10-30-2010, 02:35 PM
Join Date: Jun 2010
Fuel Pump Issue w/ Troubleshooting
For the past 2 mornings, when I go to click the key to start, my fuel pump doesn't turn on right away. Usually my Check Engine light pops on as I put the key to start it, but it doesn't come on. The engine will turn over, but obviously not start. If I remove the key & do the same, the check engine light comes on as usualy for a second & then I can hear the fuel pump firing up. Then it will start as normal. It doesn't happen after I have the vehicle running for the day, only upon initial startup in the a.m. Any tips or areas to look for troubleshooting? It's a 2.5l 95' YJ, 5spd.
Update from today's troubleshooting;
- I replaced my PCM with a new rebuilt one.
- Removed the connectors on the wiring harness & sprayed them clean with electrical cleaner
- Traced the grounds from the negative terminal to the body & engine block. I used sandpaper to clean the terminals as well as removed the paint from the body.
- Wire wheeled the terminals on the battery & connections
- Had my battery tested (it's in great shape)
- Swapped relays in the PCM box around, cleaned terminals on all the posts with electric cleaner.
- I tested Terminal #30 & #87 at the Fuel Pump relay, shows 12.65-12.7 volts with the key in the ignition position.
Regardless after all of these tests & procedures, I'm still experiencing delays of 2-5 minutes before the fuel pump clicks on in morning. Once the vehicle is started it experiences no issues at all while running. Only after the Jeep has sat over night in sub 50degree temperatures do I have this problem.
Does anyone know a decent electrical shop to take this to in Northern VA, or recommend someone who would be able to help with this problem?
95' YJ, 4" Suspension, 31" BFG A/T, 2.5L, 5-spd., 95% of work done by yours truly.