Help,
I have fitted the TPS to my Megajolt system.
I have rotated the TPS fully anticlockwise, tightened the screws and started the engine, got it up to working temp, connected the multimeter to the earth and reference wires and achieved a reading of 5v as required.
slackening the screws and connecting the MM to the earth and the signal wires and rotating the TPS clockwise I get a max reading of 0.5v (Alpha Weber suggest 0.75v) at idle. Switch off and ignition on, open the throttle and the maximum I can achieve is 2.5v (should be a min of 3.8v).
I took the car out anyway and it is still pinking under load and the ignition light remains on albeit dimly.
How can I tell that everything is talking to each other or not, the car feels exactly like it did before the MJ was fitted. It's getting me down now, I haven't driven it in anger since April!!!!
What am I doing wrong? Help!
TPS setting
Moderators: JeffC, rdoherty, stieg, brentp
Well, we can probably sort
...the car feels exactly like it did before the MJ was fitted...
Well, we can probably sort that out!
...the ignition light remains on albeit dimly...
Highly unlikely to be anything directly to do with the MJLJ. Check the charging system (easier said than done!)
My recommendations:
1. Confirm the basics of the EDIS first:
- DISCONNECT the MJLJ completely (ie remove the molex plug from the unit)
- does the engine start? If it does, then the EDIS system is OK and is defaulting to 10 degrees BTDC in the absence of any response from it's ECU (in our case, the MJLJ)
- if it doesn't start, sort out the EDIS system!
- if it does start, try to rev it up (3000-4000rpm). It should not be willing to rev since the timing is static at 10BTDC
2. Confirm the basics of the MJLJ
- disconnect the TPS - let's get the MJLJ definitely running on a 2D map then worry about the TPS
- make sure you've got a reasonable starting map, 10-15 degrees at idle going to about 30-35 degrees at high rpm ...or whatever figures your engine should be comfortable with. Put the same advance against each TPS row, i.e all rows are the same. Doesn't matter what the TPS value is on each row
- at engine idle, EDIS only, plug in the MJLJ
- the engine rpm is highly likely to change as the MJLJ advance probably won't be exactly 10 BTDC
- try to rev it up (3000-4000rpm). It SHOULD be willing to rev since the timing is now being controlled by the MJLJ and you should be getting larger advances at higher rpms.
3. Assuming all is OK so far:
- connect your PC to the MJLJ in the car and start it up
- start the Configurator, and go to the Run Time display
- watch the display as you rev the engine and let it return to idle
...the highlighted map point should move right and left along one of the rows.
...the 2 real time values at the top of the run time display should be showing sensible values as you blip the throttle - advance increases, rpm increases.
4. Assuming all is OK so far:
- reconnect the TPS
...now 3 real time values at the top of the run time display should be showing sensible values as you blip the throttle - advance increases, rpm increases, TPS increases
- at idle and zero throttle, note the realtime TPS value - this is your 'zero-throttle value'
- reprogram the map so that the top row is for your 'zero-throttle value', the bottom row is for a TPS of 255 and the middle rows have a TPS value that varies between the top and bottom row values
- add (as a starting point) a TPS advance
....on the bottom row add about the following advance figures to those already there ie the ones that should be the same on all other rows
At 1000rpm, 2 deg;at 2000rpm 4 deg;at 3000rpm 6 deg;at 4000rpm 8 deg
- for each row between the top and bottom rows, fill in values for each column so that there is a constant increase in advance as you go from the top row to the bottom row
- This should be a reasonable 3D starting map
- Now watch the runtime display as you blip the throttle - the highlight should take an interesting journey across the map, left to right, as you blip the throttle and hold constant engine revs.
The (next to) final part is to set the bottom row TPS value to whatever the MJLJ reads for your particular throttle pot at max throttle, Unfortunately, the engine has to be running to do this (I think), so best to do it on the road (assume you have a laptop PC or a very long serial lead!). Drive along at max throttle and note the realtime TPS value. Reprogram the map so the bottom line is for your own max TPS reading (about 200 I'd guess) and adjust all other rows to make a smooth map.
The final part is to get the best map possible - a lot of time on a real road, playing with the configurator to give the best map possible for real world driving, or an hour or so on a rolling road with someone who understands ignition timing a lot, to get a great map!
Pinking at load is caused by too much advance, so if/when it occurs, you have to reduce the advance at that rpm/TPS point.
