Author Topic: 1991 Crew Cab Going 6.0 LS  (Read 11472 times)

Offline Captkaos

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #30 on: February 01, 2017, 05:03:01 PM »
That is what I used.

Chris Lucas
73-87chevytrucks.com
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Offline ehjorten

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #31 on: February 15, 2017, 01:18:43 PM »
Okay...next question...what do you need to do to get the factory gauges to work...oil pressure and water temp?  I've got a '91 so my 454 had electric gauges and senders.  It would be great if I could tap off of the stock LS senders, but I have a feeling it won't be that smooth.  I confess I haven't looked into this much myself, so I am asking you guys without much prior research.

Thanks!
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline Captkaos

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #32 on: February 15, 2017, 10:47:29 PM »
Yours should have the electronic speedo with a VSS so everything should work.  Just use the same sensors and run the VSS to the ECM

Chris Lucas
73-87chevytrucks.com
squarebody.biz


Offline ehjorten

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #33 on: February 16, 2017, 08:39:37 AM »
Yeah...speedo will be fine.  Was wondering about the other gauges.  My 1991 NP205 has the VSS that is 40 pulse per rev AC Sine wave and the LS uses the same 40 pulse AC Sine wave and apparently in the configurations you can set the output for the cruise control which is 2,000 pulses per rev, so I'm looking good their too.
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline hatzie

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #34 on: February 16, 2017, 09:51:11 AM »
Just use the 1991 senders for Oil and Temp.  Autometer makes bushings made to go from LS to sqaurebody OPS.  I don't believe the ECM uses the oil pressure for anything.
I assume the LS heads are ambidextrous like the smallblock with a bung in the unused temp sender hole. Soooo...  If the ECM sender is in the front of the LH cylinder head you can install your gauge temp sender in the back of the RH cylinder head.

You can drill and tap for your stock squarebody temp sender.  See post #9 below...
http://ls1tech.com/forums/conversions-hybrids/1261954-oil-sending-unit.html
« Last Edit: February 16, 2017, 09:54:02 AM by hatzie »
SVC & wiring mans --> Here http://tinyurl.com/7387BRD-SVCMAN or My Bucket @ http://tinyurl.com/SQ-SVCMAN
Parts & Illustr Books -->http://tinyurl.com/SqParts
GMSTG Textbooks-->http://tinyurl.com/STG-TEXTBK
Radio Manuals-->http://tinyurl.com/DELCORADSVC

Offline ehjorten

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #35 on: February 25, 2017, 08:39:21 PM »
Finally got my engine brackets sorted out and set the engine in the truck for the first time!  The LQ4 pan just sits on the ORD crossmember on the RH side where it is more square and there is about 5/16" of clearance on the LH side of the pan where it is scalloped out.  The engine is sitting in there nice and square, so I need to raise up the mounts about 1/4" and it should be golden!

One question:  How do the stock engines sit in these square body trucks?  Are they angled down to the back some, like 2-3 or something, or are do they sit pretty flat?

I did notice on the LQ4 power steering pump, that the lower return line tube (the one that is longer and welded to a brace on the back of the pump) is hitting on the frame and it got bend some.  I will either have to put a little notch in the frame, or modify the return tube.

Other than that, the engine fit in there nicely with plenty of clearance for the stock coils to the 4 Seasons AC Evaporator box.
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline Captkaos

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #36 on: March 01, 2017, 12:54:13 PM »
3 degree rake

Chris Lucas
73-87chevytrucks.com
squarebody.biz


Offline roundhouse

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1991 Crew Cab Going 6.0 LS
« Reply #37 on: March 05, 2017, 09:46:07 AM »
You're gonna love the new engine
« Last Edit: March 05, 2017, 10:07:13 AM by roundhouse »

Offline ehjorten

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #38 on: March 05, 2017, 09:08:52 PM »
My 12-yr old son helped me redo the rear cover and main seal yesterday.  Today I got the stock pan gasket off and am cleaning up the pan.  Gotta get the front cover on and aligned before I can do that.

