4AG dissy ignition question

[terryo]

i bought a MEC717 as per Ians recommendation (also, as listed on your drawing). Ive taken it off, as it did not solve the problem . if anything, it was worse with lower peak voltage according to my inductive pick-up/tester

I cant find a part number on the "original" red Bosch oil filled coil which has been on it for years (its not a GT40 one). none of my local vendors recalls ever seeing one exactly the same . i've refitted it and the car runs, just has all the haulmarks of poor ignition. The Motec dwell is set at 3 msec

The igniter , also on it since i got the car 20 yrs ago , is Bosch 127022008. A quick Google search says its Vauxhall/Opel, so possibly a Camira one . i cant find any tech data on-line.

can you pls confirm if the Motec can work with the factory Denso igniter & coil and if so, are there any special settings i need?

Ive done some Pico scope work on it, but i need to change some settings to better examine the data. i'll send you a copy and hopefully you might be able to see something that i cant.

thanks again

[terryo]

steve, every time i try to attach a Pico log file this crashes out and i lose the message i've written. can you send me an email contact please and i'll send you the log files

after much cleaning, crimping and soldering i've got it to start reasonably well but it still randomly runs on about 3.5 cylinders. i really dont know what i did, as the only thing of any note was some minor oxidation on the igniter terminals. when its running at high idle, it will randomly run beautifully, then revert to 3.5, then run beautifully again.

looking at the pico traces, all 4 cylinders have different peak voltages (8-14kv) despite have identical plugs and gaps (BP7ES and 0,8mm) and all new cap, leads, rotor etc. i dont really know if this is important or not, but Iain said i should be looking for more like 20kV with a very high comp engine. when i change to the MEC717 coil the voltage goes up fractionally but is still highly variable

when testing the we decided the dELL of 3 was not allowing the coil to charge properly as it was peaking out at about 4amps. we changed it to 6 and it instantly sounded better and peak secondary voltage increased with both coils

do you happen to have any info on the igniter part number i sent you, as i think my 'safest" option is to use the matched pair coil and igniter. That Bosch transformer coil however is not period correct

[SprinterTRD]

A 717 coil with 008 module should use around 3ms dwell any more and it will be heating the coil up. See the MoTeC website for module/coil information.

You should use a current clamp and scope to do a dwell map for your setup. The 717 can handle around 7amps @ 13.5V

The 717 coil will get you to 9700 RPM before the coil energy drops off at 3ms dwell.

There are Bosch coils that have a higher energy output than the 717 however will drop energy at lower revs due to electrical differences requiring different dwell values.

It the TVIS functioning correctly? If not this will cause poor airflow at idle resulting in bad idle with the big cams.

[terryo]

this is all old news, but i thought i would close it out in case anyone wants the info for another project

The Bosch igniter suggested by Motec for the M4 , Bosch # 1 227 022 008, is obsolete. The current igniter is Bosch # BIM137 or 0 227 100 137 . No longer made in germany. The one i got was malaysian. Its pin 7 output will NOT operate my old TRD tacho and Bosch tech help confirm some versions dont even have functional PIN 7

This BIM137 igniter seems to work with either an oil style oil filled cylindrical coil or a modern transformer Bosch MEC717. No matter what i do, the max i can get out of any coil/igniter/plug/lead combination ive tried, is 13KV.

The dissy magnetic pickups give about 3V @ shaft 500rpm when at factory gap of 0.20mm and almost 5V when the gap is reduced to 0.08mm. I checked several dissys and this was fairly consistent and well in excess of the 1V that Motec show in their set up chart on T11 drawing. On my dissy there is negligible variation in gap as its rotated, but that should be tested. I still dont know if this signal voltage is a problem??

The CRIP (CIP on drawing T11) will change depending on which upper (sync) 3 teeth have been filed off the factory dissy, and which one remains. whilst this now makes sense, nowhere was that mentioned in any Motec documentation. The 1 tooth remaining on mine roughly aligns with the rotor arm and i have a CRIP of 180, not 20 as per T11.

