out on the road but just pulling it in and out of garage seems weak. Heavy gas smell and old plugs seemed wet. Cleared codes by pulling battery terminal and ran it. Get the codes in the subject. So far I have replaced the MAP sensor, plugs, wires, coil pack, new battery, check for vacuum leaks with carb cleaner, and I pulled the intake to check for the burnt wires on the fuel injector harness. The next two items seem to be PCM/ECM however I did pull it and no visible corrosion or short that I can see but packed in a gel so who knows. The other option I see quite a bit is valve spring which I would require a mechanic to do. Before I break down and take it to a mechanic, wondering if there is anything else a rookie mechanic like myself can try. The codes I get from doing the key three times are above, would it make sense to limp it a mile to Advanced Auto to read codes there - would I get any more info. Any help is appreciated.
 

·
20 year old enthusiast
Joined
·
10,108 Posts
What year van and engine?
 

·
20 year old enthusiast
Joined
·
10,108 Posts

·
Registered
Joined
·
511 Posts
I would first try a compression test/leakage test.
That would involve pulling the plugs again...I would not do that. You said "wet plugs" meaning more than one. A broken valve spring would not result in multiple cylinders running poorly. I had the same problem not too long ago...changing out the plugs and wires solved the trick...but all my codes were mis-fire codes, and nothing else. You really did install new wires? Exactly how did the plugs look? All of them looked wet? If you look at the engine in the dark when running...see any electrical archs?

Also, buy a scan/code reader...and get one that not only gives the code number but also the narrative name...really helpful and you can clear your own codes.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #8
So i went back and got antoher map sensor, plugs and wires all seem good. I pulled off the top of the intake again and looked at the wiring harness - pulled it out and continuity on all wires. I followed an article to test the map sensor and found what I think is my problem...I am not getting power to the MAP. In the article it tells me to touch my red lead on my meter to the middle wire of the MAP harness and the black to the battery negative. I should get a 5V reading with KIEO but I do not get a reading at all. I do get a 12V reading from the ground to the battery positve lead. I also tested at the connectors past the fuel injector harness and get the same reading. I tested continuity to the PCM and while I don't have a pinout for my dodge, I get continuity to pin 43 on the harness. My assumption is this means a bad PCM. Is my reasoning logical here? Looking for a sanity check. If it is the PCM, what is the best option for a used PCM? Any reputable sites or just find one local?
 

·
Registered
Joined
·
1,093 Posts
I followed an article to test the map sensor and found what I think is my problem...I am not getting power to the MAP. In the article it tells me to touch my red lead on my meter to the middle wire of the MAP harness and the black to the battery negative. I should get a 5V reading with KIEO but I do not get a reading at all. I do get a 12V reading from the ground to the battery positve lead. I also tested at the connectors past the fuel injector harness and get the same reading. I tested continuity to the PCM and while I don't have a pinout for my dodge, I get continuity to pin 43 on the harness. My assumption is this means a bad PCM. Is my reasoning logical here? Looking for a sanity check. If it is the PCM, what is the best option for a used PCM? Any reputable sites or just find one local?
Hmm.. the center pin on the MAP sensor connector should be the ground:

You can verify that with a continuity check between the center pin and a grounding point (not the battery).
Pin 43 on the PCM should be the sensor ground; pin 36 is the MAP sensor signal.
 

·
Registered
Joined
·
320 Posts
That test you did sounds off. Try what was stated above.

I had an issue with my IAT sensor. Checked everything and blamed the PCM. Ended up changing the wire that goes to the PCM and all was fixed.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #12
I re-tested based on your recommendation and agree that the info I had was wrong. I am getting about 5V on the MAP and continuity on the ground. I did the same check with the IAT and get the same. Just FYI, I also replaced the TPS while I had the intake off for the $20. So I have replaced PCV, TPS, MAP, plugs, wires, coil pack, battery, checked the fuel injector wiring harness. One thing I noticed when checking continuity is that I do get bleed over throughout the harness but readings are only 0 on the correct wire/pin. I am not an electrician, I assume that is to be expected or does that mean a short or something? Keep in mind, at the end of the day, my only code after clearing and running again is P108, high voltage on MAP. Any other suggestions are very welcome.
 

·
Registered
Joined
·
1,093 Posts
I re-tested based on your recommendation and agree that the info I had was wrong. I am getting about 5V on the MAP and continuity on the ground. I did the same check with the IAT and get the same. Just FYI, I also replaced the TPS while I had the intake off for the $20. So I have replaced PCV, TPS, MAP, plugs, wires, coil pack, battery, checked the fuel injector wiring harness. One thing I noticed when checking continuity is that I do get bleed over throughout the harness but readings are only 0 on the correct wire/pin. I am not an electrician, I assume that is to be expected or does that mean a short or something? Keep in mind, at the end of the day, my only code after clearing and running again is P108, high voltage on MAP. Any other suggestions are very welcome.
I'm not an electrician either, and some of this stuff makes me glaze over when trying to read documentation on it. As I understand the systems - and please someone correct me if I'm wrong - most of the sensors share a common 5V power line and common grounds. The signal wire for the sensor sends back the voltage from the sensor based on the resistance imposed by the sensor's reading. The PCM interprets that voltage to a value set in the EPROM of the PCM. Given the routing of the ground and power lines to all the sensors, getting some resistance bleed-through (not a full-open, zero resistance reading) could be expected.

