DodgeTalk Forum banner
Status
Not open for further replies.
1 - 7 of 7 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter · #1 ·
I have a 94 dakota with a 3.9 V6 motor and i have a problem with it idling and staying running. Sometimes it will start up and run and idle fine and then sometimes it will spit, sputter, and then eventually stall out but it will restart just fine. Sometimes when it starts up real hard and idles hard the check engine light comes up with a Code 14 which is for the MAP sensor. But like today i went out there and it started fine and i could actually put it in gear and pull it out of my garage and back in without it stalling WOO HOO .. Is it just my timing that is off or is it something else that i need to check or replace or whatever. Any help is greatly appreciated.
 

·
Registered
Joined
·
20 Posts
Hmm.. I'll just re-post what I posted (well, cleared up) on the other site ya went to, so people on this site can see it, 'n hopefully you'll give your results on both sites. ;)

Applicability: 1995 and previous model years, all engines.
The MAP sensor is located in one of two spots: on the passenger side firewall, or the throttle body itself. It has a 3-wire connector (those wires being: black/light blue, dark green/red, and violet/white)

Test procedures:
Disconnect battery negative cable. Remove connector from single-board engine controller (SBEC, may also been called Powertrain Control Module [PCM]; its located on the passenger side fender side shield). FAILURE TO DISCONNECT BATTERY NEGATIVE CABLE BEFORE DISCONNECTING OR CONNECTING SBEC/PCM CONNECTOR COULD CAUSE PERMANENT DAMAGE TO SBEC/PCM. Disconnect MAP sensor electrical connector.
Test continuity/resistance between:
Pin 1 of the SBEC and pin 2 of the MAP. Both will have the dark green/red wire.
Pin 4 of the SBEC and pin 3 of the MAP. Both will have the black/light blue wire.
Pin 6 of the SEBC and pin 1 of the MAP. Both will have the violet/ white wire.
All should have continuity/low resistance. Repair circuit(s) as needed.
Reconnect MAP sensor electrical connector. Reconnect SBEC connector. FAILURE TO DISCONNECT BATTERY NEGATIVE CABLE BEFORE DISCONNECTING OR CONNECTING SBEC/PCM CONNECTOR COULD CAUSE PERMANENT DAMAGE TO SBEC/PCM. Reconnect battery negative cable.

Disconnect MAP sensor electrical connector. Turn ignition key to ON, do not start motor. Test for 5 volts (+/- .5 volts) between the outside cavities of the connector (violet/white being the power, black/light blue being the ground). Make note of this voltage. Turn ignition key to OFF.
Reconnect MAP sensor electrical connector.
Turn ignition key to ON position, again, do not start motor. Output voltage (center cavity, dark green/light blue) should be 4-5 volts. Make note of voltage.
Now, start the motor. Voltage; on that same wire; with a hot, neutral, idle speed condition should drop to 1.5-2.1 volts. Make note of voltage.
Stop the motor. Test complete.
Repost with outcome of continuity/resistance, and voltage tests.
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #3 ·
Well i went out there and tested everything that you told me to in the last post and evrything tested good. The output of the MAP sensor is 2.1 volts when idling and running. So that means that the MAP sensor is good but now i have another little problem/question to ask. How does a backyard mechanic set the timing on this truck??? Any help is greatly appreciated.
 

·
Registered
Joined
·
2,140 Posts
Matt2348 said:
Well i went out there and tested everything that you told me to in the last post and evrything tested good. The output of the MAP sensor is 2.1 volts when idling and running. So that means that the MAP sensor is good but now i have another little problem/question to ask. How does a backyard mechanic set the timing on this truck??? Any help is greatly appreciated.
Don't forget that the MAP may test good when it's operating correctly. I have seen this many times. Most of the MAPs I have replaced have been on Fords that act funny at idle and then get progressively worse. The computer is telling you that you have a MAP sensor circuit failure which can only be the MAP, it's wiring, it's vacuum source or the computer(rare). I would replace the MAP, check the connector for corrosion and place a small amount of dielectric grease on the terminals.
 

·
Registered
Joined
·
385 Posts
The timing on the magnum engines is controlled by the ECU. Rotating the distrubutor will only throw the fueling off. What is causing you to think that the timing needs to be set? Are you still having issues after replacing the MAP sensor?
 

·
Registered
Joined
·
20 Posts
Like dirt_devil said, the timing on the Magnum (1992 up) engines is not adjustable, and is computer controlled.
Like I said in the other forum you posted on, there was a person with a similar problem, and after much money and time wasted, the problem was a bad timing chain. When he checked his timing, it appeared good, but just because your timing is good does not mean the chain is good.
Attached is instructions to measure timing chain strech. If it has too much play, replace it. (The guy whos chain was bad said he had about 7degrees of play in it, which he said was about 1 inch!)
 

Attachments

1 - 7 of 7 Posts
Status
Not open for further replies.
Top