The victim: my step-son's '00 Mercury Villager Estate, ~160kmi.
He was driving to school a couple weeks ago & it died on him. It restarted briefly, but died almost immediately. I was out of state, so we had it towed home.
I finally got a chance to look briefly at it. It started right away, but ran rough for a couple seconds. Then it ran fine until it warmed up, it still ran OK, but there was a slight stumble occasionally. I was afraid to drive it further than back/forth in the driveway, but it seemed OK. At that point I was thinking fuel pump/relay, but didn't have time to dig deeper.
I tried it again yesterday. It started rough again, but smoothed out after a couple seconds; however, within a minute it was running very rough & eventually died. I was able to get it restarted, but only by feathering the throttle. I smelled the exhaust, it wasn't running rich - I can only describe it as a "catalytic converter" smell. I looked underneath & it wasn't glowing, but it hadn't been running long either. I tried giving it gas & it bogged bad, and eventually died again.
I still need to check fuel pressure, but is there any way to trouble shoot the catalytic converter other than unhooking it?
Try swapping mass air flow sensors. On Nissans (Villager is a Nissan powertrain IIRC) they like to start reading low, which would explain why it runs okay cold (ECM adds fuel for cold start) but when warm it can't.
Any codes? MAFs will normally throw P0171/P0174 (fuel system lean bank1/2)
petegossett wrote:
The victim: my step-son's '00 Mercury Villager Estate, ~160kmi.
He was driving to school a couple weeks ago & it died on him. It restarted briefly, but died almost immediately. I was out of state, so we had it towed home.
I finally got a chance to look briefly at it. It started right away, but ran rough for a couple seconds. Then it ran fine until it warmed up, it still ran OK, but there was a slight stumble occasionally. I was afraid to drive it further than back/forth in the driveway, but it seemed OK. At that point I was thinking fuel pump/relay, but didn't have time to dig deeper.
I tried it again yesterday. It started rough again, but smoothed out after a couple seconds; however, within a minute it was running very rough & eventually died. I was able to get it restarted, but only by feathering the throttle. I smelled the exhaust, it wasn't running rich - I can only describe it as a "catalytic converter" smell. I looked underneath & it wasn't glowing, but it hadn't been running long either. I tried giving it gas & it bogged bad, and eventually died again.
I still need to check fuel pressure, but is there any way to trouble shoot the catalytic converter other than unhooking it?
Infared temp gun will tell you if the cat is plugged. It will be dang hot on the front and at least a 300F drop to the back.
But I echo it being a MAF problem. But if you had a data stream capable scan tool, you could eliminate a LOT of possibilities, such as a bad cat, plugged exhaust, MAF, etc....
No CEL. Might be time to buy/build(?) a scan tool for the ol' laptop.
Thanks for the tip about the MAF, I'll check that out!
The long forgotten vacuum gauge will tell if you have a plugged convertor/exhaust.
