Questions and Answers
Weird Reliant Problem
Q. I have a 1985 Plymouth Reliant 2.2 liter Throttle Body Injection, automatic transmission.
Problem: After starting it up and driving for a while, I will come to a stop light, the car will idle rough and will get to a point when it will act like it is out of gas. I go to take off and will mesh the pedal to the floor and it will be flat and act as it is out of gas but the tank is full.Some times it will cut off but in a few seconds. it will start up again. When I get to the stop light and cut the car off, wait for the light to turn green and start it, it starts and take off ok. The fuel pump has been changed, O2 sensor, coil, computer (SMEC), cap & rotor all have been changed and it still does it. I have had a computer diagnostic check done and it checks out okay but I still have the problem. Is it fuel (TBI) or electrical??
The engine and transmission have been rebuilt also. As long as I am driving everything is okay but if I get stuck in traffic or at a stop light and have to idle for a short period of time then it starts to idle rough. If I speed the engine up at this time and go back to idle it gets worse and acts like it is out of gas. When I go to take off in that condition, I can mesh the gas pedal to the floor and the car will act like it is fuel starved for a few moments and then it will take off and run like nothing is wrong!!
Stumped???
A. I have seen this before in the carbureted engines, but not in the TBI models. Yet the symptoms are exactly the same. In the carbureted engines it was due to vapor lock or fuel foaming. I suppose it could happen to the TBI version, there weren't too many of them in 1985. I'm tending to believe both variations would experience the same problem.
Vapor lock and fuel foaming cause similar conditions. The following are characteristics of each condition and should be observed on a fully warmed up engine. (These conditions do not affect cold engine driveability.)
Vapor Lock: Engine performance is gradually reduced in high ambient temperature or high altitude driving due to a drop in fuel pressure, which starves the engine for fuel (goes lean). Engine may not start until fuel system components cool off.
- Occurs after hot soak, prolonged idle, or highway speeds at any throttle opening.
- Sag due to lean mixture.
- No black smoke at tailpipe.
- Fuel pressure drops to 0.
- Engine may not sustain heavy loads.
Fuel Foaming: Engine sags and/or exhibits poor performance following a hot soak restart. This condition occurs when cool incoming fuel meets the hot fuel in the carburetor fuel bowl, which creates an over rich condition. Engine will start (unloading technique may be necessary).
- Occurs primarily after hot soak restart or prolonged idle only on medium to heavy acceleration.
- Sag due to rich fuel mixture.
- Black smoke at tailpipe.
- Fuel pressure is normal.
- Will start immediately (unloading technique may be necessary).
Chrysler came out with three different kits to correct this problem. Three different kits were required due to the various fuel gauges and fuel tanks used from 1983 through 1985. I would say that you have a Chrysler Dealer take a look at this to see if it does indeed apply to your vehicle.
Additional Information provided courtesy of ALLDATA
