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LS1 electric fans, Nelson Performance Harness and California Smog

thespacepope

Full Member
Joined
Aug 5, 2016
Messages
16
I have been reading up on doing the LS1 electric fan conversion on my 2002 5.3L Avalanche and have not been able to figure out one part of the puzzle.

It is my understanding if I choose to go with LS1 fans and the Nelson Performance harness, I would need to get the PCM updated to activate the PIN for the fan.

What I am not clear on is if I get the fan activated in the PCM, is that change permanent? I am curious, questioning because I live in California and I don't want to fail smog when they hook up the OBDII.

A follow up question is regarding the DiabloSport inTune i-2030. I purchased one so that I can install a tune and then return to stock when I go in for the smog test.  Can I activate the fans with that thing (still learning about it) using the stock tune and still pass smog?  My concern is that I don't want to overhead the truck when I go for a smog test because the electric fans are not working.

I realize that the electric fans are not a big HP or MPG boost but I am doing it for fun and the experience of doing it.

Thanks.
 
When I converted my '03 to electric fans at least 10 years ago, Nelson was offering 2 different harnesses - 1 that had the PCM controlling the fans (which required custom tuning) and one that used a temp sensor on the radiator to control the fans which didn't require custom tuning.  I don't live in CA, and don't have vehicle inspections in my area either, and tune myself with HPTuners so for me it was a no-brainer.  If I were to happen to move to CA I could easily put the stock tune back in for inspections and then replace with my custom tune using HPTuners.
 
Having an custom/performance tune in you ECM will not cause a fail when going in for a smog test, they do not make it put out worse emissions than a stock tune, they do not change or alter any of the OBDII parameters unless you tell them to because it's for an Off Road vehicle only tune.

The testing machine is not looking to see if you changed your tune, added electric fans, tire size etc., it's looking to see if there are any codes set that would cause the engine to not be performing as designed which would cause excess emissions. It then measures exhaust emissions of your vehicle and looks to see if they fall outside the parameters for it.

I live in California and had a Performance tune in mine for more than 10 years with many changes over the years with no issues at smog test time every two years.


Nelson still has the electric fan harness that's needs a custom tune
 
Thanks for helping me understand how CA smog testing works with regard to PCM/tune changes.

I had been thinking of the FF dynamics kit only because of the PCM reason but now I can reconsider the LS1/Nelson/PCM option.
 
No problem..

Oh my tune is by Nelson, I do have electric fans but control them with a Flex-a-Lite Variable Speed Controller. No problems been working great for around 48,000 miles...
 
Randy said:
No problem..

Oh my tune is by Nelson, I do have electric fans but control them with a Flex-a-Lite Variable Speed Controller. No problems been working great for around 48,000 miles...

Hi Randy.  It's been a while since I've been around here, but I do still check in on the Facebook groups.


  Anywho...I also have used the variable fan speed controls in the past and have had numerous issues with the probes that go through the radiator fins failing and the fans not coming on.  I have also melted more than my share of relay plugs.  Not sure why, other than the draw of the electric fans must be enormous! 

  So, I haven't had a/c since the motor was built back in...what...2008?  I tried to use the cans of refrigerant you get at Walmart, but it wouldn't take any.  Then I came to the conclusion that I need to draw a vacuum on the system, as the engine work necessitated removal of a/c lines, etc, and now has air in the system.  No problem.  I just did a top end service on the wife's Grand Cherokee and had to crack open the a/c lines to get the passenger side valve cover out...$125 later and Firestone had my a/c going again.  But back to my Avalanche...

  I haven't been able to get the compressor to even come on.  I figured there must be a pressure switch that senses the system is empty and won't allow it to come on.  I bypassed everything and ran a wire to the battery and sure enough, the compressor started running.  I hooked up a can of R134A, and it seemed to take it for a few seconds, then I heard a "pop" and all the R134A exhausted out near the compressor.  I am hoping it is just an over-pressure protection or some such.  Long story short...I assume I need to run a vacuum on the system and draw in the R134A.  No problem, but I want to make sure I have all the electrical component hooked up properly.  I would think that, regardless of the compressor working or there being R134A in the system, when I push the "A/C" button on the dash, the electric cooling fans should come on.  So, I'm thinking, the line I ran from the battery to the compressor, which caused it to come on (work the compressor clutch) needs to be run to the relay controlling the electric fans so they come on.  Am I on the right track or am I way off track here?

