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whats up, so just bought a 93 touring awhile back 5sp.
apexi computer, apexi intake and apexi full exhaust.
The car starts up really really fast, the car never leaks any fluids.
ive never seen it smoke at all. The car runs and drives great.
how ever I notice the car does like to heat up.
im in Arizona it was 111* yesterday outside.
I replaced the radiator cap cause the old one was leaking.
The car once it gets to 200-230* the car would bounce the idle in neutral. But while driving it drove fine.
so when I’m at a red light it idles at 1500-2800 just bouncing back and forward like
im Reving the car. But when you go to take off the car acts normal just once you push the clutch in
the idle will surge again.
however when the car isn’t hot the car idles perfect no bouncing nothing.
so I replaced my radiator cap, I have a thermostat in the mail and I’ll be installing a new koyo radiator all at once with a coolant flush.also checking my fans. Hoping I can get the car to run colder and not 210-230*
(When the car hit 230 I tossed the heater on and brought the temperature down)
what you guys think is causing the heating issue and the idle issue?
Regarding your bouncing idle I would first check the TPS. It may need to be adjusted. Fortunately with the PFC and a commander you can read the TPS voltage right from the commander.
There is also an idle air adjust screw under the TB elbow you can play with to try and get the idle down. Don't try and mess with any of the set screws/stops on the throttle body until you've exhausted all other options. They are easy to mess up and very hard to get right once they are off.
Regarding your bouncing idle I would first check the TPS. It may need to be adjusted. Fortunately with the PFC and a commander you can read the TPS voltage right from the commander.
There is also an idle air adjust screw under the TB elbow you can play with to try and get the idle down. Don't try and mess with any of the set screws/stops on the throttle body until you've exhausted all other options. They are easy to mess up and very hard to get right once they are off.
Wow seriously? Yeah on the fc it was 110c which is 230*
damn is that normal for a fd then if that’s when the stock fan kicks on?
As for the tps would that be a constant issue tho? It only happens when the car gets hot.
if the temps are low the idle is normal.
just curious.
Wow seriously? Yeah on the fc it was 110c which is 230*
damn is that normal for a fd then if that’s when the stock fan kicks on?
As for the tps would that be a constant issue tho? It only happens when the car gets hot.
if the temps are low the idle is normal.
just curious.
thank you for the fast reply
Thank you
Yeah, it runs that hot from the factory.. it's nuts. Presumably for emissions. The FC thermoswitch swap gets it to a much more reasonable fan on temp.
Agreed, but it couldn't hurt to check the TPS at some point if you're stumped. I forgot about the idle learn procedure arghx linked to. That's a good one, but be warned you will lose your settings including any tune when you reset the PFC.
Yeah, it runs that hot from the factory.. it's nuts. Presumably for emissions. The FC thermoswitch swap gets it to a much more reasonable fan on temp.
Agreed, but it couldn't hurt to check the TPS at some point if you're stumped. I forgot about the idle learn procedure arghx linked to. That's a good one, but be warned you will lose your settings including any tune when you reset the PFC.
i have a new koyo im going to install I think I’ll just wire both fans to ignition so they always run
well that makes me feel a little better it’s my first rotary and I had a voice in the back of my head
saying motor is fucked lol
ill go Get a tune once I do a few more things and have them work on the idle
I’m more focus on the heat part right now
Wow seriously? Yeah on the fc it was 110c which is 230*
damn is that normal for a fd then if that’s when the stock fan kicks on?
As for the tps would that be a constant issue tho? It only happens when the car gets hot.
if the temps are low the idle is normal.
just curious.
thank you for the fast reply
Thank you
Originally Posted by jason.az1
i have a new koyo im going to install I think I’ll just wire both fans to ignition so they always run
well that makes me feel a little better it’s my first rotary and I had a voice in the back of my head
saying motor is fucked lol
ill go Get a tune once I do a few more things and have them work on the idle
I’m more focus on the heat part right now
thank you
The original engine in my FD ran for 130k miles with the stock 230F fan switch before I rebuilt it. Yours will be just fine until you swap out the switch. Wiring the fans up to run constant is just a waste of fan lifespan and alternator output IMO. If the fan speed system is working I'd leave it alone.
So, first off.... welcome to FD ownership. I've owned mine since 2000 here in Phoenix and can tell you from experience that Summertime is not good on turbocharged rotaries, especially ones stock configured like yours. Have you tried activating your AC compressor when it's surging like that? If so, does turning the AC on smooth out your idle? I would encourage you to minimize driving your car when it's above 100F, but if it's your only driver, I would take steps to get it cooled down. Aftermarket rad and AST would be my first mods. Plugging all of the air gaps around the undertray would be second. When I did that to mine cooling improved significantly. Dual oil coolers would be my third mod. Anything you can do to add more cooling capacity will help. Also, not sure what you're running for coolant mix, but going more aggressive on your distilled water to EWG mix can help. I ran mine close to 80% distilled water and 20% prestone at one point to get it cooling better. Watch your intake charge temps on the Power FC, and if temps climb above 50C do no push the car on boost. Drive it gently until you get intake temps below 40C. Even then, I limit Summertime boosting significantly. We have a group of rotary enthusiasts who've been at this game now for nearly 20 years and would be glad to share what we've learned. PM me for my best email contact info if you'd like to continue the conversation via email, or I'll keep monitoring this for updates!
