Started the process of switching CSFI to Port FI using Ramjet intake

[speedygonzales]

This is basically documentation for someone wanting to get information to try this themselves. Just in case they "google" search it. I found a few small incidents of this being attempted but nothing of significance. Thought I would try to document it. At least for the path I chose.

I have finally started the process of getting away from CSFI (Central Sequential Fuel Injection). The dreaded "spider" for some of us. This is used on the original Vortec engine, the 5.7L 350 that came out in 1996.
Here's some pics of the system as it comes from GM assembled
http://www.truckforum.org/forums/att...ck-engine2.jpg
Top manifold removed
http://troubleshootmyvehicle.com/ima...98/image_1.jpg
Notice the greasy filth build up from the EGR.
This is the engine that created the "vortec" intake bolt pattern. Which in my mind stinks because instead of having 6 bolts on each side of the intake to spread out the load of clamping it down to the heads. It only has 4 on each side with 2 on one end and 2 on the other end and there is, get this I measured it, nearly 13 inches between the bolts at one end and the bolts at the other. Think of it as old school SBC with the 2 center bolts removed. BTW this CSFI was also used on the V6 and the 305 V8 of the same years.

I had already changed to the newer style injectors that don't rely on the poppet nozzles. Shown here
http://www.summitracing.com/parts/smp-fj504/overview/
Here's some more good info on changing to the new style injectors
http://www.theautoshop.net/VortecMPFI.htm
However I found that they usually have too low an operating pressure. I had to "modify" my return line to get the proper pressure out of 3 different sets of these that I tried. The second set crapped out by one sticking and had to be changed. Ugh I hate that job. Yes I had mistakenly thought it was the FPR or the fuel pump and changed both of those before discovering this pressure issue with these.

I Had read some did a conversion with the marine Vortec manifold using their original PCM. Like this:
http://www.pacificp.com/forum/viewto...r=asc&start=80
Although the marine manifold is an improvement over the automotive Vortec manifold in that it is port fuel injected, I didn't feel it was enough return on the effort. Also these are nearly impossible to come by and I really don't want to modify the original wiring just to keep the original PCM.

For one thing, the original PCM has to be programmed with some changes to the engine. I want a self learning ECM. I wrestled with this change for some time as question after question kept coming up. Namely, how to keep the dash from lighting up with SES, Brake inop, Air bag lights etc.........

Here's a little information regarding inspections in our part of the country. In southern VA, there is no tail pipe emissions check. There obviously can't be a SES light on when they check the dash. Of course they want to see the SES light come on during pre-check start up and then it should go out. There are obviously other safety checks done on the rest of the vehicle, but that's it as far as the operation of the engine.

I discussed with and later had one of my PCM's reprogrammed by PCMFORLESS to remove the engine controls but keep all the rest. This will give me transmission control, ABS, AC, still compensate for bigger tires on the speedo etc.... Air bags are not impacted by this so they will function normally. The reason I have 2 PCM's is when I rebuilt the bottom end a few years ago, I had bought an extra to have EGR and the rear O2s removed and the speedo compensating for larger tires. Remember that picture above of the nasty greasy spider injectors. Mine stays perfectly clean now because of no EGR.

Rather than put the truck down for a time to have the original PCM programmed, I bought a spare that was programmed and shelved the original. I am running the replacement PCM and sent off my original to be modified to remove engine controls.

I will still have the pre-check SES light on start up and it will then go out like it should. The running of the engine, or in this case lack of engine feedback will not set a SES. However the other items like ABS or transmission codes will still be able to set a SES.

So the engine controls in my case will be done by a FAST EZ EFI 2.0. This will work similar to the original PCM however it uses speed density for engine controls instead of the original MAF process. This FAST system does control fueling and ignition timing and it self learns so over a short time it will improve it's control to "fine tune" the controls to parameters that are set.

Here is were I learned a few things. One, many aftermarket EFI systems are fuel only control and do nothing with ignition control. If for example, you look at the original FAST EZ EFI system, it is this way. It relies on a mechanical distributor to do it's own thing. This would be for the guy that wants to replace a carburetor with more reliable fueling but doesn't want the expense of changing the ignition system.

Most if not all the aftermarket EFI systems require the use of an ignition box to control ignition timing. So it's not just a matter of plugging the EFI system into a distributor. Many of the systems require 2 reference signals for ignition timing and get them from a distributor.

Now for the meat and potatoes of the system. As I mentioned, I am starting with the Ramjet intake. The obvious first reason I chose it was, it has the Vortec bolt pattern. here's a few pics of the Ramjet if you aren't formiliar with it
this is the engine
http://www.summitracing.com/parts/nal-12499120
This is the intake kit if you want to purchase it minus the harness and controls
http://www.summitracing.com/parts/nal-12498032
This is the intake by itself
http://www.summitracing.com/parts/nal-12489371
I'm using the bare intake cause I have fuel rails and injectors left over from another engine that I will make work (I hope).
Also the intake kit requires a deposit and I don't know what intake they want in return. I only needed to order the throttle body for $350. I'll talk about that in another post.

Incidentally, I want to say here that the only intake gaskets you should look at with a "Vortec" intake is these.
http://www.summitracing.com/parts/fel-ms98000t
They are metal centers with rubber on both sides. (I never found them individually, only in the kit shown)
Here's a better picture of them
http://troubleshootmyvehicle.com/ima...66/image_3.jpg
I had tried the original intake gaskets 3 times and the old timey fiber ones and nothing worked like these do. They have been great. I had an oil consumption issue from the time the truck was new. It never showed up on the plugs, and never came out the exhaust or showed up in the coolant but it went through oil even between changes. After going to these gaskets, I never worry about oil consumption any more.

Break here cause this is getting long. Be back with more info later.

[speedygonzales]

It was said the Vortec, LS1 and Ramjet had the same throttle body. So I thought maybe I could save by using the old intake but here is a picture of them side by side.
http://carphotos.cardomain.com/image...5/19058259.jpg
Original on the left, and the new Ramjet on the right. Notice the throttle connections are rotated. There is a difference with the IAC vents also but more importantly is the top of the air horn. The Ramjet is larger to accommodate an air filter. I doubt you could get an air filter to attach to the original Vortec TB lip.