HaulnA$$

Pin F2 = Trans Input Speed High, Pin F3 = Trans Input Speed Low. They both go directly to the sensor. HTH

dimented24x7

iTrader: (2)

Well, its been over a year, and Ive reversed and commented everything in the $0D hack but the transmission code and formatted it to assemble so it can accept my 16 bit FM MAF code, LS1 MAF, cool fan, and other tweaks. Just have to make it assemble (oh yeah... that should be fun).

Assuming I can get the car running again before hell freezes over, it should be cool to see how it actually works with true MAF fueling and high tech code. Ran ok before with the crappy stock romless ECM, but running like it has a holley carb on it got old fast.

Now that thats said, who wants to do the transmission code and take a little carpel tunnel for the team? Its only a portion of the overall code, like, maybe, 10,000 lines or so... Just a little typing... should be done in no time.

HaulnA$$

I'll take a stab at the tranny code. I have the auto trans stuff running on the bench without throwing a code (most of the time). I know I'm not as proficient at it as you but what a good opportunity to get up to speed. It might take me as long or longer than it took you but I am game.

dimented24x7

iTrader: (2)

As you can probably tell from my above post, I dont expect it to be done overnight by any means. Definatly takes some time to pull it all apart. Also takes some knowledge of how an e-trans is supposed to work. I dont have one, and my knowledge of autos is confined to the old fashioned non-CC trans', so Ive left the code untouched. Ill post the latest when I get it cleaned up.

Fast355

iTrader: (2)

I am looking into starting the 1997-1998 Vortec style PCM when I get more time. It is a project that I am sure will get over my head, quickly!

My modified TPI 305 G10 with the 4L60E runs great using the stock code in it, but I am wanting to do alot with this PCM though.

HaulnA$$

Do you have a disassembly of the .bin? If so is it at least partially commented? What do you know about the hardware platform? How proficient are you at assembly language? Down the road, I might be interested in joining the project if it gets some speed.

Fast355

iTrader: (2)

Unfortunately, I haven't gone farther than having the actual PCM and a cable for tunercats (I just got an unused copy of it). Unfortunately tunercat is very limited in what you can do. I am looking to have a 500+ HP SFI engine running off of the vortec PCM in a few years. I have worked with TBI ecms for the most part. I have not played with the assembly language on the newer stuff. I don't see me getting too far in the imediate future. If I get momentum on the project, you will be the first to hear about it.

dimented24x7

iTrader: (2)

The hardware is one of the sticky points with the newer 32 bit PCMs. Without any knowledge of the hardware, itll be hard to do a reasonable disassembly.

Thats one of the reasons that I want to get the $0D completed. Without this, theres nothing to bridge the gap. Given the radical changes that where in these, Id guess that the mid 90's truck/LT1 PCMs formed the bases for the later vortec and LS1 PCMs. Hopefully, there will be enough similarities to make those first few all important guesses.

HaulnA$$

At least we know it is possible or John at TunerCat would'nt have been able to develop calibration definitions for the pre '99 OBDII stuff. I have looked pretty hard for info on 'em but whoever has it isn't sharing a bit. I have been able to find some info on the LS1 style PCM's but nothing substantial like a commented hack. If a fully commented hack could be developed for both flavors of PCM, the EFI world would be turned upside down. Oh what I would give for the high level decompiler to do it with.

dimented24x7

iTrader: (2)

Alright, here is the finished product. Compiles, and I also fixed a few minor boogers and an error that was in the original mask. Also includes teh BWDM.bin, which was the source for the code. As far as I can tell, its correct.

dimented24x7

iTrader: (2)

Updated version uploaded. Made some changes, commented the error code handling, and fixed a few mistakes that I ran into.

