2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

12 MPG.....I need some help

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Old Oct 11, 2005 | 05:34 PM
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Exclamation Super RICH----12MPG

Ok, so i have been breaking in my rebuild, and i have had some trouble with the car running rich The car smells strongly of raw fuel, it back fires if you are running like 2500rpm and let off. I clocked my gas milage today and I wanted to cry----12.5 MPG. this is with no boost and shifting below 3000RPM. I think it might be the TPS but im not sure. Her is a list of my mods.

Kevin Landers rebuild
Streetport
all emissions removed (no rats nest)
Racingbeat 80mm full system.
Rtek v1.7
new Greddy 720cc secondaries
battery relocation
cone filter
e-fan
Greddy type S BOV
fuel pump
someother stuff maybe?

Thats about it as far as the motor goes. I also think it might have something to do with grounding possibly. I ran a thick wire from the fire wall to the UIM, and the ground wire were the battery used to go was fastened to the inner fender. I also noticed that it has a hesitation when the secondaries come on (I slowly ran it up to there). Perhaps I have the 720s in the wrong place?.. you should be able to see them without removing the UIM right? Someone please help me out so that i dont have to buy a HUGE SUV just for the fuel economy.



Thanks
-----James

Last edited by red87tll; Oct 11, 2005 at 05:45 PM.
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Old Oct 11, 2005 | 05:56 PM
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Just a guess here, but have you checked the engine bay for leaks? You may have a fuel leak.
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Old Oct 11, 2005 | 06:13 PM
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yeah i look under the car everytime i take it out
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Old Oct 11, 2005 | 06:37 PM
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Checking under the car often won't show a fuel leak.

Pressurize the system with the fuel pump test connector (yellow, passenger's side near the airbox, jumper it and turn the ignition on). Look for leaks.

The secondaries are the ones you can see without pulling the intake manifold off, correct.

Also, what fuel pump do you have? If it's pumping more than the fuel pressure regulator can control, your fuel pressure might be high (which would lead to running rich). Check your fuel pressure.

-=Russ=-
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Old Oct 11, 2005 | 06:43 PM
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the pump isnt a big one its just about the same as stock. is a 255 too big for stock regulator.....i didnt think it was
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Old Oct 11, 2005 | 07:58 PM
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There's a lot of threads on how to improve your MPG.

Such as: https://www.rx7club.com/showthread.p...&highlight=mpg

For the most part it seems to be that it's a good idea to do a full tuneup. Check for Vacuum leaks... etc.
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Old Oct 11, 2005 | 08:54 PM
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i think it might be more than just a tune-up.....it shoots fire and such
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Old Oct 11, 2005 | 09:18 PM
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Shooting fire isn't particually uncommon as long as you've removed emissions and are running with no cats and such. It does mean it's running rich, but not necessarily harmfully rich. From what I understand, if you take the emissions/cats off a stock N/A it will do this. Could be wrong though.

Oh, this is assuming you rev it up then let off.
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Old Oct 11, 2005 | 09:32 PM
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Sounds like a problem, but with that description, combined with none of us being in front of or inside the car to hear and feel it, it'll be hard to make any sort of diagnosis.

I would tend to think the timing might be off a bit, or that you have problems with the primary fuel injectors dripping or spraying poorly.
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Old Oct 11, 2005 | 10:50 PM
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From: Morgantown WV
thanks guy
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