What could be causing 2004 Durangoâ€™s starting issues?

Q: My 2004 Dodge Durango with 170,000 miles has recently developed starting problems. It will start up in one of three ways: 1. Start fine. 2. Start with a knock and go right to idle rpm. 3. Start with a knock and stall. I then have to crank the motor for 5-10 seconds before the motor slowly starts and goes right to idle rpm. I have no dashboard warning lights, the battery is OK and the engine runs fine with no detectable power loss or knocking. My mechanic looked at it and drove it but was not able to diagnose the problem, even after replacing the cam and crank sensors and disconnecting various sensors, cables, etc., trying to identify the problem. Could this be an issue with the starter motor since the engine operates fine once it is running?

A: I wonder if the knocking noise is tricking the knock sensors into retarding ignition timing to protect the engine. Knock sensors are effectively small microphones that listen for the sound of detonation in the cylinders and signal the ECM, which retards the timing. Mechanical noises that mimic the sound of detonation may fool the ECM. The retarded ignition timing might explain the engine's idle rpm and restart characteristics.

You didn't identify whether your Durango is equipped with the 4.7-liter or 5.7-liter V8 engine, but both appear to utilize a geared starter motor. You could have the starter tested for amperage draw on or off the car. Once the starter is removed, the teeth on the flex plate ring gear can be inspected for damage. I found remanufactured starters for under $100.

One final thought: Years ago we had a Malibu wagon that developed an intermittent but very loud knocking noise. After much knuckle-busting, teeth-gnashing and head-scratching, it turned out to be a loose torque converter mounting bolt that intermittently hit the inside of the bell housing.

...

Q: My wife's 2001 Ford Escape has a problem with the cruise control. On a recent trip, when I turned on the cruise, the green light went on but when I attempted to set the speed control it would not set. The light to indicate that the speed control was set did not come on. Repeated attempts also failed. Then the green light indicating that the speed control was on also went off and wouldn't come back on. Yesterday my wife informed me that the green light did come on but the speed control would not activate. Could you help us diagnose this problem?

A: Your best diagnostic strategy is to use a scan tool and the cruise control's self-diagnostic capabilities to identify the problem. This may lead to pinpoint testing of the speed control switch, servo, deactivator switch, brake switch and other components. Also, make sure all brake lights are operational.

Please note that Ford issued a recall back in 2000 addressing potential corrosion or binding in the speed control cable.

L L L

Q: My Ford Fusion has about 85,000 miles on it. It has a set of Goodyear tires with about 12,000 miles on them. Both right-side tires leak air enough that the "Low tire" light comes on every two weeks or so. The tires have been removed and resealed to their aluminum rims by the tire shop where I bought them and by my Ford dealer. Nothing seems to work. I've thought of buying new tires or even trading the car, but I like it a lot.

A: Typically, there are two possible causes for air leaks from replacement tires on alloy wheels — corrosion around the bead contact area on the rim or porosity of the wheel itself. Shops remove the corrosion and apply a special sealant to the bead to seal the tire.

You have three choices — have a tire specialist try resealing the tires again, replace the wheels or replace the car. I'd go with option one.

Paul Brand, author of "How to Repair Your Car," is an automotive troubleshooter, driving instructor and former race-car driver. Readers may write to him at: Star Tribune, 425 Portland Ave. S., Minneapolis, Minn., 55488 or via email at paulbrand@startribune.com. Please explain the problem in detail and include a daytime phone number. Because of the volume of mail, we cannot provide personal replies.