cab91089

iTrader: (3)

I know the purpose of the double throttle diaphragm is to limit the amount of air flow into the engine during warm up and that once the engine is fully warmed up, the butterflies will close. I also know that there are differences between turbo and non turbo, manual and automatic.

For this question I am focusing on a 1990 13b non turbo engine from a convertible. I took this engine out of a automatic 1990 convertible and installed it into a manual 1990 convertible. I realized that the vacuum lines at the thermowax are different then the manual one. I changed some vacuum lines around and block off some on the throttle body and thermowax to match the manual throttle body set up. Now that I have read more in depth into every part on the throttle body I realized that I may have messed with the opening and closing of the butterfly valves. When I start my car it will hold the RPM's at 3k for awhile (I know about the AWS but the RPM's are held at 3k for too long) and sometimes the RPM's will start to drop to idle but bounce by a few hundred RPM's at a time while doing so all the way to idle and continues to do so once at idle too. My question(s) is can I use the automatic throttle body in a manual Rx-7? If I can do I have to do any mods? What mods if so?

I was thinking of switching the vacuum lines back to how they were originally set up. I learned that the plates are spring loaded on the double throttle diapragm so even if there was no vacuum theyd be held open. I was also thinking that could contribute to my high idle. I am learning how to check the clearance between the throttle plates and the bore to set the plates correctly and the fast idle cam but I dont want to waste my time if I need a manual throttle body in order for my car to run right. Its starting to get tiring but Im pretty sure my problem is in my throttle body. Any help is appreciated.

cab91089

iTrader: (3)

Thanks for all the help. Decided to just do the TB mod.

satch

iTrader: (1)

Throttle body mods make for more problems as opposed to reducing them.

cab91089

iTrader: (3)

In my build thread 2 guys explained it to me. I read up on it but theres people saying its good and people saying its bad. I have a 2k to 3k high idle so i thought simplifying my TB would get rid of the problem. Now after reading more I think its the fast idle cam out of adjustment and Im pretty sure my TPS is too but the multimeter i have sucks and doesnt read correct voltage and yes i am using it right.

satch

iTrader: (1)

There is an upside down screw that points toward the Thermowax. Press downward on the linkage associated w/the upside down screw and chances are your idle will drop significantly. Also, look at the piston which extends from the Thermowax that should come in contact w/the screw. Look at the piston before starting the car and then look at it after the car is fully warmed as you should notice it extending further downward towards the screw. If there is little to no extension exhibited then there is something wrong w/the Thermowax. It also might be the screw is not tightened enough thus not making as much contact w/the piston as required. Also, make sure the throtte cable and perhaps cruise control cable, if equipped, are not contributing to your high idle. And of course make sure the CAS is set correctly.

cab91089

iTrader: (3)

As of right now the intake manifolds are off the engine again to replace the lower intake manifold gasket. I know exactly what areas you are talking about so when I get my manifolds and everything back on and hooked up correctly Im going to check everything out you listed for me above. I dont think the crank angle sensor is off because I never messed with it but its a possibility the previous owner of the engine has. I do have cruise control but its not hooked up and Im debating on eliminating it altogether because I never use it. The throttle cable should be set correctly but again I could be wrong. Im going to have to double and triple check everything you mentioned once I get everything back on. Seriously though, I appreciate the help! Ive been running in circles with this car all summer long.