| How do I know what EFI system is on the GMC that I am buying? [message #242256] |
Tue, 04 March 2014 08:40  |
Ultravan Owners
Messages: 443
Registered: March 2013
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What do I look for to find out what EFI system is on the 1973 455 GMC that I am buying?
Thank you,
Tony (Ontario Canada)
Marie and I are blessed to have had a 2nd chance to buy our farm.
Still hoping and more importantly praying to be able to build a garage.
Our 1970 Ultravan #520 has an Olds Toronado 455 in back.
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| Re: How do I know what EFI system is on the GMC that I am buying? [message #242274 is a reply to message #242256] |
Tue, 04 March 2014 09:52  |
rvanwin
Messages: 325
Registered: April 2007
Location: Battlefield, MO
Karma: 6
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| Ultravan Owners wrote on Tue, 04 March 2014 08:40 |
What do I look for to find out what EFI system is on the 1973 455 GMC that I am buying?
Thank you,
|
If it doesn't have a carburetor then chances are it is EFI. Take the air cleaner off and look for two injectors sitting above the butterflys. If it is port injection (not likely) check for injectors on each intake runner close to the cylinders. Also, check for the ECU (small silver box with lots of wires connected) which is usually located under or near the passenger seat.
Should be fairly obvious.
Randy & Margie
'77 Eleganza II '403'
Battlefield, MO
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| Re: How do I know what EFI system is on the GMC that I am buying? [message #242295 is a reply to message #242256] |
Tue, 04 March 2014 14:21 |
Ultravan Owners
Messages: 443
Registered: March 2013
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Thanks everyone.
I do not have the coach here with me and I will hav eto wait until I see it.
It is TBI..
The current owner that I am buying it from has no idea what "aftermarket" kit has been used on this 73 455 GMC.
The current owner does not know if the person he purchased the GMC from had it done or when it was done.
I have heard members talk about the different kinds of EFI available for the GMC as a kit.
I simply wanted to have some idea of what to look for when I got there and was servicing the GMC for its long road trip back east.
Tony (Ontario Canada)
Marie and I are blessed to have had a 2nd chance to buy our farm.
Still hoping and more importantly praying to be able to build a garage.
Our 1970 Ultravan #520 has an Olds Toronado 455 in back.
[Updated on: Tue, 04 March 2014 14:22] Report message to a moderator |
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| Re: How do I know what EFI system is on the GMC that I am buying? [message #242312 is a reply to message #242274] |
Tue, 04 March 2014 18:10 |
mikethebike
Messages: 331
Registered: January 2014
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| rvanwin wrote on Tue, 04 March 2014 09:52 |
| Ultravan Owners wrote on Tue, 04 March 2014 08:40 |
What do I look for to find out what EFI system is on the 1973 455 GMC that I am buying?
Thank you,
|
If it doesn't have a carburetor then chances are it is EFI. Take the air cleaner off and look for two injectors sitting above the butterflys. If it is port injection (not likely) check for injectors on each intake runner close to the cylinders. Also, check for the ECU (small silver box with lots of wires connected) which is usually located under or near the passenger seat.
Should be fairly obvious.
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What else could it be? Hilborn? Lucas? Rochester? 
It will tell you what it is. If it was my coach, it would be UP-4-SALE so I could put a Q-Jet back on it and not worry about some 1-off electronic gizmo dying in the middle of Kansas and be stuck there for 3 days while Summit or Jegs kisses Holley's left cheek in just the right spot with just the right touch to have them charge me $700.00 + overnight shipping $$$$
Holley and Accel make the kits. There is another that uses Ford components and is a very good system.....but the one a friend put on his F/F Cobra Kit Car cost more than $3500.00.
[Updated on: Tue, 04 March 2014 18:16] Report message to a moderator |
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| Re: How do I know what EFI system is on the GMC that I am buying? [message #242314 is a reply to message #242295] |
Tue, 04 March 2014 18:33 |
rvanwin
Messages: 325
Registered: April 2007
Location: Battlefield, MO
Karma: 6
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Senior Member |
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| Ultravan Owners wrote on Tue, 04 March 2014 14:21 |
Thanks everyone.
I do not have the coach here with me and I will hav eto wait until I see it.
It is TBI..
The current owner that I am buying it from has no idea what "aftermarket" kit has been used on this 73 455 GMC.
The current owner does not know if the person he purchased the GMC from had it done or when it was done.
I have heard members talk about the different kinds of EFI available for the GMC as a kit.
I simply wanted to have some idea of what to look for when I got there and was servicing the GMC for its long road trip back east.
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Sorry, I misread your post thinking you were looking to see if it had EFI.
The most common EFI update for the GMC has been the Howell kit. Look under the passenger seat where the ECM is most often installed. Most are labelled with the name of the kit. Howell, Afordable Fuel Injection (AFI), Turbo City were the common Throttle Body installs. I'm guessing this has been installed for a while so some of the newer kits probably don't come into play. FAST or Mequasquirt might be a possibility.
There is a lot of support here for EFI systems, especially the old GM systems that the most common kits I listed above are based on.
Again, I apologize for misreading your original post.
Randy & Margie
'77 Eleganza II '403'
Battlefield, MO
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