Digital Tuning Chip tuning in 2025, what are my options?

[AnthonyA1234]

So I have a HCI car and I’m getting pretty fed up with the idle. No matter how many base idle resets I do and fiddling with timing and idle speeds it just always seems like the car needs to be tuned.

I’d prefer to do a chip since that’s much easier for me than installing a standalone setup. I can’t find much info on chip tuning a stock a9l computer.

What are the options for this? Who should I buy from?

 

[Noobz347]

What are the options for this? Who should I buy from?

Buy from the dyno-tuner that tunes the car.

 

[AeroCoupe]

SCT is what I have on my Coupe and the only way to get a really good tune is to do it on a dyno just as Noobz pointed out.

Finding tuners that still mess with the older ECU’s is a challenge but they are out there. This is the chip I have:

Best Performance Tuners for Vehicles | SCT Products

Take control of your vehicle's performance with SCT's performance tuners and monitors. Unlock hidden horsepower and torque for an exhilarating ride.

sctflash.com

They have a dealer locator and a box you can check for “only custom tuners” but you will still need to call them and see if they will tune your car as some will only do ECU’s they can directly flash i.e. no chip.

SCT Dealer Locator - SCT Performance

Locate SCT Dealers near you. Simply plug in your info to find a convenient SCT dealer in your area.

sctflash.com

I have no idea where in Florida you are so I cannot help narrow down a tuner. I literally put my car on a trailer and drove 4 hours the last time it was tuned but there just are not any tuners here in Oklahoma that have a really good reputation. Texas just has more people so I went to the Dallas area.

 

[2000xp8]

I've seen the mildest to wildest cars idle just fine on the stock computer.
You have a mechanical problem.

 

[AeroCoupe]

@2000xp8 - I will agree with you on that statement but the ECU can only compensate for so much and we do not know what heads, cam, or intake he has on the car and he may even have larger injectors and an aftermarket MAF (OP this is a hint so provide that info).

I have programmed PLC's at manufacturing facilities and if what you are trying to automate is in great shape mechanically and electrically then automating it is easy and it usually works great. These cars are the same in that you need to have all the mechanical and electrical up to snuff so the ECU has a prayer of controlling it. This also holds true for tuning one with a chip or putting a stand alone system on it. The old adage of garbage in garbage out holds true.

 

[AnthonyA1234]

@2000xp8 - I will agree with you on that statement but the ECU can only compensate for so much and we do not know what heads, cam, or intake he has on the car and he may even have larger injectors and an aftermarket MAF (OP this is a hint so provide that info).

I have programmed PLC's at manufacturing facilities and if what you are trying to automate is in great shape mechanically and electrically then automating it is easy and it usually works great. These cars are the same in that you need to have all the mechanical and electrical up to snuff so the ECU has a prayer of controlling it. This also holds true for tuning one with a chip or putting a stand alone system on it. The old adage of garbage in garbage out holds true.

My car always idled ok. What happened is that over the past couple years where I’ve been restoring it and not really daily driving it I’d never drive it with it on maximum AC. Now that I’m daily driving it I notice the car likes to surge and die with the max ac on.

The issue I’m running into is that I raise the idle so that this won’t happen but then my idle with no ac on is way too high.

I’ve replaced every sensor on the car except the BAP, TPS, and VSS so I ordered those three from rock auto and will be changing them out just to have peace of mind that all my sensors are new. After that I also plan on shipping out my ecu to ecu exchange just to have that professionally looked at and fixed if any capacitors are blown. If that doesn’t fix it I’ll probably try out one of those iac adjustment plates to let some more air through.

To answer your questions about my car, I have cobra upper and lower intake, edelbrock performer heads, and from what the previous owner told me (he didn’t know much but he told me this is what the guy he bought it from said it had) X303 camshaft. I also have the stock intake tube with a pro-m calibrated maf for my 24# injectors

 

[Dan02gt]

I used Decipha at efidynotuning.com to tune my car with a Moates Quarterhorse and have been really happy with the results. Getting your's hands on a QH might be difficult though as they went out of business, but now I hear they are back in business so who knows.

