The vehicle - Series 1, TJ Executive 3.5, basic 4 speed auto. No traction control, no ABS.

The questions;
How do I determine if my engine has "number 4" or "number 6" camshafts?

Provided I have "number 6" camshafts, can I switch the ECU from the "Series 1 ECU" to a "Series 2 ECU" without any trouble?

The questions come about after digging around on the forums here and learning about the differences between each TJ series. If I can squeeze a few more KW, or general performance, just by switching the ECU it would be a (relatively) cheap mod.

The factory manual doesn't seem to shed any light on this.

I'll be replacing my valve cover gaskets within the next few weeks. If the camshaft number is stamped on the cams I can get a better idea of where I stand.

Failing being able to identify camshafts directly, would there be an engine number series that can tell me if I have the "number 6" camshafts?

I'm also assuming the ECU switch will be better suited if I have the number 6 camshafts. Would it be possible to still switch the ECU on number 4 camshafts and still yield any improvement?

Not interested in a piggy back, or reflash. Just looking for a trip to the wreckers for simple plug 'n play mod.

Any help would be appreciated.

If you remove either your dist or cam shaft end cap on the front bank, the numbers are stamped there

TJ onwards had the #6 cams

Thanks Madmagna, I'll check it out when I do the valve cover gaskets.

My concern was that I may have one of the TH engines they squeezed into TJ's in the early run. At least that's what I was lead to believe after reading a post on the forums here.

If I spot #6 I'll leave things well alone.

If you swap ECU's your car wont start, Cos of the Immobilizer

If you swap ECU's your car wont start, Cos of the Immobilizer

Okay, cool. Thanks for that.

Not interested in a piggy back, or reflash. Just looking for a trip to the wreckers for simple plug 'n play mod.

If you can score the muffler from a TJ Sports in good nick from a wrecker, that's about as much bang for the buck as you could get performance wise.

Failing that, you might want to investigate a new Lukey AL4-5597 muffler, which is a direct bolt-on replacement for the stock muffler (on sedans at least, don't know about wagons) - a year or two back they could be ordered through Supercheap Auto for under the $250 mark as I recall, but don't know whether that's still true.

If you can score the muffler from a TJ Sports in good nick from a wrecker, that's about as much bang for the buck as you could get performance wise.

Failing that, you might want to investigate a new Lukey AL4-5597 muffler, which is a direct bolt-on replacement for the stock muffler (on sedans at least, don't know about wagons) - a year or two back they could be ordered through Supercheap Auto for under the $250 mark as I recall, but don't know whether that's still true.

Thanks. I have sourced something in the way of a better rear muffler through Mits-Fix. But, thanks for the part number.... if somebody like me were to work at a place like the aforementioned proprietor one might be ale to investigate further.

(I work at Supercheap Auto)