Plans for L32/3X00 Hybrid

[bszopi]

Well, which vacuum lines are used on the 3.4L plenum? I would guess the T-fitting on the back goes to the FPR (small) and brake booster (large). I have no idea where the MAP sensor is on the 3.4L, so I can't help you there. And honestly, it doesn't matter, as long as you have vacuum where you need it. Just use whatever ports work best for you.

[tkoforpresident]

Using this picture as a visual groundwork I'd like to take things one step at a time and try to figure out the best way to run all the vac hoses.



Here's a list of necessary components:

#1- pcv valve /hose - Solved
#2- MAP vaccum hose/ mounting bracket-Solved
#3- HVAC hose- Solved
#4- Brake booster hose- Solved
#5- FPR hose- Solved
#6- Purge Solenoid thingy vacuum hose/mounting
#7- Valve cover breather - Solved
#8- EGR valve- Solved

Let's start with the one's that I know already.

#1. PCV valve. Without going into much detail I can explain what needs to happen. The RWD and FWD setups are completely different as far as PCV valve is concerned so I will have to purchase the FWD vaccum hose that runs from the passenger side valve cover (where the PCV valve is located) to the top hole located just above and behind the throttle body on the upper intake. I will need to also buy a new pcv valve. This is a done deal.

PCV- Check

#4- Brake booster hose- On the RWD intake the booster hose comes to the "T" at the very rear of the upper intake and fits onto the larger of the two metal tubes. On the 3400 the brake booster line runs to the right side of the upper intake where the "black plastic" tube is. This tube looks to be almost the same diamater as the RWD one and I know for a fact thatt the booster hose will have proper length to reach over to it. Therefore all I need to do is run the old hose to the new "black plastic" inlet on the 3400 UIM. Therefore, this is also a done deal.

Brake Booster -Check

#3 Hvac Hose- On the 3.4 RWD there is a small vacuum hose coming out of the wiring harness at the very back of the motor at the firewall. This hose fits into the "smaller" metal tube on the metal "T" located at the rear center of the intake. The only possible port to tap into is the far back right inlet that currently on the 3400 UIM is "plugged" with a small rubber nipple. The pipe is a "little" smaller in diamater than what I would have liked but if you look at the 3400 UIM, there simply is no other tube close by to tap into. I may have to cut the vacuum hose out of the wiring harness but I don't see why it shouldn't reach that port with a little elbow grease. We can then therefore consider the Hvac hose a done deal.

Hvac Hose- Check

#8 EGR- I have to mention it since it has an inlet on the UIM. But this will be a non-issue since I've purchased the EGR block off plate. 2 bolts later and we can consider that gaping hole next to the throttlebody a DONE DEAL.

EGR- Check




Now, after all this, things get hazy. So let's start by figuring out the valve cover breather tube. ON the 3.4 RWD the breather tube comes out of the passenger side valve cover and runs all the way to the rubber intake elbow in front of the throttlebody.

So does the 3400 have a valve cover breather tube? I'm pretty sure I've seen pics of a tube going into the top of the rubber intake elbow just before the TB but I have never seen where that hose comes from. Is it the driver's side valve cover? (or what would be on the FWD the REAR valve cover)

My options could be something as simple as putting a filter onto the breather hole (if one exists) and then just plugging up my current intake elbow inlet since it is no longer necessary.

So who knows anything about the location/routing of the valve cover breather tube on a 3400? We'll start there.

[tkoforpresident]

Thanks Brad, that's very helpful.

too bad I just snapped a bunch of pics lol

What I need to figure out is which vacuum hoses that are stock on the 3.4 will be REUSED and WHERE they will go. I am glad to hear there are extra vacuum ports available.

I think it may be more appropriate for me to post up pics of not my 3400 UIM, but rather the stock rwd 3.4 plenum so that I can show you the vacuum ports on that plenum and tell you where/what those hoses come from.

I'll get some pics up later and we can go through things one at a time until it's all sorted but Brad, you've given me a good head start.

thanks

[bszopi]

With the plenum rotated like it would sit in a FWD vehicle, and looking at it from the radiator position, you should have the following vacuum ports:

Back left: Not used/capped
Back middle (LARGE): brake booster
Back middle right: MAP sensor
Front right: Not used/capped

This is how it is on my 3400 Rendezvous. I know on engines with the 4T60E, the front right port goes to the vacuum modulator on the tranny. The FPR is usually fed off of a T fitting from the MAP sensor.

