I have a 1987 RX7 13b, the engine has 125,000 miles, In the morning when the engine is cold it hesitates. It seems like it is not getting fuel. During highway driving at 80 miles per hour/ 3000K RPM the same thing happens. The problem gets worst when I turn on the a/c. With the extra engine load, it continues to hesitate. I have used after market fuel injector cleans. With no luck, still having the same problem. Can you help?

 

hey, welcome to the forum. i have the same problem. it you check one of my previous threads, someone gives an answer one what it is, and how to fix it. its something with the secondaries kicking in. the thread was titled 3800 burp, or 3800 hesitation.

 

It can be one of 2 problems. The first is electrical related and basically the 2nd set of injectors do not come online at 3800 rpms. This is a simple fix and is documented at teamfc3s' site in the FAQ section:

http://www.teamfc3s.org/main.shtml

The next can be leaks in the air intake piping between the air box and engine or possibly the metal air intake on the engine.

If it's the 2nd problem you'll see check engine lights and the hesitation usually happens in any gear, in neutral, or at any rpm range.

Before attempting to fix either one I'd have a qualified rotary mechanic (NOT THE DEALERSHIP) peform the 60K mile service and fuel injector cleaning services.

 

replacing my secondary injectors fixed the 3000 rpm hesitation. thanks to everyone.

 

he said 3000, not 3800 guys. I have a hesatation at 3000 sometimes too (not 3800) but it's only for a sec as the revs climb, and only under normal driving. I think the airpump and afterburn cr*p turns off at 3000 so maybe it's something to do with that. I don't know.

when it's hesitating "while cold" how much are you pressing the pedal?? you shouldn't be driving past 1/3 or so when cold. the secondary throttle plates don't open while the engine is cold. so if you try and floor it you won't go anywhere on purpose.