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Back story:
Just acquired this car with 130k. The previous owner owned this car all throughout college and dumped an obscene amount of money into it for what it is. I have a stack of receipts and work orders several inches high that came with the car, with every single oil change nut and bolt this guy bought for it. It was sitting in his driveway for several months because couldn’t get the thing running…it just stopped out of nowhere. He decided to part with it since he is working full time and has a wife and child to support.
The work that has been done from previous owner. All of this has been done in the past 2-4 years:
Fuel system: gas tank drained and cleaned out, fuel pump, fuel filter, fuel pressure regulator, new injectors.
Ignition: distributor, distributor cap & rotor, spark plugs, spark plug wires. Coil is still original.
Electrical: O2 sensor, ECM coolant temperature sensor, ECM (mom and pop shop replaced it with a junkyard unit from a different car, not 100% compatible with a 93 Excel).
Engine: cylinder head rebuild, timing belt and components replaced.
Misc: thermostat, coolant hoses, PCV valve, all vacuum hoses replaced, brand new exhaust from the converter back, converter has been hollowed out, new struts/shocks, tons of front end work, tires, MAF cleaned with appropriate cleaner, etc.I can barely get this thing started. When certain conditions are present (about to go into detail on that), I can get it running and it runs PERFECTLY for about 10 seconds and then just dies out. If you push on the throttle it immediately dies. This car has the 1.5L Mitsubishi engine that is found in several cars in that period of time. On the throttle body there is what is referred to as an idle control servo. It’s a unit that has two electrical connectors. One functions as an idle air control valve and the other is known as a “motor position sensor”. If the motor position sensor is plugged in, the car will absolutely NOT start. If it is left unplugged, it will eventually start…idle fairly high…level off, and then die. I have tried two different units, and both have the same effect. I guess I am just trying to figure out why the car will run fine and then just die, or immediately die when you press on the throttle. If I just BARELY touch the gas pedal I can actually rev it up but it will eventually stall out and die. I started it at one point with the motor position sensor unplugged…I then went under the hood with it running and plugged it in, car immediately died. It did this with both units.
Here’s what I have done:
I replaced the throttle position sensor, replaced the air filter (it had a K&N that did not fit right), replaced the idle control servo, and also replaced the ECM with the correct one. I am not sure where to go from here. Any help would be appreciated.
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Replies
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Is the engine light on? this may help.
http://www.justanswer.com/car/1f161-ok-1993-hyundi-excel-morning-go-go.html
Check engine light was not on previously (or now) but I did check for passive codes using the analog multimeter method. Came up with motor position sensor code. The coolant sensor was also in spec. Thanks for the reply!
I just spent the afternoon yanking the entire ECM wiring harness out through the firewall. I checked the entire length of the wire and found a few different crimps connectors and redid them just to be safe. Put everything back together and still does the same thing. I also just swapped out my MAF with a known good one just to rule it out, still the same issue.
On this engine the motor position sensor and the throttle position sensor are two different things, but yeah, I still have a code 14 which is the TPS. I checked the harness, I am getting power to the sensor from the ECM and also a good ground. The only other thing I can think of is that the actual sensor output wiring is bad. (It’s a 3 wire sensor)
This is where I think my problem might be. Going to run a fresh wire from the sensor to the ECM tomorrow and see what happens.
Instead of running new wire for possibly nothing. I poked a hole in the output wiring insulation close to where it goes into the ECU and tested voltage with the ignition in the ON position. It registered about .5 volts and I slowly opened the throttle all the way, and the voltage slowly went up to around 4.5-4.8v which is pretty much in spec per the FSM.
It still can be a little hard to start. It stumbles a bit but finally runs, and runs perfectly for about 10-15 seconds and then slowly stalls out. Giving it more than just a tiny amount of throttle kills it. I am once again stuck.
[video width=425 height=344 type=youtube]3p3taA50WEo[/video]
This is what is going on. As you can see, it’s a little hard to start…but it DOES start. It seems to run fine until you mess with the throttle.
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