horrible gas mileage issue

[daveskatesallday]

i have been getting really crappy gas mileage the past maybe 5-6 months my car went from $25-30 lasting for a week or two to around $20 within a day or two i don't drive the car hard i usually shift around 3k i don't race, speed or any of that

the engine is rebuilt, and i thought that would do the trick but it didn't then i started replacing a number of parts, swapped out my old tps with a known working one also a working maf, new O2 sensor, fuel filter, etc.
and for some reason i'm still getting bad gas mileage the distributor is stabbed right, cam timing is correct the only thing that is off is the ignition timing im not sure how far off it is but in the past i wasn't able to get it set to 10*deg and i was told that sometimes if the tps is bad it can make it hard to set the ignition timing im just curious if anyone has also had very bad gas mileage and what you did to solve the problem would like to make it to the 86 meet but it takes me $20 to get to atx and back and basically im on E afterwards @_@

[joe81]

first off all reset the tps sensor by following this link
http://www.ae92gts.com/ae92gts_tps.html" onclick="window.open(this.href);return false;

then set the timing to 10 degrees before tdc with the car in diagnostic mode.

after that see how it fairs out.
it might be no harm to use some fuel cleaner also

report back when you have it done

[joel26]

Good info... and great to know

[mooreofit]

check all your sensors. clt sensor could cause this kind of issue also high resistance on this or any other temp sensor circuit.

clogged cat if you got one.

also a ground wire kit or better engine to chassis grounding.

ive had a spark plug leak cylinder pressure causing a power loss.

also on a fresh rebuild everythings still a little tight causing more friction and power loss. you will see better gas milliage around 5-10k.

[daveskatesallday]

first off all reset the tps sensor by following this link
http://www.ae92gts.com/ae92gts_tps.html" onclick="window.open(this.href);return false;

then set the timing to 10 degrees before tdc with the car in diagnostic mode.

after that see how it fairs out.
it might be no harm to use some fuel cleaner also

report back when you have it done

tried to reset the tps but with the multimeter the readings were jumping all over the place i also heard that some ppl could not set the tps this way for one reason or another gonna try to set the ignition timing now

[daveskatesallday]

well set the ignition timing correctly also had to just adjust the tps while shooting the belt with the timing gun and got it perfect couldn't get it with the multimeter and feeler gauges for some reason but it idles at 800 and feels extremely smooth also has more power than it did before im pretty satisfied now im just going to keep an eye on the mpg hopefully that's all i needed thanks for the help

[dr.occa]

Lookey there! Dave'll be a 4AG expert in no time

[daveskatesallday]

haha i dunno about that but thanks just wanted to get it right so i can make the meet

[joe81]

glad you have it sorted now

[Overdrift]

did the timing solve your fuel economy issues? My 4age in my mr2 would give 32-35avg (2.5-3k shifting with sprints to 6k getting on freeways) and about 40mpg solid highway cruising at 60-65 (2.9-3.1k) but now I can't get over 25avg and about 30 highway. When I drove to nyc I was able to get 36 driving super conservative around 55-60 and easing up hills.


So far I replaced the TPS (complete throttle body assembly) and two coolant sensors from a 4age that runs like new and was giving the same mpg before the mr2 was wrecked, my timing is at 12 degrees, I set it by sound and checked with a timing light.

Oh btw my mr2 has straight pipe and a glass pack, no clogged cats for me. I swapped maf sensors as well, but the doner was no good. it will shoot fire if reved passed 4.5k and let off. It did not used to do this when getting good mpg. NT66 recommends replacing/checking injectors. I replaced the cold start with a good one so far.

http://www.youtube.com/watch?v=97gnwVk2MWk" onclick="window.open(this.href);return false;

[Scooter979]

Now here is a question is it worth running the cat or not will you lose mpg or stay the same if running a stock pipe not a pissed off bumble bee exhaust

[daveskatesallday]

.

[daveskatesallday]

did the timing solve your fuel economy issues? My 4age in my mr2 would give 32-35avg (2.5-3k shifting with sprints to 6k getting on freeways) and about 40mpg solid highway cruising at 60-65 (2.9-3.1k) but now I can't get over 25avg and about 30 highway. When I drove to nyc I was able to get 36 driving super conservative around 55-60 and easing up hills.


So far I replaced the TPS (complete throttle body assembly) and two coolant sensors from a 4age that runs like new and was giving the same mpg before the mr2 was wrecked, my timing is at 12 degrees, I set it by sound and checked with a timing light.

Oh btw my mr2 has straight pipe and a glass pack, no clogged cats for me. I swapped maf sensors as well, but the doner was no good. it will shoot fire if reved passed 4.5k and let off. It did not used to do this when getting good mpg. NT66 recommends replacing/checking injectors. I replaced the cold start with a good one so far.

http://www.youtube.com/watch?v=97gnwVk2MWk" onclick="window.open(this.href);return false;

yea timing had a lot to do with it. I'd suggest trying to get a known working TPS OR buying a new one if possible. A lot of them may look fine but can be just as bad as the next. Also the same with the AFM try to either get a new one or find a working one. Backfiring definitely indicates that the timing is off usually. Check the gap on all four plugs, spark plug wires etc. Also with the injectors they don't seem to go bad too commonly (from my experiences) but it wouldn't hurt to take them to a place that specializes on injectors just to make sure they are all flowing with no issues. Good luck let me know what you find out.

[daveskatesallday]

also did you set the engine to TDC and check the Base timing? it should be at 10deg with the circuit being tripped