E28 Megasquirt FAQ
alright a few quick questions:
grounds: I wired my grounds from the Motronic box straight to the db37 connector, I noticed pics of turbodan's (I think) setup where he has the grounds on eyelets going to the body. should I do it this way also?
Idle control: Brad, I notice you have an option to input actual frequency as seen in the pic on the bottom
MS2extra has a different option where you enter a number from 0-8. WTF?
Also the car will start and surge slowly from 400-600 rpm and eventually die, I can try to give it some throttle only to kill it. It will start back up. I tired changing the idle control settings with no help, the car seems to be running edit> LEAN by the looks of the WB (about 17) Any ideas?
grounds: I wired my grounds from the Motronic box straight to the db37 connector, I noticed pics of turbodan's (I think) setup where he has the grounds on eyelets going to the body. should I do it this way also?
Idle control: Brad, I notice you have an option to input actual frequency as seen in the pic on the bottom
MS2extra has a different option where you enter a number from 0-8. WTF?
Also the car will start and surge slowly from 400-600 rpm and eventually die, I can try to give it some throttle only to kill it. It will start back up. I tired changing the idle control settings with no help, the car seems to be running edit> LEAN by the looks of the WB (about 17) Any ideas?
Last edited by alijonny on May 08, 2009 12:21 AM, edited 1 time in total.
A wideband reading of 17:1 is lean. Remember for gasoline stoichiometric is ~14.7:1. Anything below this considered rich, above lean. That is probably far to lean for it to ever idle right. Try it around 13:1 and begin to lean it out until the quality of the idle goes away then richen it back up, say half an AFR point. The screenshots are from my earlier beta code. The box you are referring to is a scaling multiplier. The frequency will be the value you enter times 30.5Hz. At my setting it valve works in 1% steps. This probably isn't a major factor right now in your idle settings. It can be used to increase or reduce sensitivity of the frequency to aid the PID.
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I grounded mine the sam way you did, except I did make a complete seperate ground for the sensor heater. Double check your wideband settings, double check the ms settings. Make sure that the voltage params are the same and that megatune is set correctly as well. Seemed like on mine when I first getting things set up, the lc-1 wanted to lose it's voltage parameter settings. I must have free air cal'd that thing a dozen times. Just to get the car idling and moving, turn off the idle and just bump the throttle open a little with the set screw. Get the fuel map set up a little first. I've got 60 lb/hr injs and my priming map looks about identical to Brad's. I use all the tables I can for cold starts, so you'll have to go back and mess with it over and over, but it's got to pull from a correct fuel map. If you have some numbers in the fuel map already, bump the req fuel up until it stays lit, then when it's warm you richen the fuel up and set you req. fuel back to where it's supposed to be.alijonny wrote:possible... however I calibrated the WB according to the instructions for open air calibration. Nobody answered my questions about grounds, might that be causing the problem?
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I would avoid utilizing the priming pulse. It just dumps fuel in every time you turn the key to the run position. Unless you start and run the car every time, the fuel will just trickle down into the oil. You can get it starting easily with the correct cranking PW and probably some afterstart enrichment.
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air gap is 1.02mm, 1-2 is 544 ohms, 1-3 is 2.41 M ohms and 2-3 is 2.46 M ohms.
readings are supposed to be 520ohms give or take 30 ohms for 1-2, 1-3 and 2-3 is supposed to be >100 K ohms
I am using a sensor from a 1990 525i (m20), it bolts to the b35 sensor bracket just fine and I think it has longer wiring.
readings are supposed to be 520ohms give or take 30 ohms for 1-2, 1-3 and 2-3 is supposed to be >100 K ohms
I am using a sensor from a 1990 525i (m20), it bolts to the b35 sensor bracket just fine and I think it has longer wiring.
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Those are good readings for that sensor for gap and resistance there is supposed to be a lot of resistance on those two pins, and that is what you are showing. You will want to make sure that the wire shielding is good, and (remember that I am not experienced with MS) that your VR pots are adjusted properly. I guess it is possible that your signal is breaking up and that it is giving you less fuel than required because it thinks that the motor is turning slower than it really is.