home register FAQ memberlist calendar

Go Back   Turbobricks Forums > Mechanical > performance & modifications > aftermarket engine management

Reply
 
Thread Tools Display Modes
Old 09-11-2020, 01:19 PM   #26
FROSTED_BVTTS
Newbie
 
Join Date: May 2020
Location: Eagle Rock, MO
Default

Ok, I checked the timing light to make sure I had it set on 4t and no advance, and it was. Dropped dwell to 3ms and she got real pissy. Light wasn't flashing much, seemed like #1 wasn't sparking very well at all. Bumped it to 3.5ms and it was less pissy, but still not flashing consistently at low RPMs. It seems like it just might have reduced the rate at which the timing runs off with RPM, but I'm not certain of it. I think I'll dig around in my spare parts and see if I have another coil to try.

update: Cannot get to spare parts stash

Last edited by FROSTED_BVTTS; 09-11-2020 at 02:11 PM..
FROSTED_BVTTS is offline   Reply With Quote
Old 09-11-2020, 08:45 PM   #27
bobxyz
Board Member
 
bobxyz's Avatar
 
Join Date: Aug 2014
Location: Boulder CO
Default

I have one other idea - you may have both a misaligned distributor and an incorrect Spark Output setting, resulting in your coil charging on the wrong half of the cycle, but the spark firing at about the correct place due to the disti rotation.

To check this, try:
- plug in the battery charger, you may be cranking with injectors unplugged for a while

- by hand, rotate the engine clockwise to TDC

- pop off the disti cap and see if the end of the rotor is roughly over the scribe mark on the edge of the disti housing. If it's off by half a rotation, crank the engine around to the next TDC. If it's within adjustment slot range, rotate the disti to align the scribe mark. You will probably need to remove the disti and move it by a gear tooth. If it's already aligned OK, stop and report back. (If you have a copy, see the Bentley manual for alignment pics)

- once the end of the rotor is roughly over the scribe mark, put the cap back on and unplug the center lead from the cap. Fixture it ~1/4" from a solid chunk of metal (a magnet and a single plug wire holder work great)

- in Tuner Studio, setup for SparkMode:TriggerReturn, TriggerAngle:60deg, IgnitionCapture:RisingEdge, SparkOutput:GoingLow, FixedTiming, TimingForFixedAdvance:12deg, CrankingDwell:5, CrankingAdvance:12deg, NominalDwell:3.5 (The 12deg is the factory timing spec for LH2.2)

- unplug the injectors

- go to the TunerStudio CAN/Diags:OutputTestMode Inj/Spk screen. Enable Test mode. Enable Fuel Pump if the fuel pump relay provides power to the coil. Try coil testing One_coil/CoilA/3.5ms dwell. You should be able to see the sparks. Check that the ignition module and coil are not getting hot, or else the SparkOutput:GoingLow setting is wrong and you should stop here.

- OK so far? If so, get out of the test mode, plug the coil wire back into the distributor, and crank the engine (injectors still unplugged). Use the timing light and rotate the distributor to get to 12deg advance while cranking. Unless you removed it, there's a test terminal near the top center of the bulkhead that can be jumpered to +12v to crank the engine from the engine compartment.

- OK? Timing during cranking now 12deg?

- Plug the injectors back in and hopefully start the engine. How's it run? What's the timing light say? You'll probably need to use the timing wizard to adjust the 60deg TriggerAngle up or down to get to 12deg fixed timing. Finally, try reving the engine and see if timing stays fixed.

Sorry for the rambling instructions, I'm never sure of the talent level, and future readers, here.
bobxyz is offline   Reply With Quote
Old 09-12-2020, 03:38 AM   #28
FROSTED_BVTTS
Newbie
 
Join Date: May 2020
Location: Eagle Rock, MO
Default

Quote:
Originally Posted by bobxyz View Post
I have one other idea - you may have both a misaligned distributor and an incorrect Spark Output setting, resulting in your coil charging on the wrong half of the cycle, but the spark firing at about the correct place due to the disti rotation.
Quote:
- pop off the disti cap and see if the end of the rotor is roughly over the scribe mark on the edge of the disti housing. If it's off by half a rotation, crank the engine around to the next TDC. If it's within adjustment slot range, rotate the disti to align the scribe mark. You will probably need to remove the disti and move it by a gear tooth. If it's already aligned OK, stop and report back. (If you have a copy, see the Bentley manual for alignment pics)
I actually had to replace the distributor at the beginning of this install and neglected to clock it correctly, but I fixed that before any of this. I went out and double checked anyways, and it's lined up. #1 at TDC has the rotor pointing at the scribe mark under the #1 plug wire. I've tried setting Spark Output to Going Low before as well and got no spark at all, but I could try it again if it might tell you something.
FROSTED_BVTTS is offline   Reply With Quote
Old 09-12-2020, 10:34 AM   #29
bobxyz
Board Member
 
bobxyz's Avatar
 
Join Date: Aug 2014
Location: Boulder CO
Default

GoingLow should generate a spark, but the rotor may not be in the correct position to steer it to a plug tower. Try cranking (injectors unplugged) and see if you're getting a spark off the unplugged coil wire itself.