TOOTH RATIO is irrelevant and does not matter what value is in there

there are numerous versions of the Toyota 4AG dissy that outwardly look the same. some interchangability of internal parts is possible but some only have 4 lower teeth, so these are useless with a Motec which wants 24 teeth. some factory versions have a single upper Sync tooth, but this item cant be swapped to newer dissys that have the 24 tooth lower, as the shaft size is different. if you have a 4 tooth upper sync wheel, you need to grind off 3 of them.

[SprinterTRD]

Hi Terry,

Sorry to be pedantic but your statement "some only have 4 lower teeth, so these are useless with a Motec" is incorrect.

This tooth pattern ( one tooth per TDC ) can be used in group fire mode without a sync sensor or full sequential if you add a sync sensor.

[terryo]

thanks Steve, yes, thats correct, i was referring to my 4AG application.

would you like to comment on the voltages im finding from the sensors

[SprinterTRD]

Hi Terry,

For the older distributors I used to fold a sheet of 80 GSM copy paper to set the gaps on the old style sensors. This worked reasonably well. Also depending on which PCB revision M4 you have will determine which voltage trigger level settings you have at your disposal.

The 4AG drawings work and the crip are for standard 4AG dissy & cams.

It sounds like you have a mechanical offset somewhere for your crip not to be a multiple of around 5 plus 180 DEG. The standard Toyota ECU fires the coil when one of the four teeth line up when the engine is cranking then switches over to the other teeth when the engine is running.

[terryo]

thanks again Steve for taking time to reply. electronics is not really my main thing and i struggle a bit sometimes, give me a crank to fix or head to port, and i'm happier

anyhow Motec is #2140, with v6.2 software. I took the M4 to Iain recently to upgrade to V6.2 and he pronounced it all OK, BUT i'm still not totally happy its optimally configured

Iain said the CRIP is immaterial. Just set it at whatever is needed to get the 10BTDC cranking and leave it alone. Dont bother trying to cut up another dissy. You may not be aware the upper toothed wheel can come off the shaft, so its indexing is always a bit hit and miss once a dissy has been dismantled for new seals etc. my single tooth is roughly aligned with the rotor arm.

I have not been able to get simple english answers to these questions...perhaps you can help?

rEF (mode) is set as 14. Help does not help. what version of "multi-tooth" is this supposed to be?.
rEF (mode) is displayed in yellow with an asterix beside it. what does this mean?
Should a 4AG have IGN as 1 or 2??. car runs the same whichever is chosen
Crank index in IGNITION is set at 180, and CRIP in Main setup is set at 180. why is it listed twice?

[SprinterTRD]

Hi Terry I suspected that the distributor was dismantled at some point

Yes Iain is correct it does not really matter what is is as long as the ignition timing on the crank matches what the ECU is displaying. However you need to check the mechanical position of the rotor/cap post alignment to make sure you can get the advance you want without the spark falling off the rotor button. On that note you are using the wide style rotor button?

rEF mode 14 means any multi tooth setup with the ref and sync sensors both having a falling edge as the straightest edge of the waveform. The online help does explain this.

rEF Mode in yellow means the mode you have selected is not supported by your hardware once again the F1 help explains this. What is the revision number on the sticker Ax, Bx or something else.

IGN setting depends on your ignition module you are using. Selecting the wrong type will overheat and destroy the module and/or coil.

I havent looked at a M4 for at least 10 years so I am not sure what you are asking but

CRIP = C rank I ndex P osition and are the same thing

[terryo]

again, thanks. hopefully this will also help others

comment on ign button noted. yes its wide one and set correctly as per instructions in M4 book

the tag on the M4 says. Motec M4. 9903 Serial 2140 EPS B8. it has the "pro" upgrade and Iain recently checked it over.

where is this on-line help about rEF mode you refer to?. I'm using V6.2 software. when i hit F1 help. it does not answer my question. it says 11-14 is multi-tooth with no further explanation. its also not in the book that came with the unit. A Google search brings me back to this forum/post. Your drawing T11 says 14, so, i still dont know what it should be or why 14 is "not supported"

i am using the Bosch 7 pin igniter and a cylindrical oil filled, 12V coil. dELL its currently set as 3. IGN is set as type 1 (falling) . . your F1 help suggests thats OK. Also, ign delay is set as 40 usec not 50 as F1 help suggests. i recall all that was chosen after scope testing of the ign system some years back. Any further comment on what might be causing such a low secondary voltage?