BHall71

Thank you very very much! I usually just lurk (this is actually my first post here) and have received lots and lots of great information. Your dissassembly comes at a perfect time. I've been programming $OD in my 95 silverado for over a year and a half mostly using Tunercats ecm definition and the one out there for tuner pro. I have just recently dived into the $OD hack and found much more valuable stuff than what is listed in the off the shelf ecm definitions.

Once again thank you very much!

Brian

HaulnA$$

Excellent work Adam. Hopefully I can come close to your efforts. Again, congrats!

dimented24x7

iTrader: (2)

Thanks, It definatly took a good deal of work, especially the idle routines. There werent any original comments and the calibration section wasnt of much help. Hopefully some of this will carry to the 32 bit PCMs. Having an LS1 or vortec PCM would be sweet. I think on the code side we'd collectivly have enough info with this and the LT1 stuff to make some good guesses, but who knows about the hardware, or disassembling/decompiling. I guess we'll have to wait until someone spills some of the beans

Right now Im weeding out all the code for the EGR and probably alot of the code that handles IAC flow transitions in the idle routine as I dont have A/C or an automatic. Thats also probably one of the best tests for how good the disassembly is. If it works like you expect it to w/o the code, then its good. If it does something crazy, then you know theres a 'slight' mistake somewhere

Dave Farr

Have a 1989 K1500 with a basically vortec engine, Edelbrock Hiflow base and runners and a 7747 that I haven't been very happy with for some time since switching to Edelbrocks TBI to MPI vortec conversion. Just picked up a LC1 and right know am considering which way to jump as far as computers go- still wanting to retain EGR function. At first I was going with the Megasquirt for fuel and fire and leave the rest to the 7747- now reading with interest with these somewhat newer ecm's and how you guys are getting the wideband to work. The vortec pcm looks very interesting but probably a little more involved than I want to go- I have my eye on a couple ecm's and was wondering what if any is the difference with 8625 vs 7427 of which being a layman would go with the newer 7427- just because. I am not a programmer and pay for that expertise but I can do everyting else.

dimented24x7

iTrader: (2)

Other then the wide band, the PCM can handle MPFI and also has lots of functionality. As far as the wideband goes, getting good wideband control could be difficult. In addition to the fact that processing time is at a premium, the PCM only has an 8-bit A/D converter, which will place some limits on what kind of dynamic range and resolution you can get.

It got alot of other neat hardware updates and add-ons for the e-trans, but the A/D's are the typical type provided with the standard MPUs.

Dave Farr

Yes I suppose it was wishfull thinking and I misread the LM1 as LC1.

dimented24x7

iTrader: (2)

I finally installed the PCM in the car. Works alot better then I thought it would without any tuning. The main issue Im having is the MAF underreporting the airflow. Datalogged frequency looks ok, but a little low. I hope its just the intake configuration and not an issue with the MAF itself. I had to resort to unplugging the MAF to force the PCM into SD mode in order to get the car to not stall when transitioning. Runs at 18-20:1 everywhere with the MAF hooked up and has a hard time idling until the ECM goes into closed loop. After that it runs ok and is even drivable over short distances. Still needs a good deal of tuning, though.

One question I do have is how are you guys handling datalogging? Does someone make a reasonably priced OBD1 cable? I rigged up a two transister 'cable' that works, but its basically just a bunch of parts on a proto board with some wires hooked to it. It would be nice to have a pre-fabbed cable.
----------
Another question, do I have to worry about only having one wire for each injector in the pcms harness? The old ECMs had an extra wire spliced in for each injector.

HaulnA$$

It runs! Awsome! One of these days I'd like to try out your MAF setup. It will be interesting to play with. As for datalogging, I built the MAX232 cable on the TechEdge site. I used an experimenters Proto PC board and cheap plastic case from Ratshack. It has worked flawlessly for more than three years. I've even used it many times to flash the LT-1 PCM's. As for the wiring, it should be fine. The way the trucks are wired, there is one wire for the low side of each injector and the 12V side is a single wire spliced into two. HTH

dimented24x7

iTrader: (2)

Once Im confident that it actually works as it should, Ill probably post the MAF cal. up. Its fairly generic MAF code. Basically, the PCM reads in the frequency through the TOS input (problem if your using a 4l60-E), looks up the flowrate, and calculates the fueling. The MAF read-in is 16-bit with 32-bit code rather then 8-bit, so it should be a little more precise and has better dynamic range then the earlier f-body MAF systems.

