I've got so far searching the forums but now need some advice.I can't connect to the megajolt with the laptop and when useing hyperterminal to test the coms the first "C" gets me the line of rubbish but the second has the same responce with no "Z".Can some one point me in the right direction.
All the voltages are OK and I get an output for the rev counter (although about 50% low). But the engine has the same advance with or withought the megajolt conected.
Thanks. Russell
hyperterminal responce
Moderators: JeffC, rdoherty, stieg, brentp
You could try the
You could try the instructions on the 4th post down on
http://picasso.org/mjlj/?q=node/628
about the Bray Terminal method of trouble shooting. Displaying the returned data as hex avoids the 'rubbish' that Hyperterminal gives you and gives a better chance of seeing what might be going on
The MJLJ unit, when working properly itself and when correctly connected to a PC/laptop, seems completely reliable in responding to C and S commands from the Bray terminal.
By the way, don't play about trying to sending any other commands to the MJLJ to see what it does - C and S are perfectly safe, but others might not be!
http://picasso.org/mjlj/?q=node/628
about the Bray Terminal method of trouble shooting. Displaying the returned data as hex avoids the 'rubbish' that Hyperterminal gives you and gives a better chance of seeing what might be going on
The MJLJ unit, when working properly itself and when correctly connected to a PC/laptop, seems completely reliable in responding to C and S commands from the Bray terminal.
By the way, don't play about trying to sending any other commands to the MJLJ to see what it does - C and S are perfectly safe, but others might not be!
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russell_west
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Thanks Martin.
Thanks Martin. Took your advice with the the Bray terminal, but all I get in responce to an S or C is the same letter back. Is this down to the chip or a comunication problem? Your help is much appreheciated.
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russell_west
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Still stuck on this
Still stuck with this if anyone can help please.
Unfortunately, IMHO, the way
Unfortunately, IMHO, the way forward is (potentially) painstaking fault finding.
Getting the same character back as sent is very strange - almost like your connecting lead is a 'null modem' lead rather than a straight through serial connector.
What leads are you using?
Have you got any adapters in the lead?
Are you using a real serial port or a USB to serial adaptor?
Are you sure the lead is OK - each pin should be wired straight through to its equivalent pin at the other end ie 1-1, 2-2, 3-3, 4-4 etc
Give more details, and I'm sure more help will be forthcoming....
Getting the same character back as sent is very strange - almost like your connecting lead is a 'null modem' lead rather than a straight through serial connector.
What leads are you using?
Have you got any adapters in the lead?
Are you using a real serial port or a USB to serial adaptor?
Are you sure the lead is OK - each pin should be wired straight through to its equivalent pin at the other end ie 1-1, 2-2, 3-3, 4-4 etc
Give more details, and I'm sure more help will be forthcoming....
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russell_west
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I am using an old laptop
I am using an old laptop with a serial port running windows 98 so no adaptors and have used the same setup on a Megasquirt install about 3 years ago.
the magajolt kit is about a year old and was purchased from Brent so I guess the chip is pre programed.
the magajolt kit is about a year old and was purchased from Brent so I guess the chip is pre programed.
So if you use the Bray
So if you use the Bray Terminal and send a 'C' (with the MJLJ powered up and connected), you get a 'C' back?? Likewise with 'S'??
What happens if you don't have the MJLJ connected?
What happens if you don't have the MJLJ connected?
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russell_west
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- Joined: Mon Mar 01, 2004 3:20 pm
Now getting responce
Silly mistake on my part not using capital C and S on bray terminal.
So now I am getting 3 lines of numbers and letters aranged in pairs when I send C and "00 00 00 00 00 61" when sending S.
Still unable to comunicate through tuning softwear though.
Sorry for the silly mistake.
So now I am getting 3 lines of numbers and letters aranged in pairs when I send C and "00 00 00 00 00 61" when sending S.
Still unable to comunicate through tuning softwear though.
Sorry for the silly mistake.
Excellent! So there's
Excellent! So there's nothing wrong with the MJLJ ... or the cable ... or your serial port.
It must just be the tuner software configuration.
I'm afraid you'll just have to go EXACTLY through the instructions at http://picasso.org/mjlj/?q=node/6. You can't miss anything out, or do anything extra. The only change you are allowed is that the java version (j2re1.4.2_04 on that web page) might be different. A later version will be fine, but I wouldn't try with an earlier version
If that doesn't work, maybe try another tuner program - you could try mjtuner from the 'most recent' downloads on the right of this site. I haven't tried it, so can't give any advice.
