GM V8 into a TJ Q's...

[waynehartwig]

Timpanogous also had constant overheating problems with a 5.3 and a Novak. His son accidentally murdered the radiator on a K-rail... he has had zero cooling issues with the Advanced Adapters he replaced it with.

My dad asked me tonight - why not keep my current radiator and electric fan? Sure, the outputs are in the wrong place, but any radiator shop can fix that. I have a 3 row CSF and a Flex a Lite fan.

So I ask you the same question..... Why not? I'd save ~$500.

 

[Bart]

Do you have an aftermarket radiator already? I think the stock rads have plastic tanks and are not good for swapping intake and outlet sides.

 

[waynehartwig]

Do you have an aftermarket radiator already? I think the stock rads have plastic tanks and are not good for swapping intake and outlet sides.

Yes, currently I have a 3 row CSF and a Flex a Lite fan. I'd probably ditch the current fan and upgrade to a different one with a higher CFM rating if I went this way....

 

[waynehartwig]

Going with AA on everything that I can - Damn Vic (salesman over there) lol In the past, I've always used AA products through other dealers, Tom Woods, etc. Now I'll just do the buy in and be able to buy direct.

 

[ProStreetZ28]

LSx engines use 60 PSI steady fuel pressure, the easiest way to use the non-return style LSx fuel system is to buy the LSx Corvette Fuel Filter, it has abuilt in 60 PSI fuel pressure regulator. It has two 3/8" quick dis-connect fittings and one 5/16" quick dis-connect fitting (return line). The easiest pump to get is the 97 Suburban 7.4L fuel pump, it's a 190 LPH factory fuel pump.

 

[Spidey]

wow, both me and Z28 have handed over the gem of gm swaps and no one has even commented on it.
another thing. there is an easy way to use your stock gauges and swap the motor. I have all my original gauges.

 

[waynehartwig]

wow, both me and Z28 have handed over the gem of gm swaps and no one has even commented on it.
another thing. there is an easy way to use your stock gauges and swap the motor. I have all my original gauges.

What is the gem? Corvette filter?

How do I keep the stock gauges without running two computers?

 

[ProStreetZ28]

I've only done one LSx swap into a Jeep, but it was an older one. All of the gauges worked when I did that one. The tach I had to send out to clock-doc to get it modified to work with the signal from the LSx computer. For the oil gauge you simply drill and tap the little bypass plate above the oil filter for an 1/8" NPT fitting and used the stock sending unit. The temp gauge sending unit I drilled an tapped the top of the water pump right where the upper hose connects. I don't know if the late model Jeep dash has seperate circuits for each aguge or if the get a multiplexed signal form the ECM, I'd have to look at the service manual.
Spidey is right though, the LSx engines have the easiest and most reliable fuel system built. You can run any 190LPH pump or more and the Vette filter and your done. I've used the Street & Performance fittings, but I've also built the system with parts from Auto Zone. They sell the hard lines with the quick dis-connect ends and I used the Corvette Stainless Steel factory fuel rail lines. It looks really clean under a car when you have all factory type fuel lines and you don't have to worry about them failing.
In the past I've built what is called an EZ-Swap harness for LSx swaps, the ones I built use the factory F-Body engine harness and it's all plug and play. Just to prove a point we took one of the easy swap harnesses to a shop and plugged it in and started an LS1 on the ground in less then 15 minutes.

 

[Greg]

I've only done one LSx swap into a Jeep, but it was an older one. All of the gauges worked when I did that one. The tach I had to send out to clock-doc to get it modified to work with the signal from the LSx computer. For the oil gauge you simply drill and tap the little bypass plate above the oil filter for an 1/8" NPT fitting and used the stock sending unit. The temp gauge sending unit I drilled an tapped the top of the water pump right where the upper hose connects. I don't know if the late model Jeep dash has seperate circuits for each aguge or if the get a multiplexed signal form the ECM, I'd have to look at the service manual.
Spidey is right though, the LSx engines have the easiest and most reliable fuel system built. You can run any 190LPH pump or more and the Vette filter and your done. I've used the Street & Performance fittings, but I've also built the system with parts from Auto Zone. They sell the hard lines with the quick dis-connect ends and I used the Corvette Stainless Steel factory fuel rail lines. It looks really clean under a car when you have all factory type fuel lines and you don't have to worry about them failing.
In the past I've built what is called an EZ-Swap harness for LSx swaps, the ones I built use the factory F-Body engine harness and it's all plug and play. Just to prove a point we took one of the easy swap harnesses to a shop and plugged it in and started an LS1 on the ground in less then 15 minutes.

