merc mefi 3 question
#11
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Water temp sensor is working all other readings on the computer are fine set tps at .8v as per high end of specs
only thing off is the map sensor at idle volts are too high and also is injector pulse is high. which I believe is why it is loading up so bad at idle
Does anyone make a map sensor that has different values that may help? Someone suggested a v6 module
Trash thanks for the input but you are talking way over my knowledge, Always willing to learn, I don't know what a two stage throttle body is, but mine only has a butterfly a tps and a iac. my laptop reads the iac desired and iac actual and they match so i assume it is working properly
I grew up on holley carbs but am slowly learning efi
Thanks to all for taking the time to respond.
only thing off is the map sensor at idle volts are too high and also is injector pulse is high. which I believe is why it is loading up so bad at idle
Does anyone make a map sensor that has different values that may help? Someone suggested a v6 module
Trash thanks for the input but you are talking way over my knowledge, Always willing to learn, I don't know what a two stage throttle body is, but mine only has a butterfly a tps and a iac. my laptop reads the iac desired and iac actual and they match so i assume it is working properly
I grew up on holley carbs but am slowly learning efi
Thanks to all for taking the time to respond.
#12
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Join Date: Aug 2013
Location: Newark, DE
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He is referring to the double blade throttle body, when you look at the throttle body there is 2 holes and each have a blade in them. the tps works directly off on of them, and the other you can adjust a certain amount with out it effecting the voltage. Voltage at .8 is to high, you want that voltage .6 maybe even a little under or a little over. You want your IAC counts at idle to be 0-10, but i found 8ish worked well. You can see the effects of everything if you watch your timing advance, and iac when its trying to idle. when it stumbles down you will see the IAC counts go up, that is the IAC opening to provide air to bring the idle up to where it wants it, along with some timing advance. Then when it surges up you will see the IAC counts start to come down, and the timing advance should go negative when bringing idle down. Pretty cool actually when you see it all work together. I have the software so I can watch it on the computer and have all the reading on 1 dash board. The V6 module is in the distributor. I am unsure if there is anything out there for a different value MAP sensor, and not sure I would do it if there was as thats the Pinnacle of what controls your air fuel mixture. Your fuel table is going to determine how much fuel to add based on your MAP reading (a few other readings 2 but this is the main reading it uses), so my suggestion is that it needs to be set up with 02's and have the fuel tables set up based on the map readings it is seeing.
What are your cam specs, in particular the LSA? this is very important in this scenario, as you may not have a fuel injection friendly cam and that is your whole issue. I ran a 588/596 lift, 236/242 duration on a 114LSA and had no issues with MAP readings. A buddy runs twin 502 mag set ups in his sonic, and has no issues with 620 lift cams with a little more duration then the one that was in mine and on a 114LSA.
What are your cam specs, in particular the LSA? this is very important in this scenario, as you may not have a fuel injection friendly cam and that is your whole issue. I ran a 588/596 lift, 236/242 duration on a 114LSA and had no issues with MAP readings. A buddy runs twin 502 mag set ups in his sonic, and has no issues with 620 lift cams with a little more duration then the one that was in mine and on a 114LSA.
#13
Action, Sorry didn't mean to raise more questions but Ealesh33 answered them. You may have a single blade (single stage) throttle body which might make bringing the IAC count down slightly more involved, but NOT impossible. But first you need to get a wide band O2 on it to read the AFRs. Don't try to look at plugs. Once you have the wide band hooked up you will never go without it. Mine is installed in place of my fuel tank gauge! I run it continuously.
Anyhow, back to topic, many can tune the MEFI 3 or you can do it yourself. There are several in this forum who can do it. The choice is yours. I will also echo Ealesh33's cam advice, the wider LSAs tend to be more tolerant to EFI sensor inputs around idle, short answer they idle better. If you are rich or loading up at idle the wide band should show that, something likely in the 10-12.0 region would cause this. If I crank my BPW up so the idle AFR is 10-10.5 the motor sounds like a top fuel motor, IAC surges full throw etc. Trimming it back to the 12.5 (cold motor) to 13.8-14.0 (warm, no load idle) the IAC settles down to 0-10.
Hope this helps.
Anyhow, back to topic, many can tune the MEFI 3 or you can do it yourself. There are several in this forum who can do it. The choice is yours. I will also echo Ealesh33's cam advice, the wider LSAs tend to be more tolerant to EFI sensor inputs around idle, short answer they idle better. If you are rich or loading up at idle the wide band should show that, something likely in the 10-12.0 region would cause this. If I crank my BPW up so the idle AFR is 10-10.5 the motor sounds like a top fuel motor, IAC surges full throw etc. Trimming it back to the 12.5 (cold motor) to 13.8-14.0 (warm, no load idle) the IAC settles down to 0-10.
Hope this helps.
#14
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Water temp sensor is working all other readings on the computer are fine set tps at .8v as per high end of specs
only thing off is the map sensor at idle volts are too high and also is injector pulse is high. which I believe is why it is loading up so bad at idle
Does anyone make a map sensor that has different values that may help? Someone suggested a v6 module
Trash thanks for the input but you are talking way over my knowledge, Always willing to learn, I don't know what a two stage throttle body is, but mine only has a butterfly a tps and a iac. my laptop reads the iac desired and iac actual and they match so i assume it is working properly
I grew up on holley carbs but am slowly learning efi
Thanks to all for taking the time to respond.
only thing off is the map sensor at idle volts are too high and also is injector pulse is high. which I believe is why it is loading up so bad at idle
Does anyone make a map sensor that has different values that may help? Someone suggested a v6 module
Trash thanks for the input but you are talking way over my knowledge, Always willing to learn, I don't know what a two stage throttle body is, but mine only has a butterfly a tps and a iac. my laptop reads the iac desired and iac actual and they match so i assume it is working properly
I grew up on holley carbs but am slowly learning efi
Thanks to all for taking the time to respond.