cwbyinjeep

So I threw caution to the wind and ditched my stroker in-line 6 engine quest in my 91 Jeep Wrangler and decided to install an LS2 out of a 2007 TrailBlazerSS with 57k miles. It took just under a year but it's in and running,...albeit VERY POORLY. I'm now at the point where a local tuner ran it on his dyno after fumbling through provisioning the E67 ECU for the new chassis and the second I picked up up and went 100 yds it was missing and running like a slug. Yes it's pushing 40" Goodyear MTR and 1ton drivetrain, however I've had this jeep just under 20 years and put 200k miles on the stock 4.0,...80k with these big of tires.

So, I had an intermittent Check Engine Light, hooked up scanner and no codes. I had requested the local tuner do a basic tune up as I had left them with a the Jeep that was very unhappy in the ECU looking for things such as an auto trans and speed sensors and a whole bunch of stuff that wasn't there anymore. They went straight to the digital tuning and never verified plugs, coils, wires etc. They finally get it running on the tuner and hands me off a Jeep with less than impressive dyno numbers in the 267rwhp range and within 100yds of driving off it was missing and sputtering. Left it with them they accused the wiring harness and an intermittent MAP fault. I picked it up, installed new MAP, metered out the harness/sensor and all's well but it's missing horribly and still throwing a CEL once in a while. I discover the front right spark plug is completely unplugged and the second back left is not connected but boot is in place at least. So I do the tune up I asked of them before having it on a dyno and now it revs nice enough, idles smooth with no more misfire but it's the slowest turd I've driven in a while. So, now to figure out what total ignition advance this thing should be running and figure out if it's in a limp mode or if I should yank this LS2 right back out and go back to a stroke in-line 6 and spend some money on a better ECU for that set-up.

I'm wondering what could possibly induce a limp mode while not generating a CEL with this E67 ECU. I'm using electric fans and ECU has been toggled for that, however I'm not sure the Oil Pressure Sensor is deactivated as it's not plugged in and the scanner indicated to me that there was a Catalyst and pre-cat heater system active,....which is not equipped. Anyone been down this road with a TBSS LS2 by chance????

rpturbo

iTrader: (47)

I really can't help much on this particular issue, other than to say I completely understand. All of these swaps have their own challenge, but are massively rewarding once done.

I will say, if you specifically asked them to do a solid once over BEFORE tuning it, and they didn't do it, don't ever go back. There are honestly a lot of tuners who are just that, tuners. Many of them are not mechanics by any stretch of the imagination, and many mechanics are not tuners, so don't confuse the 2.

In this situation, my guess is your tune is WAY off. Does this have a MAF on it I would guess? This is where it becomes handy to have HP Tuners, because then you can pull a histogram and see what is what. Hopefully someone else will chime in on your very cool project. Post up some pics, we all love to see what the project is.

DavidBoren

Deactivate that active system. I don't know if there's a code for it, other than whatever the pre/post O2 sensors would throw, but there is a limp mode associated with overheating the catalytic converter(s)... If I remember correctly. I think it was the cts-v crowd making mention of this limp mode when switching to aftermarket cats. It doesn't throw a code unless the catalytic converter is so clogged that the O2 sensors pick it up, but it does trigger a limp mode until the catalytic converter reaches a normal operating temperature... In your case, due to either sensors being deleted, or something needing to be deactivated in your tune, but it sounds like your computer thinks it has overheating cats.

PS. I don't think there's a physical sensor for the catalytic converter temperature. It's based off an algorithm (time spent @ rpm vs afr readings equals predicted heat, I think), either way, I remember people talking about it being one of the first things to tune out.

rennat_2006

iTrader: (10)

Wish i could get a copy of your tune and take a look at it.

I just put a stock 5.3l into a 85 cj7 and it runs out pretty good.

jcvett56

If your engine is stock and using a MAF you can contact me at Speartech 765-378-4908 and we can reflash your computer for you. When you call we can go over some details. We tune ECM's for swaps all the time.