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  #11  
Old 08-09-2012, 04:46 PM
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ahhudgins ahhudgins is offline
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Quote:
Originally Posted by wtrskr View Post
Now I am really learning. I had assumed that giving more throttle just meant giving more gas. So it sounds like, with EFI, punching the throttle allows the engine more air flow and sends the signal to the ECM to give gas. At the same time, the ECM uses the sensors to make sure the gas given properly matches the airflow. Adjusting a carb is then searching for the spot that gives the correct fuel/gas ratio when when the throttle is pushed. Correct me if any of my statements are wrong. Thanks.
A guy I know (not a friend thank goodness) thought that “more gas in the engine” meant it would start better. He was having problems getting his carbureted truck to start so he had his wife turn the key while he dumped gas down the carb. He ended up in the hospital with 1st and 2nd degree burns after it backfired.
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  #12  
Old 08-09-2012, 04:52 PM
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Quote:
Originally Posted by ahhudgins View Post
A guy I know (not a friend thank goodness) thought that “more gas in the engine” meant it would start better. He was having problems getting his carbureted truck to start so he had his wife turn the key while he dumped gas down the carb. He ended up in the hospital with 1st and 2nd degree burns after it backfired.
How is that going to be better than pumping the pedal a few times before cranking? Back when carbs were common, little kids knew that you could flood an engine by pumping the pedal- how did he not learn this? It's safer, too- I suspect he did learn that.
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  #13  
Old 08-09-2012, 06:18 PM
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Originally Posted by JimN View Post
You didn't already have another filter just after the tank?
no...the hose was connected to the fuel take up and went directly to the fuel pump. 95 TBI
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  #14  
Old 08-14-2012, 06:21 PM
DRRICK DRRICK is offline
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Originally Posted by JimN View Post
Here's an article that explains some of the tech behind fuel injection.

http://www.fourwheeler.com/techartic...h/viewall.html
Nice article. I am casting about for someone with the knowledge to help with my EFI. Specifically does anyone have experience with recalibrating The Mastercraft LT-1, and if so how did you do it? I have a '94 Prostar 190

see my other posts for further information. ROller rockers 1:6, etc.
I have been in contact with Bob At MEFIBurn, but I was hoping someone here would have already been down the road less traveled..................which I am on.


for example, how to make an O2 sensor work in a marine environment and the difference between closed and open loops as they relate to the marine engine. and that stuff

or.............do I really need the O2 adaptor from Howell or something like it, in addition to the O2 sensor and separate gauge, since the ECM doesn't listen to an O2 sensor...

1. ADAPTOR, O2 SENSOR for Marine use
Part # HM206 O2 sensor adaptor designed to install heated Oxygen sensor in water cooled marine exhaust manifolds. Oxygen Sensor is priced separately.
http://howellefi.com/?subcats=Y&type...search.results


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I will continue my search. When (not if) I get it settled I will post results here.
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  #15  
Old 08-14-2012, 07:33 PM
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Originally Posted by DRRICK View Post
Nice article. I am casting about for someone with the knowledge to help with my EFI. Specifically does anyone have experience with recalibrating The Mastercraft LT-1, and if so how did you do it? I have a '94 Prostar 190

see my other posts for further information. ROller rockers 1:6, etc.
I have been in contact with Bob At MEFIBurn, but I was hoping someone here would have already been down the road less traveled..................which I am on.


for example, how to make an O2 sensor work in a marine environment and the difference between closed and open loops as they relate to the marine engine. and that stuff

or.............do I really need the O2 adaptor from Howell or something like it, in addition to the O2 sensor and separate gauge, since the ECM doesn't listen to an O2 sensor...

1. ADAPTOR, O2 SENSOR for Marine use
Part # HM206 O2 sensor adaptor designed to install heated Oxygen sensor in water cooled marine exhaust manifolds. Oxygen Sensor is priced separately.
http://howellefi.com/?subcats=Y&type...search.results


--------------------------------------------------------------------------------
I will continue my search. When (not if) I get it settled I will post results here.
If you want to go closed-loop, I would suggest putting the engine on a dyno, like the person who was interviewed for that article. He did the original setup for your engine and when MC was working on O2 and catalytic converters, it was done at his shop, too. That's where we went for MC testing before they changed to their current location. It takes a lot of testing to get it right- the emissions & in-cylinder temperature measurements are needed and his dyno labs are equipped to do this. If you try to do this on the fly, it's pretty easy to set it up too lean or too rich, neither of which works well and if it's too lean, you can cook your engine. One main thing you would need to do for the O2 sensor is keep it dry and if it gets wet, it's toast. Unless you're a manufacturer, you really don't need an O2 sensor and open-loop will work fine for performance. Besides, it's not like you're driving a light-weight car that hooks up to the road really well- a prop turning in water isn't the most efficient way to propel something, although it is more efficient than doing it in air. I have talked with Bob and I would say he should be able to get you where you want to go.
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  #16  
Old 08-15-2012, 08:42 AM
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If you're going to do any type of tuning you will need to data log what's happening in the motor. The O2 sensor is going to be needed to map the VE tables. Without out the O2 sensor you wont know what's being burned.

