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Topic Review (Newest First)

  • 05-17-2015, 06:19 PM
    Bonzen
    hahaha yeah good call on that...pretty sure that's what he'd say. Thanks for the link!
  • 05-15-2015, 12:56 PM
    bp298
    Quote Originally Posted by Bonzen View Post
    I need a link to an in-stock setup if anyone knows of a good one that doesn't cost a fortune. The Rex marine kit doesn't seem to be available anymore. It's times like this I find myself thinking, "what would Bob say?" lol
    try this: Hardin Marine - Thermostat Housings

    gn would probably say, take that dinosaur pos catastrophe off the engine, find a garbage can that will accept it, and then toss a carb on it. or upgrade the whole thing to something designed in this century...

    just sayin...
  • 05-14-2015, 01:04 PM
    Bonzen
    I need a link to an in-stock setup if anyone knows of a good one that doesn't cost a fortune. The Rex marine kit doesn't seem to be available anymore. It's times like this I find myself thinking, "what would Bob say?" lol
  • 05-13-2015, 10:02 PM
    bp298
    Quote Originally Posted by Unchained View Post
    Wow every possible suggestion besides hooking it up to a laptop.
    wow, have you ever hooked a laptop up to a mefi 1? without having a mefi 1 program on the laptop to talk with it?

    and what would megasquirt have to do with mefi 1????

    from what I have been able to gather from a few people that have worked with mefi 1, both in boats and on the dyno, it is not even close to user friendly. and you can't just unplug the 1 and plug in a 3 or 4.

    at this point, I hate to say it, but the best bet is probably a bypass thermostat housing. and in doing that, if you don't have an oil cooler on the thing already, you might start thinking about one.
  • 05-13-2015, 01:37 PM
    Bonzen
    Obviously the best way would be to hook it up to a computer and turn the cold start setting off completely or at least set it to turn off once the water temp hits 130 degrees or so. Not sure how that effects open loop because I definitely want it to go into open loop at WOT... I do not know anyone or have any means to do so or else I would have gone that route the first time. That's why I sent the MEFI out to get reflashed but never thought about the rich condition or engine temp being cold. AZSpeed never asked me if I was runnin a t-stat or not. I do like the idea of testing the coolant sensor and/or tricking it..but that might be more of an informative thing and not a permanent thing. Good ideas though and I am always down to rig stuff haha as long as safety isn't a factor. Whats really crzy is besides the fact that it didn't come with a t-stat, there is no gate valve either! straight shot hose from pump to T-fitting to logs.
  • 05-13-2015, 05:32 AM
    Unchained
    Wow every possible suggestion besides hooking it up to a laptop.

    The temp is low but most boats run colder than cars.
    What you need to check is at what temp are you off the coolant map.
    If the engine only runs at 125 degrees you need to be sure it's not forever running rich trying to warm up to 185 like a car engine.
    Have the coolant temp map flatline at below your running temp.
    Don't mess around with the coolant temp sensor by adding resistors, etc. , you need that to read properly.

    Then you will need an O2 sensor to tune it from there. Without an O2 sensor you will never get it right.

    Replacing sensors at random is a total shot in the dark. Most are not that hard to test.
    I hope when you replaced the MAP sensor you got a 1 bar.

    Andrew is the Megasquirt EFI authority around here.
    Look up their website for some tuning and configuration info,
    Megasquirt Support Forum (MSEXTRA) • Index page

    One more thing, trying to work with that old of a system is going to be an additional challenge.
    There have been huge improvements in the MEFI ECU since then like all ECU's
  • 05-12-2015, 06:54 PM
    gregb
    Quote Originally Posted by mpkardell View Post
    That's the direction that I was thinking. I don't know squat about his EFI system. But if it uses a thermistor for coolant temperature sensing, he could just install a fixed resistor (or even a rheostat) to fake the coolant temperature to whatever he wants/needs.
    Rheostat is a good idea too, finding the right range might be kinda difficult. But a simple resistor in the circuit with the right ohms to simulate hot coolant/water should work nice, if your good with circuits you could put it on a switch so you could toggle between the resistor and the sensor.
  • 05-12-2015, 06:50 PM
    gregb
    Quote Originally Posted by Hass828 View Post
    Would grounding the temp sensor wire trick the ecu into thinking the engine is warm? Or
    They don't go to zero ohms as far as I know, I think that would trigger some kind of trouble code and maybe set it to limp home mode. Sensors are pretty cheap, I'd buy another one, run the boat so it's what you consider warmed up, then plug that wire into the new sensor and stick it in some water that was just boiled, see if it runs different or idles differently. That's an easy way to test the theory about needing some heat.
  • 05-12-2015, 03:11 PM
    mpkardell
    Quote Originally Posted by Hass828 View Post
    Would grounding the temp sensor wire trick the ecu into thinking the engine is warm? Or
    That's the direction that I was thinking. I don't know squat about his EFI system. But if it uses a thermistor for coolant temperature sensing, he could just install a fixed resistor (or even a rheostat) to fake the coolant temperature to whatever he wants/needs.
  • 05-12-2015, 02:59 PM
    Hass828
    Would grounding the temp sensor wire trick the ecu into thinking the engine is warm? Or
  • 05-12-2015, 01:58 PM
    gregb
    Quote Originally Posted by bp298 View Post
    do you have any specs for this system? if there is a water temp sensor connected to the system that causes the system to increase fuel flow when temp is too low, what is that temp? 140? 150?