Good info guys, I've heard about the Corvette filter w/built in regulator. I opted not to go that route, used the stock regulator that is on the engine fuel rail and then dumped a E2000 fuel pump in-place of the stock TJ fuel pump.

Do you know how to strip down a factory 5.3 engine harness to the minimum? From this post and the other one, it sounds like you really know what you're doing.

 

[waynehartwig]

I just looked, and the entire instrument cluster is fed off pin 30 - PCI bus. That's all guages, idiot lights, etc.

I have no idea what I'm doing, but IMO the only way to keep the guages is by running both computers.

Also, if I keep both computers, I would need to install a second MIL light for the GM computer, or I might never know if there is an issue.

Unless someone can tell me how to keep the guages and run only one computer, their getting yanked for either a Racepak or Autometer guage set.

Someone else asked this, and I don't recall where it was as I've been reading a lot about this lately....

What if I put a Dodge V8 computer in to control the GM V8? Then all the guages and etc would function as if it were a Dodge motor. Only problem with that might be the 4l60e, since it's computer controlled. Does Dodge have PCM's that control the trans just like the GM does? Maybe that could be done there as well?

But back again to the GM PCM.... Everyone can tune them and they are cheap, unlike the Dodge PCM's.... $200-300 compared to $1400. Heck, with HP Tuners I could do the GM PCM myself. Might not be a 'good' tune, but...

 

[waynehartwig]

Spidey is right though, the LSx engines have the easiest and most reliable fuel system built. You can run any 190LPH pump or more and the Vette filter and your done. I've used the Street & Performance fittings, but I've also built the system with parts from Auto Zone. They sell the hard lines with the quick dis-connect ends and I used the Corvette Stainless Steel factory fuel rail lines. It looks really clean under a car when you have all factory type fuel lines and you don't have to worry about them failing.

As of right now, I intend on keeping the TJ pump/regulator. This motor should start and run fine with it - higher RPM's/load is where the fuel needs increase. If I find it's not enough, I'll mess with it later. But right now I just want to get it in and started before I go changing things up.

Walbro has a 255 lph pump for the TJ, from what I've read. That might be step 2. Or I might just put it in when I have the tank out and empty (to set the fuel guage empty setting).....

I'm still having a hard time with the 60 psi required, when it has the same injectors as my Jeep does, on 49.2 +/- 5 psi that is speced. Unless there is something else there that requires 60 psi, I don't see why it shouldn't work. I realize there are lots of people that say it won't, some that I would even trust without knowing them from Adam, but..... I definately mean no dissrespect!!!

 

[UNSTUCK]

Do you know how to strip down a factory 5.3 engine harness to the minimum? From this post and the other one, it sounds like you really know what you're doing.

This is very easy to do. Even more so if you are not changing the location of anything. There are write ups everywhere. If you don't feel comfortable, we could do this for you as well as get your rig tuned with the guy we use, that I told you about in another thread.

 

[Greg]

This is very easy to do. Even more so if you are not changing the location of anything. There are write ups everywhere. If you don't feel comfortable, we could do this for you as well as get your rig tuned with the guy we use, that I told you about in another thread.

Personally, I hate wiring... how much to strip down a stock engine harness and get a good ECU tune?

 

[ProStreetZ28]

When we built the HHR for GM we had Clock Doc replace all of the electronics in the dash so that we could use individual sending units, in a worst case scenario you could do that.
Running two computers isn't the end of the world either, when I added after market ECMs to the late model Camaro's and Corvette's I had to do the same thing. I ran the transmissions off of the factory PCM and the engines off of an aftermarket ECM. I'd have to look at the factory signals to see if I could figure somethign out, but it usually isn't the end of the world. the hardest part would be the crank signal, depending on what year your LSx engine is it'll either have a 24X or 58x reluctor wheel.

