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Jerry, Master Mechanic
Category: Dodge
Satisfied Customers: 1754
Experience:  ASE Master tech, 30 years exp. troubleshooter, driveability tech
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I have a 94 dodge ram 1500 with the 318 engine. The problem

Customer Question

I have a 94 dodge ram 1500 with the 318 engine. The problem it is having is that it runs rough at different times. It acts like the carb is loading up with fuel (I know this has a fuel injection system but this is the best to describe the problem). If I push the accelerator to the floor, it runs great for a while, then terrible again. It doesn't have a certain pattern as to when it happens, it can be at idle, in-town, or highway speeds. I put a fuel pressure guage on the fuel rail and it hold 42psi even when it is acting up. I have disconnected the battery to reset the computer which didn't help. The flash codes I am getting are: 12, 37, 55. I think the first and last are normal, but the 37? All the info I find is a throttle part solenoid, which I'm not sure what this is. Maybe throttle position sensor? Any suggestions for this problem is greatly appreciated.
Danny Russell
Submitted: 7 years ago.
Category: Dodge
Expert:  Ricardo Hohl replied 7 years ago.
let me look it up and get back to the mean time can you check the vacum to the map sensor and make sure the o2 sensors are conected and one mire thing check the temperature sensor conector make sure is good.
Customer: replied 7 years ago.
the temp sensor connector looks ok. its not broken and the wires dont appear broken or melted as far as i can see. the vaccum hoses on the map sensor (i think it located on the left side of engine towards the back) has 3 hose. i traced them as far as i could and the plastic tubes are all in tact. the o2 sensor is connected.
Expert:  Ricardo Hohl replied 7 years ago.
ok do you have a volt meter?can remove the tps sensor and check the voltage at all 3 wires with key on?
Customer: replied 7 years ago.
the voltage on pin 1 (closest to the front of engine ) is 0.03. pin 2 is 4.54, and pin 3 is 4.99 vdc.
Expert:  Ricardo Hohl replied 7 years ago.
ok that is good the code 37 is a/c switsh solenoid , but this is only about air conditioning .can you check the voltage at the temperature sensor in and out with key on?also voltage on map sensorin only?
Customer: replied 7 years ago.
the voltage on the temp sensor is 4.94 and .02 vdc. the map sensor is 11.87
Customer: replied 7 years ago.
i dont know if you got my responce earlier or not, but the voltage on the temp sensor is 4.94 vdc and 0.02 vdc. the map sensor is 11.87 vdc.
Expert:  Ricardo Hohl replied 7 years ago.
that is good readings it loocks like you have injectors that are dumping fuel , or leaking how many injectors are on the intake 8 or just 2 in top of the throttle?
Customer: replied 7 years ago.
there are 8 injectors.
Expert:  Ricardo Hohl replied 7 years ago.
ok have you replase the cam sensor this sensor is located inside the distribuitor and it controls the opening and closing of the injectors. is call pick up coil or cam sensor?
Customer: replied 7 years ago.

yes. its been about 3 months or so. I hoped that would solve the problem, but it didn't...


Expert:  Ricardo Hohl replied 7 years ago.
ok, i was doing some resersh on chryslers data and found a tsb about a idle air control valve wish may solve your problem and if it dont then you are going to need a scanner to take a look at all the sensor readings and see wish one is the one failingi know we chwck sensor voltage and it shows ok but runing and with a scanner its more accurate, you can try this tsb and see what happins
IAC Motor - Erratic Idle/Stalls On Decel/Hot Restart

NO: 18-16-94

GROUP: Vehicle Performance

DATE: Aug. 26, 1994

Erratic Idle, Stall On Hot Restart And/Or Low Speed Deceleration




1992 - 1993 (AD) Ram Pickup/Ram Cab & Chassis/Ramcharger 1992 - 1994 (AB) Ram Van/Wagon (AN) Dakota/Dakota Sport/Dakota Cab & Chassis 1993 - 1994 (ZJ) Grand Cherokee/Grand Wagoneer 1994 (BR) Ram Truck





Erratic idle and idle undershoot, stall on a hot restart and/or low speed driving on deceleration. These conditions will most likely occur during warm and hot ambient temperatures (above 70 degrees F). The condition may be worse with the A/C on, and the compressor running.


