New FD owner here with a idle problem.
 

So...I purchased an FD from a fellow forum member a few nights ago. The car had been ran out of gas and the original owner could not get it started again. The fuel pump sock and plugs have been cleaned/changed by Icemark and I this morning.

The car started and idled funny during the warmup cycle. Once the engine has reached normal operating temps, it starts to stumble and subsequently dies. I'm hearing a clicking sound coming from one of the solenoids underneath the UIM. I'm not sure which one it is and I didn't really have time to test each one with a 12v power source. Any of you guys have a problem of this sort or similar?

I drove the car around town just to see how smooth the engine ran and it was just fine. In order to keep the car from dying at idle, we bumped the idle up to roughly 1500-1700 rpms.

It also seems to have a hotstart problem and I'm assuming it has to do with the faulty solenoid under the UIM.

This is my first FD and all my experience has been with TII's so any insight would be greatly appreciated.

IIRC if you let the tank go down to empty. Soot and debris from the bottom of the gas tank gets sucked through the filter causing it to clog.

Which is why you're getting the intermittent dying thing.

I would lean towards a bad filter now and just change it.

Are there any mods?

nothing more than a power FC and apexi dual intakes...


oh...RB exhaust as well.

ahh power FC and idle problems. Start searching through the PFC forum. It's the most common problem with the PFC and there are multiple causes. Assuming there are no mechanical problems (vacuum leaks, clogged fuel filter), the first thing you need to do is check and make sure the previous owner cut/depinned the wires mentioned in the PFC installation manual, available on the Apex'i website. Then you need to adjust the idle screw under the TB elbow. Tighten it all the way and then back it off about 1/4 - 1/2 turn or so.

Then perform the idle learn procedure in the PFC manual. Do NOT turn off O2 feedback since you still have a cat and airpump.

You need to get a wideband to check AFR while you are having your problem. I'd guess you need to adjust in the water temp correction map.

hey my fd is having the same problem. the idle is really low when cold and even when its warm. what screw are you talking about? pictures?

^ if the idle is really low it could be a bunch of things... turning that particular screw (air adjust screw is what they call it) could make it worse in your case. turning the air adjust screw is mostly to fix idle sticking and surging, one of the common PFC problem. When it comes to idle tuning (and any tuning really) it's easy to make the car run worse before it runs better. You may want to seek a professional.

Otherwise, a low idle could be a bunch of things. Sometimes it is just a bad AFR tune. Sometimes the other screws on the TB are misadjusted. Sometimes the hot wax cold idle system isn't working. Sometimes the ISC is stuck or otherwise failed... it can be very difficult to set the idle right under all conditions without solid knowledge of the PFC, a datalogit, a wideband, and just trial-and-error. I've spent many, many hours fiddling with the idle on my friend's FD with PFC and on my own FC with PFC. They both idle solidly at 850 now but it took all sorts of adjustments in the PFC fuel maps as well as throttlebody adjustments.

chuck westbrook (cewrx7r1) has a lengthy writeup on setting the PFC idle if you buy his Power FC notes. PM him about it.

my problem is there is nobody that i know of in southern utah that knows how to tune a rotary. i have only seen 2 FD's in utah including mine. Cobb tuning in SLC might be able to but i just need to lean it out, not get it runing perfectly.

^ tow it to a trusted rotary shop or get a wideband and a datalogit and learn how to tune yourself. Those were my options, and I chose the latter.

i have a wideband, but i have no money for a datalogit. it doesnt need to be done perfectly. im going to do this anyway i just need a few tips. i think i just need to tune the fuel map because my AFR is between 10 (or below) and 11. my car had tons of vacuum leaks when i bought it and i went up 2500 ft. so its alot richer than what its supposed to be.

yeah... I'm gonna get a wideband on it at some point in the near future. I don't really think it's a problem with the PFC but I could be wrong...

This might seem pretty simple, but that sounds a whole lot like the symptoms of low compression.

nah the compression is fine. it was 3 even bounces of 80 PSI (cold). the back rotor was 75 PSI.

I think 80 PSI is a bit low and so is 75.... Good is around 95-100

http://www.rotaryresurrection.com/3r...ion_check.html

yeah i should check it again. wheni checked it before it didnt run for about a week or so. i was checking the plugs and they were fouled so i checked the compression while i was at it. agter reading that i realised i did it almost completly wrong. but at least i know my apex seals are still good. :biggrin:

I am pretty sure power fc bypasses this but there is a switch behind your clutch that tells the computer when its in and when its out. Mine went and the idle was iradic and died constantly

Well, the engine just let go on me a few hours ago. Fortunately it died about a mile from my house so it wasn't too bad of a push. ;)

I'm assuming that the shitty idle was due to a chipped apex seal seeing as how the compression wasn't up to par on one of the faces of the rear rotor. So...Now the engine freespins :lol: ZING!

Another block is in the works as I type this so I should be in good shape again in a matter of weeks.

Who's building it for you Nader?

I'm hoping the weak engine affected the price you paid for the vehicle...

yea, he got it for a good price. :)

Told ya so. :)

Good luck with the new engine. There are a couple of things I think you should do while the new block is out that are different from an FC.

You might:

-check the clutch release fork or replace it
-re-seal the oil pan with no gasket and permatex right stuff (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/mythbusters-time-oil-pan-motor-mounts-488739/)
-swap in a metal (available on some rotary specialty sites) front cover gasket

Like the FC, the FD has a weak FPD, but you can't banjo bolt it. I just replaced mine new along with the recall kit for the fuel lines.

For the record, that's not good compression. That's what my FD had when I bought it and I didn't even try to drive it... immediately started pulling stuff out of the engine bay.

Ben (karack)

I should hopefully have a new streetported shortblock within 2 weeks.

good stuff nader, when its running u need to cruise by and lemme check it. iam just starting on my fd build. cleaning parts is very time consumig!