My tune is based off of Decipha's A9LV2. For the AC idle issue I added 80 RPMs to the target idle when the AC is on to deal with the issues you are talking about. I also love the real time data logging and sensor reading the QH allows. It makes troubleshooting issues much easier than pulling codes.

 

[AeroCoupe]

When I had the 306 in my Coupe I had HCI with 24 lb/hr injectors and a Pro-M 75mm MAF calibrated for the 24's. Car was tuned by Triangle Speed in Orange, TX by Daniel Pachar (owner & tuner). He got the tune as best as he could but I was running out of air and injector. The 24's were at 100% duty which was horrible for idle being you do not want to run your injectors more than about 90% duty and more like 85%. Daniel suggested that I get a 80mm MAF from a 1996-2000 GT and that would fix my air issue. I got a good deal on some 42 lb/hr injectors from a buddy so I installed those but I will say 30's would have worked fine. Wired the 80mm MAF to the car as follows:

2000 GT MAF harness from PMAS:
Black - Ground
Red - 12V+
White - MAF Signal
Green - MAF Signal Return

1993 5.0 LX Coupe factory harness:
Black - Ground
Red - 12V+
Dark Blue/Orange - MAF Signal
Tan/Light Blue - MAF Signal Return

When you look at the pigtail for the 1996 to 2000 MAF there may be six wires. The outer two are for the IAC that is intergral to the MAF for those years so you can just depin them as you will not need them.

Went back and had the car tuned again and gained 20 hp across the tune and the idle and throttle response was way better. I am by no means telling you that you need to do this but when you get it on the dyno you will for sure know if you are running out of injector or air. I was boarder line and just decided to fix it and be done with it.

 

[Noobz347]

I used Decipha at efidynotuning.com to tune my car with a Moates Quarterhorse and have been really happy with the results. Getting your's hands on a QH might be difficult though as they went out of business, but now I hear they are back in business so who knows.

My tune is based off of Decipha's A9LV2. For the AC idle issue I added 80 RPMs to the target idle when the AC is on to deal with the issues you are talking about. I also love the real time data logging and sensor reading the QH allows. It makes troubleshooting issues much easier than pulling codes.

I think they are back up and running now: https://shop.moates.net/

 

[AnthonyA1234]

When I had the 306 in my Coupe I had HCI with 24 lb/hr injectors and a Pro-M 75mm MAF calibrated for the 24's. Car was tuned by Triangle Speed in Orange, TX by Daniel Pachar (owner & tuner). He got the tune as best as he could but I was running out of air and injector. The 24's were at 100% duty which was horrible for idle being you do not want to run your injectors more than about 90% duty and more like 85%. Daniel suggested that I get a 80mm MAF from a 1996-2000 GT and that would fix my air issue. I got a good deal on some 42 lb/hr injectors from a buddy so I installed those but I will say 30's would have worked fine. Wired the 80mm MAF to the car as follows:

2000 GT MAF harness from PMAS:
Black - Ground
Red - 12V+
White - MAF Signal
Green - MAF Signal Return

1993 5.0 LX Coupe factory harness:
Black - Ground
Red - 12V+
Dark Blue/Orange - MAF Signal
Tan/Light Blue - MAF Signal Return

When you look at the pigtail for the 1996 to 2000 MAF there may be six wires. The outer two are for the IAC that is intergral to the MAF for those years so you can just depin them as you will not need them.

Went back and had the car tuned again and gained 20 hp across the tune and the idle and throttle response was way better. I am by no means telling you that you need to do this but when you get it on the dyno you will for sure know if you are running out of injector or air. I was boarder line and just decided to fix it and be done with it.

Ok that’s good to know I’ll keep that in mind.

 

[AnthonyA1234]

I used Decipha at efidynotuning.com to tune my car with a Moates Quarterhorse and have been really happy with the results. Getting your's hands on a QH might be difficult though as they went out of business, but now I hear they are back in business so who knows.

My tune is based off of Decipha's A9LV2. For the AC idle issue I added 80 RPMs to the target idle when the AC is on to deal with the issues you are talking about. I also love the real time data logging and sensor reading the QH allows. It makes troubleshooting issues much easier than pulling codes.

