No boost need help!

[Ryanjohn]

So, bought the car a few days ago and it has an on3 70mm kit. 24lb injectors, roller rocker arms, comp cam, 255 walboro, a gm 3 bar map sensor, car is tuned on megasquirt and an aftermarket fuel pressure regulator. Car runs very well. However once it goes to make positive pressure it breaks up really bad. Car has sat for a bit and has a set of spark plugs that are very old. Hopefully the issue is bad plugs. Other than that I don’t know what it could be….gunna start with the plugs and go from there. Any input would be great!

 

[07GtS197]

Have you verified you’re getting enough fuel pressure under load?

 

[95opal]

24# seem really small for a combo like that. Have you looked at datalogs when this happens?

 

[Ryanjohn]

I’ve had the car for 3 days…haven’t had time to look at anything really.

 

[duh09]

I'm with the other guys, it seems like a fuel or tuning issue.

24# does seem awfully small for a boosted setup. Is the FPR boost referenced?

If it was my car, I'd be shooting for bigger injectors and a new tune for them. 42# or 60# would make me happier. If fuel pressure becomes an issue at that point, than a 340lph pump.

 

[Ryanjohn]

So the plugs are good, fuel pressure has been check at the rail and that’s good as well. Car runs fine but once i go half to full throttle it falls flat. Will make 3-6 lbs of boost if I ease into it however. Looking at going with a Holley terminator X standalone to get rid of the megasquirt ecu

 

[95opal]

So the plugs are good, fuel pressure has been check at the rail and that’s good as well. Car runs fine but once i go half to full throttle it falls flat. Will make 3-6 lbs of boost if I ease into it however. Looking at going with a Holley terminator X standalone to get rid of the megasquirt ecu

What are the plugs gapped at. Possible spark blow out under boost?

 

[Ryanjohn]

Plugs are gapped at .28 and they’re ngk copper

 

[duh09]

So the plugs are good, fuel pressure has been check at the rail and that’s good as well. Car runs fine but once i go half to full throttle it falls flat. Will make 3-6 lbs of boost if I ease into it however. Looking at going with a Holley terminator X standalone to get rid of the megasquirt ecu

Whats the reasoning behind going to Holley? I get that it's the "it" thing, but unless you're planning to add a lot of I/O, there's not real reason to make a change.

 

[Ryanjohn]

I have a friend that has built a few turbo mustangs and the ones that have megasquirt have all ran shitty before switching over to Holley. MS is also pretty outdated

 

[duh09]

I have a friend that has built a few turbo mustangs and the ones that have megasquirt have all ran shitty before switching over to Holley. MS is also pretty outdated

Different strokes for different folks but these are dinosaurs compared to some of the newer vehicles on the road that could justify a higher end Holley unit. There is nothing inherently wrong with a Megasquirt unit, but it's only going to be as good as the tune on it. The Holley's seem more forgiving with less than perfect tunes, but again, it all comes back to the tune loaded on it. I'm running a Microsquirt on my car, couldn't justify the $2k to put a Holley on it and don't have any complaints. There are plenty of success stories with both ECUs. I'm a don't fix if it ain't broke sort of guy.

Anyways, I imagine a quick look at data from the MS would help answer your questions. There is a FB group, Megasquirt Mustangs FAQ with a lot of super knowledgeable folks that could point out what they see pretty quickly from a datalog.

 

[Ryanjohn]

Whats the reasoning behind going to Holley? I get that it's the "it" thing, but unless you're planning to add a lot of I/O, there's not real reason to make a change.

Also, I/O?

Different strokes for different folks but these are dinosaurs compared to some of the newer vehicles on the road that could justify a higher end Holley unit. There is nothing inherently wrong with a Megasquirt unit, but it's only going to be as good as the tune on it. The Holley's seem more forgiving with less than perfect tunes, but again, it all comes back to the tune loaded on it. I'm running a Microsquirt on my car, couldn't justify the $2k to put a Holley on it and don't have any complaints. There are plenty of success stories with both ECUs. I'm a don't fix if it ain't broke sort of guy.

Anyways, I imagine a quick look at data from the MS would help answer your questions. There is a FB group, Megasquirt Mustangs FAQ with a lot of super knowledgeable folks that could point out what they see pretty quickly from a datalog.

Thats a great bit of info..I appreciate that man.

 

[duh09]

Also, I/O?

Thats a great bit of info..I appreciate that man.

I/O - Inputs / Outputs. Which on second thought, if you're running a PimpXS, that should be a MS3 unit which I think has the same or more I/O than a TermiX but I'm not to speed on them honestly.

 

[Ryanjohn]

I have a cable that runs into car in front of the arm rest in the center console. PO told me it was megasquirt and I could download tuner studios and see what’s going on. I just have no idea about tuning

 

[duh09]

I have a cable that runs into car in front of the arm rest in the center console. PO told me it was megasquirt and I could download tuner studios and see what’s going on. I just have no idea about tuning

Finding a good tuner, or at least someone comfortable with Tuner Studio will go a long ways. There is a free Tuner Studio you can download on a laptop just to watch it, but I think you need the paid version to save datalogs. It's $70 I think, I just got it again on my laptop I bought to leave in the shop for tuning stuff. You'll want a laptop either way, for this or Holley, to make life easy for datalogging. System requirements are pretty low for Tuner Studio. I ran a cheap $80 Asus little mini notebook deal until I left it on the dash and the case turned wavy in the heat. It still works but the keyboard and trackpad are hard to use so I upgraded to a $150 refurbished Dell rugged laptop that should handle temperature swings so it can live in the car or the shop. I assume you've got PimpXS based on the sticker under the hood, which is a plug and play version of MS3.

 

[Musturd]

you need a fmu if you’re Goona run injectors that small