What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

F-body or Vette ecm

7

77crewcab

1/2 ton status
Joined
Feb 9, 2004
Posts
1,620
Reaction score
0
Location
Lubbock, Texas
Trying to figure out which ecm to use. The underhood mounting of the Vette ecm is very appealing but it wouldn't be too hard to mount the Fbody ecm under the dash. I have an Fbody harness to modify so modifying it to work with the Vette isn't a problem. So which would you pick?
 
What fuel injection are you going to use? The "vette" style computer you refer to is probably for an LT1 or LS1 and they mount in the engine compartment. They are best used with their style engine/fuel injection system. The "Camaro" computer is either a '730 or '165 depending on year and are the one's that are used with the standard TPI swap. Pre 91 corvettes also used TPI and the 730 style computer.
 
TPI. The vetttes were mounted in the engine compartment then too. They used an 7730 style that was sealed up for underhood mounting and given a different number. But still essentially the same thing from my understanding.
 
Yep I think you're right, I forgot about the 1227727 computer they used in 90 and 91. Essentially the 727 is a water tight 730. I don't imagine they are real easy to find with a complete wiring harness, if you could find one for cheap it would be nice to be able to mount it under the hood and save the hassle of running the harness through the firewall. Unless you have the vette stuff loacated already in the end it would probably be easier to get a harness from Painless and plug into a 730 computer and be done. Either option is easier than a 165 MAF setup though.
 
IIRC from back in my TPI conversion day the TPI Camaro was a batch fire injection system and the Vettes were sequential fire. Or were there batch fire Vettes also? Also is the ECM the same and only the prom different? At any rate, if the ECM's are the same with the exception of one being a weather pack connection i would choose the ECM that is easiest to find.
 
The MAF (85-89) systems are batch fire and the MAP (90-92) systems are sequential. There wasn't much difference between the F and Y body systems besides the PROM calibration and the sealed weatherpack 727 ECM which is the same as a 730 as far as PROMS go.
 
Well I already have a 730, I see the vette 727s on ebay all the time with wiring pigtails. I figure that if I am going to be redoing the wiring my self i could just as easy wire it up for the 727 and have everything under the hood.
 
From what I understand the 'vette ECM's are not water *proof*, they are water resistant. Meaning they are better off mounted in the cab if your truck gets muddy and/or wet.

Even my truck gets wet and muddy underhood when driving around wet logging roads, I wouldn't want the ECM in there. Besides, it tends to be a lot hotter in the engine bay.
 
Good point, I hadn't thought of that. Guess if it would be mounted in the cab anyway, then the 7730 is the easiest way since I already have it and the harness for it.
 
Yea, I've still got a ton of wiring I'm not sure what I'm going to do with...the F-body wiring harness must have been setup in the car kind of weird, I've mounted the ECM in the stock truck location, but probably have 2 feet of extra main wiring harness.

So do you have 'vette hard parts, or f-body stuff?

Been trying to get my hands on a set of 'vette fuel rails, so I can tie into the stock TBI fuel lines on the new truck. Pretty hard to find unfortunately.
 
I have a mix of everything. I think I have 3 1/2 full setups. How do you plan to tie into the TBI fuel lines with a Vette fuel rail, it still comes down the front of the block.
 
77crewcab said:
I have a mix of everything. I think I have 3 1/2 full setups. How do you plan to tie into the TBI fuel lines with a Vette fuel rail, it still comes down the front of the block.
Click to expand...

The Vette fuel lines exit out the rear. Back when i did my TPI conversion i was dealing with Street & Performance in Mena, Arkansas and they sold the Vette fuel rails.

bigblock72
The MAF (85-89) systems are batch fire and the MAP (90-92) systems are sequential
Click to expand...

I ran a MAP system from a Camaro and they are batch fire not sequential. That's why i was asking if the ECM or the PROM is different between Camaro and Vette because i was running the 7730 ECM.
 
Man my TPI stuff is rusty (some I just plain blocked out) looks like they are all batch fire even the vettes according to all of the wiring diagrams I've looked at.
 
