EFI to carbureted

[Rajobigguy]

This thing just showed up so I had to take a look and yep it's got carbs on it! View attachment 944305 View attachment 944306 View attachment 944308

Just think how much better it would run with EFI.

 

[Shlbyntro]

Just think how much better it would run with EFI.

Probably wouldn't even get off the trailer before burning down

 

[Wheeler]

On a side note this is the longest thread for me that I started!

And a very fine thread it is. Lot's of interesting info.

I'll try to keep my BS to a minimum.

 

[Andy B.]

And a very fine thread it is. Lot's of interesting info.

I'll try to keep my BS to a minimum.

Screw that it makes me chuckle carry on!

 

[Wheeler]

Screw that it makes me chuckle carry on!

After reading your thread last night I searched a few videos on Carbs vs. Efi. and came across this video. I found this interesting as they spoke of remote tuning and information overload.

 

[SBMech]

After reading your thread last night I searched a few videos on Carbs vs. Efi. and came across this video. I found this interesting as they spoke of remote tuning and information overload.

It's not rocket science, but to most people it's black magic haha.

It's a learned skill, like any other trade. I do modern vehicles, shit in toys is easy as fuck compared to the shit bogged down by smog laws.

You'd be floored at the integration level of the new shit.

 

[rivermobster]

After reading your thread last night I searched a few videos on Carbs vs. Efi. and came across this video. I found this interesting as they spoke of remote tuning and information overload.

You came across that vid?? Yeah right!! LoL

 

[Wheeler]

It's not rocket science, but to most people it's black magic haha.

It's a learned skill, like any other trade. I do modern vehicles, shit in toys is easy as fuck compared to the shit bogged down by smog laws.

You'd be floored at the integration level of the new shit.

I've been kicking 'round the idea of getting out of the trades and get into tuning. I think I'll start with the easy stuff before I move to Detroit.

 

[Ouderkirk]

What are the pros and cons its an 99 502 mpi? I mainly boat at mead with an occasional trip to Havasu.

I'm not sure that I would revert to a carb. I never really had problems with carb'd engines, but starting a BBC with a carb was not as easy as it is with EFI. EFI =turn the key and it runs. No need to pump the throttle 2x and give it some accelerator pump while you turn the key and hope you don't give it too much.

Unless I was racing or had some super tricked out mega-speedster, I'd stick with the EFI.

 

[Wheeler]

You came across that vid?? Yeah right!! LoL

It was that or search through old threads to bump. What would you have done?

 

[rivermobster]

It was that or search through old threads to bump. What would you have done?

Well (unlike you) I'm not pals with Shane T's dad.

Sooooooo. I'll just stick to what I know.

 

[Wheeler]

Well (unlike you) I'm not pals with Shane T's dad.

Sooooooo. I'll just stick to what I know.

Us Parkabilly's gotta stick together, eh?

 

[BDMar]

So here is a question...... has anyone ran a Holley Sniper EFI system on a boat. I know they are self learning, and have great reviews with mild cars engines. I don’t know how aggressive a cam it can accommodate, and how radical a motor will it support.

Being a Holley WD and installing, tuning and using LOTS of Holley EFI systems. The Holley HP and Dominator systems are one of the best out there. The Sniper is one of the worst out there. I Tune Holley for customers weekly. I refuse to do the Sniper system anymore. It was designed for the consumer that want's an inexpensive (cheap) system. They don't work period. The injector location in the throttle body is just plain bad. The O2 sensor is terrible and the ECU being inside the throttle body causes interference. They can be made to run "decent" above 1800 rpm's but the idle quality will never be consistent. When you can buy a complete system that costs less than just the ECU on the HP or Dominator, it should tell you something.
I've had Holley on my engines for 7 years with not one issue. I've upgraded at least 6 systems from MEFI this season and every customer is in love with how much better and cleaner it runs.
It's not cheap, but you only do it once and forget it.

 

[wet hull]

Being a Holley WD and installing, tuning and using LOTS of Holley EFI systems. The Holley HP and Dominator systems are one of the best out there. The Sniper is one of the worst out there. I Tune Holley for customers weekly. I refuse to do the Sniper system anymore. It was designed for the consumer that want's an inexpensive (cheap) system. They don't work period. The injector location in the throttle body is just plain bad. The O2 sensor is terrible and the ECU being inside the throttle body causes interference. They can be made to run "decent" above 1800 rpm's but the idle quality will never be consistent. When you can buy a complete system that costs less than just the ECU on the HP or Dominator, it should tell you something.
I've had Holley on my engines for 7 years with not one issue. I've upgraded at least 6 systems from MEFI this season and every customer is in love with how much better and cleaner it runs.
It's not cheap, but you only do it once and forget it.

