BigJim

So at low rpm, between 1000 and 4000 my car runs really crappy. It sounds higher pitched and chugs a little. After 4000 rpm it just gets it like it used to do through the whole rpm range.

84 -se
~10,000 miles since rebuild
MSD Ignition
Streetport
RB header/presilencer

cant think of any other important info.

drunkclever

check the 2ndary? ports.. the ones that open with the back pressure? of the xhaust. maybe there stuck open. just a thought. why whould I suggest that? I think I read somewere that they open at or after 4000 rpms.

I don't know much about trouble shooting. I just usally search untill I find something that leads me to a logical end to any problem I might have.

whole rpm range = 0 to 800o or more rpms. so now you confused me.

BigJim

engine idles right around 1000 rpm, i can feel my 2ndary ports opening at 4000 rpms so they are fine. if feels to me like fuel or spark is cutting out not sure thou, and no clue how to check either.

Sireel One

My 85 GSL has the same problem, it sputters at low rpm when the engine heats up. I can feel the secondarys engange like normal. I recently replaced the cap and rotor for the distributor, put in some new plugs, and checked all the ignition wires. The problem does not seem to be electrical. Any one have any suggestions as to what is making making run this way? My only other ideas are that it is is something wrong with the fuel pump or acv valves (because it randomly stumbles around 2500rpm)

BigJim

i wqas actaully thinking fuel filter. Lower rpm, lower fuel demand, higher rpm higher fuel demand so the pressure is greater. I have no idea how accurate my theory is. Any ideaS?

trochoid

iTrader: (6)

First, idle is a bit high. If you can't bring it down to 750-800 rpm, start looking for vacuum leaks. With the engine running normally when the secondaries come on line, you might have primary throttle plates sticking. Clean and lube all of the linkage externally, run a can of Seafoam internally. You may wish to take the intake duct off of the tb and do some cleaning in there with carb or brake cleaner.

Your fuel pressure theory is backwards.

trochoid

iTrader: (6)

This thread is refering to the fuel injection version. You might read up on the 1st gens here first. If you can't find a solution, start a thread pertaining to your problem.

https://www.rx7club.com/1st-generation-specific-1979-1985-18/1st-gen-rx-7-faq-page-237777/

Welcome to the Dark Side.

BigJim

at 800 the idle surges, at 1000 she runs fine, plus with the streetport i have no power that low anyways. i have some sea foam in the garage, so i guess now the fun party of getting it in the engine

trochoid

iTrader: (6)

Draw the gas tank down to 1/4 or less and pour the entire can in. There are a couple of vacuum ports you can use, but it needs to go in just before the throttle body. You can take the intake off of the tb and tap a 3/8 NPT fitting that has a 1/8" barbed end, then cap the nipple when you're done.

If the engine is loping at 800 rpm, clean your bac and check the tps. You should be able to get a streetport to idle at stock rpms.