The only software I have looked at for marine use is DIACOM and it's some what costly. I think it's right around $700 bucks for the software and one or two cables that go from the laptop to the DLC. With that software and the stock tune you'd have a starting point.

I've never seen that O2 sensor adapter and I never new they made them. The only issue I see with it is if the current EFI isn't using an O2 sensor then you'd have to do some pretty major work to get the EFI to use it. If I was going to try this I'd be looking for a MEFI that is wired and programmed for an O2.

The neat thing about that O2 adapter is it gives a method to get an O2 in to an older carb motor if someone was looking to do an EFI conversion.
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  #17  
Old 08-15-2012, 01:08 PM
DRRICK DRRICK is offline
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Originally Posted by CantRepeat View Post
If you're going to do any type of tuning you will need to data log what's happening in the motor. The O2 sensor is going to be needed to map the VE tables. Without out the O2 sensor you wont know what's being burned.

The only software I have looked at for marine use is DIACOM and it's some what costly. I think it's right around $700 bucks for the software and one or two cables that go from the laptop to the DLC. With that software and the stock tune you'd have a starting point.

I've never seen that O2 sensor adapter and I never knew they made them. The only issue I see with it is if the current EFI isn't using an O2 sensor then you'd have to do some pretty major work to get the EFI to use it. If I was going to try this I'd be looking for a MEFI that is wired and programmed for an O2.

The neat thing about that O2 adapter is it gives a method to get an O2 in to an older carb motor if someone was looking to do an EFI conversion.
The way I understand it, the MEFIBurn setup is used to remap the delphi computer already in the boat=MEFI I, in my boat. The O2 sensor is only used to monitor the a/f mixture, and as a such becomes a gauge that one would mount either on the dash or "under the hood". The O2 sensor does NOT interact with the ECM. It is just used for tuning, although according to Bob, the heated O2 sensors can operate in a wet environment, but this is the part I do not understand. I am going to talk to Bob again today.

The other option would be to replace the ECM with an external ECM like Holly or Accel make, but I have yet to find someone who has done that in this particular boat/engine combination.
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  #18  
Old 08-15-2012, 05:20 PM
DRRICK DRRICK is offline
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Originally Posted by DRRICK View Post
although according to Bob, the heated O2 sensors can operate in a wet environment, but this is the part I do not understand. I am going to talk to Bob again today.
I misunderstood Bob. Apparently one can drill through both jackets on the riser and braze (not weld-cast iron) an O2 bung, or ??a plate between the log and riser?? Either way, the O2 sensor has to be removed after the new ".bin" is uploaded to the ECM.

After all this, I am going to send my ECM to Bob. He will re-program it with a program from a similar project he has helped fix (one of many). And send it back to me.
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  #19  
Old 08-15-2012, 07:17 PM
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I know of NO O2 sensor that will work in a wet environment. If there was one then no one would be building dry exhaust for boats. Clearly they could not get a reading of A/F ratio when the air is combined with water. After all its not air/fuel/water ratio that engines are tuned to.

The entire purpose of the O2 sensor is to provide real-time feedback of A/F to the ECM so it can make real-time adjustments to the tune. What good is a an O2 sensor if the ECM does not use the data that it provides?

Why would the O2 sensor have to be removed to reprogram the ECM? That would NEVER be the case. I had my ECM flashed and the sensor was not removed. There's no reason to remove it.

If Bob reprograms your ECM to a "similar project" without any data logs you are just taking a very big swing at it. Sure this would be an ok place to start but you really need to log data and then make corrections to the tune. The only way to correct VE and spark tables without a dyno is to get data logs from the ECM while the boat is on the water.
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  #20  
Old 08-17-2012, 07:25 PM
DRRICK DRRICK is offline
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Quote:
Originally Posted by CantRepeat View Post
The entire purpose of the O2 sensor is to provide real-time feedback of A/F to the ECM so it can make real-time adjustments to the tune. What good is a an O2 sensor if the ECM does not use the data that it provides?
The MEFI I ECM is not capable of using the O2 sensor. Weren't built that way. Cannot be made to use an O2 Sensor.

The new boats have O2 sensors and ECM's that are capable of responding to the A/F.

The point is, I realize that the BEST way would be installing and O2 sensor, but in this case the only use It would have is using the number on the external gauge in combination with the data you have referred to and tune the boat that way. Again, the ECM in my boat does not have the capability to be attached to an O2 sensor, that I know of. I sure wish I were wrong.
Quote:
Originally Posted by CantRepeat View Post

Why would the O2 sensor have to be removed to reprogram the ECM?
Bob said that the O2 sensor would eventually get contaminated and be ruined. Suggested that during the tuning phase one would not perform any maneuvers that would possibly get moisture on the O2 sensor? If I should be brave enough to make further changes to the motor, I would be able to reinstall it for the next tune episode.

Thanks for your input!
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