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Just some basic questions. I want to start datalogging and tuning my 1991. Previous owner installed a chip from PCM of NC, so it already has an adapter socket for taking flashable chips. I got this cable: http://aldlcable.com/products/aldlobd1u.asp
Looked through that thread, I don't exactly follow.
Are there any plugs/leads on the factory TPI harness that normally receive voltage as part of say the EGR or smog system that can be re purposed for taking in wideband data, and seen in a log?
I'm not familiar with that programmer as I'm using the GQ now. For editing software I swear by tunercat. They continue to support and update all the OBD1s. Is you prom soldered in? Or easily pulled out? If it's soldered there are adaptors to plug from the programmers to it.
Dang... that is all Greek to me. Not sure where to start.
Correct me if I am wrong but really how are you supposed to do good WOT tuning without a wideband datastream?
I briefly skimmed over that link...you need to download 84Elky's xdf and follow the "read me's" which would probably shed some light on which wire to use for input perhaps C21??? The other mumbo jumbo about the WB...you need to modify the adx with the right calculation (math) for the WB in order for the datalog to interpret the data into sensible data.
Additionally since you're working on a '90...you're going to need a adx that tells the CCM to be quiet on the dataline or the datalog will look like garbage.
Third gen /dyi is the only place to look. tuner pro is the software to use. 84 elky is a very smart dude, his hacks are excellent, SAUJP v5 is the bin file you should use. No, it's going to take a while to understand. If you listen for a while and don't ask stupid questions, there are a lot of guys there who will help you.
I'm using EBL P4 now so on the WUD the wideband is integrated. Before I switched to EBL I used a wide band after I had worked on tuning closed loop and part throttle without it. I just used the wideband for WOT and PE adjustments.
Made an appointment with a local dyno tuner for Wednesday May 24th. He says he has spare 28 pin chips, and has an emulator to help speed up the process. I told him we need the $8D definition file for the factory 1991 ECM.
Any other things we should consider or prioritize?
Do knock sensors go bad?
Also can anyone suggest some base mechanical timing for me set the car at? Right now it is at 7 degrees advance or so.
Mod list:
1991 L98 TPI long block
LT4 Hot Cam
GM Performance 1.6 Full Roller Rockers
LT1 Converted intake manifold, 24lb LT1 injectors, LT1 fuel pressure regulator
Gasket matched and intake ported manifold, gasket, and 113 heads
Hedman Elite 1 5/8" long tube headers
Dual 2.75" straight pipe exhaust cat and muffler delete
SLP claw cold air intake
Also sorta silly, but if I set a base mechanical advance to 6-8 degrees, can the rest of the timing be handled by the tuner?
My converted LT1 manifold setup has the typical slow leak from the distributor clamp area. I was gonna RTV it after setting the timing, so the base timing is semi permanent in that way?
I am so excited to get this thing tuned. Gonna do a full compression test all 8 cylinders here before hand.
The timing even base can be altered in the tune. Base is more than likely 6. The ecm takes over and uses multiple tables closed throttle, main and extended sa ect.. you asked about knock sensor KS
Okay sweet so a "semi permanent" install of the distributor resulting in a fixed mechanical timing ought not be a problem if I set it around 6-8 degrees?
I haven't removed or touched the knock sensors, just was wondering if they go bad or if I should replace them before this dyno tune. That and wideband AFR are the main measurements used to inform the tables right?
You might consult with your tuner but dyno tuning will focus on wide open throttle PE. The Blm/int locks .a wb o2 will be used to monitor afr. Might want to target 12.5 afr.
You might want to use (tunedport90) Brian's services in tuning and base files to start, as he's one of the few people left who knows how to do it well... I've done a lot of tuning for over 20 years, operated my own dyno, attended numerous schools/training, and I absolutely wouldn't mess with it. It's also the same crap for my 1986 Porsche 944 Turbo.
When I first started to go that direction, he installed an EEPROM and set it up to datalog an AEM wideband/controller setup, and also with a much improved base file. I wanted better tuning capability for myself so I didn't go any further down this road, but I can certainly recommend it if he's willing.
Just watched a video last week Fasterproms tuning perhaps a 1991 on the dyno, felt sorry for this guy, knows what he was doing and his Dad started the business doing exactly this... in summary, it needs infinitely more patience than what I have... not a how to video but perhaps entertainment:
I have a dyno tuning session scheduled Wednesday May 24th next week with an Albuquerque local dyno tuner SQC tuning. He has a MOATES emulator he said we are likely to use, as well as a chip burner, extra chips, and he did say he has experience tuning TPI cars before.
At this point though I think my setup is closer to an LTx car however.
04-30-2023, 02:37 AM
1991 Tuning Basic Questions, Software, Computer, Logging
