The GM LT-1(92-97?) ign module is only a four pin, no term for the 5v input.
A: Coil+
B: Ign Control
C:Groud
D: Coil neg
I have not tried it yet (still not running, $ shortage) but I was thinking this would be easier than the 5v relay setup, if it works.
The unmentioned GM IC Module
Forum rules
Read the manual to see if your question is answered there before posting. If you have questions about MS1/Extra or MS2/Extra or other non-B&G code configuration or tuning, please post them at http://www.msextra.com The full forum rules are here: Forum Rules, be sure to read them all regularly.
Read the manual to see if your question is answered there before posting. If you have questions about MS1/Extra or MS2/Extra or other non-B&G code configuration or tuning, please post them at http://www.msextra.com The full forum rules are here: Forum Rules, be sure to read them all regularly.
-
Bernard Fife
- Super Squirter
- Posts: 1009
- Joined: Mon Feb 16, 2004 3:15 pm
Budman,
Yeah, the LT1/LT4 coil module looks to be straight-forward, with a signal ignition control connection (on pin B). I'm not able to find the control algorithm for this at the monment, but I wouldn't be surprised if it is the same as HEI (high for dwell, low for spark).
Most of the problems with the LT1 center around the input signal. On the camshaft, there are two sets of LED sensors, one of which has 360 evenly spaced slots, and the other has slots for four of the cylinders: #8 is 7° long, #3 is 12° long, #5 is 17° long, and #2 is 22° long.
For MegaSquirt, you need one signal per spark event, so you need 4 per crankshaft revolution, or eight per camshaft revolution. So neither of the existing signals is right.
There are people working on it, try this:
http://www.msefi.com/viewtopic.php?t=6916
and/or do a search for more recent developemnts.
Lance.
Yeah, the LT1/LT4 coil module looks to be straight-forward, with a signal ignition control connection (on pin B). I'm not able to find the control algorithm for this at the monment, but I wouldn't be surprised if it is the same as HEI (high for dwell, low for spark).
Most of the problems with the LT1 center around the input signal. On the camshaft, there are two sets of LED sensors, one of which has 360 evenly spaced slots, and the other has slots for four of the cylinders: #8 is 7° long, #3 is 12° long, #5 is 17° long, and #2 is 22° long.
For MegaSquirt, you need one signal per spark event, so you need 4 per crankshaft revolution, or eight per camshaft revolution. So neither of the existing signals is right.
There are people working on it, try this:
http://www.msefi.com/viewtopic.php?t=6916
and/or do a search for more recent developemnts.
Lance.
The same type module, 4 pin w/ no 5v in, is also used on all the vortec trucks, 96-00, 4.3, 5.9 5.7, etc. This is why I figuered it would work.
The LT-1 was probably a bad example due to the opti-spark.
On the Lt-1 subject though, why not just use the crank sensor 4x that was on the 96-97 for obdII misfire diag as the msII input and output to the module of your choice and use the opti-spark as a cap and rotor only?
Again, any truck(vortec) uses the same 4x signal from the crank and then uses a hall switch in the distrib to find #1 for the sequential fuel.
The LT-1 was probably a bad example due to the opti-spark.
On the Lt-1 subject though, why not just use the crank sensor 4x that was on the 96-97 for obdII misfire diag as the msII input and output to the module of your choice and use the opti-spark as a cap and rotor only?
Again, any truck(vortec) uses the same 4x signal from the crank and then uses a hall switch in the distrib to find #1 for the sequential fuel.
Can you give a bit more information on the 4x signal? I assume it's an evenly spaced signal showing pairs of cylinders? If so, I think that there might be someone on the board that can help you with your problem. There is code out there to do this with the buick c31 ignition and the DIS that use a 3x wheel for v-6 motors. It would be very interesting if this code could be adapted to handle the lt1. Ignition control for these cars is one of the few reasons I don't want one now, but if that was fixed....
Okay, heres what I have on it so far. The reluctor has 4 evenly spaced teeth. The sensor has three wires, 12v,ground,and signal. Power and ground set the magnetic field, the sensor then sends its signal to the pcm.
This morning I had a 96 truck w/ a 5.7 vortec in here. I hooked my dso to the signal wire while at idle and got a nice square signal that was 6.02 v on my meter.
This should be fine for the MS2 input on opto/hall setting. Use a module to recieve the MS2 ic output and drive the coil, and as long as the distributor rotor is aligned with the correct cylinder you should be gold. It wouldn't matter if the dist was conventional or the opti-spark as you are just using them to throw the spark to the correct cyl.
I think this should work, however I have been wrong before
Doug
This morning I had a 96 truck w/ a 5.7 vortec in here. I hooked my dso to the signal wire while at idle and got a nice square signal that was 6.02 v on my meter.
This should be fine for the MS2 input on opto/hall setting. Use a module to recieve the MS2 ic output and drive the coil, and as long as the distributor rotor is aligned with the correct cylinder you should be gold. It wouldn't matter if the dist was conventional or the opti-spark as you are just using them to throw the spark to the correct cyl.
I think this should work, however I have been wrong before
Doug
-
lt1will620
- MegaSquirt Newbie
- Posts: 3
- Joined: Thu Sep 08, 2005 2:18 pm
I've got an LT1 in a 240Z that i'm helping with.. The motor ran with the stock optispark settings, the wheel actually has 8 slots in it, 4 of them are just really small like 2-3deg's long the others are longer like lance states.
This "should" be enough to trigger MS I'm going to try more of that style tomorrow and see if i can make optispark work, if not i'll be working on the signal from the Crank since its a 97 block from a Camaro.
I'm hoping lance is right on the HEI style ignition module i cant find any information either..
Dave
This "should" be enough to trigger MS I'm going to try more of that style tomorrow and see if i can make optispark work, if not i'll be working on the signal from the Crank since its a 97 block from a Camaro.
I'm hoping lance is right on the HEI style ignition module i cant find any information either..
Dave