The original engine in my FD ran for 130k miles with the stock 230F fan switch before I rebuilt it. Yours will be just fine until you swap out the switch. Wiring the fans up to run constant is just a waste of fan lifespan and alternator output IMO. If the fan speed system is working I'd leave it alone.
thank you. Hopefully this engine will last a while
it seems super healthy vs all the other fd I went
to look at before buying this one.
ill go hit up the dealer or amazon for a fc switch.
Originally Posted by RCCAZ 1
Hey Jason,
So, first off.... welcome to FD ownership. I've owned mine since 2000 here in Phoenix and can tell you from experience that Summertime is not good on turbocharged rotaries, especially ones stock configured like yours. Have you tried activating your AC compressor when it's surging like that? If so, does turning the AC on smooth out your idle? I would encourage you to minimize driving your car when it's above 100F, but if it's your only driver, I would take steps to get it cooled down. Aftermarket rad and AST would be my first mods. Plugging all of the air gaps around the undertray would be second. When I did that to mine cooling improved significantly. Dual oil coolers would be my third mod. Anything you can do to add more cooling capacity will help. Also, not sure what you're running for coolant mix, but going more aggressive on your distilled water to EWG mix can help. I ran mine close to 80% distilled water and 20% prestone at one point to get it cooling better. Watch your intake charge temps on the Power FC, and if temps climb above 50C do no push the car on boost. Drive it gently until you get intake temps below 40C. Even then, I limit Summertime boosting significantly. We have a group of rotary enthusiasts who've been at this game now for nearly 20 years and would be glad to share what we've learned. PM me for my best email contact info if you'd like to continue the conversation via email, or I'll keep monitoring this for updates!
Pm you,
i havent tried the a/c when idling weird.
i don’t know which mix the car has I haven’t done a flush yet. Only thing I’ve done is add waterwetter.
i normally don’t drive the car during the day or heat this the first time it’s ever got to 230*
when it was cooler outside in the 90s the car still got 220ish tho
The ISC system adjusts idle air flow using the ISC solenoid. It tries to meet the three set idle speeds.
This type of problem normally can happen under many conditions. It is caused by the ISC running on the edge of it operational range.
Then conditions change and the ISC tries to either add or reduce air flow but it can not do it sufficiently.
This is the reason the throttle body has the Air Adjusting Screw aka Air Bleed Screw on the bottom rear.
It allows a fine tune of air flow without affecting the main throttle setting.
CCW adds fuel and then of course CW reduces air flow.
As hot air is thinner than cold, I assume the ISC is trying to add air and can't'.
Try adjusting the screw in 1/4 turn increments to alleviate the problem.
But first, make sure the throttle body is properly set up for the main manual adjustments and TPS voltage.
That is the first thing I do on any car I tune and I have found that most are messed up. Throttle not closing 100% and or not even opening 100% with out of range TPS.
Most FDs have had a recall for hoses under the UIM for 92-93 years.
When they did this they also:
(1) replaced the harness for the 4 cooling relays.
(2) put a short jumper harness between the engine and chassis harness inside where the engine harness comes through the firewall.
(3) then from #2 they installed a black box behind the ecu along with a seemingly unused female black spade connector.
This connector was really for testing but it has a very useful function. You run that wire to a switch on the console to ground.
When grounded that wire causes the cooling system fans to bump up 1 more speed. And if left on for about 2 minutes, when the engine
is turned off and the engine is hot enough, the fans will run for a 10 minute cool down.
Many of us use it for extra fan cooling when needed. I run the Koyo "N" pass radiator with 75% distilled water, 25% antifreeze, and a bottle of Water Wetter.
Then a Sard 175F thermostat helps as I live in Houston.
Pettit sells a 180F one: Thermostat 180° F
Having water or water/meth helps with summer air temps for induction..
There are tricks to improving engine cooling by increasing air flow through the RAD and engine compartment.
Moving the battery to one of the storage bins.
Removing the two rad inlet corner pieces. Blocking the open holes behind these two pieces.
Forcing the bottom of the rad inlet down a little.
Thank you! I’ll look into everything you mention thank you for being detailed
i added some water wetter. Drove around last night
it was 95* outside in Phx at 1am drive around for maybe 1hour
hottest the car got was 206* and no idle surging
07-24-18, 09:21 AM
