A9L vs. A9P computer on a Manual Transmission Foxbody Mustang
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- čas přidán 10. 02. 2020
- This video shows the differences between the A9L and A9P computers for a Foxbody Mustang. The A9P was the common computer for a Mass Air Mustang with an AOD Automatic Transmission. The A9L was the common computer for a Mass Air Mustang with a T5 Manual Transmission.
Often when swapping a mustang from auto to manual, people leave the factory auto computer installed. Some owners report that after performing this swap, they have issues with stalling coming to stop lights. Others claim there is a performance benefit to running the auto computer with a manual transmission. Who's right? Watch to find out.
Spreadsheet Link: drive.google.com/file/d/12-6w...
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Awesome analysis! Thanks for taking the time.
We’ve always wondered, Now we know.
Good pull Bud
Great information and content, very informative and interesting to say the least. I have a 33 year old car and only now I'm figuring out information on the computer, lol. Thanks for the lesson I appreciate it. I have been subbed to your channel from about the 400 people range..
💯🔥👊
Thank you! Super helpful and very informative
youre so rad -many thanks for the information
Appreciate the support. And please help spread the word. We are trying to get to 1000 subs by the end of the year. We only need about 100 more.
Thanks for the knowledge.
Always happy to assist. Let us know if you have any ideas for future video topics or need assistance in a particular area of your tune.
Awesome video, and thanks for sharing your knowledge. This must have taken some time. I will for shure be looking for a A9L for my project now(passing the A9P I bought to someone else). Thanks!
Awesome video thanks for the knowledge,and all this time I been running A9p.i been on the look out for a A9L it has been killing me on everything.
Thank you for this informative video and the reference spreadsheet. For those of us with both A9L / A9P available your analysis clears up a lot of the "what is the impact?" when we compare the two factory tunes. Basically turning data into information.
Glad it was helpful!
You the man. Thank you.
Brilliant video, and deep dive! Thank you!! Can you reprogram an automatic computer with manual values, so that it performs as a manual computer?
Yes. You can run the gufb strategy (which is for manual transmission vehicles) using the auto computers like A9P.
Love me some Fox-body content!!
Tyler I should mention. If you use the Core Tuning database for the GUFx series strategies you can compare the differences between A9P and A9L within BE. Nice video by the way!!
Thanks Clint. I sure feel important. No sarcasm. The dude, himself, has arrived! Lol. At some point we need to link up. I’ve got some ideas I’d like to run by you.
No problem anytime.
But Clint isn’t that like cheating? Lol
@@LeechMotorsportsnope. Lol BE can compare all kinds of different strategies. Makes it nice. You can even copy from different strategies.
I wonder how this same thing applies to a 4 cyl mustang. I have a 89 auto car that i haven't fully dug into yet but i believe something is wrong with the ecu and is causing the iac to hang wide open even after countless adjustments and going through reseting etc. I found a t5 ecu for dirt cheap im thinking about swapping in
Answer me this someone please, I picked up a auto 89 foxbody. Guy swapped it with a 5 speed. Had the wrong o2 harness and trans harness. So I ended up swapping everything over. I couldn’t really find a true answer to this but I was told if I cut the wire going to the neutral safety switch that sends like 5volts to pin 46 I could run a a9l. So I’m running everything as if it was a 5 speed harness besides the actual main harness under the dash. All I did was cut the wire that sends the 5 volt signal and grounded that to pin 46. If not it burns up that pin 46 and I get power to all my sensors when it should be grounded. Which led my car to a no start and over flooding issue
Keep in mind that the auto vs stick HEGO wiring harness is different. If you do not swap them or re pin the harness you will fry a couple traces inside the PCM. You can google this and fin out the pins that need to be re pined.
I actually thought about that after making this video. I may make a new video specifically about that, as it seems to come up a lot.