I know that Street & Performance does conversions to make them rails come out the back. But I was under the impression that the Vette rails still came out on the front of the block, passenger side rather than driver side like the f body. I know it is possible to install the railse backwards to get a rear exit but then the pressure regulator rubs the bottom of the plenum a little.
 
RE batch fire and SFI
All TPI is batch fire. The ECMs do not have the drivers to support SFI
SFI did not come out untill 1994 and is an OBD2 type system.
Also as Dorian said the ECMs are not water proof. Just water resistant. GM did not expect people to go sliding their vettes thru mud bogs.:D
ECMs should be in the cab.
 
Yeah I am thinking I gave too much credit to the GM engineers thinking that they would make something underhood waterproof. Under the dash it will be, using the 7730 ecm. Thanks.

Eventually it will be a SFI, OBDII, coil on plug TPI though. I have been following all that stuff on thirdgen and am just amazed. I know I could just get it all with a gen III. I had one I planned to put in the K5 but I am really wanted something that I could tinker with more and have a little fun experimenting with.
 
You are correct on the Corvette stuff. From the pictures I've seen, it is run essentially the same way as the drivers side F-body stuff, just to the passenger side.

I'm running stock TBI truck lines now (albeit re-bent and UGLY) on the drivers side frame rail on a truck I assembled from scratch. I intend to take the lines off of the '87 I own, and install them on the passenger side frame rail as stock (or use the '87 frame, undecided yet), on the '81. Either way, the distance from the front of the block to the termination of the TBI hard lines is the same, just on a different side in my case right now.

The rails backwards is intriguing, is the plenum/FPR issue resolvable? Shorter lines are better! :)
 
I don't know how the FPR issue can be resolved with the rails backwards. The bottom of the plenum actuall hits the FPR and the aluminum housing that is part of the cross tube. The only way I can think of would be to find a way to mount another "rear" crossbar in the FPR spot and use an inline FPR external to the intake assembly.

On the other hand I have an idea that might work for putting the TPI lines in the same approximate location as TBI. Basically bending the lines back so that they run towards the back of the intake and stop just rearward of the EGR. By putting a TBI and TPI intakes side by side that is about the same location as the fuel line hookups on the TBI unit. It would probably mean cutting and splicing the lines to make it work, but should be possible.

Another option would be to splice into the line coming out of the fuel rails and bend new lines to go back to where the TBI flex lines start. Or buy the AN adapters and just run braided line back to the hardlines on the frame.

I am in the same boat sort of. I am converting my truck to TBI just to get it driveable while I finish my TPI plans. Once I am ready for the TPI I want to just plug into the TBI lines.
 
Yeah, the AN stuff was too expensive for me. I really hated having to use adapters when all I really needed was a way to make the Saginaw fittings.

From what I hear the tools are out there now, but still expensive enough that they probably aren't worth it for a one time use.

I wonder how much "slack" there is on the fuel rail "connecting link" that the FPR sits on? Depending on how much interference there is with the plenum, perhaps it's possible to simply bend it down where the FPR is enough to clear. Would certainly be easier than trying to bend the lines backwards...I can't recall how the lines are held into the rails, I suspect something along the lines of the Saginaw fittings(at least o-ringed). It would be nicer to make completely new lines, as re-bending steel line is pretty bad. For tight radius bends, they tend to dent pretty badly. Maybe with a high quality tube bender it wouldn't be so bad, but I don't have one of those either. :)
 
There would have to be a lot of bend down to clear the FPR. The plenum wont even bolt up because of it. Street and performance offers a conversion which looks like a new line out of the FPR that goes to the rear and an AN fitting that goes in the back of the pass. rail, but it is pricey. I think that the bending would be best way for trying to fit it to the TBI lines. I think the Vette lines would be the easiest to bend due to how they come out of the rails. The other option would be to simply cut the ends off the hardline extensions and splice them onto new line, which you could bend to run back along the rail and down the back of the block to meet the TBI flex lines. Once I get a chance to play with some I'll figure something out.
 
You must log in or register to reply here.

Latest Posts

Top Bottom