RedCarmel

iTrader: (7)

So I'm having issues with this Link. My setup is pretty standard, FM cast manifold, SR20 turbo, RX-7 550cc injectors, 2.5" exhaust, AEM UEGO.

I'm working through the tuning manual - TPS is ok, MAP sensor is ok, IAT is ok, idle...sucky and very lean. At first it was surging between 1000-1500RPM. Called FM, found out I need to adjust the injector offset to account for the fact I'm using RX-7 injectors.

Long story short, I reset the turbo map and before even starting the car up and I programmed the new injector offset, disabled the EGR, set up the AEM WBO2, and checked the TPS, MAP and IAT again, and did my best at trying to set the timing even though the idle wasn't the best.

After all this, now it idles decent at startup, at about stoich. After about a minute it leans out and starts to idle rough. If I adjust the master fuel map and/or idle fuel (zf100) it helps smooth out the idle and brings it back to 14.5-14.7. Problem is it's never idling well (roughness with occasional stumbling and surging) and it won't hold revs consistently (ie if I try to hold it at 2 or 3k it stumbles and almost sounds like it's missing).

Called FM again, and they said it's not going to improve by sitting in the garage and I need to center the fuel map by adjusting master fuel until I can start autotuning zf230. Well I tried this today and it was not easy to hit zone 2 much less 3000-3500 RPM and it would barely autotune. Most of the time it would just show error codes, V, T, and sometimes ?.

After about 5 minutes of trying to get it to autotune on the road, it would just die. The tach would go dead, the engine would putter down and just die. In order to get it home I had to turn off the car, turn it on, wait for the keyboard to wake up, start it, drive 100 ft until it died again. Then repeat until I could make it to the top of a hill and coast back to my house. Oh, and about half the time the keyboard would just display gibberish so I'd have to unhook the cable and reconnect it, all while sitting on the road.

By the way I've checked all of the vacuum lines I messed with during the install and there aren't leaks. I tried spraying the injector isolators with carb cleaner twice and did not hear any indication of a leak there. I also tried FM's method of adding 5psi of compressed air at the intake and listening for a vacuum leak and heard nothing.

I hope someone has some good recommendations other than to buy an MS. I've already spent money on this thing and hope it will just work.

reddragon128

iTrader: (2)

Hmmmm if it idles fine at startup maybe your startup enrichment is fixing things so everything might need to be a bit richer? Also did you sync the timing like in the guide?

RedCarmel

iTrader: (7)

Hey thanks for the suggestions. The master fuel map was bumped up to 120 to account for what you're suggusting. That's about what it needed to idle at about 14.7 once it was relatively warmed up. And yes I did reset the base timing at 10deg per the tuning manual instructions.

reddragon128

iTrader: (2)

Hmmm, can you post screenshots of your fuel and timing maps? And what was your injector offset?

RedCarmel

iTrader: (7)

Injector offset was set to 85 which was the number FM gave me.

No serial link, so no screenshots. I only have a keypad. I guess it seems like this isn't going to work without DLL. I have my name in for one of the new link to USB adapters but they are a few weeks out.

reddragon128

iTrader: (2)

85 sounds about right. My car was set to 80.

I think this map was old but here was what I had for a bit that I think was running okay.
ImageShack® - Online Photo and Video Hosting

Are you pretty sure you are running a default basemap? FM has some default values that you can check against here, not sure if it will help at all...

Flyin' Miata : ECU defaults

I know it'll be kinda tedious with the keypad. Also if it displays gibberish usually your cable is failing. I just had remove the connector carefully, chop a little cable off and reclamp into fresh cable.

mcfandango

iTrader: (1)

I had my IAC valve stick. Fixing that cured my no load 2.5k stumble. The engine did similar to what you describe. Rev and hold between 2-3k and the rpm would dip/engine stumble. However, I also alternated between a decent idle and a 1200 idle (as the IAC stuck and unstuck).

V and then T (after the 90seconds from starting) means your Z0 value needs to be adjusted. I see V on the keypad very often on my rebuilt motor. I haven't had time to get a proper tune on it though.

But first, buy or build a new keypad cable. You'll need that cable to be good even if you move to DLL instead of the keypad.

RedCarmel

iTrader: (7)

Thanks for the sample map! Do you recall if you moved the master fuel from 100? Also, did you arrive at the offset of 80 by trial and error? Since I'm running your injectors, maybe it's worth a shot to try that.

I have checked it against the FM site a couple times and it's seems to me I have the correct turbo map.

Thanks for the tip on the cable repair

I have been somewhat reluctant to mess with anything that worked just fine before the turbo installation. Was yours any trouble to you before going turbo?

The thing about the z0 setting is the directions say I need to drive the car at highway speeds in 5th gear to find the value. I can't get my car going that fast. Not sure where that leaves me with that setting?

Noted on the cable!

mcfandango

iTrader: (1)

I've been turbo for 7+ years now. That was the original 90 IAC. It was acting up for quite a while before getting 100% stuck open (1200 rpm idle always).

Just a point of data. The LINK runs fine on a mechanical idle and no TPS. Only issue is cold starts sometimes stumbles and if you blip the throttle cold it occasionally dies. My car is now 100% race car so less wires = less weight. Especially if the parts don't buy you any power.

What year LINK are you running? I remember some headaches after loading defaults and forgetting to set for sequential injection once. IIRC, This only applies to 90-93 though.

RedCarmel

iTrader: (7)

Ok, thanks. I'm running a 94-95 link.

RedCarmel

iTrader: (7)

Well it turns out the advice in this thread was pretty close. I had issues with the base FM fuel map values, and had an issue with my IAC valve. In addition, I've also learned I have a solder joint that's cracked and is very likely causing some of my random shut off issues.

Reddragon, I tried your fuel table values but they didn't fix my problem at the time because I was still battling what ended up being an IAC issue.

What's interesting is that it appears my IAC isn't bad, or isn't stuck...just something happened at the connector and after I removed the connector and plugged it back in several times, it seemed to be working OK again and playing with the LINK just fine. Perhaps there was just some corrosion that was cleaned off, or my IC piping was bumping into it and was messing with it.

Next I changed some of the fuel values in the first two zones to numbers that I got from Ken Hill. He helped me review those numbers as well as other values I was seeing on the keypad to make sure it was safe again to take back out on the road. He also clued me in on where to look for cracked solder on the ECU board.

I appreciate everyone's comments here, and the great assistance I got from Ken. I've exchanged several emails and phone calls with him and he's been such a huge help.

I took it out on the road for about a half an hour on Sunday and started the autotuning process, and so far other than the random shutting off issue, it runs fantastic now.

ecc3189

Sorry to bring this back from the dead but I may be having similar problems with the miata I just bought. I will have to take a look at the ISC to see if it is sticking or has a bad connection.

RedCarmel, where did you look for the cracked solder on the board? do you happen to have a picture from back when you worked on it?

Thanks!
-Evan

RedCarmel

iTrader: (7)

It seems the most common place for cracks to occur is at the voltage regulators that are connected to the large heat sink in the middle of the board. I actually sent my ECU to Ken Hill because he has devised a brace that does a fine job of keeping that heat sink from ever moving again. It was probably overkill for me but I never wanted to screw with it again. Having the car cut out in the middle of the road can be scary. I just had him resolder those joints when he was installing the brace, and it's worked flawlessly since then.

I did have a picture but I can't find it right now. But the heatsink is pretty obvious.

ecc3189

Ok thanks, I will have to take a look at it when I go through the car in the next month or so.