Yes, make that video pls. I think that's what happened to my car. 1990 Lx 5.0 5 speed with an A9P cpu. It does out all of a sudden and I'm getting no spark now. I've changed the usual suspects, Distributor, tfi, cap n rotor, plugs, wires, coil, and still nothing.
It died out all of a sudden*
Amazing video to the situation I find myself in! My 89 5speed has a 8LD and it just fried, would you know if a A9L would be a good replacement?
Great video. Haha. The old myth I remembered hearing was the auto computer had more agreesive timing. Nothing else...
Thanks. Yeah it’s that damned fine print that’ll get ya. lol
So could a A9P be tuned to work better with a manual? I have a 89' Bronco that was A9P swapped and then we changed to ZF5 manual trans afterwards. It's only real qwirk is cold idle. It doesn't like idling for the 1st couple minutes. I always thought it had more to do with the displacement difference.
Yes
This had just enough information to clean up my tune on my manual swapped Lincoln Navigator. I pulled my "manual" values from the 2000 Mustang SVT R that has a similar engine. I've still got to figure out how to wire in a clutch sensor though. If you would happen to know anyone that has access to SVT R ECU info I could really benefit.
Just a question .Will the 1/4 horse work with a the 5.4 computer
We aren’t big mod motor guys. Hit up Ben Head at Core Tuning or look at the fire tuning.net website where they list all of the vehicle strategies in their database. That page will show you if it’s supported and weather you will use a quarterhorse or a mongoose to connect from laptop to ecu.
My 92 coupe is a bit of a basket case so bear with me. Originally a 4 banger manual car that was converted to a 5.0 AOD. It also has a speed density computer of which I’m not sure what year maf ones began. My question is being that the engine is stock other than headers (shorties) and an E fan upgrade, will a maf conversion net some benefit and what ECM would be ideal?
It is has a stock long block and injectors, it should run how fire intended it to… without needing a mass air swap or a custom tune.
Did a t5 swap on a 88 gt it has a mass air retrofitted and it had a A9t computer the some kind of tuner chip and it dies when comes to a stop what do you think is going on kinda driving me nuts
It’s likely going to be either an issue with the dashpot settings in the tune, the idle air coming through the throttle body, faulty idle air valve, or a failed vss sensor or neutral safety switch setup preventing the car from entering idle speed control mode.
I have a 93 lx AOD transmission, can I install an A9L and will it work correctly? Thank you
At a bare minimum you would need to modify the pins on the oxygen sensor harness before installing the a9l. Otherwise you will fry the ECU.
@@LeechMotorsports Thanks, my fox was a 4 cylinder and I'm doing 5.0 but it had no harness.
I am about to buy tomorrow a harness of a standard fox and ecu A9L 1990. I have the doubt if I should also change the pins of the oxygen sensors?
My 1990 Mustang GT (manual) has an A9P and my capacitors for the fuel pump just crapped out. Do you recommend fixing them or just getting the whole thing replaced?
If the capacitors are the problem, they are very cheap to buy. I’m not very skilled with a soldering iron, so a buddy (Sean O’Hagan at Midwest Motorsports) does that work for me. If you can solder, you can do this for under $10.
@@LeechMotorsports I’ll look into it, thank you! I have zero experience soldering so I’ll have to look for someone to do it for me. Only reason I asked about replacing the whole thing is because it’s a 30 year old computer so I thought having a “fresh” one would be beneficial in the long run.
Hey man is there a website that you can go to that can give you a whole freaking list of different computers ecms and all the functions exactly what you're talking about you probably already answered this question s it would make it very handy for me and clarify a lot of things lol without having to pester you but I really do need your help cuz hopefully one way or another this will get done conversion from my F-150 computer to a mustang computer so it'll be a must truck 150 lol
mind blown, great video. so now i have a question. are the a9L and a9p ecms the same hardware? if yes, is there any reason that a9L firmware or strategy can't be flashed to a a9p ecm? i ask because i have a t5 swap in progress and also adding a 351W, so i will need a tune anyway. thanks!