As for the cable, I was thinking of trying the USB OBD-1 cable from Moates. It would be nice to have the added flexibility of a USB port rather then a serial as its getting hard to find computers that still have serial ports and arent slow.

Fast355

iTrader: (2)

Great work Dimented

As far as the under-reporting of air flow, check for any type of leak between the TBI and MAF sensor. Out in the field Ford Rangers/Explorers are notorious for the little hard plastic PCV tube coming off the intake elbow, when it does it runs very poorly and pops lean codes. My point is that it doesn't take much of a leak to cause all kinds of problems, especially at or near idle.

What are you using for TCC control for your 700r4?

dimented24x7

iTrader: (2)

I transferred my old tune over to the PCM and tried it out. Definatly was better but it just seemed to get worse and worse as I drove the car. Ran fine but its had a nasty shudder under load ever since I pulled it out of storage. I went to try to restart it today and nothing. No fuel pump, injectors, tach... ignition was totally dead. Pulled out the crap accel module that was in there and put in an old spare from my S-10.

Car didnt feel any different driving down the road. Just to elimate the ignition as the source of my problems I turned onto a stretch of road, stuck it in first, jammed the gas to the floor, and waited for the PCM to transition into PE. Once it finally entered PE, it REALLY took off. Like, holy**** kind of acceleration!!! Ive never felt a car take off so fast before. It even feels like it pulls harder then my friends late model 3000GT VR4. The AFRs are kinda rich out top. It hovers around 11:1 the whole way up in PE, so scaling the entire MAF table wasnt a good idea. Only the low flow rates mustve been off. None the less, it doesnt seem to be slowing it down any. That stupid PE transition routine also has to be disabled. Good for a low output truck hauling 8 imigrants and 6 lawnmowers , bad for a car. The code still needs a few tweaks and some more testing, but that'll have to wait for the subframe connectors. Right now, the back of my trans tunnel and rear subframe rails look like sheet metal raisins from the engine torque and one corner sits several inches lower then the other. If Im not careful, Ill be driving half a car. Literally...

Fast355

iTrader: (2)

That sounds like great news. Just too bad you had to use the 4L60Es speed sensor. I bet it would be possible to use the turbine shaft sensor position for the 4L80E? That way you could run MAF and a 4L60E. I love the way that I can change around the shift-points on the 4L60E and don't want to have to run a piggy back PCM to do it.

As far as the PE goes, change the %TPS for Fast PE to something more reasonable. 85% SUCKS. Drop the regular PE down to 45% or so and the fast down to 65% or so. The BJYM calibration that I started with has a 15 second PE delay on standard PE. At 85% the delay is non-existant. Why GM stuck in the rediculous delay time is beyond my comprehension. Even heavy vans, suburbans, and trucks don't like running in closed loop past about 1/3 throttle.

I actually have an awesome calibration for a LT4 cammed(not the Hot cam, the production one), Dart Iron Eagle 180(Fast Burn style chamber) headed TBI 355 for the standard $OD setup. It pulled a 4,600 lbs 1994 G10 empty shell of a Cargo Van around fast enough to suprise alot of people.

dimented24x7

iTrader: (2)

I think something could be made to work for the turbine inputs, but it would require taking the pulsetrain from the MAF and converting it over to some sort of waveform that can be read in by the turbine input. IIRC, I think the operation of each is equivelent in the code. Currently, the TOS requires no additional hardware and is plug n' play, so I used that. Since I cant use an automatic without replacing my crank, I went ahead and just ran with it. There may also be some issues with running the trans code and MAF code simultaniously. Theres also additional 16 and 32 bit code for the MAF thats kind of intensive processor wise.

