I am trying to track down the problem with my 90 YJ not starting every now and then... couple of questions:
How much power should run to the fuel injector? If no power, does that mean a bad ECM?
...The engine will turnover constantly and not fire. Then the next day it starts up just fine! Thanks in advance for any help...
I had similar problem with my 87 YJ, 2.5l 4banger, TBI, stock. I thought it had something to do with my fuel pump. What I found was 2 Relays that transmitted electrical signals to componets (such as fuel and ignition). Also known as (ASD) Auto Shutdown relay. They are located on passenger side next to battery, one was black the other blue plugs. the cost was around $8.00 each. After replacing them my problem was cured.
I went through something like this last week, but when I traced the wires going to the fuel pump I found a 4 foot section that was dead.
Check to see if you are getting power to the fuel pump, clean your crank position sensor, clean all your grounds and connections, check for cracks in the distributor cap and see if the rotor is good.
I started replacing too many things and it was a simple piece of new wire and she starts and runs everytime. Trace all the wires to the pump and test them every foot. There is a section that wears out just above the rear axle where the wire rubs on the frame. Mine wore through the plastic protector.
It's worth a shot and at least you'll know if you have power to the pump, then you can eliminate other things as you go.
A rebuilt '05 Unlimited w/ 6 spd, 4.0, 3" BDS springs, front locker, warn front bumper, PS corners, rock sliders and the list goes on and on.
Former Jeeps: 79 CJ7, 81 CJ7 Renegade, 85 CJ7 and a 95 YJ.
Project car: Big Block 4spd 69 mach 1 (it's back on the rotisserie for the final time).
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