Great question. You can absolutely put a A9L/GUFB tune on an A9P computer. I’ve been running my stick shift turbo car this way for a few years. Keep your existing computer and o2 harness. Just make sure that during the swap, you wire up the neutral safety switch. You’ll also need to make sure your vehicle speed sensor is working correctly. It’s possible you could have one that’s gone bad and not really notice it with an auto in the car. But you’ll need it functioning correctly to get the idle logic to work how it should with the manual trans. Let me know when you’re ready and we can get a base tune out together for your car. Email Matt@LeechMotorsports.com with the build details.
Is an 8LD for MAF? I've read that it's the Cali version.
Yes. The 8LD is a maf-based fox body ecu running on the GUFA strategy.
Just got my qh and all the applicable tools. The backend makes a lot of sense, because by trade, I'm a developer. You are describing my scenario exactly, I built my engine last year and then discovered that I had an a9p ecu. I don't think there is any reason that I can't simply just replace those values on my a9p ecu correct and updated it accordingly?
Yeah man. Just load up the gufb strategy and A9L calibration and adjust from there.
@@LeechMotorsports so don’t even mess with modify the ap9 and guf1 files to match the A9l setup, simply just use the a9l and gufb and base mine tune off those? I’ll probably need to check and see if the bonehead before me did the swap correctly. I’ve been need dee in rebuilding the car since I bought it, I haven’t really dug into the wiring tranny side.
Correct. If you try to just mimic the settings of the A9L, you will find a few key areas where things aren’t the same. The logic is slightly different, and it won’t be possible to create the same settings in guf1.
Awesome, thanks brother. I tried tunerpro and the a9l2 first with gufx and oddly enough as it may sound, I just didn’t like it. It’s supposed to be easier to use, but I don’t think it gave me the detail I wanted. I prefer to start from scratch and tweak myself to see progression. Thanks for the quick reply as well.
I agree. Decipha knows his shit, but you really have to take the time to understand each change or you will still have crappy results. That said, I feel that he was the single most important source of information that gave me the confidence to start tuning my own stuff 4 years ago. I will forever be grateful for the pioneers that share information. Jrichker, Tmoss, and many others among them. Thank you.
If I get a A9L do you tune them or chipped them ??
Absolutely. We provide remote tuning services on many vehicles with A9L using a Moates QuarterHorse. Message us on our Facebook page for Leech Motorsports with info about your build and we can make some recommendations for you.
Would using a a9l computer on an AOD car be of any benefit?
No. Since the top end fuel and timing is the same for both, the car is going to be virtually identical in a race. And there’s nothing you’ll really gain in terms of better drivability either. I’d say stick with what you got.
@@LeechMotorsportsHello , I have an 88 Coupe California car 8LF computer. It's a t5 swap . It runs good on its computer. I have a an A9L , would I benefit from swapping it? Do I hae to repin it? Thank you for your time
I have a 90GT 5spd and my A3M computer got corroded beyond repair. Can I replace it with a A9L or any ECU that came from my gen manual trans or do I need to use the A3M it came with? Also should I buy used or rebuilt from Ebay or from AutoZone or another parts store?
Are you running a chip, or just running straight off the computer?
@@LeechMotorsports I have a old Diablo Motorsports chip I had custom tuned years ago, not sure if it still works. I had my car parked for about 10 years (parked running) but electrolysis ruined my old A3M ecu
You should be fine using an A9L in place of the A3M.
@@LeechMotorsports Awesome and thank you for replying!
Great videos, question on the AL9 ECU I’m swapping in a 95 5.0 into my Falcon and it haves 2 switches on the clutch pedal. One is safety start switch and the other when wires are traces go to neutral interface on ECU pin# 30. So I need to put this switch back in for the ECU to know when clutch is in? Will in cause any running issues? Thanks for your time and hope to get this swap done. It’s there anything I should make sure I hook up to help drivability? I’m using the T5 also so I will have the VSS hooked up also.
