I guys.
I have problems with the ecu on my 86 Rx.
I actually have several units with different problems.
Some have no control of the BAC.
Some have problems with the TPS.

Does anyone offer a repair service for these units?
Does anyone have schematics for the boards and the components?
I have access to an electronic shop at work but the technician says he would like to have an idea of what does what, instead of guessing.

Thanks

Ken

 

with the NA ECU being so cheap in the Parts section I would just opt to buy a used one.
I wouldn't be pitching money out to anyone to try and fix the darn thing!

 

I have bought 5 used ones and all end up having a problem of some sort. The problem is tired components, cold solder points, just overall old age and poor quality.

I need to fix this, not keep buying used ones.

 

My guess is that the ones where the BAC does't work either have an issue with the transistor of the solders on the transistors.

If you open it up it is probably a larger transistor connected to the side of the case. I would try touching up the solder joints there.

The other thing you could do is get the pin out for the ecu and follow the circuit back with a multimeter and check everything component by component.

 

I know you said you aren't looking to buy more ECUs. But if your car is an S5 NA. I have 2 for sale that came out of running cars with blown engines. You could have them both for $20 plus whatever shipping is?

https://www.rx7club.com/2nd-generati...ipped-1076263/

 

s4 n/a ecus are worth about $10. i have 2 known good, and know many people that do as well, im not sure why you have all bad ones.

 

I have bought these mostly on eBay. They seem well at first but fail soon after. The one that lasted more, did so for over a year until it started acting up when at WOT. Lots of sputtering and no power. Basically it ran poorly at anything over half throttle and more than 3000 Rpm. The fuel delivery was all wrong.
I'm hoping for a solid ECU that no only is trouble free, but also so I can send it to Rtek.
I looked around today for a place that services these older S4 units and they all say no. Only a store in Texas said: send it over and we'll check it. $195.00 flat rate. $35.00 for checking it if deemed non-fixable.

I'm still not sure I want to take that chance.

 

It's a shame that Rtek does not fix them as well as chip them.
I could trust them.

 

If you you ship it to me me I will do it for free.

I am not guaranteeing that I can fix it it, but I might be able to.

PM me.

 

Just another off the wall suggestion:
Why not buy a Good used one and get the Guy to send it to Rtek,instead of you getting it,then having the ecu shipped there and then back to you??
Seems like an awful lot of shipping!
We have some good members here and I actually Bought a used S5 Turbo and had the guy I bought it off of ship it to BNR to get upgraded before it got shipped to me in Canada.
If you get the ECU upgraded I am sure Mike at Rtek could ship it to you.
$195 flat rate fee?..I can get a car for that!

 

How will I know if it's a good one?
All those that I have were good ones and they either have a problem out of the box or work well for a while and then die.
I started the car last night and warmed it up.
One ECU has no control of BAC so idle is non existent.
One has control over BAC but even when adjusting the mixture screw all the way to rich, it still does not have a steady idle, and when I push the throttle it sputters even more.
One has control of BAC but does not respond to the TPS so there is a fixed voltage (.35 V) at the ECU pin 2G. Engine then stumbles and dies at idle.
One floods the engine. It seems to be in an overly rich state of tune so to speak.

If it was not ECU related, changing the units would not give different results.

I'm frustrated.

 

I am suspecting that the "ebay specials" were not tested or the guys that sold them couldn't give a sweet Crap of what they sold.
Tell ya what.
IF you want to..I got a N326.It works.
I can send it to RTEK in Your Name.Pay me shipping once It goes out.
YOU have to make arrangements with MIKE at Pocketlogger(Rtek) to get it Upgraded.

 

It certainly sounds more like an issue with your car than the ECU.

RTEK....pfft. Do it yourself and save a few hundred.

 

^ I'm with Sonic. Some systems work together, so it may look like one thing is bad, then another.

The variable resistor is, yes, to adjust idle mixture, but you have to make sure the engine is warm and the fast idle cam released, the TPS adjusted properly, and the timing correct. The BAC adjusts for accessory/engine load, for example, but not sure how much effect it has when no load is on the engine (and steering wheel straight and released).

I'm just not convinced all those ECU's are bad. Some of the failure areas I haven't even heard of. Open them up and look for cracked solder joints or burned areas.

 

Well, i worked on the ECU with a friend who's an electronics technician and we tested components from one ECU that seemed to be the best one but still flooded and acted weird.
After testing a lot of the smaller components we took out a few of the larger ones. Measured it and then took the same component from another ECU. They had different readings on a few pins. Took one out of a third unit and those were the same. So that one was swapped out. Same with the green ones for the injectors, as none had an equal reading so we put in a set from one ECU were all were similar and close to the value on top of it.
Car started but still acted up. After a lot of going back and forth with the adjustments, it idled better. I installed a fuel pump switch on the center console under the lid , so I can kill the pump when it floods.
This morning, I started it and same story. Then God told me to do a steam clean of the engine. I warmed the engine up, got a liter of water, mixed it with a bit of alcohol and had a hose attached to the nipple under the BAC. Did that twice.
Turned the engine off. 5 mins. later, I turned the key and it started with no trouble.
The car has been sitting since October without use.
The fix on the ECU was needed but the steam clean finished the trick.
I know that the ECU was bad since that one did not idle before and died as soon as I touched the throttle. But there must have been some crud on the inside of the keg.
I will take it out for a quick spin to see if it drives well.
Once I'm sure it does, I'll install the Crane Hi-6 I have been wanting to put in.
That and the Atkins 6 port sleeves that I installed last weekend, should help it feel a bit more lively.