Thanks for this and all the past advice you've given me.

Ian

 
 
Hey ms38w, good to see your still out there..


I know Flex-a-lite had problems with there controllers burning out at first but I think they fixed them. I have not had issues with mine but I have the thread in sensor in my radiator and it's been in for about 50,000 miles now. My fans are the Flex-a-lite 293 dual 15 inch, 6000cmf flow and 36 amp draw ties to a custom aluminum fan shroud.


And your on the right track getting the compressor to run. If the system been open to air for a while you you most like need to change the accumulator (that big round aluminum thing on the firewall) and pull a vacuum on it (pulls all the moisture out) to get it to work properly. You could replace all the parts and then have a shop evacuate and then charge it.. The accumulator has the low pressure switch on it and can be jumped to start the compress if the system is under a vacuum or low to charge it. You can't charge a system that has been open to atmosphere without pulling a vacuum on it.

The low pressure switch is N/O (normally open) and takes system pressure to close it so you have to jump it get the compressor to run. The high pressure switch is N/C (normally closed) and takes over pressurization to open it stopping the compressor.


My advice is to change the parts yourself and have a shop charge it..


Good luck and good to hear from you again..



 

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I do this to almost all my Avalanches, most are 02. I have HPT tuners like a few peeps here. I bought the year 2002 so I can freely program  the PCMs to turn on the fans and set on/off temp. Then Any tune can overlay. my first time I had  Predator tunes made a stock file to upload to all ways have it.

I go to the salvage yards and get dual factory fans that just bolt to the radiator. I also grab the fan controller harness . its under the fuse box cover closest to firewall.

you have to add a pin to the PCM#42 if I remember clear. I use that to trigger the low fan speed. some use the ac to trigger the high speed but I use a switch to manually turn on when towing and such.

Hope this helped you at all
 

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Curious if you guys have seen lower temps with the electric fans or if just doing it to save on power robbing from engine.

Looking at planning my future blown 6.0 setup and trying to look at some component upgrades before doing that job. Wondering if my stock 5.3 Radiator will be up to the task or if I should be looking at replacing that with a better unit and if electric fans are a good idea. Was under the impression mechanical fans move more air.

Rodney
 
I went to electric fans for four reasons in this order.


1. Better AC performance.

Stock fan does move a lot of air when it kicks in, but not much at idle and at low speed. More air flow at idle to make the AC work better in the summer sitting in traffic. Blows way colder due to the airflow through the condenser. Going down the highway fans never come on (unless towing) even in the summer unless the AC is on.

2. Lower engine temps

With the stock fan and 195 deg T-Stat water temp would 210-215 on a 90 deg day in traffic.

With electric fans 190 deg set point and 180 deg T-Stat water temps never see more than 195 deg on a 90 deg day in traffic.

In the winter when it's below 60 deg water temp hovers around 180 deg, right at the T-Stat opening. 


The other thing that's different and again should increase the longevity of engine and trans is with the stock set up on a hot day shutting it down after a drive the heat soak in the engine. The water temp would climb to 220-230 deg and the engine and surrounding components would be going tick, tick, tick and you could not touch anything on the engine, way too hot..

With the set up now it never sees more than 195 deg after shut down and the fan controller kicks on and cools it down for up 20 minutes if needed. Less thermal expansion no more tick, tick, tick.. That's got to help things live longer..


3. Pick up HP

When the stock clutch fans kicks on (water temp 220deg) when your on a hill towing it feels like you just lost 40 horse, that doesn't happen. You have all the power you had when you started up the hill and the only thing the ECM is going to change is timing based on things like temp, knock sensors, altitude etc.. Things you don't have much control over...


4. Pick up mileage 

And if at the end it's picks any mileage all the better. So far I've seen about 1/2 -1 mpg at highway speeds (70-80mph) on long trips.

 
Randy said it well. gm even moved on to elec fans 04-05 for the most part.

at highway speeds fans are not very effective anymore anyway. At low speed in traffic elec fans can move some air... where the mech cant
 
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