What harness, distributor, tfi module are you running? There are differences between what a 95 engine setup had and the fox era stuff.
@@LeechMotorsports I’m running the 95 wiring harness from the car. The motor and trans is also from same car. Only thing I did was to swap out bellhousing and tranny input shaft to 93 and earlier since the 95 was longer making bell housing hit fire wall and a host of other small things. As to the clutch switches one switch has 2 sets of wires. One set is to the for the safety start with the white with red strip on it. The other set is to the nutreul interface pin 30
@@LeechMotorsports finishing off last reply. The wire going to pin 30 is light blue with yellow strip. The wire the switch connects it to is gray/red and goes to pin 46 which is power for most of engines sensors and also runs to data link. The trans does not have a neutral switch. The other switch has a generic red wire and a green wire. I was thinking it had to do something with cruise control? So motor would not tee out of control if clutch is pushed in while in CC?
There is nothing in the wire diagrams and hope you can help or at least let me know if they will effect engine.
On a different note what do I need so I can or pay you to change cooling fan on off temps. I’m running the CCM from the car to run fans fuel pump AC when I put it in. That is one of the big changes from the 93 and earlier foe body’s. They put all the relays in one little 2” by 3” box. Hope you can help and appreciate your knowledge on these 5.0 motors hope to work with you soon. If you want to talk by email I can send you pictures of the clutch pedal switch since I have them pulled out of car.
@@LeechMotorsports is this something you have a ldea about or you only 93 and older fox body? 95 was last year of the 5.0 and know they moved the TFI module away from dist and I believe the maf is also different but other than that they seem identical. Thanks for any knowledge you can throw my way.
Disagree on the rev limit, unless you have heads cam and intake (and I mean good heads not iron junk) 6100 is plenty, even with bolt ons a stock head/cam car is gonna peak out at like 5k maybe 5200... 6100 is plenty, 7k is pretty ridiculous actually for anything close to factory, heck I have AFRs, aftermarket intake etc and I have mine at 6100, I shift at 5700-5900, rarely hit the limiter. Good channel tho, I subbed... rare to see another moates guy
I’m definitely not a big fan of winding out a stock bottom end 302 car past about 6k. Some guys do it with great success, but I’m just not convinced they’ll reliably hold much more than that. Again, it’s been done on a stock block, but with good zero balance deal. Lots o of machine work.
@@LeechMotorsports So we agree, 6100 is plenty? :P
Ummm.....cast iron heads are not necessarily junk.
Ask my buddies in Stock Eliminator class.
12 second and under in the quarter
At about 6,500/7,000 rpm.
And they are prohibited from doing any mods to the heads. No porting, no valve changes.
Sir I have questions. The person who tuned my car actually changed my pcm. Saying things about performance improvements. Everything you just explained is happening to my car. Can I change the pcm back to a A9L with the chip I have already
What physical ecu and chip are in the car?
There will be noticeable performance improvements between those computers. That’s an old myth. There’s a few spots in the timing table with a 0 - 2 degree difference in timing, but that’s just at part throttle. Full throttle timing still follows the same curve and stops at 26 degrees total at 5k rpms.
I still have the idle issue at stop lights. It will go up and down. Or when I idle for a period of time it will shut off.
@@alexgarza2759 this is a tuning issue.
Moving to the A9L/stick shift logic is the first step. But even with that logic, you’ll need to make a bunch of corrections in the turn to get everything dialed in. And that may be in combination with throttle stop screw adjustment as well.
Great video, I learned a lot!! I have a 90 LX, originally an auto, that has been converted to manual, still running the A9P it came with. I have an A3M I could put in it, but what do I need to do to make it work with the 90 harness. Would you happen to know? I've heard you can burn up the computer if you're not careful. Is it even worth it, or should I look for an A9L, or just stick with the A9P? Thanks!!!
The issue you are describing is burning a tracer on the computer due to an improper match between computer and oxygen sensor harness. Do you have a quarterhorse chip on your setup already, or just trying to run directly off a stock computer with no custom tune?