Do you have a dwell meter, or does your timing light include one? If the GoingHigh/Low edge is wrong, you'll be charging on the wrong half of the cycle and a dwell measurement should be way off. For instance, 900rpm idle is 33ms between sparks. Your 4.4ms out of 33ms should show a dwell reading of (4.4/33)*90deg = 12deg. If it shows 78deg, the coil is charging on the wrong half (actual dwell time of 33-4.4=28ms), and the coil is probably getting pretty hot when powered up (only when fuel pumps are on if you're using the standard MS setup).
bobxyz is offline   Reply With Quote
Old 09-12-2020, 04:49 PM   #30
FROSTED_BVTTS
Newbie
 
Join Date: May 2020
Location: Eagle Rock, MO
Default

Went out and tried it, still no spark when set to Going Low. Afraid I don't have a dwell meter and my timing light doesn't have that function. Both the coil and the ignition module get warm pretty quickly in Going Low.
FROSTED_BVTTS is offline   Reply With Quote
Old 09-12-2020, 06:18 PM   #31
bobxyz
Board Member
 
bobxyz's Avatar
 
Join Date: Aug 2014
Location: Boulder CO
Default

I'm still stumped. Something certainly isn't right.
Quote:
Originally Posted by FROSTED_BVTTS View Post
I'm using the resistor method for spark output through D14 as described in the hardware manual here.
^^^ this link confirms that it should be GoingLow. Check your SparkA circuit -- make sure it's connected to D14 (R26 is used for a different SparkA circuit), and that there is a 4.7K ohm (shown as 4K7) to +5v.
bobxyz is offline   Reply With Quote
Old 09-12-2020, 07:32 PM   #32
FROSTED_BVTTS
Newbie
 
Join Date: May 2020
Location: Eagle Rock, MO
Default

Quote:
Originally Posted by bobxyz View Post
I'm still stumped. Something certainly isn't right.

^^^ this link confirms that it should be GoingLow. Check your SparkA circuit -- make sure it's connected to D14 (R26 is used for a different SparkA circuit), and that there is a 4.7K ohm (shown as 4K7) to +5v.
Checked it over and it's wired exactly as the manual specifies. 5v through a 4.7k resistor to -ve of D14, which is jumpered to IGN.

In the section for the Bosch 124 module in the manual here, it specifies that Going High should be used, but it also references the FET logic driver circuit rather than the resistor driver circuit I'm using. Conflicting information, or maybe it just means the resistor method isn't suitable for the Bosch amplifier.

Megamanual has a completely different scheme for connecting the 124, shown here. I don't have any of the proper FETs to build the circuit in MSExtra 5.3.1.3, so maybe I should try the Megamanual method instead... Sound reasonable? I don't have an open spot for the BIP373 on the heatsink since I'm using a PWM idle valve, but I suppose there are ways around that if it comes down to it.
FROSTED_BVTTS is offline   Reply With Quote
Old 09-13-2020, 07:09 PM   #33
FROSTED_BVTTS
Newbie
 
Join Date: May 2020
Location: Eagle Rock, MO
Default

I knew it! I really was an idiot all along. Megamanual's instructions for logic spark output tell you to jumper JS10 to IGN. MSExtra's resistor method has you jumper D14 to IGN. When I switched to the MSExtra method, I neglected to remove that jumper. Seems they don't play well together

Going Low now produces spark and with no unreasonable heat and my timing is stable. Super stoked to finally get this thing back on the road better than ever! Thanks for all the help!
FROSTED_BVTTS is offline   Reply With Quote
Old 09-13-2020, 09:49 PM   #34
bobxyz
Board Member
 
bobxyz's Avatar
 
Join Date: Aug 2014
Location: Boulder CO
Default

Glad you figured it out! I was certainly perplexed....

I think that connecting both JS10 and D14 to the ignition module resulted in a very low coil charging current, and that the only way to get a spark was with a really long dwell time from the wrong GoingHi/Low setting. Connecting JS10 and D14 wouldn't have hurt anything in the MS itself. If you have future spark issues, replacing the 124 ignition module, and maybe the coil, would be good - I think they're fine, but it's an unusual enough failure condition that some damage might be posible.
bobxyz is offline   Reply With Quote
Old 09-15-2020, 11:10 AM   #35
linuxman51
BRANDSCHUTZVORSCHRIFTEN!
 
linuxman51's Avatar
 
Join Date: Dec 2002
Location: mont, AL
Default

the modules usually take the heat alright, the coils... well they'll explode, so if you haven't leaked black ooze out of the top, you should be ok for now lol
__________________
"They bum rushed them in their own crib, they drank all their beer, they partied with their ladies and they left with the trophy"

Now with in-house Dyno tuning!

Megasquirt Tuning!
Plug and play LH 2.4 Megasquirt, now with stealth mode!
linuxman51 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -4. The time now is 06:24 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.