Posted on November 12, 2011 - by Richard

97 Chrysler Town & Country Mileage Problem

Symptoms for 97 Chrysler Town & Country Mileage Problem:

My neighbor’s 97 Chrysler Town & Country Mileage problem was reported to ATS for advice. It has a 3.8L engine and the vehicle was bought since it was new. According to them, it’s been a while since their mechanic did a tune up and they felt that lately that the engine is running rough.

During yesterday’s check up, the mechanic took the fault code and got P0300 random misfire code. He tried repairing some leaky vacuum hose but the engine was still running rough. He also got the same P0303 code. Thinking that he had a bad #3 cylinder, he took the cylinder #3 compression reading and it was normal. The same compression reading goes for the rest of the engine cylinders.

Thinking the problem was not mechanical; he replaced the ignition coil pack and finally, replaced the egr valve which might be sticking intermittently. The code P0303 came back and this is where he got stuck. My neighbor now is now asking me how to help his mechanic. After all the things the mechanic did, what other reasons could cause a P0303 which result in having an engine with bad mileage?

Diagnosis for 97 Chrysler Town & Country Mileage Problem:

Fixing this 97 Chrysler Town & Country Mileage needs a complete analogy of this P0303 fault code which can be caused by:

1.) Bad or worn cylinder but compression test showed it was good.
2.) Bad ignition coil which he replaced already.
3.) Sticky egr valve which can cause the fuel mixture to run lean and was replaced already.
3.) Bad fuel injector or defective injector wiring connections.

In all probability, it is safe to explore the 4th option. I would start by checking the injector signal in cylinder #3. Using a noid light, you can disconnect the #3 injector plug in and connect the noid light tester. When the engine is crank, you should see the noid light blinking. If it does, injector circuit is fine.

To check, test and compare the rated resistance of the injector windings. Otherwise, the we need to check the injector wiring circuit from the ecm upto the injector plug in. You should get a resistance not higher than 5 ohms or you have a short or open connection in the wires. To do this properly, you need a complete wiring diagram of the ecm circuit from ATS.

Assuming the noid light is blinking OK and the same goes for the next 2 cylinders, I would go to the removal of the injector itself. This requires the removal of the intake manifold so you can access the injector. Once the injector is out, a proper inspection is in order or… if the entire injector fuel rail can be lifted with all the injectors intact; crank the engine and see which injector is leaking. A bad injector will drip all the time while the good ones will have a quick spray and shut off.

Final fix for 97 Chrysler Town & Country Mileage Problem:

When the mechanic got hold of this information, he removed the intake and lifted the injector fuel rail with all the injectors. During cranking, he found #3 injector is leaking. After removing the injector, he also found that the injector inlet screen was full of debris. When he informed ATS about it, we informed the source of the debris: dirty or corroded fuel tank.

To correct this, the tank has to be removed along with all the fuel lines/rail to be blown by air. This clean up process also needs the replacement of the fuel filter and all injectors because of the fuel contamination. Three days after we told him about it, he reported the engine was running smooth as if it was brand new. No codes returned.

More tip for 97 Chrysler Town & Country Mileage Problem:

1.) The egr can be tested using a scanner by using the LTFT and STFT features which are the fuel mixture indicators of the engine management system. The safe % range value is +10 for LTFT and -10 for STFT. This can be observed during idle.

Using this feature can avoid the unwanted replacement of the egr valve. This is also the best way to save in vehicle cost if you have your own scanner in situations like this. Using scanner with multiple features like “live data stream” monitor will help you pinpoint the problem right away.

Thanks,

Richard