Another poor mpg thread.

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

LS1FJ40 said:
I believe this is the fuel pressure regulator.
Click to expand...
No. The FPR looks almost exactly like the FPR on the 3FE and is almost in the exact same location relative to the fuel rail. That plastic guy is a VCV valve for the evap system off the charcoal canister. You're smelling fuel because that's off the purge port of the canister that feeds back into the intake.
 
LS1FJ40 said:
Had him send me the air filter too. Anything else you can think of.
Click to expand...
I would add a new PCV valve and grommet.
Anything that could lead to vacuum leaks in the top half of the motor. Same concept as the 3FE.
I believe the 1FZ is more tolerant of top end vacuum leaks than the 3FE, so it won't idle as horribly as the 3FE would with just a small leak. That's likely because the 1FZ ECU has a larger adjustment window and can correct/adjust more, ie. slightly smarter. It's still 1980s technology, just 2nd generation EFI.
 
I did the PCV and grommet already. I followed your tune up list for the most part. I believe.

jonheld said:
I would add a new PCV valve and grommet.
Anything that could lead to vacuum leaks in the top half of the motor. Same concept as the 3FE.
I believe the 1FZ is more tolerant of top end vacuum leaks than the 3FE, so it won't idle as horribly as the 3FE would with just a small leak. That's likely because the 1FZ ECU has a larger adjustment window and can correct/adjust more, ie. slightly smarter. It's still 1980s technology, just 2nd generation EFI.
Click to expand...
 
I'm getting about 8mpg in the city and about 9.5mpg on the highway. wtf. I knew it was thirsty but this is a bit too silly.

better have another thorough read through this thread and change some stuff.
 
welll.....I'm very happy I'm better than you !!!!!?????? Ha !!!!!

on my LX450 SC I get consistently 320KM - 330KM for a fill-up 78 to 82 litters premium gas !!!!! that's about 24.8 l/100K !!!!!. That's about 11.3 MPG !!!!!! (totally ridiculous in my opinion.....!!!!)
So I used to complain a lot about this dismal consumption.... 11.3 MPG (totally outrageous in my opinion....) but I see it can get a lot worse !!!....so....I have to consider myself lucky.....!!!!
 
At 5520lbs on 285/75/R16 MT's and stock gearing I am getting 13.3mpg in mixed driving. I haven't checked highway mileage since my tuneup. I am due for new tires this weekend which should help. I'll report back after my coming trip this weekend. Crossing my fingers for 15mpg on the highway.
 
oh wait up, I have 285s on, how do I recalculate that?
 
junior80 said:
oh wait up, I have 285s on, how do I recalculate that?
Click to expand...
Depends on how new or old they are but as an average take your mileage and multiply by 1.06.
 
MODist said:
Depends on how new or old they are but as an average take your mileage and multiply by 1.06.
Click to expand...

just worked it out and I have surprising news; It's still s*** LOL

I just fitted new plugs gap checked (1 heat range colder than oem due to the svi LPG system), new plug leads, AFM clean, upper engine clean, I have the timing advanced, I run it on 98octane, I have a new rotor button and dizzy cap to go onto it just haven't picked it up yet.

this engine had a very basic lpg system on it a while ago which was removed because it was backfiring through the airbox, this does damage the AFM but i'm pretty sure the PO had that replaced. It also may need a valve job. i can't actually find any record of hardened valve seats being fitted into the head and there's a pretty detailed history of everything done to it over the years.

maybe I need to do a compression test.
 
11mpg city, 12mpg Freeway. somehow I always manage to have the nearly the same MPG city/freeway. Guess I need to slow down on the freeway instead of doing 75mph all over keeping up with traffic.
315s, fully load 1FZ
 
junior80 said:
just worked it out and I have surprising news; It's still s*** LOL

I just fitted new plugs gap checked (1 heat range colder than oem due to the svi LPG system), new plug leads, AFM clean, upper engine clean, I have the timing advanced, I run it on 98octane, I have a new rotor button and dizzy cap to go onto it just haven't picked it up yet.

this engine had a very basic lpg system on it a while ago which was removed because it was backfiring through the airbox, this does damage the AFM but i'm pretty sure the PO had that replaced. It also may need a valve job. i can't actually find any record of hardened valve seats being fitted into the head and there's a pretty detailed history of everything done to it over the years.

maybe I need to do a compression test.
Click to expand...
What tires and pressure are you running? My mileage improved going from 35psi to 40psi.
 
KWalkerM said:
11mpg city, 12mpg Freeway. somehow I always manage to have the nearly the same MPG city/freeway. Guess I need to slow down on the freeway instead of doing 75mph all over keeping up with traffic.
315s, fully load 1FZ
Click to expand...
Yea going above 65mph drops the mpg quick.
 
MODist said:
What tires and pressure are you running? My mileage improved going from 35psi to 40psi.
Click to expand...
bit lower than that at the moment, I have 30 in them now because it was just that little bit too rough at 40psi
 
junior80 said:
bit lower than that at the moment, I have 30 in them now because it was just that little bit too rough at 40psi
Click to expand...
Yea I know what you mean. 32 rides real nice. I take it up to 40 when traveling long distance on the highway. I end up airing down to 15 once I leave the pavement.
 
MODist said:
Yea I know what you mean. 32 rides real nice. I take it up to 40 when traveling long distance on the highway. I end up airing down to 15 once I leave the pavement.
Click to expand...
Offroad the stauns are set to 16. Drop from there as needed in my cases.
 
retrofive said:
38psi seems to be the best compromise for me. (315/75/16, MTr's)
Click to expand...

How is the road noise on the MTRs in an 80? I had old school MTRs on my 60 and I could hear their racket above the v8 and flowmaster, awesome tire but terrible for road noise
 
You must log in or register to reply here.

Share this page

Back
Top Bottom