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Discussion Starter #1
This is really strange. I can't figure out what the hell is going on and it's pissing me off.

Tuned my car at ~11.5:1 in and it was happy for about 500 miles.

This last weekend, I nailed it in second, the back end broke free, and I hard shifted to third. At about 5krpm I looked at the FJO and it was at 14.7:1. I backed off. I then romp on the gas pedal looking for it to respond to the variation in TPS position and it did nothing...14.7:1 without budging. Tried getting on it at WOT one more time with the same results. At 5krpm I was still at 14.7:1 and I backed off. No matter what the pedal position was, the AFR was at 14.7:1.

Relevant Specs:
T78
Stock ECU
Fields SFC
VPC
FJO

I reset the ECU, drove around with the same condition (no help). Turned the car off, started it back up and bingo! The AFR responded to the variation in pedal position. Made a hard run in third, logged it, and uploaded it to my PC. Perfect AFR at ~11.5:1 in the higher rpms.

This has happened 3 times now over the course of about 1500 miles. I'm adding about 5% fuel at 4k rpm and maybe a percent or two (very little) anywhere else in the higher rpms. I do have my VPC gain at 2 clicks right, as this seems to bring the entire AFR curve down to give me a bit more fuel in the lower rpms when the turbo starts to come on-line. From reading I know that the gain is supposed to be left at zero and tune made with the FC, but it works well for me (better tune and ECU doesn't re-correct).

Any ideas on what may be causing this? Has anyone else experienced anything like this? No change in gas or weather, although I had just added some more of my standard 93/33% toluene mix running at 23psi. Also, I have tried two different TPS sensors with the same result.

I hate having to have my eyes glued to the AFR readout all the time!:mad:
 

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Same thing happens on the older Techedge v1.0 WBO2. If the control box didn't get 12.7V or more, it'll default to 14.7 on the display. What's the min voltage requirement on the FJO? Maybe your battery or alternator is not up to par and causing the problem.
 
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Discussion Starter #4
Wow! Great ideas guys.

The car is a 97 w/ 21k miles. The altenator should be fine?

Now for the battery, it was replaced 1.5 years ago but has been killed 2-3 times since. Left interior light on and didnt't start he car for a few months while I did the APU mods. And the car did turn over sluggishly when I let it sit for 3 weeks recently. Hmmm...

As for the FJO, this is my second one and it has the same problem as the first. It clips rpm output at 5 krpm and won't read higher. My first FJO did it at 4k rpm (running the rpm input from the tac signal). Also, the first one had display issues so maybe this controller is bad as well?

Oh, and btw, the car seemed to be cycling throught a good AFR range up until the point where I nailed it. The AFR was dropping fine in second, then it third it just went to 14.7 a stayed! Weird!

Anyway, thanks for suggestions. I was thinking my stock ECU is just flaking out for no reason! I'll have to check the obvious as mentioned.
 

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Was there a batch of bad FJO units...If so, about what date did the bad controllers ship?

I'll have to check this out.
 

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Spool said:
Was there a batch of bad FJO units...If so, about what date did the bad controllers ship?

I'll have to check this out.
Greg's first controller was a 1st-generation logging controller that was designed for use with an inductive RPM pickup. On some vehicles you could hard-wire the RPM pickup to the tach signal and acquire an RPM signal (instead of using the inductive pickup). However, on the Supra and certain other vehicles, hardwiring would result in a clipped RPM signal at about 4-5K RPM. I don't know what's up with the RPM signla on the current controller, but it sounds like there might be some problem that needs fixing in the controller as I seriously doubt that Greg has it connected incorrectly.

But regarding your original question, there hasn't really been a bad batch. There was a few that came thorugh with poorly crimped connectors on the end of the O2 sensor wire (I don't recall what serial numbers were affected, but I think there were only about 30-50 controllers in the production lot that contained some loose connectors, and I think it was about 18-24 months ago). FJO caught it and provided free repair (re-crimping the wires -- some people did themselves) or free replacement connectors (which could be installed in the field by the customer).

FWIW, I've sold several hundred kits and I've had about 4 kits that required the replacement connector and about 3 controllers that otherwise didn't operate correctly. So, it's not a widespread issue at all.

