Hey crew

Anyone have a good working (early 91-94') 960 AMM around?

Turns out my turbo chips for the b234+t were tuned for a 3" amm, so I want to see if swapping over fixes some of the issues I've been having.

What issues are you having. What EMS?

The afr's at idle vary wildly at warmup, occasionally goes lean enough to stall. Everything's peachy when you have your foot on the gas, and even in boost. I've gone through it looking for vacuum leaks, but I can't seem to find anything. So AMM was one thing on my list of possible suspects.
It's running 16vt chips from fred, bought back when he was on turbobricks. It's designed for 42lb injectors which I have, and a 3" 960 AMM.

Any thoughts?

If your chips were designed for a 960 AMM, I would agree that you've got the right idea in tracking one down before further troubleshooting. However, I would also check your O2 sensor once you do get the AMM figured out, but you may be better off (MAY???) swapping to an aftermarket EMS. My experience with and observations of TLAO chips have not been positive, to say the least.

Thoughts - yup, I've got a few. I've tried the "parts cannon" approach to fixing LH in the very recent past and achieved nothing but a pile of good used parts. From AMM's to coolant temp sensors and TPS's to name almost all the sensors on 2.4! My car still ran like a$$ and tossed codes like an angry chimp tosses feces. It would tell me all manner of stories one blink at a time.

Here are my suggestions...get your multimeter out and verify the function of every sensor on your engine. All of them. Use the harness for most as measuring the sensor directly is a PITA for quite a few. There is a procedure in the Bentley Manual that covers the ECU pin out and testing procedure (IIRC it's 30 steps).

Once that's done, you'll know if your AMM is at fault. It probably isn't.

What I learned was that LH can't scale a 42 lb/hr injector on the stock AMM. I tried it and ran it like that for a reasonably long time until problems (seemingly random) ones would crop up and would have me chasing my tail. Thought it was a leak (when I found a missing cap on an vac connector on my intake), fixed the leak and it worked better, thought it was solved. Only to have it come back later for no reason. When racing, I was never sure which car I'd be driving - the powerful one, or the one that was running terribly.

So after much research and one locked thread on TBrix (thanks Dale ) I trimmed the injector back to 36 lbs/hr and bingo, thought it was fine. And it was - could make a full throttle pull up to 15 psi. Then after a few weeks of relaxing - bang - idle all over the map, crazy behaviour, codes - codes - codes. I was ready to sell the car (and I'm DEAD serious). Then I changed to my spare ECU - no chips, no random generic tune, nothing. It immediately ran perfectly. Set the base idle as per the manual and it's been months including cold weather and it's just as happy as a clam. No return to silliness. Still running a chipped ICU, but the ECU is bone stock and just fine.

So long story short - check all sensors, grounds and tests first. Then change the parts that fall out of spec, and if it still runs poorly, swap out Fred's chips and get a stock ECU.

Interesting, thanks for the feedback guys!
I'll keep hunting for the AMM at the junkyard. I wonder how a stock 8v turbo fuel computer would handle things paired with the 16vt ezk chip. Anyone in town have a spare to lend by chance?
I also suspect that the sensors are fine, especially with how well it runs off idle. I've tried changing the O2 sensor with no change there. Just running out of ideas.
In the meantime I'll try and get my hands on the Bentley manual.

Rather than get rid of the car my mind keep wandering to just swapping in a 5cyl. To save time y'know

Just to be clear and put to rest a personal misunderstanding: do you actually have a 960 AMM in the car now, or are you running it on a stock one?

I'm sure someone's tried mixing and matching LH and EZK boxes before, and you'd have heard if it works or not. I doubt the 16V EZK has any timing values for anything into boost, so you'll be running way too much spark. A B230FT LH box will be way off the map for a 16v+T, and the B230FT EZK box will ping like a bastard on that engine (in case you had that crazy idea).

Two words: Megasquirt.

^What Matt said...and to add to that one simple question. Did it ever run properly under it's current state (B234+T) or not? If it used to run and now won't run, then test (even self-test...you know you have that right?) the ECU and see what values you get for all the sensors. These instructions litter the internet.

You won't randomly find a 960 sitting at the JY in row 59 on the end very often . So it cruise on over to TBrix and ask if the JY monkeys have one (in wanted) or watch For Sale, they come up often enough.