LQ4 intake/harness help/advise
 

Well I had a complete 01 LQ4 out of an 01 Denali fall into my lap. It is a complete motor minus the wiring harness, ecm and of course no pedal or TAC. I was told the motor was no good so I tore it down and found it had a spun main bearing. I found a fresh rebuilt 06 LQ4 short block for CHEAP and swapped the heads and everything else over and now it is sitting as a long block. I have been trying to educate myself on the Vortec motors and have come across several differing opinions (surprise surprise!!!)

Anyway to get to the questions and to see if I can clear the mud out of my head a little bit here goes. I have everything I need to take it back to a complete 01 style motor but have been looking for a wiring harness, ecm, pedal and TAC that will work and get it running. From what I have seen the 01-02 LQ4's seem to be a pain in the a$$ since they are what seems to unique to those years. And to add to it the required parts to get it running (ecm and TAC) appear to be much higher priced. I was thinking if I could find a complete 06 intake with fuel rails, injectors and TB then I could get the less expensive ecm, pedal and TAC. Does this sound like a good route to go or should I be looked at doing something else. I am trying to put this motor back together as inexpensively as possible because cost is an issue.

Oh and I will be looking to put a 4l80e with it.

Re: LQ4 intake/harness help/advise
 

was the original 01 an iron-head motor?

Re: LQ4 intake/harness help/advise
 

No the motor had aluminum heads. That is another thing that is making me wonder because I know the 01 should have had iron heads. I will get a pic tomorrow. I was also thinking that the throttle body should be a 4 bolt with a 2 plug sensor but it has 3 bolds and a single sensor plug and the fuel rails are return type rails. There are several things about the motor that has me scratching my head.

Re: LQ4 intake/harness help/advise
 

Early DBW/Traction Control, This set-up was used in '99-'04 Vettes & '01 & '02 SUV/C3 Sierras with Traction Control, Unless you have the PCM, TAC & Pedal...Don't use this set-up.

Re: LQ4 intake/harness help/advise
 

Well lets say that it is an 01, if its late production making it built like an 02.

If thats the case, the 3 bolt TB and aluminum heads make sense. In that situation, your best bet is to find; the TAC, ECM, TB and Pedal all from an 02-04 truck or van with DBW and a 4l80e (hint, look for a G-van). This will get you a matched set of components that will fit on the 3 bolt intake, run together, and be tuneable.

Re: LQ4 intake/harness help/advise
 

Tarzan! Hello neighbor!

I am in Ft Worth! Have you checked with the WY on Mansfeild Hwy, First one, left side as your heading south! they used to have tons of vans and have been real good to me when I was doing my swap!

Good luck!

Re: LQ4 intake/harness help/advise
 

99-00 6.0's had iron heads, pretty sure 01 was when they switched to aluminum. Also all Gen3 engines used 3 bolt TBs. You will need the all plastic TAC module and a red/blue PCM, like a 411, this DBW was used on 01 and 02 truck. Personally i dont see anything wrong with this set up at all. And, just an fyi. I searched high and low to find a pre 08 van with DBW and never found one, even though Mitchell wiring diagrams show there was an option for it.

To the OP, If you need a TAC, let me know, I have some. The pedal is the same from 01-05 so they are easy to find.

Re: LQ4 intake/harness help/advise
 

My setup was a late 03 2500 time warner van

Re: LQ4 intake/harness help/advise
 

No I have not checked there yet. Planned on hitting the WT's Monday to see what I can find.

I was at the shop this morning to take another look at the TB to make sure I was remembering everything right and this is what I found that I was wrong about. The TB is a 2 plug TB which takes a different TAC than the 1 plug but everything else was what I stated before.

I will be needing an ecm with wiring harness, TAC with matching pedal and harness for either the 2 plug TB or 1 plug if I find one that is reasonably priced.

Does anyone see an advantage or disadvantage to turning this into a 03-06 style motor since I will have to get all the parts above anyway? And what about the fuels, should I leave the return type or go with the returnless style?

