[capps]

I have a 97 Vortec 5700 350 that I purchased out of a rolled Tahoe. I have the complete underhood wiring harness, computer and all accessories as it came out of the truck.

I have searched for information on how to make this swap simple into my 84 Suburban Hummer kit Truck. I was told that I needed about 65 psi in the fuel rails and power to four of the computer wires to make it work. After searching for several weeks at multiple sites I still have the same information I started with.

The closest information I have was in a post started in Aug 2003
http://hotrodders.com/showthread.php...ight=96+vortec

Any help on this swap would be great.

I am assuming that I can use the stock fuel lines, but I will need to connect to the high pressure fuel rails with either a high pressure hose, or one of the quick disconnect high pressure fittings.
The original truck was a Diesel and had a rusty tank. I am replacing the fuel tank with a newer tank, but believe I will need to purchase an in tank fuel pump that puts out enough pressure to make the vortec happy.

This would take care of the fuel issues. The only other item is how to connect the wiring into the vortec harness. Since I am building a kit, the original suburban harness was discarded and is being replaced with a painless wiring fuse panel. This is basically a modern day street rod build. Has someone performed this swap, or have access to what wires need power on the Vortec underhood harness?

Thanks in advance for all of your assistance.

[NXS]

did you hear the donor vehicle run?

[capps]

I did not hear the engine run, but I did buy it from a reputable salvage yard I did however see the truck with the 37,000 miles prior to the engine being pulled. The computer would turn on the digital dash, but the front corner was crushed. The only damage to the engine was a cracked fuse cover and a bent power steering line.

[NXS]

Do you have ALL the grounds hooked up? I have never hooked up a later Vortec multi point harness but the older tbi harnesses are not always color coded correctly. I now Always hear one run first and pull the harness with the engine running and label every wire that is critical for the engine to run.

Nonetheless it sounds like you may have a ground off and GM has been tricky in that department before. On some of the tbi's they ran a brown w/black stripe(i think it was brown) wire to run the fuel pump relay. Whoa! I about lost a brain over that once Who was the genius that decided to run a brown wire with a black stripe as the energizer for the pump relay anyways?

[capps]

I have performed a ground up restoration in building this kit. I stripped the frame and painted prior to mounting the body. I am now reinstalling the fuel and brake lines. Once this is complete I will install the engine, transmission and transfer case. I was trying to get some information up front so that when I started this weekend, I would have a plan on what is needed.

[NXS]

Sorry!
I was on another thread...the thread you left the link to

anyways, i have done a couple of swaps and if you are able to afford the "painless" route that is exactly what I would do, buy the Painless Vortec kit and incorporate that into you current painless harness. it should be easy that way.

Like I said in a previous post, the factory harnesses are not always color coded correctly. I tried a '96 4.3 vortec with a cut harness and had problems. I went to Daryl Hickman(local Chevy dealer where I used to work) and the harness i had was color coded different than the dealer books! If your current harness is cut buy the "painless vortec" harness. If i was there i could help you but over the net i cannnot. sorry and best of luck. Please let us know how it goes!

[NorthStar]

I have a wiring diagram I can email to you if you want.

[capps]

Thanks Greg, I have sent you a PM with my email address.

NXS - I do not have a painless underhood vortec wiring harness.

As with most street rod builds, I have a new fuse panel. The underhood wiring harness and computer are stock GM. If the computer only needs four wires to receive power, I could not justify the $350 - $700 underhood harnesses that I have seen advertised. Perhaps the wiring diagram from Greg will help.

Has anyone other than Adam Mclaughlin performed one of the late model vortec engine swaps? Do you have any lessons learned?

[NXS]

Yea, painless is painless until you gotta read the credit card statement! lol

I cannot justify that expense either. Just as a furtue idea:

If possible start the vehicle first and cut the harness wires one by one(being very careful). When your assistant says a gauge dies mark the wire as being "oil" or whatever. When one kills the engine take a DMM and test to see if the wire was a ground or hot, mark it and reconnect it. Continue until the entire harness is cut and the install will be sooo easy becayse YOU have already marked each wire. I know it won't help you now but for future reference or anybody else thinking about doing a swap like this it could be worth(compared to painless) $350- 700.

Greg, can you e-mail that to me also? If so> nisancatron@msn.com

-Thanks guys and good luck Capps!

[NorthStar]

Ok its on its way to you guys. Good luck and keep us posted on the progress.



Im looking for a wiring diagram too.

Does anyone have a wiring diagram for a GM 350 vin K with PCM computer(about 1994 vintage)?

[NXS]

Well those are nice and clear! Thanks, and I bet that helps Capps out tremendously!

Here is what I'm talking about>
pin8/ PNK w/BLK / #632 CMP sensor ground!

lol, chevy? pink to ground?

[bluesman123]

I have attached an Excel file that has all the pinouts for the 97 and 98 Vortec VCMs. That should help you get started on the wiring.

The MFI system requires 63 psi in the rails. You will need a pump that can deliver that much pressure...the stock submersible pump works just fine. Be aware that the original 97/98 MFI system was so bad about leaking down that GM put out a tech note (don't remember the number). Many got upgraded. To see if yours has the upgrade, pull the top off the intake manifold and look at the injectors. If there are both wires and tubes leading to each intake runner it has been upgraded...if only tubes lead to the runners it is the old style system and you may want to replace it (about $300 for parts but a very easy swap)..

Send me a PM if you have any questions. I will be happy to try to help you out.

Bluesman

Oops...I justy tried uploading the file and it won't let me do it (wrong extension). Send me you email address and I will email it to you.

This is a link to Hot Rod Lane in Mesa. They have several .pdf files available with wiring harness diagrams.

http://www.hotrodlane.cc/Instruction...heetindex.html

Bluesman

[gopogo]

I swapped a '99 5.7L Vortec into an '85 S15 Jimmy and built a website showing the process -- not exactly what you're doing, but it might help:

Vortec Swap Site

[bluesman123]

Very nice web site! It would have heped me a lot. I glanced at your section on the fuel system and agree with your cautions about the need for high-pressure hose.

I bought the 2 sections of factory flex that GM uses to connect the rails to the lines. I cut off the connectors that would normally go to the supply and return lines, and connected them to the steel lines that I plumbed back to the original fuel lines from the tank using high pressure compression fittings (that sounds pretty confusing, but it worked ). They weren't that expensive, and they have worked like a charm. It really helped to have the parts guys at my local Pontiac/GMC on my side.

Bluesman

[BIGKAT_83]

EXCELLENT ___WEB SITE I bet it took you almost as long to do the website as the conversion. The website is better than most of the books I've seen.

THANKS