CDM1386

Hi there hoping to get some guidance on a build I am doing with my fj60. I recently purchased a fj60 with 5.3 lm7(carb legal swap, I am in cali) in it. The swap was done pretty poorly the motor, tranny, diffs and anything that can leak does. So I am going to pretty much do a full build on this rig and started looking at options.

I thought about going EROD ls3 but it seems you can't get those anymore and then started researching LT1 ERODs. LT1 EROD feels a bit more complicated than I want since I am going with tremec tr4050, it feels like I would be the tip of the spear with this kind of swap. It's been done before but not by many and not much info out there. Also seems like LT1 ERODS are not that available either.. Not sure but seems like GM might be discontinuing the EROD program.

From what I have read the EROD connect and cruise setup needs a VSS signal and the tremec tr4050 does not provide this. It just seems complicated to make the tranny speed signal work with the GM ECM, maybe it's not that complicated but definitely out of my pay grade. Input here would help?

This all kind of pushed me into the 6.0 route. I feel like for smog purposes the 6.0 would cover all my bases since its basically a 5.3 and can produce a fair amount of power while still keeping reliability.

What I need from the forum is some guidelines or assistance on what would be a great 6.0 set up? Build the 5.3? EROD( I did find one LT1 EROD available)? Or maybe some other input on what route to go?

Any help would be greatly appreciated.

Thank you all in advance.

the_merv

iTrader: (88)

Gen III 6.0l would be an easier swap.

CDM1386

What is the gen III 6.0l called? LQ9?

Thanks

G Atsma

The standard version used in many heavy duty trucks was the LQ4.
The LQ9 was a higher compression version used in Escalades and others as a premium version.

RB04Av

^^^ This ^^^

LQ9 is the one you want if you're not gonna do any short block work but rather just use it as-is. If you're wanting to replace pistons anyway, such as if you want a complete "new" rebuild", LQ4 is exactly the same as LQ9 in the parts you'll reuse (block, heads, crank, rods from 05 up) and is cheaper. 04 back LQ4 will probably have the lesser rods (press-fit pistons) than the LQ9 and newest LQ4 (floating-pin pistons).

the_merv

iTrader: (88)

LQ4 with 243 Heads is a proven combo.

G Atsma

Yep, good flow with decent compression.

the_merv

iTrader: (88)

243 and 317 Heads have the same Ports, but the Chamber of the 243 is better.

LQ9 factory Compression is 10.1:1.
LQ4 with 243 Heads is close to 10.5:1.

John Christenson

I did an LM7 to LQ4 swap on my 99 silverado. I have a question about the Oil Sending Unit/Oil Pressure sensor. The LM7 sensor is taller with a single terminal connection. The LQ4 is a shorter sensor with a three terminal connection. The connections are a little different in size also - they are not interchangeable. I've been using the LM7 sensor because I am using the LM7 wiring harness. I've been running this setup for ~7 years. Recently, I have had low oil pressure issues using the LM7 sensor on my LQ4 engine. I'm no mechanic or motor guy. I'm trying to eliminate everything I can before I determine it's the oil pump or I take it to a mechanic to pay them to troubleshoot.
The Question: Is it possible, the LM7 Sensor is not compatible on the LQ4 engine? Can I rewire the LM7 wiring harness's single terminal connector to the LQ4 3 terminal connector and the computer read this and accurately tell me the oil pressure?

strutaeng

If it's ran fine for 7 years, what makes you wonder if they are not compatible now?

They are different sensors that need to match to the plug. So what you are proposing won't work. Either the sensor failed and needs a replacement, or you truly do have low oil pressure. You can check with a mechanical fuel pressure gauge.

Last possiblity is a wiring issue. The wires near the connector tend to get brittle and the bare conductors can short out each other (mostly on the 3-wire type.)

John Christenson

About a year ago, ~6 years after the swap, was the first time the oil pressure dropped. I changed the oil and the drop in oil pressure went away. Since then, the oil pressure does drop when I come to a stop at a red light but if I keep the engine revved up the oil pressure will not drop. And, this only happened a few months after an oil change. With fresh oil, the pressure didn't drop. When the pressure started to drop, I would change the oil and everything is fine again.

But recently, I changed the oil and immediately the oil pressure dropped when I come to a stop at a light.

The lifters have never rattled. The oil is the correct color/there's no water in it. I started to assume I was getting fuel in the oil (not sure what this would look like) causing the oil to thin out over time and causing the pressure drop (a few months after an oil change) but my last oil change proved this wrong when the pressure dropped immediately after I did the oil change.

The fact it worked fine for 6 years before the first oil pressure drop, has me investigating what the issue is.

Any advice is appreciated.

the_merv

iTrader: (88)

It's a bad sensor, change it. Literally is that so you wasted a ton of money on oil changes. You don't need to go to some mechanic about the Oil Pump. Think about it, that's the one thing you haven't even thought to replace. It's an electronic sensor, the thing that kills electronics is heat. Back of the block touching hot oil, so they fail.

If either sensor went into the block with no issues what makes you think any of them would not be "compatible" with an Engine block? It's a piece of metal with a threaded hole.

Tall black single wire sensor is the early style up to mid 2003, after that all the DBW stuff got the low 3-wire sensor. No need to re-wire for anything because the 3-wire one won't work with your factory setup. Get a new tall black sensor, preferably a GM one, and put it in. I have 5 spares I keep on hand from my junkyard visits over the years.