Ill post it up so people can modify it as needed. Im sure something can be worked out to get both to work.

Fast355

iTrader: (2)

So the TSS is a square wave input? Never knew that, thought that it was sine-wave like the TOS. If that is the case, it seems easier to convert the TOS signal to square wave, then use that signal for vehicle speed for the transmission. Would keep the fueling more accuate and should still give reasonable accuracy for the transmission.

dimented24x7

iTrader: (2)

The TOS is basically a switched input. There appears to be a +5 volt reference with a pull down resistor there. Ground it, and it triggers the counter and timer capture.

I have no idea what the TSS looks like on the hardware side. Inside the computer, I think its just a pulse accumulator and counter capture like the TOS.

dimented24x7

iTrader: (2)

Heres the MAF version. This should only be used as a reference for future development, since its talored to what I want, which is likely not to be what you would want. Im not sure if both the MAF and e-trans code can be run simultaniously. This PCM is only 2x faster then the C3's and yet its running 8x the code. Another thing is that the accel enrich DC and substitute MAF value for when there is an error are calculated using DRP's based on a V8 engine, so this would have to be changed for a V6. Lastly, the only error checking provided for the MAF is lost signal. I thought of coupling the MAF and SD together, but Im not quite sure how closely they would agree given all the fuel dynamics with a wet flow system. Provided you keep the MAF sensing elements clean, underreporting shouldnt be a problem. As for cleaning, the MAF will definatly need that periodically. With TBI everything collects heavy coats of varnish, so cleanings every six months will be needed. Basically a q-tip, some naphtha, and a steady hand are all thats needed.

Also, the MAF table in there likely wont be a good match, especially at low flows where the flow transitions from turbulent to laminar. This really reduces the rate of heat transfer and causes the MAF to report too little airflow. This can be adjusted in the flow table. I suspect there is also some temperature dependance for when this will hapen, so I also set the BLMs up to be based on flow rather then RPM/MAP so they can correct for error around idle, as well as any error in general.

ben73

Well almost 2 years later I have actually done this!
I have the 0-5v output from my Zeitronix WB connected to the MAT input and have rescaled it so that 14.7 appears as 147F etc etc..

There is a table in the hac that scales the MAT input, all I had to do was change the scaling and it is working.. It still needs some work to tweak the upper and lower ends of the scale, but its accurate from 11.0 to 15.5:1 at the moment. Very happy!

HaulnA$$

Thats great that you got it to work the way you want. If you ever need to use the MAT input for a sensor, you know that you can use the linear EGR input for WB datalogging. It is spelled out earlier in this thread. On my TPI conversion, I have a MAT sensor and WBO2 logging. I'm happy too! Things are getting better and better for the PCM users all the time.

ben73

I had it working on the linear egr input also, but I didn't like doing the egr% - AFR conversion when looking at the trendlines in datamaster. Have you rescaled the EGR to represent EGR?? It would be easy to do it if I was logging with tunerpro, or the new logging softwre that Mark is developing, but doing it in the ECM code is too tricky for me.
I'd really like to do it properly like the $8d guys do, but developing a patch like that is beyond my ability.

Ben.

ben73

Well my car sat for the last year or more while I did other things, but I'm back into it now with fresh enthusiasm and getting reaquainted with the PCM.

HaulnA$$, which pin is the CPI Manifold Tuning Valve/A C Clutch control output on? I have been thru all my notes and drawings and havn't been able to find it
Ben.

HaulnA$$

That would be pin E3. HTH

ben73

Many thanks for that! What is a CPI Manifold Tuning Valve anyhow??
I've never come across that terminology before????

