few megajolt questions

benjamin · Post by **benjamin** » Wed Jun 27, 2007 9:35 am

hello im ben from australia i have a 1976 mini clubman with an 1152cc a-series engine that is turbocharged and running megajolt.

first questions is about shelded wire , i didnt use any when engine was on engine dyno and i didnt have any problems or missfires so gathered it was ok. Since engine has been installed in the car i have a few mis fires? is sheilded wire crucial? should i use

next question is the map sensor , at the moment i have BOV , boost guage , boost controller and megajolt all running of the same vacum line i was told that the blow off valve should be separate as spikes could harm the map sensor?

last question is the RPm , im using the factroy rover cooper 3 guage cluster and the rpm works fine up to 2500rpm the flickers on and off dependent on engine loads. The tacho is hooked up to the megajold tacho line is the anything i can try to fix this easliy ? using the same takoff from megajolt

thanks
ben

MartinM · Post by **MartinM** » Wed Jun 27, 2007 9:48 am

Hi Ben

Welcome!

Shielded wire - highly recommended, but not mandatory. First option, rather than re-wiring, would be to make sure you have V3.2.1 firmware in the MJLJ. This is more immune to noise pickup. If that doesn't solve it, then shielded is the way to go

MAP sensor - it's got a physical min/max rating of circa 0 to 10 bar (only measures between 0 and 2.5 however). Presumably the BOV just dumps excess pressure. I can't see any problem.

RPM - a common problem! Try hooking the tacho to the EDIS PIP line (MJLJ pin 2) instead. That often solves it.

Report back, especially on the RPM problem please!

benjamin · Post by **benjamin** » Wed Jun 27, 2007 11:13 am

ok tried to install the nw firm ware but keep getting stuck

c:\>cd c:\mjlj
c:\mjlj>hc08sprg.exe COM4 mjlJunior_V3.2.1.s19
Waiting for HC08 reset ACK...received 0xfc (good).
Calibration break pulse sent. Count: 1347
cant send bla bla

?? helpp

Gilesy998 · Post by **Gilesy998** » Wed Jun 27, 2007 12:55 pm

Type the "hc08sprg.exe COM4 mjlJunior_V3.2.1.s19" part with the ECU powered down.
When you get "Waiting for HC08" etc power-on the unit and you'll see a stream of results on the screen.

MartinM · Post by **MartinM** » Wed Jun 27, 2007 2:31 pm

Looks like that's what's being done....the reset ack (0xFC) is associated with the power up of the MJLJ

It's a bit of a cop-out, but all I can suggest is trying it a few more times - sometimes it is a bit temperamental.....

capri_turbo · Post by **capri_turbo** » Thu Jun 28, 2007 8:56 am

I recently upgraded my firmware... I had real trouble... tried it on 2 separate computers with the same error of something about "forgot to set single wire mode?". What I eventually found with mine was that I had to have the MJLJ powered up before running hc08sprg, and when it was looking for the reset, I powered the unit down and then back up again and it worked fine.

This was on an old laptop (win95) with proper serial port.

benjamin · Post by **benjamin** » Sat Jul 21, 2007 6:21 am

MartinM wrote:Looks like that's what's being done....the reset ack (0xFC) is associated with the power up of the MJLJ

It's a bit of a cop-out, but all I can suggest is trying it a few more times - sometimes it is a bit temperamental.....

ok tried a few more times on two computers with no luck??? just keeps counting higher and higher im using a usb to serial. ?

Post by **brentp** » Sat Jul 21, 2007 7:10 am

Hi Benjamin,

The hc08sprg.exe program has problems with certain USB-Serial adapters. Are you able to try a computer that has a regular serial port? If you need to move the unit away from your car you can power it temporarily with a fresh 9V battery.

Brent

benjamin · Post by **benjamin** » Sat Jul 28, 2007 9:38 am

ok finally got it to work

went a bought a more expensive usb-serial cable and it worked straight away no troubles. The cruising miss seems to have gone and doesnt hesitate coming into boost anymore, so much happier. Still hesitates wehn taking off but could be something else , will investigate.

Re the tacho, spliced into the pip line megajolt nuber two for the tacho and it seems to work fine now although havent taken for a drive it works reving in nuetral.

will add some pics in the gallery soon.

thanks
ben

MartinM · Post by **MartinM** » Sat Jul 28, 2007 10:58 am

Good news

Another couple of votes for:
- decent quality USB-serial adaptors
- running the rev counter off the PIP line

Look forward to the pics....

Post by **brentp** » Sat Jul 28, 2007 3:38 pm

Thanks for the update, and great you're seeing improvements!

As you probably know, noise on the PIP line can cause the MJLJ to see them as extra PIP pulses, which translates into RPM spikes.

The software based noise filtering in the 3.2.1 firmware attempts to disqualify those noise spikes, which helps in many cases.

However, for optimal results, think of an installed system designed with 'robustness in depth'. Meaning:

Robust (rigid and accurate) VR sensor bracket mounting and alignment to feed a clean signal to the EDIS module
Robust (shielded , properly grounded and preferably solder-connected ) wiring for both MJLJ and EDIS - to reduce noise and provide a clean signal path between EDIS and MJLJ
Last in line is robust signal processing in the MJLJ - with 3.2.1 we attempt to filter out these extraneous PIP signals.

If you can, try to perform a datalogging session and see if you can correlate any RPM spikes with the remaining hesitation you're seeing.

Will love to see your pics in the gallery!

Regards,