marklindholm
New Member
94 MX Got a check engine light (running about 45 mph, no strain), which did not come back after shutting the car off and restarting. I pulled the EEC-IV code and got a single 172 code and nothing else. 172 is heated 02 sensor fault or lean on bank #1. This means I have a bad sensor, or the rear bank of cylinders went lean for a while.
I noticed trouble starting (long crank before engine starts) a few years ago and noticed that turning the key on twice (without cranking) would alleviate the problem. (builds up fuel pressure) I thought I had a fuel pump problem and was activly avoiding doing anything about it because I did not want to drop the tank.
I am pretty sure I am losing pressure in my fuel rail. A while ago I changed the fuel filter and I put a hose on the schraeder valve and depressed the valve to relieve the pressure and there was none. (yea I know I have been ignoring a lot of warning signs).
So,...if I am losing pressure in the rail; I read it can go three places, 1. back into the tank on the fuel pump out side, by leaking back thru a check valve. 2. thru the fuel injector(s) into the cyls. 3. Through the fuel pressure regulator to somewhere? back to the tank?
So my questions, am I going in the right direction for a single 172? can I rule out the leaky injectors because the engine starts fine when it does start (no coughing or smoke)? I am going to get a fuel pressure guage to do a leak down test on the rail. Can someone give me some guidence on where to block the lines to the tank and from the regulator to determine which side is leaking?
I noticed trouble starting (long crank before engine starts) a few years ago and noticed that turning the key on twice (without cranking) would alleviate the problem. (builds up fuel pressure) I thought I had a fuel pump problem and was activly avoiding doing anything about it because I did not want to drop the tank.
I am pretty sure I am losing pressure in my fuel rail. A while ago I changed the fuel filter and I put a hose on the schraeder valve and depressed the valve to relieve the pressure and there was none. (yea I know I have been ignoring a lot of warning signs).
So,...if I am losing pressure in the rail; I read it can go three places, 1. back into the tank on the fuel pump out side, by leaking back thru a check valve. 2. thru the fuel injector(s) into the cyls. 3. Through the fuel pressure regulator to somewhere? back to the tank?
So my questions, am I going in the right direction for a single 172? can I rule out the leaky injectors because the engine starts fine when it does start (no coughing or smoke)? I am going to get a fuel pressure guage to do a leak down test on the rail. Can someone give me some guidence on where to block the lines to the tank and from the regulator to determine which side is leaking?
