I've got a Silvertop in an AE92 GTS running on a Blacktop ECU. Everything seems to work well but I do get some backfiring (very little, but it's there). I was just wondering if anyone knows where I could find technical specs on the fuel and ignition maps for the Silvertop and Blacktop?
I'm pretty sure this is where my problem is but I'm not 100% sure. Any help would be great.
in simple terms, popping out the tailpipe when getting off the gas usually means its rich, lets go over some things, your motor first, is it the big port with tvis or the small ports, and the control system, is your ecu that you are using set up for a map or mass air meter, are you using the right sensor harness for the ecu?
^^ He has already stated that he is running the 20v Silvertop, which is neither the small or big port, does not have the tvis system. The Silvertops run AFM systems and he has to be using the right ECU, or the thing wont run.
As for the backfiring, it is normal as far as i can tell. They come out of the factory rich and i have a similar problem with mine. what it was put down to on mine was the vacum hose going to the fuel regulator was alternating (sort of like the AC current found in home electrics). All i really had to do to fix this was tap into another vacum hose (I used the carcol canister outlet) with a constant, not alternating pressure.
If that is not the problem, what size exaust system are you running? And are you harnessing the twin exaust system? If either of the above are too big, you will get backfiring because there is not enough back pressure and will allow air back in, and spark again.
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- 2001 AU Ford Fairmont Station Wagon (The Family Taxi)
As thespud mentioned, I am running the 20V Silvertop engine which is neither a small port nor a big port engine.
Normally this engine would have a MAF setup, but, I have converted it to run on the Blacktop ECU which uses a vacuum sensor instead. Through some research I have read that the Blacktop has different Fuel maps that feed the engine more fuel than the Silvertop. If this is the case, then there isn't really much that I can do to fix the problem (backfiring).
I will try tapping a different vacuum hose for the pressure regulator. I had noticed that the vacuum line to the regulator does pulse but I never really thought about how that would affect the engine. I guess I was asleep at the wheel that day!!!
i was about to do the same set-up on my 20V ST so i can run open throttles but upon further research i found out that most people that did the swap tends to have the same problem. also that the powerband is not as smooth and almost rough. you can solve this problem with a piggyback system on your ECU. like a programmable air/fuel cotroller. most guys use the Apexi V-AFC. that's what's stopping my project. i don't have the cash right now to get a $300+ system!
__________________ 1982 Toyota Starlet (SP61) boosted since 2007
I will try tapping a different vacuum hose for the pressure regulator. I had noticed that the vacuum line to the regulator does pulse but I never really thought about how that would affect the engine. I guess I was asleep at the wheel that day!!!
MississaugaGTS
There is another option that i used to stop the pulsing too that i forgot about, but it takes all the fun out of the engine.. The old Series III Land Rover Diesels had a regulator before the actual regulator that slowed the air flow down, thus giving the slow decline in revs that a diesel needs. As i said before tho, this takes the fun out of it as it runs like a diesel. Takes the jumpy-ness and lag out of the engine tho. Although, finding a steady vacum hose does that too
As for your pics Ren69:
That is just a stock 20v tho Dont have any pics of the tapped vacum hose as yet... My digicam is in another city with my folks atm
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- 2001 AU Ford Fairmont Station Wagon (The Family Taxi)
there used to be a site that had standalone ignition and fuel maps...... i found it through www.mr2oc.com in the mk1 section..... there was a 20V ST set in there....
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1) 2004 IS300 Manual/LSD/Sportdesign 2) 2010 Corolla S 5 speed 3) 1986 MR2 "MK1.22" 5sfe/s54 swap 3) 1995 Ford Explorer 4x4, TT/AAL/custom shackle lift, 31"s
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Dont have any pics of the tapped vacum hose as yet... My digicam is in another city with my folks atm 
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