Steve Hayes
 

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Greg,

Let me know if you need me to discuss this with FJO (perhaps you're already talking to Gerald about it). If it weren't for the fact that the AFR is going to 14.7:1 and staying there, I'd think what you are seeing is not too uncommon for the stock Supra ECU.

Here's why I say it's not too uncommon. I've been somewhat close to 4 different big single Supras (different turbos, different fuel systems, different fuel controlers, all on the factory ECU, 3 of the 4 with raised rev limiters) 4 out of 4 of these cars have exhibited the following trait: Tune the car carefully to about 11.5:1. Then within a week or so, find the car suddenly running about 2 FULL points leaner under the same boost, same weather conditions, same fuel, and with no changes to the electronics! Then, retune the AFR and they pretty much hold that tune indefinitely.

However, from your description, I don't think your car is doing the same thing because these 4 cars I'm talking about didn't peg at any particular number and stay there. They flucuated normally -- they were just way leaner than they'd been previously. If your AFR is reading steadily at 14.7 as you accelerate throught the RPM range, I would strongly suspect a problem with the wideband as I seriously doubt that you will, in reality, have a perfectly flat AFR curve (without so much as a .1 point change) across the RPM range, no matter what. Have you ever checked the security of your O2 sensor connector (you're not one of the ones who expereinced the connector problem, are you?)

Steve Hayes
 
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Discussion Starter #8
Regarding the FJO, I have heard of no problems with them at all with the exception of a single individual with a gen 1 and rpm clip problem as I had.

The first time this happened is when I put in GT 104 and turned the boost up for the first time. The car would go to around 14.1:1 and stay there. It seemed that no matter how much fuel I added the car would not come down in the 11's:1. I immediately put the car on a dyno and the dyno WBO2 correlated to the FJO. I reset the ECU and it went way rich in the 10's:1. Took away some fuel and all was happy for a while. However, I did see some fluxuation on the FJO -- not a constant 14.7 like this last weekend.

As for the rpm thing, I don't know. Here is a log I made a couple weekends ago when the car was behaving properly:



This is a pull starting out in [email protected] and shifting through 4th. As you can see the rpm is clipped at 5k and is clipped again at 6krpm where it falls off the graph. I was going to try the speed sensor signal as opposed to the tac signal but haven't got around to it.

Pretty good shift huh!? You can see the AFR burp but the rpms never came back so I was over 5krpm when I hit fourth.

I also took a log of when it was hung at 14.7:1. The line is flat all the way to 5krpm when I backed off. I would ocassionaly see it go to 14.8:1 so it was apparently getting some kind of signal.

What was the O2 connector issue? Just not seated properly? I'll check it out and re-fit the connector.
 

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Hmmm.... it kinda sounds like it's actually running those AFRs, doesn't it?....

The problem with the connector (the connector on the end of the FJO wire that plugs into the O2 sensor) was that the wire-end terminals inside the connector were not tightly crimped onto the wires from the FJO controller. The crimping die had lost its adjustment and wasn't crimping the terminals tightly enough. To check yours, just tug on the wires a little bit. If they are loose, they'll slide out of the connector. This only happened to a few controllers out of one production lot, so chances are that your's wasn't affected, but it MIGHT be.
 
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Discussion Starter #10
Yeah, I'm confused at this point. I don't want to go AEM, but it's shit like this that makes me seriously consider it.

I'll just keep an eye on it and try some different tunings. I'll zero everything out and start from scratch. Maybe the 4krpm addition of 5% fuel has something to do with it? By adding with the VPC gain I have to lean out a bit on the top end, so if I zero everything I should get my 11.x:1. I may run a bit leaner from 3.5 to 4.5k at WOT though. Moreover I'm starting to think that open loop is based more on TPS position and can be manipulated at lower rpm to some extent (another topic in itself).

My PDA has been acting up after I dropped it a while ago (whoops :) ) , so there's a remote chance it is the PDA. I have a new PDA arriving soon. Also, I'll be able to see what the timing is doing with some new software I got.

Just thank God I've ran this FJO on the car ever since I put fuel control/VPC on the car. What an engine saver!!
 
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