Hello everyone i recently purchased my 1992 rx7 here in japan. After driving around the block or so i start to get the "-Heat-" red light caution. I have these mods. (i bought the car for 1200 dollars so i was expecting some problems)
-Aluminum intake pipes w/ K&N air filters
-Sard cat/mid pipe
-Cat back exhaust
-Apexi Power FC
-No fuel upgrades
-stock radiator
-stock intercooler
-stock duel oil coolers

water temp is at 85*C and oil temp is 60-70*C. I looked at the sensor check in the ECT page and notice the VMOP was illuminated and reading from .91 volts to 1.25 (going up and down every 3 seconds along with the illumination)
-No black smoke
-After a few under load pulls the idle will jump from 1000 to almost 2000 every 2 seconds . But over a few minutes keeping the car under 3k RPM (while driving) the idle will mellow out and stay between 900-1000 RPM.
-I haven't found any broken vacuum lines or anything falling off.
Is my oil pump sensor not working? Thanks for the help.

 

Sounds like a clogged cat/precat... or a bad sensor

 

Yes that could be it. I have a stock downpipe. Should i be cautious about the VMOP on the powerFC sensor page?

 

"Heat red light" caution is possibly a result of your bad idle. Un-burned fuel getting into the cat will overheat it and cause the red overheat light to illuminate. IMO, solve the idle/misfire problem, and the overheat light will disappear.

 

you should be very concerned. That could mean that not enough oil is being injected into the combustion chamber. Might want to use some premix until you straighten it out. The VMOP values are typically the same range as the Throttle Position Sensor value from closed to full open position (check when car is not running pressing throttle all the way down)

You can check whether the cat is clogged by unbolting the 2 front bolts from the downpipe, angle it down a bit and shine a flash light down into it to try and see the front of the catalytic core. If it looks like a fine mesh or honeycomb structure, it should be OK. If it looks like a clogged shower drain, its probably clogged.

The idle issue is probably due to:
- throttle body mechanical settings
- TPS sensor settings

You want to search on here or read the Factory Service Manual on checking and adjusting the TB settings first (since that affects TPS). Then check the TPS readings to determine if in spec - there is a good thread for that in the Archives.

Cheers.

 

?????????

I thought the Japanese FD's did not have a pre-cat, and thus had a plain tube downpipe? Am I wrong?

Dave

 

you should also get a boost gauge to read the vacuum reading on idle to check if your hoses are leaking pressure somewhere.