Hello! Looking for help with a Blazer 4.3 Vortec

[CadillacPat]

Hello all on the Turbo Buick board!
Looking for info on the Vortec 4.3 on Google, I found a link with threads here.
I have a '99 Blazer of my daughters that I am replacing the original engine with one from an '03. There are a few differences, the main one being the '02's up don't have EGR. The other two being '99 having a year-only electric smog "secondary" pump and the other being different type of knock sensor. The knock sensor fix is easy as you just drill out the mounting hole to the older 1/4" pipe thread and use the older sensor. I'd like to ditch the air pump and EGR, but running without the EGR hooked up will probably give a light. One seller on ebay, "S10Wharehouse", who I didn't buy the engine from claims you can just install the engine and leave the "check engine light" on. Because it's my daughter's truck, I would like to keep the service light working properly.
What I am contemplating, is to use the newer non-EGR intake and connect the EGR valve to the wiring harness, but since the intake has no mount for it, to just leave it tied up. I also want to leave the air pump connected electrically, but disconnect from the exhaust manifolds (and use the newer exhaust manifolds that don't have air pump connections).
Finally, the newer engine has a different style "spider" in the upper plenum. The older style has poppet-style injectors (mounted in the lower plenum) at the end of the lines with the "solenoids" in the center piece. The newer style has the lines running from the center to the individual injectors (also mounted in the lower plenum, but with a shorter recess in the injector hole so you can't interchage the injectors between intakes) at the end of the lines, and the wiring running to each injector. Both styles share the same 12-pin connector at the center connection. Would they both be sequential injection? Is the new style injector cleaner-running, and being at least part of the reason for no EGR?
Somehow, GM did away with EGR on the later engines, and not by the use of VVT (variable valve timing), as used by engines such as N*'s.
Being very up on injectors, I am hoping someone on the board can at least shed some light on this.

Thank you in advance,
Cadillac Pat

 

[charlief1]

Pat, the systems are simular but not interchangable. One used a injector set up that fires all at the same time and the the newer fires in a "batch" series. As far as EGR both engines have them but they're different. To change engines you're gonna have to use the earlier intake and exhaust manifolds.

 

[CadillacPat]

Chalie,
Thank you very much for the reply. I was hoping someone such as yourself with more EFI knowledge would answer. As I mentioned, both systems use the exact same 12-pin plug, right down to the same numbers molded in. It is because of this that I thought the older '99 style also has six individual injectors, but housed inside of the plug. I was hoping both were sequential. Is it possible that the '99 style is batch-fire and the '02up sequential (I thought there was "batch", "bank-to-bank" and "sequential", all of which being "multi-port", but only the last being truly "sequential")? Could you fire sequential injectors in batches? The timing would be slighly off, but then the injectors would fire like the older batch style. I ask this because the older aftermarket EFI controllers had adjustments to fire batch, bank-to-bank or sequential. Sequential is really nice as you can set each cylinder to it's own fuel curve. Part of my reasoning is that I believe the newer style runs cleaner, with a better fuel spray (and better injectors; the newer injectors are different), and allows the engine to run without EGR. Also, besides no EGR, there is no type of AIR or provision for it. The older engine is supposedly a '99-only electric auxiliary air pump system. Earlier and later engines had a belt driven AIR pump. What I was hoping was to take out the EGR, AIR and associated exhaust manifolds, piping and AIR pump for a cleaner installation, both astetically and emissionswise.
Finally, I should also note that the replacement engine is extremely clean inside, with only 29,233 miles. Also, I had to take the intake off anyway due to the need to check the intake gaskets. As you might know, Vortecs, especially 4.3's, are notorious (and there is a class-action lawsuit, but my engines are too old to reap the benefits of the payouts) for "swelling" intake gaskets that fail. The older engine had them replaced, as it had newer Felpros and the newer engine has signs of swelling on both sides.
Pat

 

[charlief1]

Pat, You need to go look in the syclone/typhoon section and it will give you a better idea of the earlier systems. It uses a "spider" injection system. As far as sequential firing in a batch patern the GN did this when there was a problem but the 4.3 Vortec is a little different. As far as EGR, even the last of the SBC engines that the 4.3 is based on use EGR so it has some sort to keep down NOX emissions and reduce knock. There should be a place on the exhaust manifolds that looks like a pipe attaches and on the intake you should also find a simular one. This is the EGR pipe location.

 

[CadillacPat]

Charlie,
Thanks again for your help. I will check the sy/ty section. I had thought about the turbo sy/ty, but thougth they were totally different, especially since they have water-cooled intercoolers. However, I didn't check this site. Do you mean that even in the Buick 3.8's, that the ECM would change the fuel sequence from sequential to batch if it detected a problem? Also, I realize the older '92-'93ish 4.3 Vortecs (the first of the Vortecs) had a large aluminum top (upper plenum) that covered the original "spider". This was the original "poppet" valve system that used one injector. It was problematic, especially since it required a high differential pressure to open the poppet valve. Even a slightly low fuel pressure would not allow the poppet valve to open. Later designs, like the ones on my engines, will allow the engine to run as low as about 14 psi. I found this out when the fuel pump went on my ex's '99 ZR-2. The truck ran for about 15 seconds after I changed the bad intake gaskets. I played around with it for a bit, thinking I had done something wrong. The truck had spark, and a quick shot of starting fluid made the truck run for a short time. I couldn't believe the probabilitiy of the fuel pump going at the same time I had the truck in the driveway to change the intake gaskets. By that time, the truck had about 14 psi at the fuel rail. I changed the pump and the pressure went back up to 62 psi.
As far as EGR, the '02 up engines really don't have it or AIR. While the driver's side exhaust manifold on the '99 has an exhaust connection near the rear for the tube that brings exhaust up to the front of the lower intake plenum to provide exhaust gas to the EGR, and, front connections to allow the secondary pump to blow fresh air into both exhaust manifolds (through a "T"), the newer engine has no connections anywhere or an EGR valve. I knew when I bought the newer engine that this was so. The seller "S10Wharehouse" states in his auctions for these newer engines that you can either change over the intake/exhaust manifolds, or just run with the service light on.

Pat

 

[CadillacPat]

Charlie,
I went to the sy/ty tech forum...not much there.
Also, it's looking like I will be going with the original EGR intake and injectors, but keeping the non-smog exhaust manifolds and just pluging the intake EGR connection to the exhaust, so thanks for your help on that. I got the same advice from a local guy who has worked on Vortec intakes (but he hasn't had one of the newer '02 up ones apart)The EGR valve will still be installed and connected, but the valve will not get any exhaust. Yes, I know these engines can need exhaust gas to reduce knock, but I have it deleted on my C3500 with no knock. I was told that if it did knock, to just run premium. I'm not sure about NOX, but wouldn't premium reduce it as well? As far as the auxiliary AIR pump, I don't know if it would be better to just leave it connected electrically and leave the air discharge disconnected or disconnect it electrically and remove it. I think removing it will give a code. I could leave it in at first, but disconnected, and see if I get a light. If even connecting it gets a light, I had previously found a seller on ebay, "spareecm", that will reflash the PCM to remove things such as the Passlock II (which wouldn't allow my '98 C3500 to start due to a bad theft deterrent module; I"m putting in a 500, so the PCM is coming out anyway), EGR, AIR, speed and rpm limiters and delete the rear O2. If so, whatever lights (EGR and/or AIR), stay on, I will have deleted (along with rear O2).

Pat