The LS Swap Begins

[beaufrusetta]

Didn't you put a decent cam in yours?
is it shifting at too low of an rpm?

What about the power enrichment delay? Eliminating that will make quite a difference compared to stomping it and then waiting for the pcm to finally go rich.its a long time.

Yes, I did, it is supposedly designed for better torque response with the sweet spot between 1800-6000rpm, and I agree about the PE delay…on stock truck tunes it is usually like 90% throttle and > 4000rpm before you get there…

 

[Longhorn84]

Didn't you put a decent cam in yours?
is it shifting at too low of an rpm?

What about the power enrichment delay? Eliminating that will make quite a difference compared to stomping it and then waiting for the pcm to finally go rich.its a long time.

It's hard for me to articulate so I may try a ride along to describe in a video, I'm not sure how to phrase the issue but I'm confident anyone who has dialed in performance before would have ideas on how to improve. To the tune question, I may take it to a performance shop in Houston to get opinions on best tune and any mechanical improvements I might need to make.

 

[Longhorn84]

It's hard for me to articulate so I may try a ride along to describe in a video, I'm not sure how to phrase the issue but I'm confident anyone who has dialed in performance before would have ideas on how to improve. To the tune question, I may take it to a performance shop in Houston to get opinions on best tune and any mechanical improvements I might need to make.

I just drove to my sons soccer game and can better explain. If I press the pedal 10-20% its smooth acceleration but it reaches a point passed that where the rpm’s shoot up and so maybe I’d describe the pedal as touchy. Does that make sense?

 

[beaufrusetta]

I just drove to my sons soccer game and can better explain. If I press the pedal 10-20% its smooth acceleration but it reaches a point passed that where the rpm’s shoot up and so maybe I’d describe the pedal as touchy. Does that make sense?

Are you drive by cable or wire? Has the throttle always been touchy like that?

 

[Longhorn84]

Are you drive by cable or wire? Has the throttle always been touchy like that?

Drive by wire and yes I think it’s always been touchy. Sorry to hijack the thread!

 

[beaufrusetta]

Drive by wire and yes I think it’s always been touchy. Sorry to hijack the thread!

I know on my throttle body, I can replace the throttle position sensor. Can you do the same on the DBW throttle body’s? Maybe you’ve got a bad one. But if it’s always done that, it might be your ETC settings in your tune in relation to your MAF calculations and variations in the intake tube diameter vs stock.

If you take it down to a shop that can tune it, they can hook it up to a scanner and watch the throttle values and get everything lined up for you included in the pricing of a “tune”. I bet it’s just that…because Novak can only do so much without having the actual vehicle running in front of them and adjusting accordingly.

 

[Longhorn84]

I know on my throttle body, I can replace the throttle position sensor. Can you do the same on the DBW throttle body’s? Maybe you’ve got a bad one. But if it’s always done that, it might be your ETC settings in your tune in relation to your MAF calculations and variations in the intake tube diameter vs stock.

If you take it down to a shop that can tune it, they can hook it up to a scanner and watch the throttle values and get everything lined up for you included in the pricing of a “tune”. I bet it’s just that…because Novak can only do so much without having the actual vehicle running in front of them and adjusting accordingly.

Makes sense, thanks for the input!

 

[Jamison C]

I just drove to my sons soccer game and can better explain. If I press the pedal 10-20% its smooth acceleration but it reaches a point passed that where the rpm’s shoot up and so maybe I’d describe the pedal as touchy. Does that make sense?

FWIW we had an 02 Yukon that was drive by wire and the pedal on that thing was stupid touchy. Our family had that thing for 15 years and that was always a point of conversation whenever we drove it. Maybe a tune can sooth that out but at the time there was no evening the throttle out.

 

[Longhorn84]

FWIW we had an 02 Yukon that was drive by wire and the pedal on that thing was stupid touchy. Our family had that thing for 15 years and that was always a point of conversation whenever we drove it. Maybe a tune can sooth that out but at the time there was no evening the throttle out.

Helpful thanks, the pedal and engine came from an 04 suburban so could just be the pedal sensor or the way I mounted the pedal, who knows. I’ve learned how to drive it but when others have tried it’s not so easy.

 

[NashvilleTJ]

I use the Jeep PCM to control AC, video here:

I do still need to figure out how to turn off the Jeep check engine light, anyone know?

Main thing I'd like to improve is the throttle response, I have good response it seems from 1-2k rpms but then if I push the gas down it shoots up and just doesn't feel smooth at all, maybe that's the 4 speed or my gearing but long term I'd love to fix. Everyone who I tell about my jeep asks if it's fast, the answer is it's certainly faster than the 4.0 but it's far from a speedster with a stock 5.3 and stock 4l60e, 4.56 gears and 35" tires. Anyone with a similar LS swap think their TJ is "fast" or "quick"?

Don’t feel bad. No one thinks their LS swap TJ is “fast” or “quick.”



But seriously, can you get a code on the CEL? That’s where to start.

As has been stated, the weird throttle response is likely a tune issue at some level. I fought many throttle control related issues when I built my Hemi. A good tune by Flyin’ Ryan finally resolved them all.

Not being smooth is one thing. Imagine a built 392 Hemi going wide open and not being able to stop it. Ahh, good times…

 

[Longhorn84]

Don’t feel bad. No one thinks their LS swap TJ is “fast” or “quick.”



But seriously, can you get a code on the CEL? That’s where to start.

As has been stated, the weird throttle response is likely a tune issue at some level. I fought many throttle control related issues when I built my Hemi. A good tune by Flyin’ Ryan finally resolved them all.

Not being smooth is one thing. Imagine a built 392 Hemi going wide open and not being able to stop it. Ahh, good times…

I’m currently at the muffler shop getting a cat fixed and then I plan on finding a good tune / dyno shop in houston to see what they can do. In hindsight I wish I would have cam swapped but maybe one day down the road.

 

[NashvilleTJ]

If you have HP Tuners (or similar) and an AFR Guage, someone like Ryan can tune it remotely. The nice thing about tuning on a chassis dyno is you get insight to the power you are putting down, but you can get just as good a tune (as far as I understand) remotely. Especially regarding drivability issues like you are having.

The first guy that tuned mine was a very talented and knowledgeable local tuner with a huge, successful business, and he who did know his stuff - but was mainly experienced at tuning drag racers and similar setups. After many, many attempts he did get it running OK - but not great (he is the one who unwittingly introduced the WOT problem). Ryan did 10 or 12 rounds and it runs like a top.