I am doing the HP on mine currently. Where in your opinion is best spot for the O2 bung?

EMI Thunder exhaust.

 

[guest hs]

Coming along nicely on my carbureted engine 500 cid

 

[rivermobster]

Being a Holley WD and installing, tuning and using LOTS of Holley EFI systems. The Holley HP and Dominator systems are one of the best out there. The Sniper is one of the worst out there. I Tune Holley for customers weekly. I refuse to do the Sniper system anymore. It was designed for the consumer that want's an inexpensive (cheap) system. They don't work period. The injector location in the throttle body is just plain bad. The O2 sensor is terrible and the ECU being inside the throttle body causes interference. They can be made to run "decent" above 1800 rpm's but the idle quality will never be consistent. When you can buy a complete system that costs less than just the ECU on the HP or Dominator, it should tell you something.
I've had Holley on my engines for 7 years with not one issue. I've upgraded at least 6 systems from MEFI this season and every customer is in love with how much better and cleaner it runs.
It's not cheap, but you only do it once and forget it.

Some people think that Sniper system is the best thing since sliced bread. I just tell em, computers do NOT belong on the top of a hot engine!

FiTech was cutting into there sales and I guess they felt they had to compete. It's a rush to the bottom of the barrel. Sad.

 

[DaveH]

I am doing the HP on mine currently. Where in your opinion is best spot for the O2 bung? View attachment 944645 EMI Thunder exhaust.

i would put the 02bung at the bottom of the riser, not to penetrate the water jacket if possible.

 

[DaveH]

Being a Holley WD and installing, tuning and using LOTS of Holley EFI systems. The Holley HP and Dominator systems are one of the best out there. The Sniper is one of the worst out there. I Tune Holley for customers weekly. I refuse to do the Sniper system anymore. It was designed for the consumer that want's an inexpensive (cheap) system. They don't work period. The injector location in the throttle body is just plain bad. The O2 sensor is terrible and the ECU being inside the throttle body causes interference. They can be made to run "decent" above 1800 rpm's but the idle quality will never be consistent. When you can buy a complete system that costs less than just the ECU on the HP or Dominator, it should tell you something.
I've had Holley on my engines for 7 years with not one issue. I've upgraded at least 6 systems from MEFI this season and every customer is in love with how much better and cleaner it runs.
It's not cheap, but you only do it once and forget it.

the top shelf Holleys have come a long ways, and finally, their software has become "decent".
my real complaint is the size of the box........WAYYYYYY to big, and their premade wire harnesses are sub-par quality for a marine (or most other) application.

 

[DaveH]

Some people think that Sniper system is the best thing since sliced bread. I just tell em, computers do NOT belong on the top of a hot engine!

FiTech was cutting into there sales and I guess they felt they had to compete. It's a rush to the bottom of the barrel. Sad.

exactly. for those that are excited about it.....they really have no clue what goes into modern EFI

 

[Wheeler]

Well (unlike you) I'll just stick to what I know.

Have you been following along? 5.94 @ 273.

Street Car Super Nationals 16 Coverage From Las Vegas

Street Car Super Nationals 16 has taken over The Strip in Las Vegas, featuring Pro Mods and other wild heads-up doorslammer categories.

www.dragzine.com

 

[rivermobster]

Have you been following along? 5.94 @ 273.

Street Car Super Nationals 16 Coverage From Las Vegas

Street Car Super Nationals 16 has taken over The Strip in Las Vegas, featuring Pro Mods and other wild heads-up doorslammer categories.

www.dragzine.com

The 1991 Mustang that Brylon pilots is powered by a 427 cubic-inch Ford engine and it feeds on a healthy diet of nitrous oxide. Roger picked this car up for Brylon to see if he would like drag racing, so far the answer is a resounding yes.

 

[wzuber]

This thing just showed up so I had to take a look and yep it's got carbs on it! View attachment 944305 View attachment 944306 View attachment 944308

Sweet..
More pix pleeeeezzzee....and some eng/blower specs would b kuul tooo...thx bud.

 

[BDMar]

their software has become "decent".
my real complaint is the size of the box........WAYYYYYY to big, and their premade wire harnesses are sub-par quality for a marine (or most other) application.

I'm curios what you consider sub-par about their harness?
In my opinion, I completely disagree with that statement. After over 20 years of after market EFI installations on cars and mostly boats, the quality of their harnesses is pretty good. The make a harness for almost every application and have NEVER had a quality issue with their harness. The only complaint is the main harness is long and has many circuits that I used to remove to work for my needs. But they have to do that for all the possible combos. I custom make all my main harnesses now so it is exactly what I need.

