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I got my '96 re-geared (3.54) and can find NO ONE to calibrate it through the ECM, so I'm got one of these.
Any input is appreciated.
Try Moe Bailey...I think he is over at LTxtech......I think this is who Lloyd Elliott uses. I was going to use PCM4less, but the LT1 guru sold it or is not there anymore
if you are running Google Chrome, take your pick of more reading, this will only pull up threads from the forum here
take note of the dates of some of those threads that talk about switching internal components, which may or may not apply, but most C4 specific components are no longer carried
All you need to reprogram it through the PCM for a 96 is Jet DST. But you must have that. So it's $180 for the Abbott box, $400ish for the Jet software, or try to find someone in your area with Jet DST and pay them $100 to let you use it on your car (an extra VIN license from Jet costs $100). Living within range of Sacramento, San Francisco, and San Jose, I would think someone there has Jet.
That's 100% true, but you always run the risk of the Jet units having one of their infamous intermittent burps and toasting the ECM. Forum member Barchetta found that out on his car when his had an issue. He had a thread about that recently and has been able to successfully fix the damage that the Jet unit does, but that involves soldering on new chips that have been flashed.
While I have a Jet box, I would not reprogram anyone's car unless I had a signed piece of paper absolving me from any responsibility if the ECM gets fried.
That's 100% true, but you always run the risk of the Jet units having one of their infamous intermittent burps and toasting the ECM. Forum member Barchetta found that out on his car when his had an issue. He had a thread about that recently and has been able to successfully fix the damage that the Jet unit does, but that involves soldering on new chips that have been flashed.
While I have a Jet box, I would not reprogram anyone's car unless I had a signed piece of paper absolving me from any responsibility if the ECM gets fried.
The key with using Jet DST, I think, is using it on a genuine XP operating system. IIRC, Barchetta said his issue was probably the car battery and/or charger not working properly. But either way, yes it's a risk.
The key with using Jet DST, I think, is using it on a genuine XP operating system. IIRC, Barchetta said his issue was probably the car battery and/or charger not working properly. But either way, yes it's a risk.
I wasn't trying to be argumentative or anything. I knew what had happened, we talk off the forum, I was just wanting to let the OP know the risks as it pertains to cost -vs- risk and a bird in the hand.
Everything that I found on the net and here on the forum indicated good results from using the Abbott box. It just has to be wired in correctly and calibrated.
I do 100% agree though, that changing it via programming is a better method than another add on box that can fail and get you a ticket :-)
I thought long and hard about the Jet DST and really weighed it out. It was even in my Amazon shoping list for about two months. It's not just the cost I was worried about. Hell, any $$$ we throw at these cars is cash we'll never see back. It's a toy. Lord knows I flush enough money down the Toylet, but when I added the cost of the Jet, plus trying to scrape together an old XP laptop from one of my nephews, and the possible risk of what happened to Barchetta, I thought best to go another route because of what I was after. I don't want to do a bunch of other things the Jet DST can do like shift points, fan temps, and a bunch of other stuff. I just want my speedo to read remotely close to correct. The Abbott gadget really seemed the ticket for the cost.
I stared at my FSM (War and Peace) for a long time and I THINK I found the correct lead. The VSS has two leads (high and low) that feed into the PCM, The lead I'm chasing is the one that comes out of the PCM that goes to the cruise control, speedo, etc... . Now I just need to find a keyed hot that's not related to the Opti and I think I have it. We'll see.....
I can't help directly on the wiring I have an 1988 Automatic.
Many years ago, when I changed my rear from a 2.59 to a 3.54, I use the Abbott box and it worked fine, no problems. You have to do a little fussy math to set a bank of switches using your old and new axle ratios.
When I converted my automatic to a TKO600 standard, they sent me a Dakota Digital Universal Speedometer Signal Interface #SGI-5. It hooked up much like the Abbott box, but it appears to be a newer and more versatile design ... and half the price. You can calibrate it using up and down buttons and any GPS device you have around. Been working fine for a couple of years.
I wasn't trying to be argumentative or anything. I knew what had happened, we talk off the forum, I was just wanting to let the OP know the risks as it pertains to cost -vs- risk and a bird in the hand.
Not at all. I wasn't taking it as an argument, just weighing the options like you said. Truth is, if I was pretty sure I was never going to modify a 96 enough to need to change its calibrations, then I'd probably not recommend it either. OTOH, one set of replacement cats would probably more than pay for the cost of the Jet software (to turn off the downstream O2 testing). It's all just pros and cons.
Originally Posted by 2LZ
I stared at my FSM (War and Peace) for a long time and I THINK I found the correct lead. The VSS has two leads (high and low) that feed into the PCM, The lead I'm chasing is the one that comes out of the PCM that goes to the cruise control, speedo, etc... .
I've identified that lead before, right where the harness plugs into the PCM. It's right where the manual says it is. Not sure if it's better to tap into it there vs under the dash. I'd give that Dakota Digital unit a good look, too. At half the price, it is a lot less painful to experiment with it.
I've identified that lead before, right where the harness plugs into the PCM.
...and that lead is right on top of the black connector. Can't get much easier than that.
I already have the Abbott unit and wired it into that same lead. The speedo lit up but stayed at "0". I thought maybe it was the power I tapped into but no.
In an utter stroke of genius, I hit the "contact us" button on the Abbott website and wouldn't you know, a nice gentleman named Jerry got right back to me.
I told him the VSS wiring in the FSM showed a "high and low". he said the high is the signal I want.
I'll end up tapping into it on the INCOMING side of the PCM and that should do it. Fingers crossed.
Very happy with the immediate email response from Abbott, that's for sure.
Super L98, one of the links that drcook fed me earlier had one of your old posts from 2005. Very informative! Thanks!
