Microsquirt with MSD 6A help

matt_ru

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I have a 1992 Gt with an on3 turbo kit & all the supporting mods. Runs great until 4k rpms, then it "blows out spark." Tuner recommended an ignition box, so I picked up the 6A. My question is should I wire this according to the diagram from MSD? Or do I need to do this a different way to keep everything working properly? Wiring diagrams are helpful.
 
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a91what

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Your not blowing spark out unless your running 15psi or more. If the car is breaking up at 4k rpm you should be checking spark hardware latency to ensure it's not retarding timing with rpm.
If you do install the msd this latency issue tends to get even worse. Lock the timing at 20* and rev the engine to 5k and hold while strobing the timing, does it retsrd with rpm? If it does bump the latency up by 10, I have had to run these as much as 210microseconds.

The microsquirt can simply fire the msd directly over the white wire or you can install it in the traditional way and let the tfi trigger the msd. Both will work, increase the spark duty to 75% with the msd box. The grey tfi used in our cars has no dwell control from the eec so if they are attempting to do so it will overheat the tfi and cause spark issues as well.

Let me know if you need anything else, I do remote tunes.
 

matt_ru

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Apr 23, 2020
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Your not blowing spark out unless your running 15psi or more. If the car is breaking up at 4k rpm you should be checking spark hardware latency to ensure it's not retarding timing with rpm.
If you do install the msd this latency issue tends to get even worse. Lock the timing at 20* and rev the engine to 5k and hold while strobing the timing, does it retsrd with rpm? If it does bump the latency up by 10, I have had to run these as much as 210microseconds.

The microsquirt can simply fire the msd directly over the white wire or you can install it in the traditional way and let the tfi trigger the msd. Both will work, increase the spark duty to 75% with the msd box. The grey tfi used in our cars has no dwell control from the eec so if they are attempting to do so it will overheat the tfi and cause spark issues as well.

Let me know if you need anything else, I do remote tunes.
I'll give that a try tomorrow and see what I can find out. I just opened the laptop to see what it's at. Currently set at 0. Hopefully that's the issue so I can return the msd. I'll post results tomorrow. Anything else I should check while I'm at it? You seem to be the MS guru around here.
 

a91what

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Set plug gap at 32 run either a 3924 or 104 autolite copper plug, no platinum or other fancy stuff.
Post the tune if you would like a sanity check.
 

matt_ru

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Set plug gap at 32 run either a 3924 or 104 autolite copper plug, no platinum or other fancy stuff.
Post the tune if you would like a sanity check.
I have a new set of ngk v power tkr6e's in the garage. Think those will work too?
 

a91what

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Yes, but for future use cheap plugs when tuning. nothing moves more electrons than copper [well silver does but they are not making silver plugs] platinum and irridium were designed for plug longevity in OEM applications where they wanted 100k mile plug change intervals.
platinum were designed for wasted spark applications that eat a copper plug in 10k miles.
 

a91what

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I assume you are using LU47 injectors, if thats the case your dead times are wrong.

Your fuel table has plenty of rows for boost, IMHO too many for a driver. the only thing the engine cares about is [am i rich] under boost. too many columns in the lower rpm range, first column should be 50 under lowest idle speed.
typically i do 700 900 1100 1400 1700 2000 2300 2600 3000 3500 and 500 apiece up to redline. as yours is set now you have many unused columns.

your ignition table is....... meh... also its super weak sauce. I mean they are pulling 10* of timing for 5lbs of boost.... if you do some reading that makes the turbo spool like a turd and its likely WAYY down on power. Rule of thumb for a super safe tune is 1* for every psi. for a 10:1 SBF with 93 pump gas .5* per psi is still very safe if you use the factory 29* total timing curve.

How long are the crank times on this engine? A good tune will fire in 2s or less.

WTF is up with the idle settings? they are adding 15* to the base curve at idle for a total timing of 37* at idle. No closed loop idle either, whats the idle speed? and what cam? The idle valve HZ is incorrect for a ford valve this reduces the useful range of the idle valve.
 

a91what

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Oh and your Accel enrichment settings are... interesting. the end PW should be 0 or this will create a false rich condition for both accel and decel events. the TPS curve does not make sense it decreases with throttle delta.. ie.. its adding more fuel with less throttle movement speed.

My conclusion: I will refrain from comment. Hopefully I am wrong
 

matt_ru

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Oh and your Accel enrichment settings are... interesting. the end PW should be 0 or this will create a false rich condition for both accel and decel events. the TPS curve does not make sense it decreases with throttle delta.. ie.. its adding more fuel with less throttle movement speed.

My conclusion: I will refrain from comment. Hopefully I am wrong
Replying to your first and second reply. Yes Ford lu47 injectors. Stock cam, stock long block with valve springs & head studs. That's pretty interesting how many issues you found. I compared my tune to the one the tuner made while he had it on the dyno (which is the one I sent you & the one loaded on the micro) and he didn't change much except smooth out the fuel table a little bit and change idle. He also changed a couple things in idle control. I was a little surprised by how much he didn't change because it didn't run that great. It starts in about 3-4 seconds and idles around 875-1000 rpms. and I need to feather the throttle on hot starts until it stabilizes itself. I guess my next question is what's your price to build me a tune?
 

a91what

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Please refer to my services page for pricing [in my signature] or you can email me at [email protected]

stock cam should idle nicely at 750 all day. We can likely get this thing worked out in a few hours road tuning with a hot spot.
 

matt_ru

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Please refer to my services page for pricing [in my signature] or you can email me at [email protected]

stock cam should idle nicely at 750 all day. We can likely get this thing worked out in a few hours road tuning with a hot spot.
Please refer to my services page for pricing [in my signature] or you can email me at [email protected]

stock cam should idle nicely at 750 all day. We can likely get this thing worked out in a few hours road tuning with a hot spot.
Okay. I'm going to get the spark hardware latency dialed in an hour or so. Then we can go from there.
 

matt_ru

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yes it would. you should watch my videos if you have not already
I have. Im going to watch them again while Im working on it too. When I think it's okay I'll send a datalog and the current tune.
 
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a91what

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Because it needs a fuel trim. It was tuned with incorrect settings.
You have 2 options, proceed with the original settings or change them and retune.
 
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