 

[kurtis500]

I had a Holley MPEFI system on my v-drive cruiser. Had digitally controlled distributor, knock sensors and every add on. I ran a closed loop and burned out 6 O2 sensors leaving me stranded each time. Moved the sensor all over the exhaust to avoid inversion. You cant. As an open loop it ran well. I sold it, put an 850DP on and tuned it with an O2 sensor and a good old timing light. Runs just as good now. I only boat in the summer in Arizona and Parker waters so I avoid a lot of cold problems. Id do EFI if you can bullet proof the system a bit better. I think mercruiser probably has this fugured out but the car system for Holley just had too many little issues. I paid around 5K for it too.

 

[Shlbyntro]

I'm curios what you consider sub-par about their harness?
In my opinion, I completely disagree with that statement. After over 20 years of after market EFI installations on cars and mostly boats, the quality of their harnesses is pretty good. The make a harness for almost every application and have NEVER had a quality issue with their harness. The only complaint is the main harness is long and has many circuits that I used to remove to work for my needs. But they have to do that for all the possible combos. I custom make all my main harnesses now so it is exactly what I need.

Too many fuel injectors attached to it

 

[DaveH]

I'm curios what you consider sub-par about their harness?
In my opinion, I completely disagree with that statement. After over 20 years of after market EFI installations on cars and mostly boats, the quality of their harnesses is pretty good. The make a harness for almost every application and have NEVER had a quality issue with their harness. The only complaint is the main harness is long and has many circuits that I used to remove to work for my needs. But they have to do that for all the possible combos. I custom make all my main harnesses now so it is exactly what I need.

try building a harness with M22759/32 wire and you will see the massive quality difference. i also agree that the "one size fits all" nature of their harness has many extra wires and terminations, that have to be stripped out. they don't have any boots or secondary sealing on the connectors. by the time you stip it all down, put on good connectors etc you may has well have just built your own from scratch.

 

[BDMar]

As I said, I build my harnesses so I know the difference. Apples to oranges. They have to build the harness to fit hundreds of different applications. For a mass produced harness it's as good as any others I've see is all I'm saying. Connectors have external seals and the terminals are all sealed, and there's plugs for any empty holes. Not sure why the hate. Anyone that installs custom EFI systems is never going to use a universal main harness and is going to make, or have made, a custom harness to suit their needs.

 

[DaveH]

As I said, I build my harnesses so I know the difference. Apples to oranges. They have to build the harness to fit hundreds of different applications. For a mass produced harness it's as good as any others I've see is all I'm saying. Connectors have external seals and the terminals are all sealed, and there's plugs for any empty holes. Not sure why the hate. Anyone that installs custom EFI systems is never going to use a universal main harness and is going to make, or have made, a custom harness to suit their needs.

Hate? where did i hate anything? or is it anytime someone feels there is something better out there or disagrees with YOUR opinion they are hating? sorry dude but I've have been building harnesses for a long time and yes....Holley harnesses IMO are far from the upper tier in their quality department and there is way better stuff out there to be had. maybe open your eyes to the possibility there is other options.

 

[Bigbore500r]

TROUBLESHOOTING 101 - Carburetors

• Does it start?
  • NO - Spray brake cleaner in it
    • Now does it start?
      • YES - Your not getting fuel
      • NO - Your not getting spark
  • YES - OK cool

 

[SBMech]

TROUBLESHOOTING 101 - Carburetors

• Does it start?
  • NO - Spray brake cleaner in it
    • Now does it start?
      • YES - Your not getting fuel
      • NO - Your not getting spark
  • YES - OK cool

Hilariously that's the same flow chart for EFI....

There is just a few more steps involved to reach the end result.

 

[rivermobster]

Hilariously that's the same flow chart for EFI....

There is just a few more steps involved to reach the end result.

Glad someone else said that besides me!

 

[Bigbore500r]

Glad someone else said that besides me!

I mean, I guess you could check injector pulse with a test light and put a fuel pressure gauge on the rail........but sure why not!

 

[Rajobigguy]

I mean, I guess you could check injector pulse with a test light and put a fuel pressure gauge on the rail........but sure why not!

Or, just plug in the code reader and let it tell you what is going on.

 

[mash on it]

Or, just plug in the code reader and let it tell you what is going on.

Fuel pump or fuel pump relay on efi won't throw a code.

Dan'l

 

[SBMech]

Fuel pump or fuel pump relay on efi won't throw a code.

Dan'l

It also won't tell you about a plugged cat, a dropped/burnt valve, bad driver in the ECU or many more scenarios....

Most people think it tells techs what to do, it only suggests the general area where it's limited logic is having a problem.