HaulnA$$

Basically it is a solenoid controlled flap in the CPI manifolds that when opened, turns the manifold from a "tuned port" manifold to a "common plenum" manifold. It aids in higher RPM power when opened and low RPM torque when closed, or so the theory goes. HTH

Fast355

iTrader: (2)

It does a good job at it, IMO. I have driven a 1995 CPI 4.3 Astro and an identically equipped 1996 Vortec 4.3 Astro. The CPI motor would clean the Vortecs clock all the way from idle-redline. I think I have mentioned this on Fullsizechevy.com.


I actually put a 4.3 CPI engine into a 1988 S10 Blazer that I had. The little 2-door 2wd version will really fly with a 210 HP CPI 4.3 in it. Mine had some chip work and exhaust.

honken

Is it dc or ground on pin E3.

I have som problem with tunerpro hexeditor and hack compar the adress D3B0 in hack 0062 but hexeditor its 9662
and adress D3BA is 01FC in hack but the 01FC is at D3BB in hexeditor.

BHall71

I have been digging into dimented24x7's $OD hack and have learned & tried many things. My quest of better mileage and performance has lead to some questions for those who are working with this mask. This looks like the place to ask.

I am currently using HaulnA$$'s wide band setup on the EGR pintle position input for data logging with an LC-1. ~Thank you Tom~ I am using Datamaster and am moving decimal places and adding a 1 to the front of the EGR value displayed to get the AFR. (I.E. if it displays 37.10% the AFR is 13.7). This seems to be accurate with what Tunerpro displays on similar data logs.

Problem is that the ECM, which is using the stock NBo2 for readings in closed loop, never seems to reach 14.7 AFR. I know the value should fluctuate above & below but it always fluctuates below/rich even with the BLM’s at or around 128. Of coarse, temperature seems to play a big role in the results but even at 180 deg operating temp (thermostat temp) the AFR is quite a bit below 14.7 (hovering between 14.0 & 13.5AFR). I have tried adjusting “48B4” (target o2 voltage) from the stock 451.39mv down to around 377mv to trick the ECM in to thinking it is rich. I have also tried adjusting “48DD” (Stoich AFR) from 14.7 to 14.9. Both did not seem to work consistently especially with temperature changes. The warmer the temp, the more it seemed to actually do what I wanted, which is to somewhat match my wideband readings. I have exported data to excel & observed areas of idle as well as areas of constant speed & map and averaged the WBo2 reading and the NBo2 voltage readings. All readings were taken with BLM’s at or around 128. One cruise example is a WBo2 average of 14.0 AFR with a NBo2 average voltage of 468.7mv. An idle example is a WBo2 average of 13.18 AFR w/ a NBo2 average voltage of 535.7mv. Is there another table that I need to be looking at or am I going about this all the wrong way? Maybe if lean cruise is possible I don’t need to even worry. The lean cruise would probably solve the drive area but it is also relatively rich at idle too.

Does the $OD have the ability to do a lean cruise? Will researching some of the older ECM's lean cruise capabilities point me in the right direction to get the $OD to do it?

How does the Baro(barometeric pressure reading) value contribute to the code. I know it is a fudged value but what is it for?

Sorry for the novel and thanks for your time.

Brian

Fast355

iTrader: (2)

First let me ask if you are running a Bosch O2 sensor. If so they ALL seem to run rich, but then again that is wise from a marketing stand point. First many cars seem to run better running slightly richer than stoich, its all about customer perception. Also it is safer for an engine to run slightly rich than it is to run slightly lean.

I have found that TBI running with speed density and without a MAT/IAT sensor are very difficult to dial in for weather changes.

Set your O2 constants back to stock, change the command A/F ratio leaner, then unplug your computer from the harness for about 5 minutes as this will clear the BLM tables. Then take it for a drive. I bet it will be closer to what you want after it relearns the BLM cells. 02 sensor temperature has a big part in it as well. Use a good old Delco 3 wire heated 02 sensor and the descrepancy might vanish.

