californiadreamin
NAXJA Forum User
- Location
- WA
I have been suffering the last couple months with an insidious problem with my 91 4.0: Every time I take it up in the mountains, far from home it starts stalling. After about 1 hr of uphill freeway, it stalls. Repeatedly for 2-5 seconds at a time, requiring a roll start or use of the starter if I was going slow enough. Issue will persist until I leave the jeep to calm-down/cool offer for 6 more more hours. And the problem does not happen with regular around-town driving. Only long-sustained uphill drives.
At first I thought it was heat related, so I installed an e-fan (since my 91 Sport didn't have one stock) and insulated some things. That didn't help. Yesterday, I thought to check the fuel pressure. While the fuel pump makes the right pressure at idle (32 psi) and with vacuum disconnected (39 psi), it won't hold fuel pressure. (pressure totally goes away in 15 or 20 seconds). I verified that it's not leaking through the injectors or back through the fuel regulator.
So my question is: could a bad fuel-pump check value cause an an engine to stall when it's at medium-heavy load?
Sigh. Thanks so much for any input you have. This problem has thrown a monkey wrench into my last 4 wheeling trips and I'm really hoping this could be the problem.
At first I thought it was heat related, so I installed an e-fan (since my 91 Sport didn't have one stock) and insulated some things. That didn't help. Yesterday, I thought to check the fuel pressure. While the fuel pump makes the right pressure at idle (32 psi) and with vacuum disconnected (39 psi), it won't hold fuel pressure. (pressure totally goes away in 15 or 20 seconds). I verified that it's not leaking through the injectors or back through the fuel regulator.
So my question is: could a bad fuel-pump check value cause an an engine to stall when it's at medium-heavy load?
Sigh. Thanks so much for any input you have. This problem has thrown a monkey wrench into my last 4 wheeling trips and I'm really hoping this could be the problem.