Hello. I have two 2003 Montero Limited 3.8L, both have 203,000 miles. Both have P017x codes/CEL that say they are running lean on one bank. One for Bank 1 and the other for Bank 2. Occasionally, over the last 3 years, either will have hard start AND crank/no-start problems that seem to stop when it warms up outside (warmer than 55 degree F). Once, this winter, one of them wouldn't start for 3 months (Dec - Mar), then started right up after it had been consistently above 50 degrees F for 10 days.
Newer plugs and wires in both. Cleaned MAF (that looked fine to begin with). I don't notice any vacuum leaks. I use and/or lose about 1-qt engine oil every 1,500 to 2,000 miles. Both have good compression and newer timing belts/tensioners.
Can a bad Upstream Oxygen O2 sensor cause a prolonged crank/no-start? I didn't think so usually. All sensors seem to be running fine voltage-wise (up and down .2 to .8v). However, downstreams all move up and down from .1 to .9 volts constantly, almost as much as Upstreams...I thought downstreams were usually steadier? I find it hard to believe all 3 catalytic converters are bad, which is what hyperactive downstream sensors is supposed to identify, right?
When I watch Short Term Fuel Trims at idle and during steady highway speeds (2500 to 3000 RPM) they seem to constantly change, from -15 to +15 usually, sometimes they'll hit +20 to +25 for short periods.
Long-term Fuel Trims are more steady and usually from +5 to +13.
MAF reads to be okay and responsive from 3.5 to 60+.
Doesn't the cold weather hard and no-start seem to be either vacuum or fuel delivery? Like maybe a leaking fuel injector or hidden vacuum leak?
I'm going to borrow a smoke machine to check vacuum and a fuel pressure gauge. Does anyone know the location to hook up fuel gauge and the needed adapter type the Montero / Pajero use? As well as what RPMs I should test at and how long it should hold pressure and what measurement?
Thank you! willie
Newer plugs and wires in both. Cleaned MAF (that looked fine to begin with). I don't notice any vacuum leaks. I use and/or lose about 1-qt engine oil every 1,500 to 2,000 miles. Both have good compression and newer timing belts/tensioners.
Can a bad Upstream Oxygen O2 sensor cause a prolonged crank/no-start? I didn't think so usually. All sensors seem to be running fine voltage-wise (up and down .2 to .8v). However, downstreams all move up and down from .1 to .9 volts constantly, almost as much as Upstreams...I thought downstreams were usually steadier? I find it hard to believe all 3 catalytic converters are bad, which is what hyperactive downstream sensors is supposed to identify, right?
When I watch Short Term Fuel Trims at idle and during steady highway speeds (2500 to 3000 RPM) they seem to constantly change, from -15 to +15 usually, sometimes they'll hit +20 to +25 for short periods.
Long-term Fuel Trims are more steady and usually from +5 to +13.
MAF reads to be okay and responsive from 3.5 to 60+.
Doesn't the cold weather hard and no-start seem to be either vacuum or fuel delivery? Like maybe a leaking fuel injector or hidden vacuum leak?
I'm going to borrow a smoke machine to check vacuum and a fuel pressure gauge. Does anyone know the location to hook up fuel gauge and the needed adapter type the Montero / Pajero use? As well as what RPMs I should test at and how long it should hold pressure and what measurement?
Thank you! willie