I've been trying to do some searches and gather quality info on what definitively, I need to do to make a TBI swap from my carb. I have a 1993 YJ Jeep that I have dropped a SBC 350 into, and the primary reason I'm doing this is to eliminate the constant elevation and angle issue I run into when I go wheeling, say like Moab, Utah where I just returned from. I live at sea-level in the Seattle area....and 8,800 ft in Moab things run different. Here's what I have:
I have a complete intake manifold, computer, wiring harness, distributor and wires, and all connections (essentially a complete TBI system) out of a 1990 Chevy Suburban. From what I see and understand -- all will pretty much be plug and play with parts....
what I don't know is figuring out what wires I actually am going to need from the wiring harness. I figure the computer will hook up -- but all my gauges are essentially independent autometer gauges, as I re-did all my gauges...so I should only need to figure out which wires out of the harness that would have orginally plugged into the firewall...that I need to put power to, and which type -- that is, constant 12V, or ignition 12V, etc. Am I off base? I have been trying to locate a good resource for such...AND/OR somebody who has done what I'm trying to do who can provide me with some direction and assistance.
I have had great luck in the past with excellent help and information from the gents here on the forum...and I'm hoping that continues. I'm trying to get started ASAP, so prompt information is additionally appreciated. Thank you in advance for the help! Cheers!! :thumbup:
1.) Am I off base with the fact I can just plug and play with the exception of figuring out the wiring harness and which parts I need and those I don't?
2.) Is there someone with an excellent resource for deciphering this, and/or previous or current knowledge of what wires are needed...ie) schematics, etc.:
but I'm looking for more specifics to the OEM setup...there was a lot of setup using the megasquirt system -- but I'm trying to be as clean and simple as possible using the OEM stuff I have. Thanks for the info -- I'm certainly gonna reference it for info!
Anybody else have solutions or info for me as well?? Thanks!
Do you know the year of your engine? If it is 86 and earlier, you might have trouble fitting a 1990 intake manifold. Other than that you should just be able to just install the complete system from the 1990 truck. You may also be able to just mount the 2 barrel TBI unit on your existing manifold using a four barrel adapter. You will still need to add the O2 sensor, ambient air sensors and other sensor inputs to your engine.
I don't know if you will find a good resource to explain the installation. Megasquirt uses a custom ECU, but it is still a good reference because they explain all the sensors you need. Most folks just keep notes (or find references) on how it was installed on the donor vehicle, and go from there.
Man, thanks for that link. Someone took a good deal of time to do a great write up! Super good info in there!
The thing I was most interested in that whole article was the "link" that was supposed to go somewhere which would describe every pin (or wire color) in the harness and what it was for and such....which...is basically what I'm thinking I need. Do you have another link for that that works? or do you know the author?
Thanks a ton for that reference...it's gonna be super useful. If you or anybody else knows where to find the specific information that I'm assuming would be contained in that link -- please let me know!
Thanks guys for all the help...the more the better!!
Silverback is correct. Spring for the shop manual for that vehicle. I did this back in '89 with a Vette crossfire system into a '79 GMC 3/4 Ton. fired on the first try. Worked great for years.
Manual will give you the pin out you have.
You will need at least the following: map sensor, air temp sensor, O2 sensor, distributor with the correct module, vehicle speed sensor (without it, you may encounter stalling when say coming up to a light.), knock sensor, oil pressure SENSOR. This protects against engine damage due to low pressure, and also as a bypass should the crank signal fail. It bypasses the crank signal once oil pressure comes up during cranking.
Wiring will need 12v constant, 12v crank, GOOD Grounds ( Can not stress that enough).
For the fuel pump, if you do not have a baffled tank, us a Holley Pro-Jection pump mounted close to the tank. It will provide proper pressure for this system. Come to think of it, I have the wiring schematic for the 1988 Camaro TBI. It is almost identical to what you have, and for that matter has not changed much from the old crossfire unit.
I can scan it and send it to you if you like.
If you are keeping the engine basically stock mechanically, I think you will find this conversion rather pleasant.
the f-body tbi setup uses a different ecm with a different harness and an additional intake air temp sensor...
Also, don't know what ecm you've got, but they used a few different ones with a similar pinout on the full size, TBI trucks, but they all used different code, the most common/best hacked/best documented is the '7747, and I'd suggest you find one if you're going to do anything besides a purely stock engine setup. You'll find some info about others like the '299, but not as much and if you really get into tuning or trying to find a problem you'll find it frustrating dealing with them
heh, I love the crossfire swap into the full size truck (monster torque, kind of cool looking...), I saved one just for that use but had to get rid of that truck before I got the chance.
the f-body tbi setup uses a different ecm with a different harness and an additional intake air temp sensor...
Also, don't know what ecm you've got, but they used a few different ones with a similar pinout on the full size, TBI trucks, but they all used different code, the most common/best hacked/best documented is the '7747, and I'd suggest you find one if you're going to do anything besides a purely stock engine setup. You'll find some info about others like the '299, but not as much and if you really get into tuning or trying to find a problem you'll find it frustrating dealing with them
heh, I love the crossfire swap into the full size truck (monster torque, kind of cool looking...), I saved one just for that use but had to get rid of that truck before I got the chance.
I should have stated that the f-body schematic should be used as a general guide. Silverback is again correct that you need the factory schematic for what you are working on. Heck, he has specific part numbers, and I have been away from this a long time. My point is only that it is a very do-able project, and worth the effort.
....and yes, Silverback, it made for some great torque in the midrange, an almost flat curve. It had a 4 speed, 373 gears, and a computer compatible comp cams camshaft. I miss that truck....
heh, it's funny how people hate that setup unless they've spent enough time playing with one to really learn about what it does well and went to town with it. I actually _really, REALLY_ want to find a nice 82 crossfire vette for a project car since I feel that it will make a great cruiser, enough low end to be serious fun on the street and still get killer MPG on crap gas.
Do a search on the GM ECM sites, they used to have schematics listed for a lot of the 747 stuff that you could download. I have the '92 '299 stuff at home, which is similar, but to be honest with you, it's a large format book that I have no way of getting good scans of.
IF IT WAS ME and I knew i had a good harness and setup to start with, I'd plug in what I thought I needed, get it running, and once that's done just pull out anything that I didn't end up using actually on the vehicle. Otherwise I would spend the $ on an aftermarket harness that is setup the way I want it. Pulling it apart on a bench you're guaranteed to do something you don't want and really pissing yourself off.
Anyway, the only real connection that I can think of that goes to the dash is the connection that goes to the VSS breakout box that converts VSS pulses to a signal to drive the speedo (it's got some dip switches to adjust that signal for tire size and gear ratio).
It's funny, I've gotten annoyed enough with some of the GM ECM weirdness enough times that in a lot of cases I recommend just skipping it and going with an MS (that's what i'm doing on my project car even though I have all the parts to do it using a few different GM ECM setups and can do all the tuning myself), but this is such a simple deal that I don't think you really will need to refer to the wiring diagrams at all if you recognize the plugs on the harness, unless you're doing something weird/custom.
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