 

[Andy B.]

Thanks for keeping this thread going learng a lot and happy Thanksgiving celebrating with friends fuck sisoshit!!!

 

[Rajobigguy]

Fuel pump or fuel pump relay on efi won't throw a code.

Dan'l

It will show low fuel pressure

 

[rivermobster]

I mean, I guess you could check injector pulse with a test light and put a fuel pressure gauge on the rail........but sure why not!

Well, as you know, first you have to determine if the problem is fuel or spark (since we pretty much always have air). Your initial diagnosis is spot on for determining that.

 

[rivermobster]

It also won't tell you about a plugged cat, a dropped/burnt valve, bad driver in the ECU or many more scenarios....

Most people think it tells techs what to do, it only suggests the general area where it's limited logic is having a problem.

Jerry is going to diagnose all that shit with his flow chart, test light and fuel pressure gauge. He's got an awesome set of tools too!

@Bigbore500r

 

[SBMech]

It will show low fuel pressure

The stuff from 2010 or so (depending on manuf and system) does have fuel pressure sensors, but mostly in direct injection systems that work from 3-8kPSI pressure.

Anything below around that age does not have any monitoring of fuel pressure.

 

[Bigbore500r]

Jerry is going to diagnose all that shit with his flow chart, test light and fuel pressure gauge. He's got an awesome set of tools too!

@Bigbore500r

It will get ya close! Add a vacuum gauge, compression tester and infrared heat gun to the mix and your golden

 

[rivermobster]

It will get ya close! Add a vacuum gauge, compression tester and infrared heat gun to the mix and your golden

This is why You get the big bucks.

 

[rrrr]

TROUBLESHOOTING 101 - Carburetors

• Does it start?
  • NO - Spray brake cleaner in it
    • Now does it start?
      • YES - Your not getting fuel
      • NO - Your not getting spark
  • YES - OK cool

It's you're!

 

[Bigbore500r]

This is why You get the big bucks.

I’m supposed to get paid? Lol

 

[Bigbore500r]

It's you're!

YORE

 

[Ancion]

Being a Holley WD and installing, tuning and using LOTS of Holley EFI systems. The Holley HP and Dominator systems are one of the best out there. The Sniper is one of the worst out there. I Tune Holley for customers weekly. I refuse to do the Sniper system anymore. It was designed for the consumer that want's an inexpensive (cheap) system. They don't work period. The injector location in the throttle body is just plain bad. The O2 sensor is terrible and the ECU being inside the throttle body causes interference. They can be made to run "decent" above 1800 rpm's but the idle quality will never be consistent. When you can buy a complete system that costs less than just the ECU on the HP or Dominator, it should tell you something.
I've had Holley on my engines for 7 years with not one issue. I've upgraded at least 6 systems from MEFI this season and every customer is in love with how much better and cleaner it runs.
It's not cheap, but you only do it once and forget it.

Hi,
I have a burnt MEFI 3 on my Mercruiser 350 Mag MPI; what is for you the best way to replace this old ECM ; Holley terminator? what I have to change in the harness? sensors?...
Thank you in advance for your help

 

[Shlbyntro]

Hi,
I have a burnt MEFI 3 on my Mercruiser 350 Mag MPI; what is for you the best way to replace this old ECM ; Holley terminator? what I have to change in the harness? sensors?...
Thank you in advance for your help

Biggest thing is to figure out what fried your ecm. They dont just go bad. Aside from that, in your position I think your best route would to be going back in with stock. thats a very popular engine platform and you shouldnt have any trouble finding used, or you can still get them new on most sn ranges too. Dont modify an engine just for the sake of modifying the engine. My $.02

I know a great MEFI tuner who can tune any MEFI to your perameters as well if you find one with the wrong tune in it.

 

[mjc]

Hi,
I have a burnt MEFI 3 on my Mercruiser 350 Mag MPI; what is for you the best way to replace this old ECM ; Holley terminator? what I have to change in the harness? sensors?...
Thank you in advance for your help

Is it really burnt or just the oscillator chip failed? Whipple was fixing the chip problem.

 

[Jonas Grumby]

Biggest thing is to figure out what fried your ecm. They dont just go bad. Aside from that, in your position I think your best route would to be going back in with stock. thats a very popular engine platform and you shouldnt have any trouble finding used, or you can still get them new on most sn ranges too. Dont modify an engine just for the sake of modifying the engine. My $.02

I know a great MEFI tuner who can tune any MEFI to your perameters as well if you find one with the wrong tune in it.

Who is this tuner you speak of?

 

[Shlbyntro]

Who is this tuner you speak of?

mefituning.com