[Mk2] [Turbo] Shocking MPG, can a faulty exhuast really do this?

[Drifter]

Well my exhaust is fubard i think, all the white fibrey hair stuff came out of it the other week, and still driving it around it sounds horrible btw but dont have £400 for a new system just yet, well my fuel consumption is crazy atm ive done 56miles since i've filled it up and im inbetween 3/4 n 1/2 full of fuel this is shockingly bad, anything i can check to fault find the problem?

Thanks
Dave

[Razor04]

check out the lambda sensor that long plug thing that goes into the turbo heatshield on the driverside by the dipstick. These can have a big effect on mpg etc if they go bad.

[Drifter]

hmm the wiring is ok, i'll whip it off 2moro when i ramp it up 2 investigate some other bits lol

Dave

[mattcambs]

The ECU will show error code 21 if the lamda sensor is faulty or the wiring is loose etc.

[Drifter]

yea, just reading how to do it now, should be fun 2moro.....

Dave

[mattcambs]

it takes two seconds. Just have to make sure that the wire actually makes contact in the diagnostics port

My car showed code 21. Luke at Pacific Works just unplugged and plugged the lambda sensor cable back in, reset the ECU and after a drive the code was gone.

[BenF]

FWIW Rev1 and 2 cars are much less fussy about their O2 sensors, and you can have a marginal one that doesn't pass the BGB test procedure, but doesn't generate a Check Engine warning light.

You checked the plugs, dizzy cap and HT leads ( eg with engine running in the dark, looking for blue flashes of HT escaping? )

The only other cause would be a big leak in the exhaust before the oxygen sensor fooling it into thinking the engine is running very lean - but a hole large enough would be loud, especially on boost.

[Drifter]

well its just came too me, the other day when we had that horrible rain all day long, my car was outside in it all day and nite and it wouldnt start, so was towed 2 toyota but they found no problem and started 1st time 2 days later.

So i just removed the EFI fuse 2 reset the ECU, then took it for a blast felt loads better and it didnt use any fuel for the 15 mile blast i did... so i think it may have cured itself, gona do the diagnostic check on it now, see what i find hopefully nothing

Dave

[Drifter]

okay that was like morse code reading lol

well here are my errors

24 25 31 47 which according to guide on OC means...

24 - open or short cicuit in intake air temp signal

25 - air-fuel ration lean or rich (im gussing rich)

31 - open circuit in VC signal or short cicuit between VC and E2 when idle contacts are closed

47 - no explanation given

ERM anyone translate that for me lol

Dave

[Razor04]

sounds like you got mucho problems there bud

[Drifter]

i know yea not good, all i got is time tho gona test the o2 sesnor 2moro using the voltmeter thingy 2 see if thats broken, take it off give it a clean etc, reset the ECU take it for a blast n see what happens then.

Been reading up in the search tho and 24 25 31 all link 2 afm, also that the apexi induction kit i have might me be 2 far away from the side vents thus not getting enough air into the engine

Anyone else shed any light onto this for me? also whats error 47? aint seen it anywhere

Dave

[mattcambs]

also that the apexi induction kit i have might me be 2 far away from the side vents thus not getting enough air into the engine

Check the filter isn't clogged I guess. It's position won't affect air flow - the after market kits don't rely on a Ram effect, they lower the restriction of the intake tract.

Do you have the air temp sensor connected to the intake pre-turbo? It looks exactly like the one that is clipped to the rain tray above the turbo.

[Drifter]

hmm didnt think rev 2 tubbys had that kind of air temp sesnor? thought it ran through the AFM?

Dave

[Drifter]

Okies, just checked the oxy sesnor using the voltmeter like it says in the knowledge base, seems ok fluctuated 8+ more times from 0.5voltsish to 5.0vish in ten seconds so im ruling that out as a problem. So i guess i need a new AFM?

Dave

[toxo]

According to http://www.mad-mechanic.com/toyota/mr2/ ... gten.shtml code 47 is secondary throttle position sensor. I'm not sold on that though, I didn't think the 3S-GTE had 2 TPS's.

Hopefully you don't need a new AFM, ISTR they're expensive...

[Drifter]

yea just looked up codes on my mr2 disc thingy that i bought,

so here is me problems lol

24 ......... Open Or Short Circuit In Intake Air Temp. Sensor Signal
25 ............... Lean Signal Sent By O2 Sensor For Several Seconds
31 ................................ Open Or Short Circuit In Airflow
Meter Or MAP Sensor Signal
47 .... Open Or Short Circuit In Sub-Throttle Position Sensor Signal

still duno what 2 do

Dave

[Drifter]

im guessing 47 maybe beacuse i have the gt4 throttle cable thingy fitted?

Dave

[toxo]

To be perfectly honest it sounds like a bit of your wiring loom is bu88ered, I can't imagine that many sensors have gone up all in one go.

Did you reset the ECU and go for another hard drive, to see if the codes came back?

[toxo]

im guessing 47 maybe beacuse i have the gt4 throttle cable thingy fitted?

Dave

Nah The TPS is on the other side of the throttle body and wouldn't be affected by the routing of the accelerator cable! All you've got there is a different bracket.

[Drifter]

To be perfectly honest it sounds like a bit of your wiring loom is bu88ered, I can't imagine that many sensors have gone up all in one go.

Did you reset the ECU and go for another hard drive, to see if the codes came back?

yep i reset the ECU and all the same codes came up, got a question for you peeps whats the PCME? gona try a couple of these tests that my bgb says and it mentions PCME terminals THA - E2 should be a voltage or somat lol

Dave