Re: LQ4 intake/harness help/advise
 

I prefer return style, just for the ease of switching rails, or adding an aftermarket/external FPR unit should you decide to go FI.

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Not to hijack... Are you absolutely positive it was a van???? I would have paid you good for a copy of that tune a few years ago. Not sure if you are aware of it, but that is the ONLY factory tune with the 03-07 DBW and also with the 12v A/C request versus the serial data A/C that the trucks come with. Just recently HPTuners added the option of switching the request signal, so its a moot point now, but its cool to actually know someone had one.

Re: LQ4 intake/harness help/advise
 

Only real advantage to the 03-07 style is availablity, which means it should be easiest to find and cheaper.

Whatever rail you go with, be sure your tune matches it. It can be changed with HPTuners and any tuner should be able to do it, juts making you aware of it.

Re: LQ4 intake/harness help/advise
 

Thanks for all the good info and helping to educate me on the new stuff. I'm sure as it all goes together I will have many more questions. I think I am leaning toward staying with the return type rails because if I'm correct they have the fuel pressure regulator built into them.

Ls1nova>> do you have a all plastic TAC that will work with the blue/red pcm and the 2 plug throttle body sensor that you would be willing to part with??

Re: LQ4 intake/harness help/advise
 

Yes, I have the all plastic TAC module. I bought it trying to make the 03-07 TB work, but it didnt work. I was trying to get the A/C request to work. Pretty sure I have the PCM too, but its for a 5.3 with a 4l60e, so it would need a segment swap to run the 4l80e. I'm not at home right now, but will be back in a week if that works for you I can look for all of it when I get home.

Re: LQ4 intake/harness help/advise
 

That would be great. I am going to the WY Monday to see what I can find and what they want for everything. I will let you know if I find any of it locally. Thanks for the help

Re: LQ4 intake/harness help/advise
 

There is not a problem as far as functionality, Availability can be an issue though.

Tazman, I do have a Harness from a '02 Sierra C3 LQ4/4L65E. If LS1Nova has the PCM & TAC you will be in good shape!

Re: LQ4 intake/harness help/advise
 

I'm positive that the engine and throttle body were out of a TW van. I don't know how much my tune would have helped you though, as I had to source the ECM seperately.

Not sure if you remember, but I had to trade you that all plastic DBW pedal that I picked up for the metal one? That was when I put it all together. The ECM was off of ebay, and I can't prove what it was from. Like most ebay ads, it said something like "ECM 2002 2003 2004 Chevy GMC silverado Van " lol.

Re: LQ4 intake/harness help/advise
 

That would be great!! Any help that I can get would be greatly appreciated. This is why I love this site, the people here are so knowledgable and willing to help. It's all about getting these awesome trucks back on the road. If you guys would let me know what yall want for the parts that would be great. Like I said earlier I will be going to the WY's Monday to see what I can find

Again thanks for all the information and help.

Re: LQ4 intake/harness help/advise
 

[QUOTE=ls1nova71;6858738]Not to hijack... Are you absolutely positive it was a van???? I would have paid you good for a copy of that tune a few years ago.

ls1nova71- On my shelf, I have the ECM from a 2003 van that I bought the LQ4 from.It still has the factory tune. Do you need it still?

Re: LQ4 intake/harness help/advise
 

I do remember that, thats why I was wondering if it was actually from a van. I didnt remember you having to piece it together. You most likely have the PCM from a truck, so it wouldn't have worked.

[quote=chuckmc8;6859150]It was a few years back when I was looking for one, and now HPTuners has added the option to change request signals, so I dont need one now, but thanks for the offer. Curious though, was the van DBW?

Re: LQ4 intake/harness help/advise
 

For the guy with the time Warner van PCM, can you email me the file from it?

Re: LQ4 intake/harness help/advise
 

Anthony, he didnt get the PCM with it. Got one off eBay, so most likely a truck PCM.

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Just asking if he has a PCM that works with manual ac I could get the file for reference. Not really caring what it came from but just that it works.