Motor swap #2 94 Z71

[beertestr]

Check that the transmission has power going to it. If you think it has a hard miss, check all plug wires first for firing and then get an injector clip and fuel pressure gauge to hook to the fuel rail. Pressure the rail up and then put 12v to the injector on one side and tap the ground wire and see that the pressure drops. Do this on each injector to see that its firing and pushing fuel into the manifold.

Bingo, it was lack of 12+ going to the trans. For some reason I had that circuit wired to some power lead coming off the dash harness.. don't ask, I have no clue. I put the truck together 4 years ago while on a time crunch (baby coming), so while it worked flawlessly, there was obviously some goofy wiring done. It's all fixed now... sorta. I need to make up a small fuse panel, and eliminate the 2001 UBEC... but that's after the road trip.

Rough idle... I felt like a vacuum leak, so I checked the induction system I built (4" PVC), and then looked to see if the knock sensor wiring got underone of the intake runners where it seals to the head. Nothing there, but I noticed some of the foam they stick to the bottom of the intakes was sticking under the #4 runner. I pulled up the intake to find that most of the port was covered with the foam. I yanked that out, and things got much better.. but not perfect. When I was loosening up the bolts around runner #7, I must have bunped the foul PCV out. I reattached that... idles MUUCCH better now. It still feels rougher than when the motor was in the 93 Sierra, but that might be due to the mounts, not the engine. There is no stumble anymore off idle.

Took it for a maiden voyage to get some t-fittings to tie the steam vent to the overflow hose, and get some more distilled water to 50/50 up the Dexcool. Speedo dropped out, but the Tech II was still reading VSS, so the bridge connection at the speedo buffer connector must have come loose (it was just some MIG wire in there to test the circuit. Also, the HVAC and wipers don't work... probably a fuse, we'll see. The truck needs front shocks, maybe tie-rods and a centerlink too. I hit a few bumps here on our glorious Michigan roads, and the front end started to shake and the tires started to shudder. I checked out the tie-rods, they are a little sloppy, the centerlink has some play, but nothing that would make it shake like it did... I had to slow down to under 15mph to get it to stop shuddering. I'll be looking for some Bilsteins or Rancho's shortly.

More later, I took some pics of the engine bay about an hour ago, but I have yet to transfer them off my Blackberry.

[beertestr]

Pics of the engine bay.. wiring almost cleaned up, and I need to paint the PVC induction. Someday I will reroute all of the wiring that goes over the intake, just not this week ..
Also need to build an enclosure for the air filter and pull cold air from the fender. If I ever go e-fans, I'll build the induction to go to the front left side of the CRFM and punch some holes in the sheet metal to pull air from beside the radiator on that side. Right now with the mech fan and the alternator location, it's a tough way to route the intake. I have a complete Trailblazer SS induction system, and a 2004 Sierra induction as well. Neither of them fit without mods, but the TBSS induction has the noise tuners that run along the right side of the intake manifold. If I can get that to fit, the induction moan will largely go away.... a nice plus from a refinement standpoint.

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[beertestr]

Quick update. Due to the sudden loss of a company vehicle, I had to get this Z71 into a running state at a pace faster than I had been proceeding. I got it running just before the 4th of July weekend.

Found out that the steering was completely shot... like a chatter bump would get the front end shaking so violently that it was hard to keep a hold of the wheel. Shocks did not fix it. Ended up replacing the tie rods (not stiff, but not loose), idler arm, idler arm bracket, and the pitman arm.. all three of which were looser than a wh**e... well you get the idea..

Washed the truck, shampoo'd a large portion of the interior to make it tolerable, loaded my motorcycle in the back and drove it from Detroit to Ithaca NY and back. Had to put a front axle bearing (just inboard of the right side CV)... that was fun doing that with the auto parts store 25 miles away, and my uncles half-assed tool set (half may be overstating it, maybe 1/4-assed)

Got home with something in the driveline HOWLING.... Checked the fluid level in the axle by adding 1.5 quarts... thought it was the rear axle, the remaining fluid stunk like hell. So I blew it apart, put in fresh 3.73's, Eaton Gov lock, new bearings and seals throughout. That was not only a small part of the problem, oh and that axle holds 2.5 qt's, so it was cooked, just not as bad as I thought.

The howl was something partially engaged in the t-case. I cycled the t-case from 2-hi to 4 low.. actually 2-low because the electrics for the front axle are not wired up yet.. drove it about 1/2 mile and then shifted it back to 2-HI.. noise went away... hmmmm.

- Still need to clean up some wiring, I have a battery drain somewhere.
- Still need to wire up the front axle 4WD actuator, oh, and upgrade the front axle from 3.42-3.73.
-Will need to look into the t-case. Might need new bearings or something.
-Still need to fab up an AC bracket to run the old R4 compressor. I am working on that design while in meetings.. I love AutoCAD on my laptop, though I wish I knew UG better.
-Still need to clean up the body. It needs to get wheeled out bad. Needs some bed rail covers, and some minor paint work where it looks like a bed cap wore off the paint on the bed rails. Oh, and I need to paint my spare tailgate, the one on there is beat to hell.

It's kinda a DD now. Just been riding my CB750 to work the last few days.. I have over 1000 miles on it with the road trip..

[beertestr]

Haven't updated this in a few months, largely since I have not really done anything to the truck. I figured out what I wanted to do for a new engine harness fuse/relay panel, but I have not wired it up yet. The truck is a full time DD now, so I have to be careful on tearing into it. I will build the panel with room for two electric fan relays so I can go efans at a later date. Most people report over 1/2-1 mpg with this swap, since it's a DD, I'll take the improvement. I did FINALLY mount the ECM last weekend. I removed the charcoal canister, and installed a left side battery tray, modified a PCM bracket to attach to the battery tray, and bolted it in. I'll upload pics soon.

I picked up a 94 Yukon trans and t-case. I now have a spare t-case to work on/refresh and swap in. Still looking for a good 3.73 front diff.

[HPICamaroSS]

Fantastic storyline. It helps me understand what I am going to be doing to my '94. If I could I would like to ask you a few questions. In (most) of the other posts, "they" say that the new harness for a LS1 wont connect to the 12 pin connector on the 94 trannys. So what do I do?

My other question...my truck has a 9" lift on it, do you think I will have any problems with headers hitting my front drive shaft? Thanks!

[beertestr]

Fantastic storyline. It helps me understand what I am going to be doing to my '94. If I could I would like to ask you a few questions. In (most) of the other posts, "they" say that the new harness for a LS1 wont connect to the 12 pin connector on the 94 trannys. So what do I do?

My other question...my truck has a 9" lift on it, do you think I will have any problems with headers hitting my front drive shaft? Thanks!

"They" are wrong. It plugged right in. You will need to have your controller reprogrammed to eliminated the ECCC, which is what pulses the converter clutch. This functionality can be turned off so that you just get a regular lockup. The 94 trans does not have the ECCC capability, and will throw a code when it does not detect the circuit. You won't have ANY TCC until you get the reprogram due to the error code. I had this cal changed, and it's been working fine for 4 months now.

as for the lift, can't help you, I am at stock ride height and using the stock LS truck manifolds.

[bowtieguy79]

Nice write up. I have a 94 SCLB as well. Just bought an 05 5.3/60E pull out from the local junk yard. Going to use the 05 fuse block, fans, harness etc. Nice to see your pics, gets me motivated

This will be my second LS swap into a OBS. Did my dad's 95 2wd last winter.