I will say that I have gotten a bad MAP sensor (NAPA's Echlin ProFormer brand) when a '97 Ram (318ci V8) threw a MAP sensor code. Turned out to be bad O2 sensors on top of the bad MAP sensor. It ran but dropped into lean-mode compensation and was dumping fuel like mad, getting less than 8 MPG where I would have expected 12-14 MPG based on the load I was pulling, with terrible performance. Normally a bad O2 sensor will throw an "x Bank Lean" code, but I didn't get that until I changed the MAP sensor with the bad one.

Wet plugs and a gas smell? Heavy soot in the tailpipe? Bench-test the MAP sensor per the link in post #4. If it passes the bench-test, and the voltage test of the pin at the MAP sensor was not over 5V, I'd start to suspect something like an upstream O2 sensor.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #14
So I will be disappointed if I got a second bad sensor and that is all it is. I did the bench test and just to confirm I did it correct I tested the far left wire by placing a hose that fit tightly over the MAP sensor while I had a meter reading of 4.97V. I sucked with my mouth and was creating vacuum but no movement. I did notice if I blew into the hose I would get a couple 10ths increase. Just to confirm no leaks, i got right down on that sucker and sucked. Same result. I also placed the hose in a shop vac and restricted the air to the hose and same result. I would assume based on other posts out there I should get some movement with my lungs. I am going to move on to a mopar MAP unless anyone thinks otherwise a wild goose chase. Merry Christmas, I'm heading out for a week but will let you know my results.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #15
So just one more point of interest here. I found the OEM MAP that I originally replaced. That throws a code 1297 when I put that back in and when I do the bench test it starts at 4.38V and does decrease to 3ish with sucking through hose. I am guessing my best bet is to get mopar MAP and start again. The engine does run differently (a bit more power) with the original sensor. Definite change.
 

·
Registered
Joined
·
1,093 Posts
Does sound like the replacement sensor is bad. You should get movement with with mouth-suction. Re-check continuity on the signal wire from the MAP connector to the connector at the PCM - should be 0.
 

·
Registered
Joined
·
1,138 Posts
... I pulled the intake to check for the burnt wires on the fuel injector harness ....
Did you lift the power steering reservoir, unwrap the outer covering on the part of the wiring bundle that runs underneath the reservior, and check each wire individually? This is where the wiring typically melts, and a detailed check is required to make sure there are no melted wires in the bundle.
 

·
Registered
Joined
·
1,007 Posts
Ditto post #17, unless you did exactly that when you said you "checked the fuel injector harness". That is a typical failure area in the harness of your year (had in my 2002 3.8L). Look for photos here.

When you say "high voltage on MAP sensor", I am guessing you mean "high measured pressure". Go "old school" and put a mechanical vacuum gage on the intake manifold pressure (can access at brake booster tube or around cruise control). Run the classic test for a plugged exhaust. As I recall, as you rev the engine to ~1500 rpm, the intake vacuum will rise slightly, then slowly creep up (~5 sec), which indicates a plugged exhaust. That can happen from a catalytic converter melted by too much fuel. That can happen from melted injector wires (paragraph 1). Usually, you will get missing, sputtering, and a flashing "check engine" light as you drive. The flashing is to warn you that you may melt the catalyst. Did your mom see any of those signs earlier? Also, repeat the test of the MAP sensor, but use a hand vacuum pump w/ gage (sucking isn't quantitative). You pretty much must have one to diagnose modern cars. It sounds like your MAP sensor works, and probably is fine. A bad PCM would be my last suspect. More likely, the wiring or corroded connectors.
 

·
Registered
Joined
·
5 Posts
I am also having a similar problem on my 2003 Dodge Grand caravan 3.3L V6. I have visually inspected my wire harness and I replaced the MAP sensor. I noticed in response #8 there was talk stating that one should be able to measure 5V. It was also mentioned in response #9 that pins 43 and 36 should lead between the module and the PCM. In response #14 a bench test for the MAP was referenced.

Is there a good place to find reliable information? I don't want to probing around on my wire harness based in information from random websites. I was looking into a membership to alldata.com at the DIY level. Do you find their memberships cost effective?
 

·
Registered
Joined
·
3 Posts
I’m gonna assume this post I’d dead because it is several years old. Did anyone get their van running? I’m having the exact same issue, took a while to throw a code but I finally got p1297. Sounds like my van is running on 3 cylinders (I have a 3.8l v6) let me know if anyone got it thanks
 
1 - 20 of 27 Posts
Top