 

[UNSTUCK]

Walbro has a 255 lph pump for the TJ, from what I've read. That might be step 2. Or I might just put it in when I have the tank out and empty (to set the fuel guage empty setting).....

I'm still having a hard time with the 60 psi required, when it has the same injectors as my Jeep does, on 49.2 +/- 5 psi that is speced. Unless there is something else there that requires 60 psi, I don't see why it shouldn't work. I realize there are lots of people that say it won't, some that I would even trust without knowing them from Adam, but..... I definately mean no dissrespect!!!

I can tell you right now that the 5.3 I just installed wont start with around 45 PSI. This was using a stock toyota pump. It is getting replaced with the walbro you mentioned. I can't tell you why this is, but it is what it is. Maybe intake deisign or something. The fuel needs a little extra pressure to get into the chamber.

 

[ProStreetZ28]

As of right now, I intend on keeping the TJ pump/regulator. This motor should start and run fine with it - higher RPM's/load is where the fuel needs increase. If I find it's not enough, I'll mess with it later. But right now I just want to get it in and started before I go changing things up.

Walbro has a 255 lph pump for the TJ, from what I've read. That might be step 2. Or I might just put it in when I have the tank out and empty (to set the fuel guage empty setting).....

I'm still having a hard time with the 60 psi required, when it has the same injectors as my Jeep does, on 49.2 +/- 5 psi that is speced. Unless there is something else there that requires 60 psi, I don't see why it shouldn't work. I realize there are lots of people that say it won't, some that I would even trust without knowing them from Adam, but..... I definately mean no dissrespect!!!

The LSx injector ratings are for the 60 PSI, not the usual 45 PSI. The LS1s had 28.8 lb/hr injectors in them, but if you run them at 45 PSI they are only 24~lb./hr. injectors. so if you run them at 49 you'll be reducing the output by quite a bit.

 

[ProStreetZ28]

Good info guys, I've heard about the Corvette filter w/built in regulator. I opted not to go that route, used the stock regulator that is on the engine fuel rail and then dumped a E2000 fuel pump in-place of the stock TJ fuel pump.

Do you know how to strip down a factory 5.3 engine harness to the minimum? From this post and the other one, it sounds like you really know what you're doing.

If you don't want to mess with it shoot me a PM, I'll take care of it for you. I cna even get the PCM re-flashed for you to remove everything form it.

 

[waynehartwig]

Just to update on the fuel stuff we talked about here, I am currently running the stock TJ fuel pump and pressure regulator with 44 PSI at the fuel rail. I drove it to/from Moab pulling my camp trailer, on the trails and etc. I still have every intention on bumping it up to ~59 PSI, but I just wanted to let others know that yes it did start and drive with the OEM stuff in it.

Actually, let me correct myself. From Spokane to Moab, I had the Walboro 255 LPH pump, the TJ regulator bypassed and the Corvette filter. I've had problems with it going rich and surging and since my fuel pressure woudl be blead off fast and only being 44 PSI, I ordered another regulator/filter from Moab GM. The new filter was the same and the problem got to be pretty bad, so I pulled the tank and put everything back in. The only problem I fixed was the fast bleed off of fuel. I think the rich surge issue is the IAT becoming heat soaked, as the problem happens after sitting with no air flowing through the engine compartment. But when you are rockcrawling for a longer period, that happens. But when there is lots of flow it doesn't happen.

 

[Kiel]

I had the same bleed off situation on mine. It would go from 60 to 0 in less then 10 seconds. I had read about stuck injectors a lot on these motors that have sat for a while. I just kept running it and seafoaming it and now it will hold the pressure and maybe drop 10 psi in a minute

 

[UNSTUCK]

There is a local shop in Salt Lake that ultra sound cleans the injectors. It is a very common problem with these swaps that have set for months or years. The varnish causes them to either stick open or stick closed. Some get so bad that even the ultra sound can not brake them free, in which case you must replace them.