Can you explain to me how this process went? is there a cable you connect to the quarter horse which then goes to a laptop and then you have a tuning software that allows you to data log for the tuner? Do you need to install a wide band?

 

[Noobz347]

I thought this had already been posted in here but it might have been another thread I was looking at:

Getting Started / EFIDynoTuning

 

[AnthonyA1234]

I spoke to some foxbody guys I follow on Instagram and got recommended thunder auto sports out of boynton beach Florida. I just spoke to them on the phone and they sell the sct chips and will do a custom dyno tune for me. That will definitely be something I do in the near future

 

[2000xp8]

The X cam has been around longer than pretty much any tuning device.
I've had a handful of heads/cams/intakes/Throttle bodies and meters.
One cam i ran on my stock shortblock was really aggressive, idled fine, made a ton up top, very little down low and required notching the pistons with the isky tool. I have never had an idling issue.

If the AC is causing a surge, the system is failing to adapt. Not sure how you tune that out.
Do i know the answer? No, likely a great question for the late Jrichker.

 

[General karthief]

The X cam has been around longer than pretty much any tuning device.
I've had a handful of heads/cams/intakes/Throttle bodies and meters.
One cam i ran on my stock shortblock was really aggressive, idled fine, made a ton up top, very little down low and required notching the pistons with the isky tool. I have never had an idling issue.

If the AC is causing a surge, the system is failing to adapt. Not sure how you tune that out.
Do i know the answer? No, likely a great question for the late Jrichker.

The first thing Joe would suggest is to run codes, should be the.first thing you do anytime, there is a surging idle checklist in the tech threads, Anthony has been here long enough to know where it's at.
Just in case;

Help me create the "Surging Idle Checklist"

Updated 05 July 2022 to add rough idle when cold and smooth idle when up to normal operating temperature. See the EGR tech information, section #15 for more help. Many of you are familiar with the "Cranks OK, but No Start Checklist for Fuel Injected Mustangs" checklist and the No Crank...

www.stangnet.com

Keep in mind the X cam idle will be a little higher than stock.
At low RPMs the computer don't like overlap.

 

[AnthonyA1234]

The first thing Joe would suggest is to run codes, should be the.first thing you do anytime, there is a surging idle checklist in the tech threads, Anthony has been here long enough to know where it's at.
Just in case;

Help me create the "Surging Idle Checklist"

Updated 05 July 2022 to add rough idle when cold and smooth idle when up to normal operating temperature. See the EGR tech information, section #15 for more help. Many of you are familiar with the "Cranks OK, but No Start Checklist for Fuel Injected Mustangs" checklist and the No Crank...

www.stangnet.com

Keep in mind the X cam idle will be a little higher than stock.
At low RPMs the computer don't like overlap.

Yea, I’ve changed every sensor and part in that checklist by now haha. No codes on the computer.

Like I said earlier I ordered the only sensors for the engine remaining that have not been replaced, the TPS, BAP, and VSS. I also just sent out my ecu today to ecuexchange to get looked it and repaired if anything’s wrong.

Once I get all the new parts in if it’s still idling weird I’ll try the IAC adjuster plates that lmr sells and then I’m going to take the car to get dyno tuned at thunder autosports.

As I said the car idles fine no surging or weird stuff it only starts to die on me when I have the ac on and it’s warmed up. It’ll start surging and die at stops or sometimes when I’m coming to a stop and push the clutch in it’ll die while I’m rolling.

One thing I was wondering if any of you guys know in regards to the X cam. Do they like more or less base timing? I’ve been running 14 degrees

 

[AeroCoupe]

If you get it tuned they will want the base timing at 10 degrees, I think you have but if not make sure the cap and rotor are in good condition and fresh plugs never hurt. Make sure the fuel pressure is 39 psi with the vacuum discounted from the FPR and plug the line. Again, tuners can only tune what you bring them.

Have you cleaned the MAF sensor?