Report back.....
PS. Long reply, may or may not all apply to you, but mayhelp others as well
DISCLAIMER: I'm not responsible for any of the above advance figures. take them at your own risk
Well, we can probably sort that out!
...the ignition light remains on albeit dimly...
Highly unlikely to be anything directly to do with the MJLJ. Check the charging system (easier said than done!)
My recommendations:
1. Confirm the basics of the EDIS first:
- DISCONNECT the MJLJ completely (ie remove the molex plug from the unit)
- does the engine start? If it does, then the EDIS system is OK and is defaulting to 10 degrees BTDC in the absence of any response from it's ECU (in our case, the MJLJ)
- if it doesn't start, sort out the EDIS system!
- if it does start, try to rev it up (3000-4000rpm). It should not be willing to rev since the timing is static at 10BTDC
2. Confirm the basics of the MJLJ
- disconnect the TPS - let's get the MJLJ definitely running on a 2D map then worry about the TPS
- make sure you've got a reasonable starting map, 10-15 degrees at idle going to about 30-35 degrees at high rpm ...or whatever figures your engine should be comfortable with. Put the same advance against each TPS row, i.e all rows are the same. Doesn't matter what the TPS value is on each row
- at engine idle, EDIS only, plug in the MJLJ
- the engine rpm is highly likely to change as the MJLJ advance probably won't be exactly 10 BTDC
- try to rev it up (3000-4000rpm). It SHOULD be willing to rev since the timing is now being controlled by the MJLJ and you should be getting larger advances at higher rpms.
3. Assuming all is OK so far:
- connect your PC to the MJLJ in the car and start it up
- start the Configurator, and go to the Run Time display
- watch the display as you rev the engine and let it return to idle
...the highlighted map point should move right and left along one of the rows.
...the 2 real time values at the top of the run time display should be showing sensible values as you blip the throttle - advance increases, rpm increases.
4. Assuming all is OK so far:
- reconnect the TPS
...now 3 real time values at the top of the run time display should be showing sensible values as you blip the throttle - advance increases, rpm increases, TPS increases
- at idle and zero throttle, note the realtime TPS value - this is your 'zero-throttle value'
- reprogram the map so that the top row is for your 'zero-throttle value', the bottom row is for a TPS of 255 and the middle rows have a TPS value that varies between the top and bottom row values
- add (as a starting point) a TPS advance
....on the bottom row add about the following advance figures to those already there ie the ones that should be the same on all other rows
At 1000rpm, 2 deg;at 2000rpm 4 deg;at 3000rpm 6 deg;at 4000rpm 8 deg
- for each row between the top and bottom rows, fill in values for each column so that there is a constant increase in advance as you go from the top row to the bottom row
- This should be a reasonable 3D starting map
- Now watch the runtime display as you blip the throttle - the highlight should take an interesting journey across the map, left to right, as you blip the throttle and hold constant engine revs.
The (next to) final part is to set the bottom row TPS value to whatever the MJLJ reads for your particular throttle pot at max throttle, Unfortunately, the engine has to be running to do this (I think), so best to do it on the road (assume you have a laptop PC or a very long serial lead!). Drive along at max throttle and note the realtime TPS value. Reprogram the map so the bottom line is for your own max TPS reading (about 200 I'd guess) and adjust all other rows to make a smooth map.
The final part is to get the best map possible - a lot of time on a real road, playing with the configurator to give the best map possible for real world driving, or an hour or so on a rolling road with someone who understands ignition timing a lot, to get a great map!
Pinking at load is caused by too much advance, so if/when it occurs, you have to reduce the advance at that rpm/TPS point.
Report back.....
PS. Long reply, may or may not all apply to you, but mayhelp others as well
DISCLAIMER: I'm not responsible for any of the above advance figures. take them at your own risk
Thanks Martin, that gives me
Thanks Martin, that gives me some diagnostics to work with. I'll let you know how I get on. Don't know when Christmas festivities are likely to curtail spannering time!
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neilthewheel
- Posts: 1
- Joined: Sat Nov 19, 2005 4:36 pm
- Location: Worthing, West Sussex, UK
TPS Settings
You should be able to note full throttle TPS with the engine stoped but the ignition on.
I think ignition timing should be retarded towards full throttle.
I think ignition timing should be retarded towards full throttle.
Neil Worsfold
Caterham 7
Caterham 7