LQ9/LQ4

[mobileaudio25]

I’m going to pass on that engine... a local junkyard less than 1 mile away from me has an lq4 out of an 04 2500 Silverado. I’m going to go take a look at it.

$800 for all accessories, harness and ecm... anything else I should see if is included? Should I check any markings on the block or head to validate?

Is there a way I can check to see if the harness is for a 4L80e or is the easiest way to look at the flexplate and see which flexplate I have.

Anything else I should look over on the engine? I’ll post some pictures and most likely be getting it next week

 

[motorheadmike]

Yeah, ensure you get an OBDII port.

 

[mobileaudio25]

Here’s what I found at the junkyard... $750 out the door 118k motor from an 05 Denali with harness and all accessories, Has 4L60e flexplate I believe and a wire driven throttle body... so I’m going to need a new cable driven throttle body and a 4L80e flex plate to make this swap go a little easier correct? If I just install a cable driven throttle body will it mess with the ECM or will it not change anything it will just now be cable driven instead of wire?

Also I need to have the harness redone to connect to a 4l80e?

It’s hard to find an lq4/9 4l80e with a cable driven throttle body ... here’s some pics of the motor

 

[Turbolq4]

It says Escalade on the flexplate. If that's true then it's likely a LQ9 but a few had lq4s. The 9s have flat top pistons. You will need a flexplate from a 2500 truck with the 6.0 and you will have to repin the trans connector. The connector is physically the same, just has a few wires that are in different spots. Any cable driven throttle body from the trucks will work but I don't think the ECU had the software to drive the idle air control motor in 05 as it's adjusted by the ECU using the throttle blade in the dbw trucks. Older ECUs can do both. There are some harness modifications needed to utilize the iac and tps.

 

[mobileaudio25]

It says Escalade on the flexplate. If that's true then it's likely a LQ9 but a few had lq4s. The 9s have flat top pistons. You will need a flexplate from a 2500 truck with the 6.0 and you will have to repin the trans connector.

That’s what I was thinking about the LQ9. Doesn’t really matter to me though I’m going to replace the pistons with forged pistons for boost...

If I did that don’t I have to do more harness work to convert the motor from DBW to DBC? Also do I have to buy any new sensors? I’ve read something about idle air control valve and another sensor ...

 

[Turbolq4]

I added more to my post while you were typing

 

[Turbolq4]

Iac comes on the throttle body. You will need the connector and related wires. There are a few tutorials on this you can watch. The only other sensor I can think of is intake air temp. It's in the maf in stock configuration and can be put into the intake itself if you go speed density, use one from a series II 3.8. not needed if you keep the maf obviously. All of the external sensors are the same for 4.8/5.3/6.0.

 

[Northernregal]

That’s what I was thinking about the LQ9. Doesn’t really matter to me though I’m going to replace the pistons with forged pistons for boost...

If I did that don’t I have to do more harness work to convert the motor from DBW to DBC? Also do I have to buy any new sensors? I’ve read something about idle air control valve and another sensor ...

If the ECM doesnt have the provision for the IAC control it wont work with a DBC, you can reflash almost any 1024k 0411 ECM for any vehicle. If you find a 2004 Blazer 4.3 ECM they definitely have the 1024k 0411. Pretty much you need to find an ECM that is 2002 and up in a vehicle that had cable throttle. The 0411 1024k is the green plug ECM.

 

[mobileaudio25]

My local junkyard has a 99 lq4 that is cable driven and has a 4l80e flex plate which is exactly what I’m looking for. I would rather have the aluminum heads 317 though. I know they bolt on but can i install the newer aluminum heads on the older iron headed block and just do a tune and Im good to go? Nothing needs to be added?

Can I install a newer 01+ 4l80e transmission to the older style 99-00 lq4 that has the longer crank without having to make any modifications to motor/converter/harness other than a tune?

I’m having trouble finding a newer lq4 that’s cable driven with a 4l80e flexplate. really hoping to figure this motor out so I can start parts gathering. Btw I’m going to boost this motor so I plan on changing out rods/pistons/rings/bolts/springs anyways.

 

[Northernregal]

My local junkyard has a 99 lq4 that is cable driven and has a 4l80e flex plate which is exactly what I’m looking for. I would rather have the aluminum heads 317 though. I know they bolt on but can i install the newer aluminum heads on the older iron headed block and just do a tune and Im good to go? Nothing needs to be added?

Can I install a newer 01+ 4l80e transmission to the older style 99-00 lq4 that has the longer crank without having to make any modifications to motor/converter/harness other than a tune?

I’m having trouble finding a newer lq4 that’s cable driven with a 4l80e flexplate. really hoping to figure this motor out so I can start parts gathering. Btw I’m going to boost this motor so I plan on changing out rods/pistons/rings/bolts/springs anyways.

317 heads up to about 2004 are a bolt on for you. No issue. you could retune to optimize but they will work.

My 2005 Flexplate is dished out, I always thought it was to compensate for the 1/4" shorter crank. I can't say for certain it will fit but I a positive it will be an easy swap of factory parts to make it work. get both flywheels and you should be ok.

Trans should be a matter of a re-pin of connector and reflash in trans sector of the tune. Tune wise anyway. I dont have a pin out in front of me but if I recall its only 3 wires to change.