How to Fix Hesitating Dodge Neon

Repair Advice on 1995 Dodge that Stumbles when Accelerating

© Vincent Ciulla

Oct 3, 2007

This weekly Q&A session answers your questions about cars and trucks. This week explores a 1995 Dodge Neon that has a hesitation and stumble when accelerating. It also has a fuel gauge that reads backwards.

Question: Dodge Neon Hesitates, Stumbles

Hi Vincent,

I'm the Feature Writer on Cats at Suite101. Of course, I discovered your topic through Google and saw that you answer questions. I have a 1995 Dodge Neon that is hesitates, like the gas pedal quit working, and then it picks back up. The past couple of days, no matter what gear you're in, when you push the gas pedal down, it hesitates, takes off slowly; sometimes it even drops to an idle, and you have to pump the gas a few times before it will take off. It's almost like it takes a minute for the fuel pressure to build up when you press on the gas pedal.

We just replaced the fuel pump and filter. Another weird thing we can't figure out is that the gas gauge now works backwards?

And it has 233,000 miles on it.

Thanks for any help!

Darlene

Answer:

With that many miles on an engine the first thing to do is eliminate the engine itself as the cause of the problem. It is recommended to have a wet/dry compression test and cylinder leakage test done to make sure it is within specification and within 10% to 15% of each other. If the compression is low then one should look at the cause of the low compression and repair it as required.

Assuming the compression is good there are several things that could cause a hesitation or stumble on acceleration. Some of the things to check are:

• Charging system and battery.
• Secondary ignition system. Distributor cap, distributor rotor, ignition wires and spark plugs.
• Ignition timing. Note: Ignition timing is electronically controlled by the Powertrain Control Module (PCM) and is not adjustable. Adjusting the distributor will not change the ignition timing. It will change the fuel system synchronization and can cause driveability complaints.
• Check for vacuum leaks inspect Intake manifold, gasket(s), and hoses.
• Check EGR valve for premature opening.
• Check EGR Transducer for proper operation.
• Check for lean Air-Fuel mixture, (O2S Sensor output).
• Perform injector balance test.
• Check fuel quality.
• Check Throttle Position Sensor for proper operation.

There was a TSB on the throttle bodies for these engines. Check the part number of the throttle body. The throttle body part number can be found on the side of the throttle body by the vacuum purge nipple. Figure 1.

4669540, 4669541, 4663077, 4669167, 4669246, 4669245, 5277745, 5277765, 4669032, 4669313

If the vehicle does have one of the throttle bodies listed above, the throttle body assembly should be replaced.

If the vehicle does not have one of the throttle bodies shown in the list above, you will need to replace the throttle position sensor and "O" ring.

Another bulletin involves replacing the Powertrain Control Module (PCM) to fix this problem.

In February of 1994 there was a recall on the PCM due to water entering through the connector openings. You can call your Dodge dealer with the VIN number to find out if the recall was performed.

The only way a fuel gauge can read backwards is if, somehow, the circuit polarity was reversed. Here is how to test the sending unit and gauge.

1. Disconnect the wiring from the fuel tank sending unit.
2. Connect the wiring to a known good sending unit.
3. Connect a jumper wire between the sending unit pick up tube and ground.
4. Check the fuel gauge as follows:

• Allow at least two minutes for the gauge to settle at each test point.
• Move the float arm to its Empty stop and turn the ignition to the ON position; the gauge should read Empty or below.
• Move the float arm to the Full position; gauge should read Full or above.

• Wiring and connections between the gauge sending unit and the multiple connector behind left kick panel.
• Wiring and connections between the multiple connector and printed circuit board terminals.
• Circuit continuity between the printed circuit board terminals and gauge terminals.

If above items are satisfactory, gauge is defective and must be replaced.

If the gauge meets specifications, check the fuel tank sending unit. Remove the fuel tank sending unit from the fuel tank and connect a jumper wire between the sending unit pick up tube and ground, then repeat the fuel gauge inspection procedure.

If the gauge is now within specifications, check the following:

• Ground wire from sending unit to left side cowl. Ensure continuity exists.
• Sending unit mechanical condition. Ensure float arm moves freely and pick up tube is not bent.
• Sending unit float. Ensure there are no leaks or deformations.
• Sending unit installation. Ensure unit is installed correctly.
• Sending unit mounting flange on fuel tank. Ensure flange is not deformed.
• Fuel tank bottom. If deformed, pick up tube may be improperly positioned.

That's all for this week. Feel free to browse the archives for past topics. And, as always, if you are stuck and need an immediate answer you can always call Vince on the phone.

Figure 1

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