Using the Mopar Diagnostic System (MDS) or the Scan Tool (DRB II or III) with appropriate diagnostic procedure manual, verify that all engine/transmission systems are functioning as designed. If Diagnostic Troubles Codes (DTC's) are present, record them on the repair order for future reference, and repair as necessary.


1 53030657 Motor, Idle Air Control (IAC) 3.9L, 5.2L, & 5.9L



This bulletin involves replacing the (IAC) Motor with a revised motor.

1.With the key in the off position, disconnect the Powertrain Control Module (PCM) 60 way connector. This allows the system to re-initialize the Idle Air Control Motor (IAC).


2.Remove the air cleaner housing and tube assembly.


3.Disconnect electrical connector from (IAC) motor.


4.Remove two mounting screws. Figure 1


5.Remove (IAC) motor and O-ring from the throttle body.


6.Install the new (IAC) Motor and O-ring, reversing the above procedure.


7.Connect the 60-way connector to the (PCM).


8.Start the vehicle and allow to warm up to normal operating temperature.


9.With the parking brake applied, let the vehicle idle in drive (if manual transmission in neutral) for a minimum of five (5) minutes with the A/C off. This allows the (PCM) to learn the idle position.


Reimbursable within the provisions of the warranty.


TIME ALLOWANCE:Labor Operation No: 14-30-23-98 1992-1994 AD, AN, ZJ, BR 0.3 Hrs 1992-1994 AB 0.5 Hrs




Customer: replied 7 years ago.
this was replaced also about 3 months ago.. it didn't help either.
Expert:  Ricardo Hohl replied 7 years ago.
ok then you are going to need a scanner to be able to see what is going on by looking at all the sensor readings can you errase the codes and start let it worm up and tel me what codes came back?
Customer: replied 7 years ago.
o.k. the flash codes are 12, 37, and 55. thats all it shows. i erased the codes by disconnecting the battery for about 30 minutes, then reconnected it and let it warm up for about 10 minutes to operating temp. is this the correct way?
Expert:  Ricardo Hohl replied 7 years ago.
12 is enter diagnostics 37 is ac relay problem ,and 55 end of diagnostics and no othr codes, can you read the temperature sensor when vehicle starts to arun bad also map sensor with the conectors conected back probe the back with a paper clip do this to all the wires on each sensor and tell me the voltage make sure engine is runing and reach temperature.
Customer: replied 7 years ago.
i cant really check the map or temp sensor because it doesnt act up at an idle very often. it is usually at highway speeds. last night, i took the map sensor and tps to the local parts store and tested them, and both tested o.k. please note: i am not fond of autozone, but i witnessed the test and agreed they were o.k. the map sensor dropped to about 2.75 volts with 15# XXXXX vac applied and to 1.5+- with 20# XXXXX the tps dimmed and brightened their test light without blinking all through the range turning very slowly.
Expert:  Ricardo Hohl replied 7 years ago.
<p>good that good readings on the sensor voltage and vacum aplied the sensors are good , do you see an egr valve in the back of the intake with a valve and a electrical wires</p>
Customer: replied 7 years ago.

i dont see any wires connected to it. but i do see the egr valve.


Expert:  Ricardo Hohl replied 7 years ago.
ok is there a vacum hose conected to it and does it has vacum upon acceleration?
Customer: replied 7 years ago.
there is a hose connected to it and it does have vac to it. the hose is attached to another part that has wires and 2 vaccum hoses attached to it. i broke my vac pressure guage last night so i can't tell how much vac it has. the part that has the hose going to the egr valve is just floating loose next to the egr valve.
Expert:  Ricardo Hohl replied 7 years ago.
can you actuate the egr valve your self by pushing on the diaphragm at the bottom and see if engine hesitates in response?
Customer: replied 7 years ago.
the egr valve seems to be enclosed at the bottom. i can't get my fingers in there to move the diaphram.