Brrraaap

Well that’s quite a ways away from me, if you could find someone closer that would be willing to swap an ecu from a running car that would be your best bet. I know there’s a place called Riggs rotary in Canada that sells a lot of used parts, if you contacted them they might have something that you could return if it doesn’t fix your problem.

wopa20

Just an update.... New alternator arrived and a new water temp sensor. Also tested the injector relay and its within spec.... just one more thing I can take off the list. If things go astray this weekend I'm going to do some back probing ecu.

wopa20

Here’s some videos

wopa20

Car still missing when throttle stomped

wopa20

I can start car decently now, idle is high at the moment around 1100 ish.

I back probed ecu with ignition turned to on and here are a few that stood out

1h - water temp switch 0.04 volts
1s - port air solenoid valve 12v (2.5 v manual)
2e - air flow meter 0.012v ( 4v)
2m - pressure regulator control selinoid 12v (below 2.0v)

car is warmish… maybe 1/3 heat

WondrousBread

So checking those against the manual:

1H - This is the switch at the bottom of the radiator. This just controls the 3000rpm accelerated warmup and some emissions functions. It looks like your car was partially warmed up, so nearly 0V is normal.
1S - This controls whether air is being pumped into the exhaust ports from the air pump. Kind of odd that it's measuring 12V based on what the manual says, but again, mostly for emissions.
2E - Definitely odd. The AFM should read about 4V with the ignition on, and then in the 2.5V - 3.5V range at idle. If it's reading 0V, that implies the car thinks it's flowing a lot more air than it is. That could certainly be the cause of the overfueling.
2M - Controls whether the fuel pressure regulator sees vacuum. Won't make a major difference, it's used for 90 seconds on hot-starts to prevent fuel boiling in the rails.

It certainly seems like you have a MAF issue that needs sorting out before the other things. I recall you replacing the MAF not too long ago - do you still have the old one? Maybe put it back on and see what happens.

wopa20

Well guess what…. 3.9v with old one. She’s running good now. Fully response on pedal…. Idle is way up tho! What next?

WondrousBread

Awesome! That's excellent news.

First thing I would do is warm it up all the way and verify all the idle settings again. The TPS and timing won't have changed, but you'll need to set the idle using the little set screw on top of the throttle-body. You can wind it down to lower the idle to 750rpm, but this needs to be done with the engine all the way warmed up

wopa20

do I have to jump the connector to change the idle?

and a heads up I did open the variable resistor too, might have changed setting some….

WondrousBread

Yes, you need to jump the connector for both. Start setting the idle to 750, then set the variable resistor (start from full rich, turn slowly towards lean until you hear engine speed decrease, then turn back a little to just before that point), then check and set idle speed again if necessary.

wopa20

Ok tinkered with idle for a bit, idle is still a bit bouncy. I heard that car needs to relearn idle etc? Will look at this further after new alternator comes in.

I’ve turned to put my dash back together …. Specifically my aftermarket stereo, I would like to focus on the power antenna to work with new equipment. I read something about needing a new relay. Will do search… but if anyone can give me coles notes on it I would greatly appreciate!

WondrousBread

Bouncy idle usually means lean mixture. Since you rebuilt everything already, I'd assume you probably just need to turn the variable resistor a bit to the rich side.

There is better information in the FAQ, but the stock antenna switches on ground whereas aftermarket switch power (or vice-versa, I don't recall which). So all you need the relay for is to reverse this.

I'm glad your Rx7 is running right now. I just checked back, and this thread is 7 months old!

wopa20

a lot of work has been done! Thanks for the help going on this. This summer is looking like fun.

Ok I think I figured out power antenna. Just wanted to check if this is ok? Three clicks after antennna down and up.

WondrousBread

That's a good question. I haven't had the stock antenna for about 7 years now, so honestly I'm not sure.

I feel like I remember there was a plastic track thing on the motor that can come loose. Your car is really low mileage though, so I'd be surprised if it was broken already. It's worth peeking behind the interior trim to see if there's anything obvious.

I still have my stock antenna someplace. I should reinstall it.

wopa20

Update: Wipers are working perfectly now. Finished up front end work and pulled it out of the garage. Going to warm car entirely outside before I pull it back in to test ECU numbers before I put carpet back and reinstall seat.