BHall71

hanging my head in shame yep it is either a Bosch or some autozone piece of crap. I will definately get a Delco. Thanks for the reply!

Brian

Fast355

iTrader: (2)

One other thing, where is the sensor located? A one wire in a header may seem to work fine, but in reality it will be too cool to get a good reading. My G20 had problems with the location of the sensor in a stock 1992 G20 Y-pipe. It was way back behind the Y and was an un-heated 1 wire. I changed it over to a 3 wire Delco, it entered closed loop much faster, and idled smoother after sitting at a light for several minutes.

On a side note, I have really started messing with this Mask here in the past few weeks after converting my G20 to the PCM with a MAF sensor.

BHall71

The sensor is a three wire and is located on the header side of the collector on the drivers side. The wide band LC-1 is in the same location on the passenger side. The headers are Hedman long tubes.

I hope you are enjoying $OD, I have been playing with $OD for about two years now and am still not a pro. I am just now getting into messing with the hack. I had been just messing with the basic stuff Tunercat and TunerPro allows to change. I have seen your different setups on your van and admire/appreciate your TBI efforts. You have definately proved many wrong about the HP limit for TBI! Mine is not a thirdgen either but a 95 Silverado extended cab. I am 95Nprogress on Fullsizechevy.com It is a daily driver too. I have read on here the different posts of MAP vs. MAF and at this time I am sticking with MAP. Could you tell me the reasons you went MAF?

Thanks for the info.

Brian

Fast355

iTrader: (2)

I have been messing with $0D for about 2-3 years as well and am far from a pro with it, HEHE. I just now decided to switch my 1983 over to it though. I actually wrote a .ECU file a few years ago from the original Hack, I lost it after a computer crash. I have taken his $0D_MAF .XDF and have expanded it with what I want from his modified hack though.

The reason that I went to MAF is pretty simple and Dimented and I lay it out better in this thread than I could alone.

I switched back to a 700R4 after I self destructed 2 4L60Es with the Weiand. I pulled the Weiand off and had a PCM still under my driverseat that was controlling the 4L60E. I re-wired for the PCM. It was about that time that Dimented posted up that he had a MAF setup running on Modified $OD code using the transmission output shaft speed sensor input. The NEW style free flowing MAF combined with the increased resolution in the code allows for a great MAF combo. The accuracy of the sensor input actually exceeds the capability of the injector drivers and injectors. I picked up the parts that I needed, mostly from a local Junkyard to run the 85mm Mass Air Flow Meter. The main reason that I swapped is that Speed Density is a Royal Pain in the rear. Change the timing, the weather changes, change the engine loading and the VE tables change. With a MAF setup you correct the MAF sensor tables through BLM tuning and that is it. Timing changes, Load changes, etc are now independent from the fueling process. The results werer well worth the trouble. I have chatted with Dimented and am looking for a way to retain the electronic transmission AND have the MAF sensor.

My long term plans are a GM Vortec top-end on my TBI engine using the TBI PCM and the MAF setup.

I also happen to have an engine-less AWD 1995 Astro Van that came with a 4.3 CPI/4L60E/ (Typhoon/Syclone style transfer case), 3.73s, STOCK. I am wanting to do a LT4 cammed Vortec 350 using the MAF sensor, Stock style PCM, keeping the 4L60E, with minimal changes to the wiring. The Astro weighs 4,300 lbs vs. the 5,600 lbs of my G20. It also has AWD, the thing would be a beast on the street with 350 HP.

https://www.thirdgen.org/forums/tbi/...ml#post3113535

dimented24x7

iTrader: (2)

As for the MAF, it may be possible to move it over to the turbine input speed input. Then all youd have to do is re-enable the TOS input in the code and you should be able to use the 4L60-E with the MAF. I dont know what it takes to trigger that input, though.

dimented24x7

iTrader: (2)

Even though SD is more difficult to tune, with MPFI or TPI, its the preferred method. Even the best MAF systems wont quite have the resolution and dynamic range of SD.

