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Sputtering, then dying: Suspicion falls on fuel pump

  • Article by: PAUL BRAND
  • January 13, 2012 - 3:50 PM
Q I have a 2003 BMW 330i. The other day, I arrived home and turned the car off. Twenty minutes later, the car started, sputtered a few times and died. It would turn over, but not fire. I tried later in the day and then the next morning. Same thing -- the engine cranked but wouldn't fire. I had it towed to the garage, where I was informed it started fine for the tech. There were no idiot lights or computer codes to indicate a problem. So, I'm driving again but a little nervous. Any ideas?

A With no check-engine light or fault codes, you have to be suspicious of the fuel pump, the fuel pump relay or a fuel system blockage. If the fuel pump failed to start when you turned the key, the symptom would be as you described: a couple of sputters, then nothing.

A fuel pressure test to ensure that the pump delivers 50 pounds per square inch of fuel pressure along with measuring the pump's amperage draw might identify a weak pump. Do you recall hearing the fuel pump start and run for a second or two when you first turned the key from "off" to "run" before cranking the engine? If so, then when the symptom occurs again and the car won't start, turn the key off, wait a few seconds and then turn the key on without cranking the engine. Do you hear the fuel pump? If not, you've identified a problem with the fuel pump, fuel pump relay or fuel pump circuit. If this happens, try wiggling or even swapping the fuel pump relay for a relay with the same part number. You might get the vehicle started by having someone safely thump on the bottom of the fuel tank with a rubber mallet while you crank the engine.

Q My '99 Ford Explorer has had static on AM radio stations for many years. I noticed this after having the manifold absolute pressure (MAP) sensor and the idle air control (IAC) valve replaced at the dealer. The dealer replaced the antenna, but the problem did not improve. When I drive close to power lines, there is considerable static on some AM stations but it's not as bad on others. The static increases in tempo and volume when I accelerate. When I turn on the heater fan, depress the brake pedal or use the turn signals there is a noticeable "clicking" sound from the radio. Where should I look?

A You are hearing radio frequency interference (RFI), which occurs when signals from the ignition or electrical/charging system are strong enough to compete with the AM radio signals and are amplified through the vehicle's audio system. Perhaps the simplest do-it-yourself test is to gain access to the radio's metal chassis in the dash and add a new ground with a jumper wire from the radio chassis to a chassis bracket nearby. If that stops the RFI, make that ground permanent. If not, use a pair of jumper cables to create another solid ground between the drivetrain and the chassis/negative battery terminal, then retest. Also, check the antenna and its mount for solid contact with the chassis. Any rust or corrosion around the mount will cause a poor antenna ground.

This type of RFI can also be generated by the alternator as it speeds up and slows down with engine speed. And RFI filter might help. Ford also issued an RFI filter for the fuel pump, but that would be more of a constant buzz.

Q I recently purchased a 1975 Ford F-250 camper special with 60,000 miles on it. On a cold start, it won't shift into drive until the engine is warmed up. What could be causing this?

A Age, hardened seals and a sticky valve body. Add half a can of SeaFoam Trans-Tune, drive it for a few weeks and see if it improves. If so, flush and refill the transmission and add the other half can of Trans-Tune.

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