SO to HO Conversion

Topic: SO to HO Conversion (Read 1371 times) previous topic - next topic

SO to HO Conversion

March 04, 2006, 11:42:39 PM

Can you help me out with a few lingering questions before I convert my SO 5.0 to HO in my '87 TBird Sport? First, will the SD 88 HO computer affect my digital dash any, especially with regards to the trip / fuel consumption computer, and odometer reading? Second, will Mustang blue silicon radiator and other hoses work on the TBird? Third, Will Series II four pintle 19# injectors work or cause any problems. Any answers from experience is appreciated.

SO to HO Conversion

Reply #1 – March 05, 2006, 01:51:15 AM

the computer wount affect anything but the engine, all my dash lights work fine. i dont have a tripminder hooked up, but im sure that would work fine too. also, i run the mustang silicone hose kit on my car, no problems what so ever. and 19# injectors came on the HO i got for my car that i swapped in.

SO to HO Conversion

Reply #2 – March 05, 2006, 09:31:43 AM

I have done the HO conversion with an SD computer from a Mustang. My tripminder works fine with it... Fuel consuption, distance, everything...

Here's an interesting little factoid. Every EEC-IV designates pin 34 for tripminder data or DOL (data output line) but the only wiring diagrams that show it are for models that had the tripminder available as an option. Pin 34 isn't even shown on the Mustang diagrams even though it is active for tripminder data. The Stang never came with that option so I guess they figured there was no need to confuse people by showing on the schematics.

The way it works is that pulse-time signals to the injectors are computed as gallons per hour fuel flow. The vehicle speed signal (VSS) is read as MPH. Each can display metric for liters per 100 kilometers. The computer uses these two signals to display the required info on your trip computer. Cool huh...

My sources for this info is the wiring schematics and pg 136 in the Probst Ford Fuel Injection & Electronic Engine Control book combined with personal experience in doing the HO swap.

SO to HO Conversion

Reply #3 – March 05, 2006, 06:19:01 PM

Quote

Here's an interesting little factoid. Every EEC-IV designates pin 34 for tripminder data or DOL (data output line) but the only wiring diagrams that show it are for models that had the tripminder available as an option. Pin 34 isn't even shown on the Mustang diagrams even though it is active for tripminder data. The Stang never came with that option so I guess they figured there was no need to confuse people by showing on the schematics.

I can support this statement through my own experience as well with my old SD setup. The tripminder works with Mass Air computers and also if you have Electronic Temp. Control this is unaffected as well.

SO to HO Conversion

Reply #4 – March 06, 2006, 11:40:22 PM

Thanks Nate, Dog Charmer and Paul. This helps to convince me to swap the cam. Next go fast add on this spring will be the Comp Cams 1.7 roller rockers I've got. I hope the SO computer will handle these. Following that will be the HO cam (maybe in the fall). I have just about all I need, including an old set of 19# single spray injectors, but I was thinking of using the later issue 19# series II 4-spray injectors instead for better atomization.

SO to HO Conversion

Reply #5 – March 08, 2006, 08:09:05 AM

the SO computer will handle the 1.7 ratio rockers without a problem. As far as the later style injectors you would need a wire harness adapter to use the new series II injectors with the earlier type 5.0 harness. They pop up on ebey once in a while.

SO to HO Conversion

Reply #6 – March 08, 2006, 10:28:18 PM

Thanks for the feedback Paul. I'm a little confused about needing a wire adapter for the four spray injectors. When I compare the 19# four spray injectors I pulled from a '94 Crown Vic, (they look newly replaced), to a spare 14# I have, These have the same geometric shape as the 14# and appear to have the same two-blade connector. Are you refering to those that are somewhat pencil thin? Need to know what the differences are before I start to take my engine apart. Thanks

SO to HO Conversion

Reply #7 – March 09, 2006, 08:19:12 AM

Quote

These have the same geometric shape as the 14# and appear to have the same two-blade connector. Are you refering to those that are somewhat pencil thin?

Yes, I was refering to the thin style injectors.....My brother in law has a '95 Cougar 4.6 with the thin style injectors. Then again he bought the car used and it also has both a tranny cooler AND an oil cooler as well so who knows what was done to that car......
If they are the same shape they SHOULD work.

SO to HO Conversion

Reply #8 – March 09, 2006, 11:44:53 PM

Thanks Paul! For a sec I was worried those injectors would end up in the "good money on parts I'm not going to use" pile. Lord knows I have enough parts decorating my garage and son's room walls already LOL. (PS: Grilles and TBird emblems of different years do dress up a room nicely although the wife wont go for it elsewhere in the house!)