Hi All

I just got my Zetec SE 1.6 running on Megasquirt 2 with Techedge 2J2 wideband O2 sensor. I have it ticking over nicely by adjusting the fuel and spark to achieve the lowest MAP. The problem I have is that the AFR gauge on the Tunerstudio screen swings wildly from about 11 to 15 about 3-4 time a second.

- I have double checked the set up in Megasquirt and tunerstudio that they are set up for a Techedge 0-5 volts
- I have monitored the Techedge with the laptop through thier software, the output is a stable 12.8 AFR
- I have checked the techedge 0-5 volts with a multi meter, it is stable (+/- 0.15 volts)

The only time Tunerstudio AFR meter is stable and reading correctly is when I disconnect the crank sensor!!!!

- I have checked and remade all the earthing
- I can take the O2 sensor out of the exhaust and leave in free air, disconnect the coilpack and the injectors, remove all the fuses I can. Then turn over on the starter and it still swings as before.

Any ideas would be much appreciated

I shall post the .msq when I find out how

rbfury

[Edited on 15/6/11 by rbfury]

I would take a wild stab at earthing problems. A multimeter will not react fast enough to show you noise in the signal.

have you access to an oscilloscope?

Thanks for the replies

My first thought was an earthing problem but they as per instructions to the engine block. The only thing I have not done was solder all the lugs, only crimp. The four MS earths were soldered though.

I don't have the use of an oscilloscope I am afraid

Rbfury

What is your lamber ego set at on the plus or minus, i had this problem and did the same checked all earths. In the end i changed some settings and all came good, my ego is set at 5 now hope this helps.

Thanks Madteg

My +/- is 15 at present. I will try other values, see what happens.

rbfury

How do i attach the msq? I can't find hpw to do it

Maybe the grey hairs are having an effect?

To test to see whether it is noise you can see if this does this when the engine isn't running. When not running the noise from ignition, alternator, injectors, etc all go away so its a simple way to investigate/eliminate noise.

Are you 100% sure you have wired up the DB37 correctly (not doubting your abilities, but sometimes the answer is simple).

Matt

Just got back from a weekend away.

The problem is there with everything disconnected apart from the Teckedge and the crank sensor and just cranking.

I have also just found out that when the techedge is disconnected the Tunerstudio AFR gauge reads minimum (as you would expect). When it turns over on the starter it still swings all over the place!! The problem must be in the MS.

I have checked the DB37 and it seems to be OK. I bought the MS from Extraefi so I will contact Phil

Thanks for your thoughts

Thanks for your thoughts, it seems to be an ecu fault so I have sent it back to the builders to check and rectify. I should get it back in a few days and will post report
rbfury

Sorted!!

Sent the ECU back to Phil at ExtraEFI who turned it around in 4 days, thanks Phil. Tested it tonight and all seems well.