...and that lead is right on top of the black connector. Can't get much easier than that.
I already have the Abbott unit and wired it into that same lead. The speedo lit up but stayed at "0". I thought maybe it was the power I tapped into but no.
In an utter stroke of genius, I hit the "contact us" button on the Abbott website and wouldn't you know, a nice gentleman named Jerry got right back to me.
I told him the VSS wiring in the FSM showed a "high and low". he said the high is the signal I want.
I'll end up tapping into it on the INCOMING side of the PCM and that should do it. Fingers crossed.
Ah, okay. So the way it works is that the incoming VSS signal is considered analog, I believe. The PCM uses that to create a true digital signal, and that's what it sends out. So the box is working with the analog signal.
ETA: Yes, that kind of customer service is wonderful but not all that common. Nice to know!
Last edited by MatthewMiller; 01-29-2019 at 08:03 PM.
I got my '96 re-geared (3.54) and can find NO ONE to calibrate it through the ECM, so I'm got one of these.
Any input is appreciated.
You need to get the JET dynamic tuning software and reprogram the car. The tune in the car bases it's shifts off of vehicle speed and the tune has no idea that you changed gears. What that means is that the ****'s will still occur at the same indicated mph as stock (stock rpm) but the car will be goinging slower but mph will read higher. In other words the shift rpm will still happen at the same rpm the only issue is an incorrect mph reading. If you add in the speedometer calibrator without a tune the speedometer will read correctly but the shifts will happen at a higher rpm. This will cause issues, you need to change the tune to fix the speedometer correctly. In JET there is a speedometer recalibrate button that adjusts the speedometer and shift points at the same time.
You need to get the JET dynamic tuning software and reprogram the car. The tune in the car bases it's shifts off of vehicle speed and the tune has no idea that you changed gears. What that means is that the ****'s will still occur at the same indicated mph as stock (stock rpm) but the car will be goinging slower but mph will read higher. In other words the shift rpm will still happen at the same rpm the only issue is an incorrect mph reading. If you add in the speedometer calibrator without a tune the speedometer will read correctly but the shifts will happen at a higher rpm. This will cause issues, you need to change the tune to fix the speedometer correctly. In JET there is a speedometer recalibrate button that adjusts the speedometer and shift points at the same time.
I could be wrong, but I would think that since the OP is changing the frequency of the VSS signal going into the PCM, then the PCM will have the info it needs to set the points correctly. Had he installed this box on the signal coming out of the PCM, then I'd agree that the shift strategy could be a problem. Let's see what the OP says after it's all installed and set up.
I could be wrong, but I would think that since the OP is changing the frequency of the VSS signal going into the PCM, then the PCM will have the info it needs to set the points correctly. Had he installed this box on the signal coming out of the PCM, then I'd agree that the shift strategy could be a problem. Let's see what the OP says after it's all installed and set up.
It will still be wrong, the input signal into the PCM will be modified to read less pulses per mile (lower MPH). The PCM is configured to shift the car at a predetermined MPH, since the stock tune is expecting to shift the car at (Lets say 40 MPH), it will still wait for 40 MPH to complete the shift. The RPM now at 40 MPH will be higher then it was with the stock gear so the shift will occur later or at higher RPM. For example lets say the car had 2.59 gears and now has 3.54 gears the shift RPM will be 3.54/2.59 or 37% higher based on the shift occuring at a speed in the tune. The PCM has no idea what gears are in the car and the PCM is looking for a speed to shift the car at (Really pulses but the pulses are converted to MPH in the tune so it is understandable). Since the speedomenter calibrator modifies the pulses to reflect less pulses or MPH the shift will be delayed until the correct MPH is met and then the shift will occur, that will be at a 37% higher RPM.
At WOT there is a fail safe that shifts the car based on the strategy of whatever condition is met first, so the PCM is looking at MPH and RPM and if the RPM condition is satisfied before the MPH condition is satisfied the car will shift to the next gear.
The best bet is to take Greg up on his offer of $100 to fix this issue.
It will still be wrong, the outut signal into the PCM will be modified to read less pulses per mile (lower MPH). The PCM is configured to shift the car at a predetermined MPH, since the stock tune is expecting to shift the car at (Lets say 40 MPH), it will still wait for 40 MPH to complete the shift. The RPM now at 40 MPH will be higher then it was with the stock gear so the shift will occur later or at higher RPM.
At WOT there is a fail safe that shifts the car based on the strategy of whatever condition is met first, so the PCM is looking at MPH and RPM and if the RPM condition is satisfied before the MPH condition is satisfied the car will shift to the next gear.
The best bet is to take Greg up on his offer of $100 to fix this issue.
2LZ already as the Abbott box, so I guess we'll get some empirical data one way or the other pretty soon.
Not for a 1996, tunercat sold their software to Jet Dynamic tuning software maybe 10 years ago and no longer sells their sofware for OBDII cars to people. If you were a previous customer of tunercat OBDII software before the sale they still support those customers but they won't sell to new customers.
Thanks for all the input guys. All good info.
The funny thing is, even with the speedo WAY off now due to the 3.54's, it still shifts basically the same as it did before. More according to the RPM's as opposed to what the VSS is telling the PCM and speedo.
On easy throttle, it rolls through the gears, maybe a little quicker?? On WFO, it holds the shifts according to the RPM's, not the speedo. It gets way up on the R's on full throttle as it did before, then barks the next gear, just as it always has.
In all honesty, that's why I wasn't to concerned about super-fine tuning and changing shift points. I really didn't notice much difference, if any.
I'll be curious to see how this turns out. The '96 is kind of an odd duck compared to the OBD1 cars.
01-28-2019, 10:12 AM
Abbott Speedo Calibrator
