2001 corolla po171..

More
1 week 4 days ago #202213 by fordguy
2001 corolla po171.. was created by fordguy
Hi guys. I have watched a ton of your videos and loads others and still stuck. i am working on a 2001 corolla.1.8l..174,000 miles. code is a po171..lean bank 1. I have high fuel trims. shrt sometimes maxs out at 19.5% and lngt is always high 15 to 20 % +. Trims will drop at 2500rpm...maf reading about 1.8 at idle and rises up to 8 or 9 at 2500rpm. I have done a smoke test and could not detect a leak. o2s b1 wave looks ok, average about .485, and does switch wave from .1 to about.800...I dont think its fuel delivery because the trims drop at higher rpms. . vacuum tested about 21 with needle bounce, possible valve guides leak?
Freeze frame showed Fsystem..cl...ECT 179Deg,,, shtft -2.2,,, lgtft 34.4%,,,rpm, 710,,,,,IAT 95Deg,,,
I am about to start throwing money at it. not sure what else to do. i need the car fixed to pass emmisions for my daughter to start college. Live in tx and have to pass emmisions. Looking at new maf,o2sensors. Already changed pcv and air filter and cleaned the maf.Help !!

Please Log in or Create an account to join the conversation.

Advertisement
More
1 week 3 days ago #202220 by relative4
Replied by relative4 on topic 2001 corolla po171..
What are the fuel trims at 3000-4000 RPM? How did you smoke test?

Please Log in or Create an account to join the conversation.

More
1 week 3 days ago #202222 by fordguy
Replied by fordguy on topic 2001 corolla po171..
I made a smoke machine and got tons of smoke. Only leaks i could find was around the plenum before the m.a.f.( fixed them anyways).. I was tapped into the brake booster line. When the booster was plugged in i could pump the brakes and no numbers changed. Vacuum test on the booster was steady and no let down after an hour.
Trims as follows. key on ing off shrtft1 0.0... longft1 14.1%....ect 59Deg..
warmed up to 178deg.... rpms at 3500..shrtft1 -1.6,, longt +1.6... several readings were just about even st -2.6,,, lont +2.6.. pretty close to even shrt and longt..sure does look like leak to me, but cant find it..i can make tons of smoke too.. i even bypassed the intake and went to the throttlebody, no smoke anyplace..

Please Log in or Create an account to join the conversation.

More
1 week 3 days ago #202223 by relative4
Replied by relative4 on topic 2001 corolla po171..
Any differences in the idle trims between hot and cold engine?

Please Log in or Create an account to join the conversation.

More
1 week 3 days ago #202224 by fordguy
Replied by fordguy on topic 2001 corolla po171..
Not really
About the same..

Please Log in or Create an account to join the conversation.

Advertisement
More
1 week 3 days ago #202226 by relative4
Replied by relative4 on topic 2001 corolla po171..
My guess is a leak on the underside of the intake manifold gasket that's diffusing the smoke before you can see it. Leaks from the old black gaskets on those cars are so common, it's almost impossible not just to assume that's the problem.
There are gasket locator tabs at the top outer corners of #1 and #4 that you can see with the engine cover removed. If those tabs are black, not orange, I'd go ahead and replace that gasket with the new orange one.

Please Log in or Create an account to join the conversation.

More
1 week 3 days ago #202227 by fordguy
Replied by fordguy on topic 2001 corolla po171..
Thanks..I figured it would be something I had not guessed.. for less than $20. It's worth a try anyways..I will update after the repair..

Please Log in or Create an account to join the conversation.

More
4 days 11 hours ago #202274 by fordguy
Replied by fordguy on topic 2001 corolla po171..
HI.. Made no difference. The gasket looked good upon removal..still stuck on same problem..

Please Log in or Create an account to join the conversation.

More
3 days 16 hours ago #202282 by relative4
Replied by relative4 on topic 2001 corolla po171..
Well shoot. Then I agree MAF sensor and upper O2 sensor are the best candidates, but given the trims drop at higher RPM, they're not very good candidates.
Air filter is OEM equivalent, not high flow, correct?

Please Log in or Create an account to join the conversation.

More
2 days 19 hours ago #202298 by fordguy
Replied by fordguy on topic 2001 corolla po171..
oem air filter.. Doesnt make any sense does it. Sure does act like a leak but i can not find it. Did another smoke test, have tried propane and brake cleaner with no luck.

Please Log in or Create an account to join the conversation.

Advertisement
Time to create page: 0.289 seconds