Please Need Help 1988 plymouth horizon throttle body injection

plymouth

#1

I need your help please! In the morning I filled my gas tank.I drove all day and turned on and off.Came home in the afternoon and shut off and unloaded stuff.Went out to restart, WILL NOT STAY RUNNING( starts then quits), if I flick the gas pedal I can force it to run,but has no power. Work I have done: new-fuel filter,spark plugs,dist. rotor button, checked and cleaned dist. pick up coil.


#2

I would check the fuel pump fuse and then have the fuel pump pressure tested. A good independent mechanic should have you going in no time. These vehicles use a fuel pump relay and a pesky decelerate fuel cut-off relay that can cause problems when they malfunction.


#3

Unplug the wiring harness from the MAP sensor and attempt to start the engine while pressing and releasing the accelerator. If it starts and eventually stabilizes somewhat to an idle replace that sensor.


#4

If you’re up to it and would like to keep the cost down, you can get a fuel pressure test kit an any parts store for perhaps $50+/-. You sound like a hands-on guy.

I’m betting it’s the pump.


#5

Turn your ignition key on and off 3 times and leave it on, Something on your dash will blink on and off. Count the blinks and you will get any 2 digit trouble codes. Then you can just google 2 digit trouble codes.


#6

Have the timing belt checked. It may have jumped a tooth (or two).


#7

Thanks for everyone’s help! Did the code retrieval approach. The code was map sensor. Runs great after replacing the map sensor


#8

Far out. Good on you for getting it fixed. That diagnostic software that came with the car worked well for you in this case.


#9

Glad for your success!


#10

You saved yourself a great deal of time and money using determination and patience. Luckily for mechanics you are among a small minority of car owners who are so inclined.


#11

Congrats to Rod Knox for pegging the problem. :slight_smile:


#12

fyi … MAP stands for Manifold Absolute Pressure. This sensor measures the amount of vacuum in the intake manifold. There’s a big vacuum at idle when very little air is making it past the throttle plate, less as the accelerator is pressed and more air goes into the engine. The car’s computer uses the intake manifold vacuum measurement from this sensor in its equation to determine how much fuel to inject, so when it fails poor performance results. On my Corolla, if the MAP fails, the computer will take a guess what the MAP reading should be based on everything else it knows – throttle position, rpm, vehicle speed, O2 readings, coolant temp – in order so the car will at least be able to limp home.