Only getting 20 MPG?

[RhodeStiva]

Only getting 20 MPG?
so timing seems good.
sparkplugs good.
fuel filter good
spark plug wires a little old.
and my speedo is 5 MPH faster because of smaller tires.
FPR is hooked start to intake manifold ( all air and idle control bypassed).
will any of this or anything else effect it?

[Flw Sock]

How is your temperature?

When my tstat went bad I lost like 12mpg.

[RhodeStiva]

my temp is perfect. my t-stat is probably always open because i always have fan running so it won't over heat.

[RhodeStiva]

i have a new pcv valve put in.
i will double check timing but haven't had any timing issues.
i know with the BP motor you lose a little mileage but only getting 20 MPG is not a little.
i just re did piston rings and head.
don't know if that may effect it or miata injectors?
or if i have air flow closed a little to much would effect it that much.

[navdoc101]

Did you put in new O2 sensor?

[Movin]

Any codes?

[RhodeStiva]

i dont have a code machine . but the CE light doesn't come on. i am thinking i might have the intake side timing off a tooth.

[RhodeStiva]

Did you put in new O2 sensor?

the o2 sensor that was in it wasn't very old.

[Movin]

If the light doesn't come on it must be something not monitored closely. Cam timing is one, poor ground for sensors, exhaust restriction, sensor poison from silicone gasket material, sensor dirty like coolant muck over temp sensor for computer..Don't take this as a check off list that you need to check but some ideas in the right direction...

I just fixed a body swap toy 4 runner , the problem was the great new ground to the right fender well did not reach the engine. The fix was to loosen, clean bolts and contact points for the core support so that the right fender ground could reach the left fender which grounded to the engine. The cranking speed doubled as well!

[scitzz]

Are you using the correct VAF? When I did my B6 swap. I got terrible mileage until I got the right VAF.

[RhodeStiva]

i got the one from the engine i got BP

[scitzz]

What wheels are you running? On deliveries, with my B6 swap, I usually get about 26MPG, which is what I got with my B3. That is with 175/70R13 from an aspire. Yeah, I drive badly for MPG's on the road. For the last 2 weeks, I was using Escort GT wheels with 195/50R15, and dropped to 20.92 MPG. Needless to say, I am back to the 13's!

[scitzz]

Plus, driving style matters! I was getting 33-34 city when I was out on workers comp and not driving like a maniac!

[RhodeStiva]

in city and cruising i am getting 20 mpg. i'll mess with it today an see what i can figure out.

[Flyin4stroke]

It's probably the screw loose between the gas pedal and the steering wheel gotcha!