Holley High-ram tuning settings

spencergt66 · Apr 1, 2026

Hey guys

Anyone ever run a holly high ram? I have a 95 gt with a MS PNP3 Pro having a heck of a time getting this thing to function or even idle worth a crap. im Running the following ad on's

Holly High ram intake
Dual sync distributor
AMP DBW
AMP wide band with bosch sensor
PNP 3 pro
LS style 90mm throttle body 6 wire
AFR 190 heads
Stock Bottom end
Ford racing X 303 cam
1.6 roller rockers
MSA 6A ignition box

My vacuum isnt the best but just trying to get the thing to idle decently for more then a min has been a chore.... The thing seems to run super rich and has been fouling plugs as i try to get it dialed

spencergt66 · Apr 15, 2026

Maybe im being to vague, so let me ask this. Is there anyone running a large cam 280ish advertised duration with a VE table for example to compare to?

X-cam34 · Apr 15, 2026

Can you drop your .msq and a data log of the car at idle for at least 3-4 minutes?

spencergt66 · Apr 15, 2026

Ill have to look for the data log I thought I had it on my work laptop but maybe not im out traveling for work for the time being

X-cam34 · Apr 15, 2026

What injectors are actually installed — brand and flow rate (lb/hr or cc/min), and what fuel pressure are they rated at?

The tune export doesn’t show a direct injector part number; the ReqFuel value only suggests roughly 19 lb/hr / ~200 cc/min, but that needs to be verified against the actual hardware.

What does the wideband read at idle once the engine is fully warm? Is it pegged rich (10–11 AFR) or bouncing around?

A couple things stand out in the tune:

- EGO minimum RPM is 1300, so closed-loop O2 correction will never activate at idle if the engine is below that. With a cammed combo, I’d usually start around 500–600 RPM.
- It’s also worth checking injector dead time/offset. Wrong dead time can make idle and cranking rich even if injector size is correct.
- FC delay is 1.0s; if decel fuel cut recovery feels lazy, 0.5s may help, but that’s secondary compared with injector size, dead time, and idle fueling.

For reference on your 5.0:
- 19 lb/hr → ~20.8 ms
- 24 lb/hr → ~16.5 ms
- 30 lb/hr → ~13.2 ms
- 36 lb/hr → ~11.0 ms

So if anything larger than stock 19s is in there, the current ReqFuel is likely too high and will push the tune rich.

spencergt66 · Apr 16, 2026

X-cam34 said:
What injectors are actually installed — brand and flow rate (lb/hr or cc/min), and what fuel pressure are they rated at?

The tune export doesn’t show a direct injector part number; the ReqFuel value only suggests roughly 19 lb/hr / ~200 cc/min, but that needs to be verified against the actual hardware.

What does the wideband read at idle once the engine is fully warm? Is it pegged rich (10–11 AFR) or bouncing around?

A couple things stand out in the tune:

- EGO minimum RPM is 1300, so closed-loop O2 correction will never activate at idle if the engine is below that. With a cammed combo, I’d usually start around 500–600 RPM.
- It’s also worth checking injector dead time/offset. Wrong dead time can make idle and cranking rich even if injector size is correct.
- FC delay is 1.0s; if decel fuel cut recovery feels lazy, 0.5s may help, but that’s secondary compared with injector size, dead time, and idle fueling.

For reference on your 5.0:
- 19 lb/hr → ~20.8 ms
- 24 lb/hr → ~16.5 ms
- 30 lb/hr → ~13.2 ms
- 36 lb/hr → ~11.0 ms

So if anything larger than stock 19s is in there, the current ReqFuel is likely too high and will push the tune rich.

Still running the Stock injectors for now as far as the AFR the wideband is not real steady and ususly sticks to the lean side maxing it out 22:1 but for sure this is not the case as the plugs are just completly blcak and fouled. Ive seen it though where if the system is too rich the O2 still will read lean.

As far as idling for 3-4 minuets, cant even get there I get 1-2 minuets at best then the car seems to just flame out. Im not all too crazy about the Holley dual sync with only the the 8 toothed wheel I ordered a 36-1 setup Im going to switch too once i get back home but I think this is only maybe just some of the issue I have.