Keep going, I reckon you're pretty close to success!
It must just be the tuner software configuration.
I'm afraid you'll just have to go EXACTLY through the instructions at http://picasso.org/mjlj/?q=node/6. You can't miss anything out, or do anything extra. The only change you are allowed is that the java version (j2re1.4.2_04 on that web page) might be different. A later version will be fine, but I wouldn't try with an earlier version
If that doesn't work, maybe try another tuner program - you could try mjtuner from the 'most recent' downloads on the right of this site. I haven't tried it, so can't give any advice.
Keep going, I reckon you're pretty close to success!
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russell_west
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- Joined: Mon Mar 01, 2004 3:20 pm
Success, well sort of.
Using another lap top ( my one has a missing dill file?) the new tuning softwear ran, conected and I even have a active run time display. Only problem is no advance at low RPM and then it jumps off the scale with no adjustment on my strobe to bring it back so can you give me some idear of SAW voltage / advance. Or is it not that simple. Once again Martin thanks for your time.
SAW voltage vs advance is
SAW voltage vs advance is not really the right concept to work with, since the advance is changed by the SAW pulse having a longer 'on' period - see http://www.bgsoflex.com/mjl/mjl_edis_summary.html.
Yes, you can put a voltmeter on the SAW line and the voltage will increase as the on period increases (longer on periods == timing closer to BTDC). However, the voltage levels you might read with say 35 BTDC and 10 BTDC being indicated on the SAW line are very difficult to predict. Maybe someone has some measurements?
Ideally, a twin channel oscilloscope is the fault finding tool you need and then you can see the PIP and SAW pulses exactly as shown in the reference above. Can you get hold of one??
Assuming you can't, here's some more simple questions...I'm assuming that you've actually got your engine running, but you don't actually say that ...
1) does the engine start and run without the MJLJ connected at all (ie pull the molex plug out)?
1a) if yes, what is the advance as measured by the strobe - should be a rock solid 10 BTDC, independent of rpm
1b) if no, there's an EDIS problem and you need to sort that first
2) (with MAP and/or TPS sensor disconnected)Set the advance in the MJLJ for all rows and all columns to 15 BTDC. Start the engine (it probably will!) What is the advance measured with the strobe?
2a) If its 10 BTDC the MJLJ isn't working
2b) If its 15 BTDC then it *probably* is
Report back - I'm happy to continue helping...it might help others/lead to a more comprehensive FAQ on fault finding and fixing
Yes, you can put a voltmeter on the SAW line and the voltage will increase as the on period increases (longer on periods == timing closer to BTDC). However, the voltage levels you might read with say 35 BTDC and 10 BTDC being indicated on the SAW line are very difficult to predict. Maybe someone has some measurements?
Ideally, a twin channel oscilloscope is the fault finding tool you need and then you can see the PIP and SAW pulses exactly as shown in the reference above. Can you get hold of one??
Assuming you can't, here's some more simple questions...I'm assuming that you've actually got your engine running, but you don't actually say that ...
1) does the engine start and run without the MJLJ connected at all (ie pull the molex plug out)?
1a) if yes, what is the advance as measured by the strobe - should be a rock solid 10 BTDC, independent of rpm
1b) if no, there's an EDIS problem and you need to sort that first
2) (with MAP and/or TPS sensor disconnected)Set the advance in the MJLJ for all rows and all columns to 15 BTDC. Start the engine (it probably will!) What is the advance measured with the strobe?
2a) If its 10 BTDC the MJLJ isn't working
2b) If its 15 BTDC then it *probably* is
Report back - I'm happy to continue helping...it might help others/lead to a more comprehensive FAQ on fault finding and fixing
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russell_west
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- Joined: Mon Mar 01, 2004 3:20 pm
Yes engine starts and runs with fixed advance
1 Yes engine starts and runs no problem with or without MJLT.
1a Advance with or without MJLT is a rock steady er 3 BTDC (36-1 wheel was set up on a slave engine and I put this down to key ways cut in different positions or I can't read a protractor.)I was hoping I can just add to the bin numbers to overcome this at the expence of poor "limp home" running.
Map offset in the firmwear anyone?