So I have an 88 which was a speed density car I switched to mass air and installed a A9P I have a manual T.
I did have a quarterhorse tune and dino. So was this most likely corrected in the quarterhorse tune? Just wondering because I have always had idle issues and it seems slow to respond from idle when the throttle is jammed quickly. Big hesitation or delay.
Your knowledge is amazing! really appreciate your videos.
It really sounds to me that it just wasn’t ever properly tuned for drivability. The tuner may not have even started from the manual transmission strategy on your car.
Muscle mustangs and fast fords always said that @the a9p would produce marginally better performance “
I don’t really agree with that. As I mentioned in the video, the WOT spark and fuel are the same with both cars so I really don’t see a reason one would be faster than the other. The real differences to me are just in terms of driveability.
I don’t really agree with there statement either but that’s what they allways said
Do you know anyone who can repair a a9l ecu
I do not. But search around on Facebook groups. There are people all around that swap these. What specifically is wrong with yours?
The Leech I need these capacitors replaced!
Timothy Williams if it’s just the capacitors, you can take it to anyone that does electrical work as long as you supply the proper replacement caps. It’s when you start burning other parts that the repairs are more specialized.
The Leech ok thanks sir!
There is a guy on Facebook named Josh Popper (and many other I bet) who will repair these for (I think) abotu $100. Search his name.
It really doesn't make a difference if you tune- you can close the gaps on all the differences if you can figure them all out (except for the missing sclars/functions/tables that may not be in both EEC's). I have A9L-like numbers in my A9P-based tunes. Just so happenned to have an actual A9P box so I went with it lol
Totally agree. I’m still running an A9P computer in my car. But running an A9L calibration off that hardware.
No issues with the auto puter and 5-speed but a new Holley or MS is worlds better.
Not making an argument for or against using stock computers vs other things, for some applications, the stock computer is ABSOLUTELY inadequate. But for most, it will work just fine in the hands of the right tuner. I’ve not tuned a small block ford yet that hit a limit here. This video is simply to discuss the differences in the two stock strategies. Tell me more about your setup. Are you running the Holley or MS currently? If so, what about them do you feel gives you an edge over what the stock computer was capable of? This is good discussion for others.
@@LeechMotorsports I see a lot of people saying the same thing because the standalones are more "dummy proof" than actually diving into your own computer. I agree, not many reasons to go standalone unless you don't feel like learning. And if MS is Megasquirt, there is no advantage to that over Binary Editor/Quarterhorse IMO (I've used both)
Just my opinions, of course!
OBD 1 vs 2 plus most 35 year old harnesses are trashed. If your car is stock and works great then that’s fine but any mods and the Holley is easier. Your tuning intelligence doesn’t matter, 1970’s tech vs 2000’s tech.
Tuning intelligence aside, the sophistication of the logic in the stock “30+ year old tech” is in many ways vastly superior to that of anything holley efi has ever made. And that superiority is within the feature set that yields optimal drivability for average street driven fox bodies. Not race cars. I will stand firm in my position here until MS or Holley can prove otherwise.
Trust me guys everybody this guy speaking the gospel truth I currently at the moment not much longer have I'm in the way he is discussing this to me I'm pretty sure it's an automatic computer yes like you said I do feel a very very slight mid-range torque variant but a big butt here the vehicle has a very aggravating dead spot in the throttle right at idle which is fine this is going to be changed soon I'm just letting everybody know if I had that option at the time I had no other choice I had to get a computer to get it up the side of the road real tall would have no more wheels on my truck lol or something so I got what I could and it's not the best but it is a very temporarily patch to get you by pretty short while so listen to this guy I sure as hell am I notice this guy knows his crap
Great vid! How does a A9S compare? Have any experience with the stock values on them?
Havent really noticed any difference from A9L that what we tune it as if it were. If you look at our social medias my blue LX hatch is factory California A9S car.