X-cam34 · Apr 16, 2026

Wideband pegging 22:1 while the plugs come out black means the sensor is lying, not the fueling. A Bosch LSU that's been soaked in raw fuel from running pig-rich will often read pegged lean as it dies — once the sensing element gets contaminated, it's cooked. Pull it, do a free-air cal, and if it still behaves like that, replace it before you tune anything else. You can't tune fuel off a sensor you don't trust, and narrowband logic (rich looks lean) doesn't apply to a functioning wideband — a healthy LSU reads true across the whole range.

Stock 19s with ReqFuel in that same range should put the base math in the ballpark, so if plugs are fouling that fast, something is adding fuel on top of the VE table. Check in this order:

- Injector dead times at actual battery voltage — wrong offset dumps a ton of error at small idle pulse widths
- ASE (after-start enrichment) — make sure it tapers and isn't stuck active
- WUE curve — should be at 100% by operating temp, not still adding
- Cranking PW and priming pulse — excessive either one floods it on start
- MAT/CLT sensor calibration — if MS thinks it's colder than it is, it'll keep enriching

On the flameout at 1–2 minutes: Holley dual sync in 8-tooth mode has a reputation for trigger dropouts. Get the 36-1 swap in before chasing the fueling any further — if sync is intermittently dropping, you'll chase ghosts.

When you get back home, a cold-start datalog through to the flameout would help a lot. Need RPM, MAP, MAT, CLT, AFR, pulse width, and whatever MS3 exposes for sync/trigger error counters.

One other thing — if it's been running rich enough to foul plugs repeatedly, keep an eye on your oil level and look at it on the dipstick. Cylinder washdown and fuel-diluted oil is real and it'll smoke a bearing in a hurry.

spencergt66 · Apr 28, 2026

OK so for sure the 02 had gone with the sensor sitting in free air it would still read 18.8 and start to drop from there I put in a new sensor along with the 36/1 CS pu car runs better but miles off still. I changed the plugs again checked the compression while i was there and sitting around 140 but still runs fattttttt.

Still dont seem to be hitting on all 8 car cant hit target idle and wil not rev Ive checked the timing again or refecrenc and signals from the cam and to the ignition module nothing seems to be missing but the RPM dont want to go much past 600 and the timing light seems to work intermitantly possiblyt due to the low RPM. Slight step in the right direction but not the results i was hoping for.

When I first got the car put back togather I had an AMP150 ignition module but with the key on before I even started the car that thing went up in smoke I thought I had something hooked up incorrect but I checked all the connections and replaced the module with a MSD 6A and still pretty much at square 1

spencergt66 · Apr 28, 2026

cam phase pole and ignition input

X-cam34 · Apr 29, 2026

dude I do not know why I didn't see it before you have a Boost tune loaded and you are N/A that is your entire issue....

Code:

Holly High ram intake
Dual sync distributor
AMP DBW
AMP wide band with bosch sensor
PNP 3 pro
LS style 90mm throttle body 6 wire 
AFR 190 heads 
Stock Bottom end
Ford racing X 303 cam 
1.6 roller rockers
MSA 6A ignition box

Direct .msq downloads (FW 1.5.2):

94-95 Mustang GT/Cobra 5.0L — Batch Fuel:https://www.megasquirtpnp.com/downloads/basemaps/fw_pro_152/dlmap.php?dlfn=9495_5.0_Batch_1.5.2.msq

94-95 Mustang GT/Cobra 5.0L — Sequential Fuel:https://www.megasquirtpnp.com/downl.../dlmap.php?dlfn=9495_5.0_Sequential_1.5.2.msq

(Foxbody if anyone else needs it: https://www.megasquirtpnp.com/downloads/basemaps/fw_pro_152/dlmap.php?dlfn=Foxbody 5.0 1.5.2.msq)

Index page (for context / other applications):https://www.megasquirtpnp.com/mspnpp_maps.php

Install/setup guide:https://diyautotune.com/blogs/installation-guides/megasquirt-your-foxbody-mustang-5-0

When you load the base map, don’t just start the car on it. You need to copy some things from your current setup before turning the key because the base tune is made for stock hardware, and you have changes everywhere.

