MPLSrx7

ok so i have an 87na. about 2 months ago my car just got really slow and started getting horrible gas millage. i will go through a quarter tank in about 40 miles. to try and fix this i have:

cleaned the injectors
changed plugs and wires
took the cats off and put in a rb dp and presilencer.

the dp and presilencer made my car faster but it did not fix the problem, it just added hp to the slowness. and i still get the horrible gas millage. i dont know what to do next or even know what the problem is. does anyone have any ideas?

Icemark

Yeah, sell it... RX-7's know if you don't like them and run accordingly.

MPLSrx7

i don't want to sell it. i want to fix it and dont know what to look at after that stuff.

Icemark

when were the basics done: fluids changed, timing checked, belts, O2 sensor replaced, TPS checked???

fcfanatic

I'm not to far from you. I may be able to help.

idsigloo

If that's the case, then when I get my car finished it will run like a bat out of hell.

socalrotor

iTrader: (1)

If your coolent temp sensor on the back on the tstat housing is bad it will run VERY RICH/LEAN,this is where the CPU uses the sensor to adjust the A/F mix according to temp. Do you smell gas under the hood? If yes, you check your pulsation dampner also check the O2 sensor/fuel/air filters. good luck

Icemark

Only Turbos and the few Rare nonturbos with an extra electric fan have a coolant sensor on the T stat housing.

and that sensor is only for the extra fan

gxl90rx7

iTrader: (1)

Icemark isnt a rotary god after all! lol

Im going to have to disagree, both my fc's have this coolant temp sensor. It will make you run in super-rich "safe mode" if unplugged/not working

Devdude

Probably not the case (I hope). But I had the same symptoms when I lost seals in one of my rotors. Had to rebuild the engine to fix.

Hope this isn't the case with yours.

Devdude

Wankels-Revenge

I think the both of you are talking about separate coolant temp sensors. Icemark was referring to the one located on the thermostat housing while you are referring to the one located on the back of the waterpump housing.

gxl90rx7

iTrader: (1)

ok, that makes sense

86se7en

ohh this exact same thing happened to my n/a. loss of power. horrible gas milage. and hesitation. cracked the engine open and the coolant seals were bad. coolant buzzer going off???

lnbrown5981

I am surprised that no-one didn't say hat his aux ports might have stopped working, or stuck open, which would equal a significant loss of torque in the lower RPMs, and also slightly worse gas mileage. check those out also.

MPLSrx7

thanks for the replies.

fcfanatic do you have a compression tester?

i changed all the fluids when i got the car a few months ago and am going to change the oil this week because its due. i dotn think its the coolant seals because my car isnt smoking at all and i dont loose any coolant. and my aux ports are working.

i dont know how to check my timing or tps so that could be the problem. and i dont know about those coolant temp sensors, or how to check those either.

MPLSrx7

i dont know if you guys saw me reply it was like 4 in the morning.

thanks

Aaron Cake

iTrader: (1)

Stuck ports will have very little effect on gas mileage.

My money is on the ECT (Engine Coolant Temp) sensor on the back of the water pump housing. If that sensor is reading cold, then the car will run crazy rich.

But this assumes that a FULL tuneup has already been done. TPS adjustment, plugs and wires, ALL filters, etc.

MPLSrx7

actually i just fixed it i think. i was bored so decided to open up the fuel tank and take a look. everything looked fine. so i put the pump and everything back, and it runs real nice like it used to. i dont know why but i'm pretty happy about it. the gas needle didnt even move to and from work.

it makes no sense to me how i would have fixed the problem that way but i think i did. so now i will probly just change both the fuel filters.

1RX7DRIVER

you need to change the fuel strainer on the end of your fuel pump i did that and im getting like 22-25mpg in the city its awesome.

MPLSrx7

do you know any websites that sell the in tank filter and the one under the hood?

Aaron Cake

iTrader: (1)

Any Mazda dealer, and most auto parts stores.

Bukwild

one fuel injector is stuck open. I had the same problem. Once primary 550 was wideopen and caused the car to run like **** and gas mileage horrible. I was getting like 10 to the gallon on the highway. Get 2 new injectors from ebay and then send 2 out to cruzin performance to get rebuilt. Then when they get back repeat the process and sell the last set as new rebuilt injectors and get your money back. Simple