 

[AnthonyA1234]

If you get it tuned they will want the base timing at 10 degrees, I think you have but if not make sure the cap and rotor are in good condition and fresh plugs never hurt. Make sure the fuel pressure is 39 psi with the vacuum discounted from the FPR and plug the line. Again, tuners can only tune what you bring them.

Have you cleaned the MAF sensor?

Ok

Yea the maf is brand new pro -m unit

 

[General karthief]

Yea, I’ve changed every sensor and part in that checklist by now haha. No codes on the computer.

Like I said earlier I ordered the only sensors for the engine remaining that have not been replaced, the TPS, BAP, and VSS. I also just sent out my ecu today to ecuexchange to get looked it and repaired if anything’s wrong.

Once I get all the new parts in if it’s still idling weird I’ll try the IAC adjuster plates that lmr sells and then I’m going to take the car to get dyno tuned at thunder autosports.

As I said the car idles fine no surging or weird stuff it only starts to die on me when I have the ac on and it’s warmed up. It’ll start surging and die at stops or sometimes when I’m coming to a stop and push the clutch in it’ll die while I’m rolling.

One thing I was wondering if any of you guys know in regards to the X cam. Do they like more or less base timing? I’ve been running 14 degrees

Instead of standing on my soapbox I'm gonna sit, it's been a day my comment was mostly regurgitation for future reference, like, the new electronic stuff for our old junk is suspect at best, you could very well swap a good, functioning sensor for a faulty 'new' one. New problem, same symptoms, now you have two things to chase, if I change a part and it does not solve the issue, I put the old part back on. Stick the new part back in the box and toss it in a parts bin never to be seen again
Sorry, 'new' electronic part don't give me that 'warm and fuzzy' feeling.
I like the bigger MAF and injectors suggestion more for the air intake standpoint not necessarily for more fuel. Not a big fan of dyno tuning mild HCI mostly because the operator can manipulate stuff that could be a mismatch of parts.
I can go on about how the valve overlap on the X cam can make it hard for the computer to control the engine at low RPMs. They flat, don't, like it!
I'm not a high horse power guy, just wanna have some fun.
I would look at the amount of air this setup needs and see if the intake system is enough,
On the other hand, a tuner could burn a chip (I guess) that will 'work around' the issue.
That's a lot to say when I could of just said 'Idonno'

 

[FastDriver]

SCT chip and/or QH should be all you need. There're idle settings on a stock tune, such as RPM and expected airflow that don't at all match reality once the induction system and cam have been changed. The tables in the computer specifically tell it how much air is moving thru the IAC at idle RPM and how much more to add with A/C, not to mention the stock EEC is told to try to get back to 672RPM.

So, it's pulling timing and air and fighting where your camshaft is comfortable, which is likely around 800 RPM. At base idle the TB is supposed to be set to throttle air below 672 and to allow the IAC to compensate back to the set RPM at something like 20-30% duty cycle, IIRC. Then, because your cam doesn't like it there, you idle the TB set screw up, the engine idles higher than 672, and the EEC commands the IAC to a lower duty cycle and to pull idle timing to try to get back to 672. You add more air, it pulls back. In the end, it cant pull any more timing or reduce IAC DC, and the air you've added finally pushes idle up enough to not only smooth out the cam, but also provide a buffer for extra draw, like from the A/C, P/S, etc... When you switch them on, the computer doesn't try to compensate, because it's already at 900+ RPM, 230+ above what it wants to get to. Whereas, if tuned right, it's base idle RPM should be set when warm to 750, maybe 800, and told how much air mass should flow at that RPM, & the TB & IAC should be adjusted to get the IAC DC in range, and finally, it should be told how much extra DC (air mass) to add when the A/C is switched on. This allows the EEC to properly target RPM and manage timing and air when it gets too far out of range, whether the A/C is on or not.

Anyways, the short story is that the settings are completely off with your combo and no MAF calibration can solve that issue. Get a tune and let the tuner tell you if you need sensors, an EEC overhaul, or anything else.

There's no point in overthinking this or any hardware problems until a tuner changes these settings and either sees dead sensor inputs and/or still can't get the car to idle.