With TBI, though, MAF is the way to go. At part throttle/idle, the gas acts as a refrigerant, and cools the intake charge down, sometimes alot. Even on a 90 degree day, my TBI and upper intake are about 40 degrees at idle while the engine is around 220 degrees and the IAT is 140 degrees. This will throw the SD calcs. off because you really have no way of knowing what the intake temps really are. With a dry flow system, the intake air temps can be accuratly estimated from the CTS and MAT readings.

Fast355

iTrader: (2)

I guess we will find out more as the transmission code is disassembled and commented.

I am not in a huge rush to do anything with TBI/MAF/and an electronic transmission though.

I know you mentioned that you had no intent to ever switch due to something about your crankshaft.

I had always thought that the Input/Output sensors put out the same signal. What the DRAC does to them, I do not know. I would think that all that would need to be done is to ground the Turbine Shaft Speed Sensor Low lead to the MAF circuit, put the Signal into the TSSS High, use the TSSS input as the MAF input, then re-enable the Output Shaft read-in. From everything that I have seen it looks like both sensor use a fequency output, just like the MAF sensor.

HaulnA$$

Pin E3 is a current sink. IOW it supplies the ground path for the signal.

As for your hack problems, you are in need of some basic assembly language and hex help. First of all, at single location in the hack, there can only be one byte, like 00 or 62. Two bytes take up two locations. Secondly, at LD3B0 is the command LDAA 0062. This does not mean that at LD3B0 is the value 0062 but rather a command Load Accumulator A with the value at location 0062. If you look at the next line in the hack, it is LD3B2. This means that the command at LD3B0 takes up two bytes, the first byte bieng the command LDAA, 96 in this case and the second byte bieng the location to load accumulator from in single byte form or 62 in this case representing L0062. Some research on assembly language and the Moltorola "Pink Book" may help you out. HTH

HaulnA$$

Both Transmission Input Shaft sensor and the Transmission Output Shaft sensor are reluctor type sensors, however, the TIS signal does not go through the DRAC, it goes directly to the PCM as an AC sine wave reluctor signal. What the DRAC does is two things, first it takes 40 PPR reluctor signal from the VSS (AKA TOS) and turns it into a square wave and then sends it directly to the PCM TOS input, next it then divides the signal by a programmed ratio and sends it to several locations in various forms. A 2000 PPM signal is sent to the PCM for a MPH input for the engine code and a 2000 PPM signal is sent to the speedo. A 4000 PPM signal is sent to the cruise control and a 128000 PPM signal is sent to the RWAL system. Tying the MAF directly into the TIS input may or may not work. It may need to have the signal converted from a DC square wave into an AC sine wave. HTH

HaulnA$$

No thanks necessary but is much appreciated. One other thing to consider is that the fuel you are now running is a winter blend and more than likely contains 10% Ethanol which reduces the Stoich value to approximately 14.2. Changing the stoich value to 14.2 shoulld help. I know when I had my open loop VE's perfect and closed loop BLM's were spot on, when the fuel here changed, I changed the stoich value to 14.2 and everything fell back in line. HTH

P.S. Wish me luck, I am going in for major surgery tomorrow and will be out of commission for a while. Don't do any cool stuff without me.

va454ss

iTrader: (1)

Good luck. Hope you have a speedy recovery.

dimented24x7

iTrader: (2)

The MAFs signal is actually from a switching transister. It briefly grounds the input line to generate its signal. The TOS has a constant +5 volts and a 4.7k resistor in the PCM. As the MAF grounds the input, the voltage at the resistor goes to zero, and it triggers the timer capture and pulse counter.

The TIS input will definatly need some sort of converter. Im wondering if an AC square wave would work instead, and what the triggering thresholds are.

BTW, best of luck in surgery.