sft3303

Hi,

I've been poking around and trying to find an answer to this, but so far I can't seem to find anything that describes my situation really that well.

I've just got done with an engine swap (just from one broken s5 13b to a working s5 13b) and am trying to get it up and running. Ran into problems with the fuel pump wiring, but i know that's all sorted out now. Got it to crank and run today, but here's what happens:

Turn key, engine revs up to about 1700 rpm. Idles (roughly) between 1000 rpm and 1700 rpm for about 6 seconds, then dies. All of the "spider" vacuum hoses are new, as are the UIM/LIM gaskets. Thoughts on what could be causing this? It started like this, then i went out and bought brand new ngk (oem recommendation) spark plugs, and that didn't solve anything. Getting new spark plug wires tomorrow. Thoughts? Any help is appreciated guys.

Thanks,
Jimmy

shiznizzletech

I am having the same type of issue with my 1988 NA. I bought a new TPS off of ebay for a very cheap price. I'll let you know if this does anything to correct the problem but please, let me know if you figure this out!!

sft3303

Two things that really fixed the problem. The car is now up and driving. I won't say well, but I'll get to my problems later.

What I did to get it fixed to this point:

Banjo bolt on rear side of intake manifold (leads to power brake booster hose/pipe for vacuum purposes) was loose. Tightened this bolt, installed new hose.

CAS was installed right, but the pickup gear had turned as it was inserted down the tube into the engine (so really it was installed wrong, but I had no knowledge of this.) I removed the cover of the CAS, noted the position of the rotor when the pickup gear was aligned with the dot on the shaft of the CAS, and made sure the housing was rotated to this same position after the CAS was installed.

New plugs and wires are also in, but if anything they only help me a little. At least I know they aren't causing it, and they looked like they needed replacing anyways...

Those three fixes got it running and idling.

Here's my current problem:
Still have a stupid rough idle. Car sounds like it's "camming" from 750 rpm up to 1100 rpm and then back to 750 and back and forth and back and forth. Also, sometimes upon startup and at random other times (stoplights, etc...) it decides to idle up around 2000 rpm (like a smooth, consistent 2100rpm, the entire time you're stopped until you begin to put load on it. Could be a cold start/Throttle body problem?). Not entirely sure what could be causing this problem, but I've outlined what my current plans of attack are:

Looking like i may soon replace ALL of the other vacuum lines (replaced all of the "spider" lines that attach to the block, manifold, solenoids, but not the crankcase breather, power brake booster, etc...) and mess around with the CAS again. The o2 sensor is not currently hooked up either, could this play a part in this as well? I was unable to use it currently because the one on the old engine (1990 wiring harness) has a male plug, and the o2 sensor from the 1991 engine has the same male plug. I'll need to solder the new female sensor onto the o2 sensor when the car is near a power outlet (currently in a storage unit).

My question to you guys is, do my plans make sense? Would getting the o2 sensor hooked up, eliminating any potential vacuum leaks, and fiddling with the CAS do much to directly mitigate my idle problems? The car definitely smells like it's running rich, and the o2 sensor seems like it'd help there too, but i read somewhere it's only used above 2k rpm? Idk. Any help is appreciated guys.

Thanks,
Jimmy

sft3303

On another note, I'm getting a bit of smoke or steam or somesuch vapor coming out of the oil fill tube. Is this normal? I know the oil is used for cooling, which leads me to believe it could be getting pretty hot, but one would think the oil cooler would take care of this... Thoughts? Thanks guys.

sft3303

Internet fail. Sorry for the doublepost guys.

fd3svs

I have some idle problem with my 89 FC NA too,
it keeps bouncing up and down between 600 - 1200 rpm.
Any suggestions?

SAT_Leo814

Dont feel bad lol , Im having the same problem with my fc 1987 rx7 , when i start the car it revs all the way to 3rpms then slowly idles at 750-1000rpms , but when "I" rev it to 3000rpms and let go of the throttle , my RPMs just drop to 0 and the car shuts off , any ideas? >_< this is my first car/rotary xD ,

RollinHeavy

88 s4 fc, n/a runs great as long as my foot is on pedal. Have a Rough idle and stall issue at stand still after car has warmed up to op temp. It requires me to 2 foot it to prevent it from stalling. Car is mostly stock. Suggested upgrades? Troubleshoot help? Or does anyone have solutions?

Help is appreciated
Thanks