Need 2nd gen FI help

C

C. Ludwig

New member
Ok, got the ITS car just about wrapped up. Finally really got to run it a bit today. And it is WAY lean under throttle. It starts and idles great and can be brought up to 7000+ under no load and part throttle. But full throttle just lays it over in a lean bog. The car only has an open header on it right now and I'm sure if that's half the problem. My real question however is what sensors are needed for proper operation of the FI? Most of the 2nd gens I've seen have had the throttle position sensor removed. Mine is unhooked as are the water temp sensor, intake air temp sensor, the barometric pressure sensor and the O2 sensor. Without the O2 sensor the car should run in open-loop, correct? But do you still need the temp sensors for the computer to pick a map? What about using resistors to force a specific map? Thanks a ton!

Chris
 
Chris - no answer here just a comment - are you running a EGT Gauge at all? I hear from Dave Lemon that these are a must when figuring out a Rotormotor...
 
A two channel setup is on the wish list.
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I do have an A/F gauge but don't have it hooked up yet. Need to wait till the O2 bungs get welded in with the rest of the exhaust.

Chris
 
Hell, I've been beside myself for about six months just thinking about getting it race ready!
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We kinda got it figured out this weekend. We hooked the IAT, MAP and water temp sensors back up and it ran pretty well. It still seems to lean out on top and I called it quits till I get the rest of the exhaust done this week. I'm gonna go ahead an hook the throttle position sensor back up too and it should run pretty darn good. Don't know how guys are getting away without running this stuff.???

Chris

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86 RX7 ITS on the way!
 
Chris, you do have to have the things you said, plus the TPS. It won't run right without it. Oxygen sensor not necessary. Make sure the AFM is hooked up also. All the cars I know have all those hooked up.
 
I had a thought. My car is an 86 but I converted everything over to 90 stuff. Like I said, I've seen cars without the TPS but got to thinking about it and they were all 86-88 cars. Will get everything hooked up this week and the exhaust gets done Friday. No more excuses now!:D

Thanks guys.
Chris
 
Chris, so you are running a '90 body wiring harness (driver's side), ECU, etc.? No wonder you are still working on your car - that is quite a task changing that thing out!
 
No kidding. Should of seen the Three Stooges act trying to find the CAS plug on that harness. Looked for two days, broke down bought a factory manual, turns out the later cars have the plug on the other loom! LOL. It was there the whole time hiding in plain view.

Chris
 
Chris, Assuming you don't have the elec.oil pump installed on your 86, how did you fool the 90 ecu about it not being there?The engine may have to be under load for proper AF ratio at high rpms(gives the FI time to adjust). New fuel filter? I'm planning the same change over on my 86. maybe you can tell me how it all sorts out.If it's not to much trouble, can you attach a copy of the emmissions elec.schematic showing the AFM wiring,fuel pump switching from your(new) 89-91 workshop manual? Also the AFM check resistance values? I wondering if it's possible to switch AFM's only?
Thanks,B
 
With my setup I could off used the electric pump. But opted to ditch it and run premix. Years of two stroke tuning makes me weary of injectors. Anyway, according to my service manual there is no input from the OMP that says if it's there or not or if it's functioning. Therefore, simply disconnecting it shouldn't be a problem. The grain of salt is that my car still isn't running properly. I'm taking it to a rotary shop Friday and will hopefully get it sorted out. I'll tell you more then.

As for the schematics. Drop me your email @ [email protected]. I'll try to hook you up.

Chris
 
Chris,

Everything I've read so far has suggested that if the 89-91 computer doesn't detect a working OMP, it goes into "limphome" mode. That was the primary reason why I chose to stay with the 88 ECU, even though I lose the 8K redline.

PaulC



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