Re: 1987 R20 Suburban LQ4 4L80E swap
 

seems like a strange place for your fuel filter/regulator. I like to keep them close to the tank to keep the return line short.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

The truck was originally a TBI equipped truck, so the hard fuel lines go to just under and behind the firewall. The feed and return lines should only be about 3-4 feet in length each from their to the regulator.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

Got my Radiator back today from Four Seasons Radiator/Racing products.
They did a great job of welding my filler neck back up!

Re: 1987 R20 Suburban LQ4 4L80E swap
 

That's a good looking weld. Also side note but I like the FPR as close to the motor as possible. Less pressure drop when demand increases and long return lines don't hurt anything if properly sized.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

**update**
Funny how life seems to get in the way as soon as you start on a project like this! The last couple weeks, my two days off work have been taken up helping friends move etc...
Found some time yesterday to work on the truck a little. I got my stainless steel flexible upper radiator hose, my air intake tube, and my fuel/trans cooler lines measured and ready for cutting. After these things are cut to length, should be able to start it!
One thing I have run into, my air intake (Spectre cold air intake) puts the air filter right where my battery sits. Instead of relocating the battery, am going to cut about 5" off the intake tube/pipe. I am worried the filter is so big it may not fit when the hood is closed and my rub my new a/c compressor. If all else fails, could I just install a filter directly onto my throttle body and mount the mass air flow sensor between the filter and throttle body?

Re: 1987 R20 Suburban LQ4 4L80E swap
 

Last night went to a friend house to use their miter saw, and I managed to get my Trans cooler and fuel lines made!
Should be able to start it on Sunday once I get these installed.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

You are probably up to speed on this, but do you have the right fittings at your trans to maintain flow? I can't recall what year they went to the different style but there is a deep fitting on the supply or return that if not used will cook your trans right away.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

Thanks for the advice. Yes I believe I have the correct fittings. The one in the rear of the transmission was longer than the front.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

Cool, no problem.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

Well here come the Gremlins!!!

I'm now in month four of my LQ4/4L80 Swap into my 87 Suburban, and have had something strange happen. For the past 3 months everything has been fine, with all the wiring connected like it is supposed to be I could turn the key and get the motor to turn over but not start because I didn't have my fuel lines connected.
Yesterday I connected my fuel lines and went to start it for the first time and now the truck won't turn over at all. I have fuel pressure, the throttle body opens when I press the gas pedal, so I know I have power to the ecu.
I broke out my multi-meter and verified I have 12v at the starter wire coming from the ignition. When I checked for voltage at the starter solenoid with the key in the start position I get nothing. Because the truck has been down for a few months, I tried connecting some jumper cables to another car incase I had a dead battery, nothing changed. I checked for wires that my have come disconnected and the only one I found is was the power wire for my torque converter lockup. Since it was late at that point and all my tools were put up I haven't fixed that wire yet. I don't think that would have any effect on not being able to turn the motor over would it? Does the brake pedal need to be pressed to start the motor?
Because I can always get 12v from the purple ignition wire, can I just wire that directly to my starter solenoid and bypass my LS harness?
I still have the neutral safety switch intact on my steering column, that I believe the ignition wire has to go through first.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

That's weird. You have cranked it over previously? I trimmed all the old tbi circuits out of my old harness and did not use the circuit for starting supplied by Howell.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

Yup cranked it over successfully about once a week for the past 3 months.
Only thing I've done since the last time I cranked it over was install the radiator and hoses, and my fuel and trans cooler lines. Thought that maybe I knocked some thing loose, so for 3 hours I checked over the wiring and found nothing.
Going to check a few more things next chance I get, if I still come up short, I'm just going to run the wire directly to the starter.

By the way, because of how far forward the motor sits, I can't get to the wires on the starter, so I'm going remove it to swap the starter wire. My question is do i need to remove the torque converter cover to remove the starter?

Thanks again for the help MTCK!

Re: 1987 R20 Suburban LQ4 4L80E swap
 

No prob. I've never had an LS motor (that I worked on) but both SBC and BBC could swap the starter and leave dust cover on the flex plate / torque converter.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

Got it running today!
http://youtu.be/NFSklMgVUdQ
Still have to adjust the shift linkage and install my fan controller and it should be ready to drive soon.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

Congrats it sounds great. Is your tach showing 2x the rpm? I think I recall Larry had to set his tach to 4 cylinder mode when he did his 8.1 swap. Maybe not it just didn't sound like you were reving to 5k. Nice work.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

Nice to see it running Cant wait to hear how it compares to the old big block. I noticed the tach seamed really high also

Re: 1987 R20 Suburban LQ4 4L80E swap
 

Looks and sounds great. The new gauges look right at home in there. :metal: :metal:

Re: 1987 R20 Suburban LQ4 4L80E swap
 

Thanks guys, has been a long and expensive road, and I'm almost there. Couldn't have done it without the help of everyone on here, thanks again! Will post some more pics/videos once I have a little more to show off.
As far as the Tach, May have accidently set it to 8cyl mode instead of 4cyl mode like I'm supposed to. Sounds like an easy fix.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

It's been a while since I've worked on the truck. Taking this whole week off to wrap things up. Today I finally got my electric fans wired up, got the rest of the wiring loomed up and cleaned up. Installed new hood insulation too.
Let it run for 45 min with no overheating, leaks or any other issues.
Before I called it a day, decided to wash it for the first time in 6 months.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

Picture of how it's looking now. With the new hood insulation.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

Looks great. Where did you get the hood insulation? Mine is hammered and it kind of drags down the look of everything now that it is clean otherwise.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

Got it from LMC Truck for $40.
Got the clips from Rock Auto for $5
After I got it and opened the box, my cats decided to jump inside the box and play around, inside the box with the insulation. Needles to say it got a little roughed up with my cats.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

Well it's done!
Took it out today for the first time in 5 months and filled it up.
Runs and drives perfect!
Now just have to make the motor look pretty and hook up AC.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

Managed to get the new engine covers on today.
Keep getting a CEL codes P0171 & p0174. I can reset them by disconnecting the battery but under hard acceleration it comes back on. Hear this may be because I have e MAF mounted to the throttle body. Going to move the filter and MAF further away to see ifs if it helps, parts should be here next week.

Re: 1987 R20 Suburban LQ4 4L80E swap
 

Cut a small hole for the fuel pressure gauge.