Dear Troubleshooters:
I have two problems:The first problem is driveability, occasional severe hesitation at 25 percent throttle (TPS 1.8 volts) pulling out from a stop or worse starting uphill.
The vehicle is a 1995 Dodge Caravan, 2.5L four-cylinder (no EGR), three-speed automatic with 97,000 miles. It is equipped with delay wipers, power brakes, power door locks, cruise control and air conditioning. The VIN is 2B4GH265K75R250516.
The vehicle has in the last six months received a new head gasket, O2 sensor and timing belt and the timing marks have been verified three times. Fuel pressure is 40 psi, the TPS was checked using a lab scope. The MAP sensor also tested good. Engine vacuum is at 15 inches. We checked for leaks and isolated the vacuum booster; no problem found. We replaced the pressure regulator. If the vehicle had a carburetor, I would bet the farm on a bad accelerator pump. That's exactly what it feels like when driving it.
The second and oldest problem is not as serious and only happens occasionally. Within the first 15 minutes of vehicle operation, if the right turn signal is used, the wipers operate until the turn signal cancels. We suspect a bad body computer. The dealer replaced the body computer and the turn signal switch during the vehicle's last year of warranty. Clue: This only happens when the weather has been hot and humid for several days or snowy for weeks with very high humidity.
I am a certified Master Mechanic and have been in business for 24 years.
Sincerely, George Lubiw - Beaver Avenue Service, Pittsburgh, Pa.
Dear Mr. Lubiw:
There has been a considerable number of intermittent hesitation problems with these vehicles that were the result of faulty Heated Oxygen Sensors. (HO2S)Try driving the vehicle while monitoring the oxygen sensor with a scan tool and attempt to duplicate the condition.
Observe the oxygen sensor voltage during the hesitation. Does the voltage swing in one direction and stay there? If so replace the oxygen sensor.
The electrical problem sounds more like a problem in the 50-way bulkhead connector that is used to join the engine and interior harnesses. The wiring for both the turn signal and wiper systems run through this connector.
Disconnect the bulkhead connector at the firewall and carefully check both connector and connector terminals for corrosion and/or moisture accumulation.
This connector can be a source of multiple electrical problems on the Caravans.
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