2 Runtime display shows advance of 15 DTDC with no change to actual advance
So some quick tests I did after work show a reading of 0.3 VAC at 1000 RPM which rises to 0.8 at around 3000 RMP.This is the same ish at the EDIS unit and the MJLT. I guess as the pulse width increaces with engine speed the RMS value must go up?
Have another EDIS unit thats the same 3 DTDC.
Only time the advance changes is when the engine is on the over run but held at a constant speed up to 4000 RPM there is still a fixed 3 BTDC.
Only other thought I had was that the screen on the SAW and PIP are only conected at the EDIS and not the MJLT but I think this is correct.
All this points to an EDIS fault but if the engine runs (with 2 different EDIS units)are there any other Ford bits that would cause the problem?
Still looking for a scope.
1a Advance with or without MJLT is a rock steady er 3 BTDC (36-1 wheel was set up on a slave engine and I put this down to key ways cut in different positions or I can't read a protractor.)I was hoping I can just add to the bin numbers to overcome this at the expence of poor "limp home" running.
Map offset in the firmwear anyone?
2 Runtime display shows advance of 15 DTDC with no change to actual advance
So some quick tests I did after work show a reading of 0.3 VAC at 1000 RPM which rises to 0.8 at around 3000 RMP.This is the same ish at the EDIS unit and the MJLT. I guess as the pulse width increaces with engine speed the RMS value must go up?
Have another EDIS unit thats the same 3 DTDC.
Only time the advance changes is when the engine is on the over run but held at a constant speed up to 4000 RPM there is still a fixed 3 BTDC.
Only other thought I had was that the screen on the SAW and PIP are only conected at the EDIS and not the MJLT but I think this is correct.
All this points to an EDIS fault but if the engine runs (with 2 different EDIS units)are there any other Ford bits that would cause the problem?
Still looking for a scope.
Hmmm....
Sounds like a wiring problem to me, but as the engine runs (after a fashion), it must be a problem with the PIP and/or SAW lines. But an increasing AC reading with rpm is what you would expect. Do you get increasing AC with rpm on both PIP and SAW?
Another fault-finding method is to set the programmable outputs to active high, RPM, and 1000, 2000 and 3000 rpm respectively. Connect an LED through a 470 ohm resistor between +12V and each programmable output pin on the MJLJ (ie 3 LEDs, 3 resistors).
Thn just run the engine at various rpm. If the LEDs light up at the right time then its a good indication that the PIP line is OK and would make you look at the SAW circuit. If they don't light at all, it narrows it down to the PIP line.
Screens make no difference if they really are just screens and you're not relying on them for earth connectivity. Ford don't screen any of the wires in the EDIS loom except for the VR sesor, and even in that wire, the screen is not actually earthed - the combination of the central wire and the screen carry the AC signal from the VR sensor to the EDIS.
Keep looking for a 'scope - it's the best tool to use by miles.
Assuming you're in the UK, whereabouts? You might be just down the road ....
Another fault-finding method is to set the programmable outputs to active high, RPM, and 1000, 2000 and 3000 rpm respectively. Connect an LED through a 470 ohm resistor between +12V and each programmable output pin on the MJLJ (ie 3 LEDs, 3 resistors).
Thn just run the engine at various rpm. If the LEDs light up at the right time then its a good indication that the PIP line is OK and would make you look at the SAW circuit. If they don't light at all, it narrows it down to the PIP line.
Screens make no difference if they really are just screens and you're not relying on them for earth connectivity. Ford don't screen any of the wires in the EDIS loom except for the VR sesor, and even in that wire, the screen is not actually earthed - the combination of the central wire and the screen carry the AC signal from the VR sensor to the EDIS.
Keep looking for a 'scope - it's the best tool to use by miles.
Assuming you're in the UK, whereabouts? You might be just down the road ....
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russell_west
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- Joined: Mon Mar 01, 2004 3:20 pm
Thanks you have given me
Thanks you have given me something to try at the weekend. Not looked at the PIP because the engine runs and shows RPM on the runtime display, am I missing something? The PIP and SAW are both screened from the EDIS plug of the loom I cut out. I am in Hertford by the way.
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russell_west
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- Joined: Mon Mar 01, 2004 3:20 pm
Tried the test with the
Tried the test with the progremable outputs using a multi meter set to buzz on continuity and am not getting a clean switch at the set RPM. Will a diode and resistor behave differently? Or is this because of a poor PIP signal?