    28 already sounds low to me? I don't know, but don't think the injectors work all that well with lower and lower pressure? I would search for someone that really knows this system inside and out and can tune it correctly.

    I'm not a fan of idea of just dumping a thermostat in it and everything will be swell. it's a single pass cooling system, and just closing down on the cooling outlet can create other problems. your exhaust needs water flow through it at all times the engine is running. if you decide you need to add a t'stat to elevate water temp for the sensor, you need one that has a bypass to keep those exhaust hoses somewhat cool. and it would be nice to know exactly what temp the sensor needs to see for the system isn't adding excessive fuel.
    I can see the coolant temp sense on the front of the intake. TBI should be fine with 28 psi, and even less, but your right, lowering the pressure isn't a solution. At wot it probably doesn't change the fuel map be it cold or hot, but at idle I'd be willing to bet there's quite a bit of difference. I think that it needs to be between 160-180 before it drops off the cold engine fuel chart. Give these guys a shout maybe they can help.
    OBD Diagnostics
  • 05-12-2015, 01:46 PM
    Bonzen
    Quote Originally Posted by bp298 View Post
    do you have any specs for this system? if there is a water temp sensor connected to the system that causes the system to increase fuel flow when temp is too low, what is that temp? 140? 150?

    28 already sounds low to me? I don't know, but don't think the injectors work all that well with lower and lower pressure? I would search for someone that really knows this system inside and out and can tune it correctly.

    I'm not a fan of idea of just dumping a thermostat in it and everything will be swell. it's a single pass cooling system, and just closing down on the cooling outlet can create other problems. your exhaust needs water flow through it at all times the engine is running. if you decide you need to add a t'stat to elevate water temp for the sensor, you need one that has a bypass to keep those exhaust hoses somewhat cool. and it would be nice to know exactly what temp the sensor needs to see for the system isn't adding excessive fuel.
    I don't have any specs on the ECU tune unfortunately, was not provided with any printouts... The 454 TBI motors do come with a coolant temp sensor, it is plugged into the intake right next to the T-stat housing on the passenger side. I actually ordered a brand new AC Delco one to swap it out to see if it changes anything. These do go bad consistently on these motors. I also bought a new MAP sensor just for the hell of it to check that as well. Cheap parts so why not and then I have spares. The FP gauge is inline after the pump and before the TBI. Now, the actual AFPR is in the TBI housing just like factory, but is a custom unit that can be adjusted for more pressure. I have what I remember as a 28-30lb spring in there, and then it's cranked for more PSI then that...so I really don't know the exact PSI that the injectors are seeing. All I know is what the pump is putting out.
  • 05-12-2015, 01:10 PM
    bp298
    Quote Originally Posted by Bonzen View Post
    No that never came up. And it's not an option on their calibration/order form. Honestly I'm afraid to touch the damn ECU as it's currently "working", it's 20 years old, and I know that they don't even make MEFI 1 anymore lol. Would decreasing the fuel pressure a bit help it to run a little leaner at idle? I think that's where most of the issue is, at WOT I don't care if is slightly rich...I have an adjustable FPR and an inline gauge.
    do you have any specs for this system? if there is a water temp sensor connected to the system that causes the system to increase fuel flow when temp is too low, what is that temp? 140? 150?

    28 already sounds low to me? I don't know, but don't think the injectors work all that well with lower and lower pressure? I would search for someone that really knows this system inside and out and can tune it correctly.

    I'm not a fan of idea of just dumping a thermostat in it and everything will be swell. it's a single pass cooling system, and just closing down on the cooling outlet can create other problems. your exhaust needs water flow through it at all times the engine is running. if you decide you need to add a t'stat to elevate water temp for the sensor, you need one that has a bypass to keep those exhaust hoses somewhat cool. and it would be nice to know exactly what temp the sensor needs to see for the system isn't adding excessive fuel.
  • 05-12-2015, 12:16 PM
    Bonzen
    No that never came up. And it's not an option on their calibration/order form. Honestly I'm afraid to touch the damn ECU as it's currently "working", it's 20 years old, and I know that they don't even make MEFI 1 anymore lol. Would decreasing the fuel pressure a bit help it to run a little leaner at idle? I think that's where most of the issue is, at WOT I don't care if is slightly rich...I have an adjustable FPR and an inline gauge.
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