Welcome to the all new Geo Metro Forum. We hope you enjoy your visit.You're currently viewing our forum as a guest. This means you are limited to certain areas of the board and there are features you can't use and images you can't see. Registration is simple, fast, and completely free. If you're already a member please log in to your account to access all of our features: Join our community! |
| Finally fixed it!; code 31 engine running bad | |
|---|---|
| Tweet Topic Started: Oct 21 2013, 05:39 PM (338 Views) | |
| rjmockster | Oct 21 2013, 05:39 PM Post #1 |
|
New Member
![]() ![]() ![]() ![]()
|
So I've make a couple of post's on here about my engine idling badly ( 95 3/5), consuming too much fuel, throwing engine codes etc etc... My codes were 14, and 31. I got a new ECT sensor which cleared the 14 code, but then I had bought a used MAP sensor off of ebay which did not clear the 31 code and the engine still ran like crap. I had picked through the wiring harness with a fine tooth comb doing continuity checks all the way back to the ECU all which were fine, checking ground points thinking I was going to have to start throwing money at this car buying parts to try and fix it and getting pretty frustrated from not getting the problem figured out. Finally I just kinda went for broke and stripped a little bit of insulation off of the three wires going to the MAP sensor, got a 3 wire plug and hooked the wires together so I could start doing voltage checks going to and from the MAP sensor. I had a solid 5vdc going to, but coming out of the sensor I had a solid 4vdc regardless of whether the throttle was open or closed. I knew that couldn't be right so I pulled the hose off of the throttle body and just sucked on it like a drinking straw. When I did that the voltage changed to about 1.5vdc and the engine seemed to respond well to it. Then I hooked that hose up to the vacuum port for the EGR solonoid valve and the engine smoothed right out. Obviously I had a vacuum problem at the MAP sensor vacuum port. And here's what caused it.....About a month ago while I was fixing a headlight ground wire issue, I decided to replace the PTC heater gaskets (PTC heater kept blowing its fuse because of it bottom gasket). I had a roll of felt paper gasket material and carved a gasket for the top and bottom of the PTC heater and threw the one gasket away that I had pulled off of the top. The fuse for my PTC quit blowing and I thought "cool, got that little issue fixed". Then it was just a couple weeks ago, my engine light started coming on and off and the engine started jerking every time I let off the gas and stuff got weird so to speak. The the engine stayed on, engine kept idling extremely low and it was troubleshooting time again,,,,,, lovely right? Long story made short, the old gasket that I threw away was a steel plate gasket (for the top of the PTC heater), the one I put on was basically paper. The vacuum in the intake actually sucked the paper gasket wide open and I lost all my vacuum to the MAP sensor port on the throttle body. So I pulled the throttle off and cleaned it up real good, pulled my old gasket out of my garage trash can and put it back on, and now my engine light finally went off and my engine is running happy again!
|
![]() |
|
| Deleted User | Oct 21 2013, 05:42 PM Post #2 |
|
Deleted User
|
Nice. You know those gaskets are available new, right? |
|
|
| 1 user reading this topic (1 Guest and 0 Anonymous) | |
| « Previous Topic · Engine Tech & Diagnostics · Next Topic » |


Welcome to the all new Geo Metro Forum. We hope you enjoy your visit.


![]](http://z3.ifrm.com/static/1/pip_r.png)
Finally I just kinda went for broke and stripped a little bit of insulation off of the three wires going to the MAP sensor, got a 3 wire plug and hooked the wires together so I could start doing voltage checks going to and from the MAP sensor. I had a solid 5vdc going to, but coming out of the sensor I had a solid 4vdc regardless of whether the throttle was open or closed. I knew that couldn't be right so I pulled the hose off of the throttle body and just sucked on it like a drinking straw. When I did that the voltage changed to about 1.5vdc and the engine seemed to respond well to it. Then I hooked that hose up to the vacuum port for the EGR solonoid valve and the engine smoothed right out. Obviously I had a vacuum problem at the MAP sensor vacuum port. And here's what caused it.....



2:18 PM Jul 11