Gonna get the heads shaved to bump-up the compression a little bit and install LS6 valve springs.  Waiting on a new set of GM head bolts and alignment dowels.
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline ehjorten

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #39 on: March 29, 2017, 09:31:34 AM »
Haven't taken many pictures, but I put new valve seals on, installed LS9 valve springs and had a little taken off of the surface of the heads.  Got the heads back on, valve train installed, new valve cover seals, and recently I reinstalled the harmonic balancer.  To install it, I got a M16 threaded rod, some M16 Fender Washers and a couple of M16 nuts.  It went on easy!  The hard part?...torquing the new bolt to 140 of angular torque!  Man that was a lot to turn that thing 140!  I thought my engine was going to flip-over on the engine stand!  It is about ready to fit back in the truck to final verify my engine mounts are good, so they can be final welded.

Here are a few pictures:

A little homebrew in the kitchen while I was watching Oregon spank the favorites, Kansas to make it into the final 4!


In case anyone doesn't know, I was CC'ing the combustion chambers.

Almost finished installing the heads and valvetrain.
« Last Edit: March 30, 2017, 12:14:35 PM by ehjorten »
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline ehjorten

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #40 on: March 30, 2017, 12:17:16 PM »
What are you LS guys doing to prime your engine?  I had some tell me...nothing...it was a drop-out engine and it has a roller cam.  Just fire it up and it will be fine!

I kinda want to prime it, but I don't want to spend money and time making a homemade primer for one engine!
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline ehjorten

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #41 on: April 11, 2017, 01:38:11 PM »
Got my EFILive Flashscan today!  Getting close to starting the wiring headache and reprogramming the PCM.

Anyone with suggestions for priming the engine?  I saw a YouTube video of just taking the oil galley plug out of the driver's side front and putting a hose in there and pouring oil into the pump to prime it.
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline roundhouse

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #42 on: April 16, 2017, 11:35:54 AM »
I ran the starter to do a compression check
Then Just fired it up


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Offline ehjorten

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #43 on: April 20, 2017, 11:40:58 AM »
So I have some questions about the DBW pedal wiring...

I am putting a 2004 LQ4 into my 1991 Chevrolet V3500. For the pedal I am using a 1999 Chevrolet 6.5 Turbo Diesel Pedal. It bolts right up to the stock location and has the exact same pin-out as the 2004 LQ4 Pedal, although some of the pin locations are swapped around between 5 V Ref. and Low Ref. The connector is the same 10-pin Metri-pack connector, only it is keyed slightly different, but it is an easy swap to remove the Metri-pack pins from one connector and transfer them over to the other connector.

My question comes with the 3 Accelerator Pedal Position (APP) Sensors.

The 2004 stock wiring harness only seems to use 6 wires and only 2 of the 3 APP sensors are wired up. However, wiring diagrams for the 2003-2004 GM Truck Electronic Throttle Control system show using all 3 APP Sensors. I know that they have done it with 2 APP Sensors and 3 APP Sensors.

I am curious...why have 3 and only use 2? Can I wire up all 3? What is the difference? I'm just curious to know why GM did that! Are there different settings in the PCM?


2004 LQ4 Pedal Wiring Diagram


2004 LQ4 Pedal Connector


1999 6.5 GM TD Pedal Wiring Diagram
« Last Edit: April 20, 2017, 03:10:59 PM by ehjorten »
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline ehjorten

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #44 on: April 21, 2017, 09:58:25 AM »
Since nobody has chimed in, I will add to this thread with information that I gained from a colleague at work...

Essentially, the newer computers don't use the third sensor. I don't need it and my code is not looking for it to interpolate a throttle value. It seems it was only used in the early computers for a finer resolution, but it proved overly redundant. The third sensor barely ranges 1 Vdc through the whole pedal range.

My colleague thinks GM engineers were really concerned with driveability at highway speeds. The GTOs have a line of code that divides by the 3rd sensor's position. All of the cars built later just use one sensor and then the other is there for OBD double checking.
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6