Couple questions, 1) horn dosnt work. replaced with new horn and no dice. Is the relay one of those sitting in the middle of the front bumper?
Second, car never really warms up to half on the temp gauge. Is ok to set idle, test ecu numbers at this temp?

WondrousBread

1. I have had many horn issues. The horn runs through the body CPU. It's the little black box next to the fusebox in the driver's footwell. The solder joints inside tend to crack and cause intermittent contact. This also causes some weird behaviour with the warning lights on the dash at times. You can fix it (permanently) by using a soldering iron to heat each joint and flowing a little bit of fresh solder onto it.

2. That's a good thing, S4 temperature gauges are a bit odd and fully warmed up is only about 1/4 to 1/3 on the gauge. It shouldn't sit at halfway when warm (well, mine does, but that's probably an issue with my gauge). If it ever crosses halfway the car is starting to get too hot and you should pull over and let it cool before diagnosing. On the plus side, it is a "real" gauge unlike many modern cars and it does react pretty quickly.

An aftermarket temperature gauge is a good investment.

wopa20

Ok so warmed car up for about half hour. Her idle is decent but fluctuating. I attempted idle adjustments as per FSM. brought it into garage and back probed ECU. I still have a couple odd values.

Intake air temp sensor value (2L) value was 4v and manual states 2-3
BAC (2Q) value is near 0 and FSM states 8-12.

I cleaned BAC, I tested using 9v, it clicked and I seen the plunger moved. On vehicle it dosnt seen to be doing anything, I pulled plug and no change in idle. So i connected 9v to terminals while idle and idle went up quickly. I tested plug end and it shows 12v on one side.

Any thoughts?

WondrousBread

Pin 2L is the IAT sensor on the dynamic chamber. This sensor isn't really used to sense IAT for fuel calculation (that's done with the IAT sensor in the MAF), it's used sort of like a switch. When the temperature of the dynamic chamber is greater than 70 degrees C, it increases the duty that the BAC valve runs. The FSM says 2-3V at 80C, so I'm assuming 4V is because it's much colder.

Short answer is, that sensor is not important for idle quality except maybe in the middle of the summer, and even then I've never noticed a difference with / without it. It's only related to BAC duty. The voltage you read with the multimeter sounds about right.

Pin 2Q is the BAC output. It works like a fuel injector, 12V constant and the ECU will pulse ground at the appropriate frequency. If you're seeing near zero that implies to me that the BAC is not being activated, or else I think you would see more voltage on this pin. This is the return from the 12V, so if my understanding is correct it should get closer to 12V as duty increases. Since the valve is working, I'm wondering if your TPS is still not quite right.

I'd recommend back-probing pin 2G. This is the TPS reading. It should be exactly 1V at idle when properly adjusted. This is the reason I don't like the resistance method and prefer the voltage / test lamp method. By back-probing this pin and adjusting, you'll make sure the reading that the ECU gets isn't affected by resistance in the wires or anything. This should be done with the car off and key to IGN, and remember to mash the throttle a few times and check again to readjust as necessary.

Lastly, there's a convenient way to test. Pin 2O is the Switching Solenoid output and pin 2P is the Relief Solenoid output. I believe these are the outputs that are tapped to use the factory test-lamp. Normally one light is on at idle and the other when on throttle, but since you don't have the test lamp, all you need to do is backprobe one of those pins. One should be 12V at idle and closer to 0 when throttle is applied, and the other is the opposite. This will let you know for sure that the TPS is adjusted right and the ECU is detecting it's idling.

The BAC shouldn't really be necessary for a smooth idle (it compensates for changing loads, but if you unplug it the idle shouldn't be bouncy or anything), but the TPS definitely can cause idle issues.

wopa20

Ok, soldered horn, pretty easy and horn is good now. As for the idle, been adjusting TPS, idle mix, variable resis, etc. Its idling ok around 1000 but something is just a tad off still but I might wait till I can take her for a ride.

wopa20

Took the car out for a ride and it was awesome! I think there still needs to be a little adjustments via TPS/variable resistor/idle etc. Felt a slight hesitation here and there but all in all was a great day out. Snow has returned and so shes back in the garage for a while.