I just bought a '91 NA that has 79K on it and has been sitting in an impound lot, than got transferred to a junk yard. It's been sitting there for something like 2 years but is in pretty good shape yet. The problem the junk yard people had with it is the idle...it won't...but it will run just fine above 2K. They said that even though the idle was bad, the thing would haul and they apparently had it up to 140MPH with plenty of room to go...I don't know if I believe that with a NA but it sounds good.



So I got it and did the TB mod, yanked the spark plugs and cleaned them off with a wire brush because they were still in good shape, and checked the rest of the engine bay to make sure there were no visible vacuum leaks, broken wires, birds nests anywhere, etc. I also got a timing gun and tried to do the timing but there is so much rust on the main pulley that you can't see the L/T marks anymore. I just loosened the crank angle sensor and adjusted it by hand until it idled much better...I know this is half-a@@ed but it works until I can scrape off the rust and find the marks.



I can get it to idle now at 1K after some tweaking but the problem is...anytime I put it into drive or reverse, the rpm's go down to 300 and then the car quits, even if I put it into neutral again, it staggers really badly and I'm lucky if I can keep it running. It also seems to be running really rich, even after letting it idle for 5-10 minutes letting it come up to temp.



The only things I can think of to do is to set the timing which I'm in the process of doing, and to set the TPS with the little X-mas bulb light tester. I'm also considering pulling all the emissions stuff off and blocking it in order to help eliminate any problems but I'd rather not in order to keep emissions ok.



What else can I check or do that would make it keep from puking every time it goes into a drive gear?

 

i would check for vacuum leaks, then TPS, then AFM, then six ports, first i would do is ATF trick to get rid of carbon etc from sitting.

 

Problem with idle on A/T 1st check inhibeter switch on right side of transmission were the selecter goes into the trany

this often s$#ts itself its purpose is to adjust rpm up or down

between n or d etc the insides are made of plastic and often break ive done 4 so far probably from hanging of it like a nutter though . might have to remove exhaust and cat to get to it though and when replaced must be glued onto shaft

or youll be doing it again a week later also be careful to line the small plastic teeth up with shaft before glueing back on hope this helps.rightnowstyle@optusnet.com.au

 

Thank you, that sounds exactly like what the problem is. The car will idle and rev up just fine in park and neutral but as soon as it goes into drive or reverse, the idle jumps up and then goes way down to about 300 and then dies, even when I rev it up to 3-4K, it still dies.



Do you happen to have or know where there is a picture of the plastic you are describing?



I'll be doing this stuff during thanksgiving so I'll let you know if that was the trick. Thanks again.

 

Automatic trannies, Why did mazda every make them in Rx-7's??

 

Rightnowstyle...



I did pull apart the shifter assembly - disconnected and reconnected everything...one of the wiring quick-connects was disconnected it turns out and the wire that goes up alongside the **** itself had a slight tear in the plastic and might have been shorting itself out intermittently, I doubt it though. I also pulled off the midpipe and made sure the metal linkage was connected correctly into the tranny itself. Everything looked ok and I lubed it up just to be sure.



So, was this the inhibitor switch you were referring to? Located next to the shifter itself under the protective cover?



While messing around with the motor afterwards...I, oops, messed up the TPS by a lot and now the car is showing both codes for the sensors (12 & 18). So now I'm going to wait until it gets warm because since there's no pollution or cold start stuff left, I really don't want to start it up just to mess around so as to not damage anything.