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Detailed ignition conops for S1, S2 cars

 
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bureau13  



Joined: 07 Sep 2017
Posts: 67
Location: South Florida

PostPosted: Thu May 10, 2018 1:20 am    Post subject: Detailed ignition conops for S1, S2 cars Reply with quote

This is undoubtedly wishful thinking, but does anyone know of a detailed description of what our ignition systems do/how they do it?

By that I mean what pieces control what, and what exactly do they do? I'm most interested in how advance and retard is done, when it is done, etc, for both the vacuum advance/retard in S1 and the DITC method in S2.

I have an S2, but someone has ripped out the DITC and replaced it with some odd sort of vacuum advance setup. I have an ignition box of some sort behind the driver's side headlight, although I don't know if it's standard or something else. There is a relay on the driver's side by the firewall, and an EGR valve on the passenger's side, and a vacuum advance can on the distributor (no retard connection, unlike the stock S1 can). From what I can tell, the EGR valve is used to connect/disocnnect the vacuum advance from the vacuum source...if I bypass it I have a very high idle. I think the relay may be switching that EGR valve, although I'm not sure. I haven't been able to ascertain when the valve is on or off, although it's obviously disconnecting the vacuum advance at idle.

I had fairly severe driveability issues, I just couldn't get out of my own way off the line, and I noticed that the vacuum line between the source connection and the EGR was collapsed. I replaced that, and things seem much better, but I still get a hesitation before the boost really kicks in. So I'm trying to find out what the stock systems are supposed to do, so I can see if whatever I have is trying to do the same thing, or what...
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1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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morghen  



Joined: 21 Jan 2005
Posts: 7806
Location: Romania

PostPosted: Thu May 10, 2018 4:21 am    Post subject: Reply with quote

Probably the crank sensor died and the owner converted the S2 ignition system to an S1.
If it were to restore the car to the S2 spec you would need the right wiring, DITC, wheel well ignition amplifier, working crank sensor and correct engine bay sensors that are associated with the S2 ignition system, including the TPS, IAT and CTS.
If you're looking for some of these parts i'm currently parting an S2 so i can even send you the wiring loom if you need it.
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bureau13  



Joined: 07 Sep 2017
Posts: 67
Location: South Florida

PostPosted: Thu May 10, 2018 5:03 am    Post subject: Reply with quote

Well, I had not really thought about what I should do yet...just trying to figure out what had been done, and if it were sufficient. It's not really an S1 conversion, although it seems to be similar.

If I were to convert back to DITC, I'm guessing that would be pricey...do you have that crank sensor? I'd pretty much need everything.

An option that looked quite attractive to me was using an programmable MSD ignition box...I was reading a post about that. However, I would have no clue what to set the timing at initially, so I'm not sure that's such a great idea...

morghen wrote:
Probably the crank sensor died and the owner converted the S2 ignition system to an S1.
If it were to restore the car to the S2 spec you would need the right wiring, DITC, wheel well ignition amplifier, working crank sensor and correct engine bay sensors that are associated with the S2 ignition system, including the TPS, IAT and CTS.
If you're looking for some of these parts i'm currently parting an S2 so i can even send you the wiring loom if you need it.

_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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