LS1 XJ

iTrader: (1)

I have an LS2/4l65e from a 2006 GTO and its going into a 1999 Jeep Cherokee Sport. I have the E40 computer, full engine harness and all sensors, C1 connector w/ pedal connector and OBDII diagnostic port, GTO pedal, and TCM.

Basically, I am trying to utilize the ECM as much as I can and how the harness is put together can make this easier or harder later on. Getting concrete information on the internet is tough. I’ve been reading a lot about re-flashing the GTO ECM to a SSR PCM but I am unsure when this is a must. I reached out to current performance with these questions about but figured it might help asking around here.

1. I am trying to make sure this swap pass smog. I would like to retain all the harness emissions equipment. Not sure what I have to do with the rear 02 sensors though because the GTO has 2 rear sensors and I need both headers to feed into one pipe pre-cat. If possible I would delete them but if I need them, is there a way to just one in the harness?

2. Does the E40 pcm need the fuel pressure sensor/GTO fuel pump assembly to pass smog or can this be “tuned out”? Is there any way to get the information from my jeep fuel pump if needed? I prefer to use the jeep pump but I can make the GTO pump work if that is difference between passing smog or not.

3. I want to run two fans (likely 2 speed Taurus or Volvo fans) off automatically off the E40 PCM. Can the GTO e40 do this or does it need to be flashed to a SSR? Is there a special relay setup required to use the two wire (low speed/high speed) in the C1 connector can I just use a traditional relay setup?

4. I am going to use all of the jeep AC system other then using an R4 compressor. Is there a way to make the harness and ECM work with the jeep air conditioning and R4 compressor to shut it off at the proper RPM and also automatically turn on the fans when the AC is on?

5. Cruise control is a nice plus. I understand I would need the GTO stalk to control the cruise but it looks like this is where you need a SSR PCM. Do I need the SSR pedal to make this work?

6. Does the ECM need info from the coolant and oil pressure sensors or can I bypass the pcm and wire those directly to the gauges?

I want to say thanks in advance for any info. This stuff is all new to me so sorry for seeming like I'm all over the place

cwbyinjeep

I'm in the middle of the tune process with my LS2 from a 2007 TBSS that was swapped into my 91 Jeep. It is possible to use the stock Jeep oil pressure sender for your dash gauge, however I think the ECU will have to have that circuit de-activated. I was able to get dual fans hooked up no issue and programmed accordingly. However I'm running into issue where I feel the LS2 is only running in limp mode as it's the slowest V8 I've had the pleasure of driving short of an old Jeep J10 with a very tired 305 in it, haha. So I'm still sorting this out myself but one thing is for sure, the CANBUS style ECU's are no where near as well supported or known with competence by any of the tuners I've dealt with. Mine has the E67, I'm strongly considering re-wiring for a E38 configuration though as I'm told there are less headaches with future maintenance and reliability.

jcvett56

SSR Flash is only needed for cruise if you are using manual setup. You would be best to just use Trailblazer SS setup with E40/E67. Then you would have to use a TBSS pedal.

Smog will need all four oxygen sensors, two pre cat, two post cat, and then evap vent, evap purge, and fuel tank pressure sensor. I don't know anything about jeep wiring but I know about GM factory controllers, E40, E38, E67.

The GTO file DOES have two fan output, primary and secondary.

IT would probably be best for you to get a GM fuel pump assembly in their unless the Jeep guys have a better solution for controlling fuel pump fuel pump pressure. It's a three wire sensor integrated in the pump from GM.

The E40 doesn't control AC so just use the factory setup from the jeep. Jeep guys on their forums can help you out there! But ive heard several of those guys maintain the factory computer when doing LS swap so gauges, AC, and such work.

The ECM has to have coolant temp sensor but not oil pressure. Most people go on the passenger side head on the rear to mount coolant temp sensor for gauge.

Speartech does several emissions and non emissions setups for individuals. So that's no problem.

jcvett56

You would not benefit at all from changing ECM's. You either have a wiring, tuning, or engine mechanical issue. The benefit of using a E67 TBSS setup is you have cruise control available out of the ECM.

LS1 XJ

iTrader: (1)

Thank you for the info. Lots of good stuff there. The jeep pump can provide enough pressure. The guys at Novak-adapt have something that bypasses the jeep fuel regulator and uses a corvettes. Sounds like a GM pump is needed though for emissions

What about the AC being "rev limited" by the GM PCM on GM cars.

jcvett56

IDK what you mean by GM being rev limited on gm cars. When you do the swap the ECM won't know whether or not you have AC so that will be irrelevant. There will be no AC wiring going to or from your ECM.

TipsyMcStagger

iTrader: (1)

The E40 uses a serial signal from the donor vehicle's BCM (Body Control Module) and PIM (Powertrain Interface Module) to generate the A/C request signal. The serial information will also disengage the A/C clutch at a predetermined RPM to provide over-rev protection. If you're not using a serial signal (the original BCM) to control the A/C, you can use an RPM window switch to provide over-rev protection. The serial information will also disengage the A/C clutch when WOT (Wide Open Throttle) is detected. I've never read of an LS2/E40 swap that is using the donor BCM for A/C control.

There is also an idle-speed bump when the A/C is turned-on. And a fan will turn on as well. Most who are using a simple analog setup to control their A/C using an E40 without a BCM have reported that the idle bump is negligible; in other words, the LS2 can overcome the additional load imparted by a functioning A/C compressor without the programmed idle bump.

And as long as a high side GM pressure switch is included in your setup, the E40 is seemingly capable of triggering the fan to operate when the compressor is engaged, even without serial control.

Tipsy

EDIT: I've also read that the idle speed will increase without the serial data, just as the fan will engage, through the E40 itself (sans BCM) through the high-side pressure switch signal.

TipsyMcStagger

iTrader: (1)

To add to what I wrote above and to clarify for the OP, there will be A/C wiring going to your PCM (E40) even if using a simple analog switch to control your compressor. I don't have my notes in front of me (and full disclosure; my swap is still a pile of pieces) but if memory serves, there will be inputs to the PCM from the compressor and high-side pressure switch. This is how the PCM knows to switch a fan "on" and (seemingly) bump the idle when the compressor is functioning.

Tipsy

LS1 XJ

iTrader: (1)

Yeah I will not be going any route that involves the BCM and PIM. Considered it, but it's just too much work and extra expense. There is a build I've seen where the guy went through hell so he can use the GTO gauges with his ls2 swap.

The only reason I would want to run the AC through the GTO PCM is to get that over rev protection instead of buying an aftermarket module. I wasn't sure if it was possible to get that with the GTO or SSR E40. If it isn't possible without the BCM, I would just use the jeep wiring and an aftermarket module.

I do wonder why harness companies like spear tech and current performance have an option to add AC to the LS2 harness if there is no way the PCM can control it anyway.

I don't want to cut into the harness or pay anyone to do a harness for me until I fully understand the ins and outs of this. Still waiting to hear back from current performance