MSefi.com read only forum (Jan.15,2018)

If you were to point someone with an interest in learning assembly language in a direction (so I can become more involved with MS programming), where would that be? I've begun accumulating some assembly language books for other processors....but not sure if I have some of the best learning material ...

I took a step back and decided to re-test and check all of my hardware. I tested everything from power & ignition wires to the fuel filter. I found that the fuel pump was not pumping enough gas to the TBI. This is what caused the engine to run "lean" (starving the engine of fuel). It all makes sense ...

Thanks for the input guys. I really won't know where to start if the regulator is not my problem. Unless it's sucking up water or some other wacky scenario. I won't know until further investigation. Any suggestions?

I may have blown the fuel pressure regulator in our boat this weekend. I'm using a pump from Summit rated at 100psi to feed a GM TBI unit with stock internal regulator. I've posted about this combination and another user said he had luck with a high pressure pump and TBI so I took a chance with it ...

Lance,
Conversely, if the VE table is so rich that the engine is misfiring, then you could get a lean O2 sensor reading (but the engine is rich, not lean). If you have EGO feedback enabled, this will drive the engine even leaner. So perhaps that's what you are referring to.

Yes, that is what I'm ...

I revisited my datalog file and noticed that the o2 sensor readings were lean during much of the driving, roughly were the rpm's maxed out. The manual states that a lean condition could occur if the ve table is too rich. This could explain the backfire/misfire we hear at the top end. Pw's are high ...

I finally got the boat I MS'ed into the water, starting and idling well. I created an initial map and took it out for a test drive. I couldn't get the rpm's over 2000 (though our first test run got it to 2800...but the water was calm and the boat moved easier in the water). There was a point that ...

I made some progress on an issue I've been having during startup with my car. I've had rpm spikes during cranking, sometimes reaching 9000rpm. I've tried modifying the tach circuit with the help of other members, shielded wire, rerouting wire, etc...with no luck. I reviewed one of my datalogs and ...

Thanks for the advice Lance. I have my MS unit out and will re-test it on the stim to be sure the circuit works. I do have some 3 and 4 wire o2 sensors laying around our shop that I could try. I have been concerned about the one wire sensor not reaching a working temp since starting this boat ...

Matt,
I tried unplugging the o2 sensor from MS and using a MS ground as reference, but still no luck. The only time I did get a reading while using the MS ground (or block ground) is when I hold the sensor wire in one hand and touch ground with the other. I know the human body is conductive and can ...

drz71288, do you have a msq and datalog you can post?

Funny, I just solved my issue. Changed from 2 squirts to 4 on my TBI (with some accel tuning) and now it revs up nice. What's you're setup?

trakkies, I'm slightly confused by your response. I understand that all sensor grounds go back to MS. And for all sensors (except o2 sensor) I have used grounds that run back to MS, which is then grounded to battery negative terminal AND engine block. Are you saying I should have a separate ground ...

I did not use a MS referenced ground....just engine block ground. I will check that and get back to you.

Sounds like a noisy TPS or noise being induced into that circuit. I get a choppy tps too, I have my threshold set at 90. I may try messing with the boat/MS again today.

MS-II, V3.0 2.891 code, Ford 351w
I started up my boat project from last spring and left it with a non working o2 sensor. I bought a new Bosch NB one wire and hooked it up, but will not get a signal. MS works on the stim and even in another project of mine with a WB - so I believe the circuitry is ...

Of course! (as I slap myself in the head) I was mistaken and thought it had worked off of resistance through the sensor. oops. Thanks for clarifying matt.

Ford windsor 351, pertronix ignition off negative coil, MS-II V3 2.86 code. Relay board.

Our engine runs but I'm not getting a reading on the o2 sensor (narrowband). It "used to" show a signal on MT, but no more. Shouldn't there be a 5v output from the MS and through the relay board? I checked with ...

Ford 351 v8, MS-II version 2.89 firing off coil negative

Update: I installed a 36volt Zener diode with the band pointing to the coil negative. This combined with the shielded cable on the tach wire to MS at first did not seem like it did anything. I still had high tach spikes on startup and RPM ...

Update, last night: I installed the shielded cable for the tach wire and TPS wires. It didn't seem to help too much. I'm still seeing erratic tach signals during startup AND tach is dropping to 0 after a throttle rev.

This morning: Looked over my msq file and noticed and changed the lag factor for ...