- **Injector deadtime curve**: Load the Ford 19 lb/hr stock curve. Your current row-0 values are already correct. You can copy that table over before you erase the old tune.

- **Wideband config**: Set the input channel and the AMP/Bosch sensor calibration so your AFR reading is accurate.

- **Trigger setup**: The base map assumes stock TFI/PIP. You need to change it to dual wheel with a missing tooth, 36 teeth, 1 missing, cam input, and your trigger angle/offset.

- **MAP sensor calibration**: Check what sensor is physically on the car (1-bar vs 2.5-bar vs 4-bar) and set map0/mapmax accordingly.

- **CLT and IAT thermistor calibration**: Use TunerStudio's thermistor calibration tool for both sensors.

- **TPS calibration**: In the Tools menu, set the closed and full throttle ADC values with your AMP DBW.

- **Fuel pump, fan, and AC outputs**: Make sure the output pin assignments match your harness.

- **ReqFuel**: Confirm the math for your actual injector size (19 lb/hr stock, but check the value the base tune shows).

- **Idle valve configuration**: The base map has an idle valve type set. If you’re running the AMP DBW for idle instead of an IAC, that needs to be changed.

Set fixed timing to 20° after loading it and check with a timing light against TunerStudio before you trust the trigger. Then go ahead.

spencergt66 · Apr 29, 2026

- **MAP sensor calibration**: Check what sensor is physically on the car (1-bar vs 2.5-bar vs 4-bar) and set map0/mapmax accordingly.

I was actually looking into this and 94/95 mustang does not have a Map sensor installed I was told that this is done from the OEM with the MAF? not 100% sure But I see I can also just turn this of and have the internal MAP sensor do the same job basically the PNP 3 pro has a 4 BAR internal MAP sensor so that all I have from what I can tell if that dont work Ill recheck some firmware to make sure I have this set correctly

X-cam34 · Apr 29, 2026

https://diyautotune.com/blogs/tech-corner/megasquirt-efi-tuning
===========================================================

You're right, there's no factory MAP on the 94-95. The MSPNP-Pro completely replaces the MAF with an internal 4-bar MAP sensor. Just be sure you hook up the vacuum line from the intake manifold to the ECU, JP4 is on INT, and the MAP is calibrated at 4-bar in TunerStudio

=====================================================================

On the internal 4-bar MAP sensor replacing the MAF:

"Since the MSPNP calculates engine load using a MAP sensor, the air flow meter is no longer needed. While not necessary, it is recommended to remove the AFM for a small performance increase."

Click to expand...
On JP4 MAP sensor selection:

"JP4 selects which MAP sensor will be used. The default setting, labeled INT, uses the internal 4-bar MAP sensor. Move the jumper to the EXT position to use a MAP sensor that is wired to the rear options connector."

Click to expand...

jumper to the EXT position to use a MAP sensor that is wired to the rear options connector."

Both are at:

https://ampenginemanagement.com/blogs/mspnp-pro-documentation/pro-eec4b8-installation

spencergt66 · May 9, 2026

Ive about had it with this dam thing... no matter what I try it runs or kind of runs the same....

I did find that 2 injectors were stuck one on each bank so I just replaced them all with a new set and again another set of spark plugs thinking for sure this was my issue but no. still dosent want to clean up still nasty rich wont rev wont hit target rpm... About 5-600 is all it will do.

X-cam34 · May 9, 2026

You started over with new Base tune? if not you will never get the car going. An N/A car will never go over 100 KPA ...

spencergt66 · May 9, 2026

X-cam34 said:
You started over with new Base tune? if not you will never get the car going. An N/A car will never go over 100 KPA ...

Yes

X-cam34 · May 9, 2026

Send over your latest .msq

spencergt66 · May 9, 2026

Attached

X-cam34 · May 9, 2026

Alright made a few changes see how this treats you.

X-cam34 · May 9, 2026

sorry the ve table was not scaled correct here you are.

spencergt66 · May 9, 2026

X-cam34 said:
sorry the ve table was not scaled correct here you are.

O cool ill try that tonight or tomorrow had to push it outside to many other things needing some maintenance

Holley High-ram tuning settings

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