Ok just traded my car for a 88 rx7 the guy told me its a s5 engine with s4 computer and electronics he has all the block offs on there anyway the problem is I drove it for two hrs and it drove fine when I got home I notice that the filler neck on the thermometer housing had a small crack I fixed it then i drove it about 40 minutes and when I came to a light the car died I waited about 5 minutes and it started right up it idled perfect at 900 I then git home and start it again and it isles at 1000 but isles back and forth between 1000 and 1200 and when I let off the clutch to shift to second it tons will slowly fall what coyld my problem be thanks at least point me to the right direction thanks again

 

Please use punctuation. That was really hard to read.

As long as all of the sensors, wiring and ECU are from the same series, it's fine. That's a common way to use an S5 engine in an S4 chassis. The front cover and MOP on the engine may also be S4, otherwise a block off plate may have been used (which means pre-mixing oil into the gas will be needed).

See FAQ for idle information. A bouncy idle may be a TPS problem or a vacuum leak.

 

Yeah I would try to get as much information from the previous owner as possible about your knew car just so you are aware of whats going on.

 

Ok thanks guys ok he did say I need to mix about three once for every fill up . I unplugged my tps sensor and the car quit running does this mean its good or bad

 

3 ounces per fill up?
that is not enough IF the car is running on Premix..it takes 1 ounce Per Gallon.
(16oz 2 stroke oil-16 gallon gas )
get some pics of your engine bay so we can see What you got under the hood.

 

Hey guys question about cooling system it not over heating but after I drive it for a little I get a bubbling in my over flow and a slight lose of coolant what could it be

 

^ The general consensus is that if you were driving hard and boosting and getting your turbo nice and hot before parking, it's better to let it cool down for a minute or two before shutting off the car, as this will help prevent premature failure of the turbo.

Some manufactures even tell you in the owner's manual to let the car idle for a minute before shutting it off after some hard driving.

However if you haven't been driving hard or boosting much you don't need to let it sit at idle... you can just shut it off immediately and you'll be fine.

 

Does the coolant even get pulled back into the engine after it cools? A cracked hose going into the overflow tank may prevent vacuum from being applied to draw it back in.

With water cooled turbos, the coolant will continue to circulate through the CHRA even after the engine has been shut off. Convection allows this, and it will pull heat away from the bearings, which will aid in preventing oil coking. You can let it idle a bit before shutting off, but it's really only necessary with oil cooled turbos.

 

Ok guys well here's my problem the car runs good on the high way boost is good now I found out the guy put block offs on all the emissions stuff on the intake he has a 255 fuel pump . And he is using s4 primary objectors and s5 secound objectors anyway my idle when warm idles up and down between 900 and 1100 which makes driving in the city hard. I've adjusted the tps to.one ohm is there anyone who lives in the Virginia area I need some major help and do not want to sell this car help please

 

^ You could always try asking in the regional section for someone to give you a hand.

Can be found here: https://www.rx7club.com/ne-rx-7-forum-30/

 

Could the idle problem be caused by a bad BAC? And the bubling from the radiator could mean that nobody bled it...

 

they're injectors and from what i've read in the past between the two series, one is high impedance and one is low impedance. check out the 2nd gen section.

 

i'm supprised a mod didn't mention bout starting ur own thread with ur questions.

 

bubbles in the coolant hhmmmmmm no bueno and rxtasy is right the 2 different series have a different impedence the low impedence injectors need resistors in the harness to function right