[tkoforpresident]

Just got my 3400 UIM, TB, and fuel rail. I will have a good amount of questions about some particular pieces on these parts. Especially the upper intake since there is a million vacuum ports. I'll take some pictures and then we can get some stuff figured out.

I got the old 3400 injectors off the fuel rail in preparation for the new 28# injectors from WOT. They were freaking hard to get out

Also, i noticed something cool. The shcrader valve is located at the rear of the rail. By decoring the valve I should be able to transplant my braided line/autometer gauge over to the 3400 rail. there is plenty of extra line so it should work out great. The gauge goes up to 100 psi I think and I'm hoping the stock FPR will still have all of its pep and put out it's required 55psi at key-on and more importantly full throttle.

[tkoforpresident]

Yup, I see what you're talking about. One of these...



sounds good. Let's just hope my stock harness reaches that far. I get the feeling that one of them won't but even then, it's just a matter of lengthening them a little with some wire. And like you said, it will serve as a double purpose by both blocking off that coolant passage way and giving me a spot for my second CTS.

[CNCguy]

Max
From what I remember most GM temp senders/sensors are 3/8" NPT. You can use a 1/2"~3/8" reducing bushing for the 1/2" hole.

[tkoforpresident]

Personally, I wouldn't use the rubber expansion plug. A metal expansion plug would work if you could find the proper size. Since it is off, you could run it by a local machine shop and have them tap it to 1/2" NPT. Then a simple pipe plug would work. On the MG swaps, we tap that hole and use it for the temp gauge sender. Max... if you have the room, you could install your 2 wire ECT in there and the 1 wire temp sender in the other hole thereby eliminating the need for a three wire ECT.

OK Marc, I see what you're saying. Basically have both of my temp sensors located there at the thermostat and just run the stock CTS wiring to their respective sensors. The only question I have is whether or not my stock RWD sensors will thread into the existing FWD (3 wire) bung.

Do they share the same thread/dimensions? I would think the 3 wire would be a bit bigger...

[tkoforpresident]

The CTS hole is directly above the hole that I was suggesting plugging, IIRC.

well if that's the case and it's already tapped for a 3 wire CTS I think the best way to go about it would be to splice my current CTS's into a 3 wire pigtail harness. I should wait to see the LIM though before I even speculate. In fact, if the guy who's selling it to me doesn't contact me soon I may have to go elsewhere for it anyhow.

[pocket-rocket]

The CTS hole is directly above the hole that I was suggesting plugging, IIRC.

[tkoforpresident]

Personally, I wouldn't use the rubber expansion plug. A metal expansion plug would work if you could find the proper size. Since it is off, you could run it by a local machine shop and have them tap it to 1/2" NPT. Then a simple pipe plug would work. On the MG swaps, we tap that hole and use it for the temp gauge sender. Max... if you have the room, you could install your 2 wire ECT in there and the 1 wire temp sender in the other hole thereby eliminating the need for a three wire ECT.

The LIM that I am planning on purchasing has been tapped already for the 3 wire CTS which is why I was considering just using it and splicing my 2 stock CTS's into it. I do not know the precise location of where this tap is other than it is locted in the thermostat area of the LIM. Maybe this very hole we are talking about plugging is the one that has been tapped for a CTS. I don't know.

[CNCguy]

Personally, I wouldn't use the rubber expansion plug. A metal expansion plug would work if you could find the proper size. Since it is off, you could run it by a local machine shop and have them tap it to 1/2" NPT. Then a simple pipe plug would work. On the MG swaps, we tap that hole and use it for the temp gauge sender. Max... if you have the room, you could install your 2 wire ECT in there and the 1 wire temp sender in the other hole thereby eliminating the need for a three wire ECT.

[tkoforpresident]

Yeah no problem. I don't know when you're planning on getting yours up and running but for myself I'd like to maybe gather all the parts nessecary over the summer and then slowly put the build together over the winter (in my buddy's heated garage ) and have it ready for spring.

That should give ample time to take these "modifications" one step at a time and get things right.

[TechRod]

I was going to try this idea myself but if you get yours running first please let me know if it works out for you.

[tkoforpresident]

thanks for the idea. It shoud work great for a novice like myself.