New YouTube video on XJ-S from Car Wizard

Car Wizard uploaded a new video today on diagnosing a non-running XJS running again. IMHO he did it right. Found multiple screwups from other repair attempts.

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great video. I’m having flashbacks to two years ago when I was going through the exact same thing! LOL

I gained the knowledge from this forum, but the other main ingredient is tenacity/patience! I feel like I’ve matured a great deal working on my XJ-S V12. :slight_smile:

Maybe he snuck a peek @ Palmdude’s Book before getting her fixed? :wink: I do wonder where all the rust is underneath her, though, esp. if she was so neglected … Heck, she is 10 years older than Superblack … :frowning_face: Oh, that I wish THAT tech was here in Dallas … :pray:

Also, he keeps mentioning the 350 Chevy lumping thing … I thought the lumping was pretty much done to the e-types? FWIW, I don’t think I know anyone personally who lumped their XJS … or remember anyone on J-Lers mentioning they did … ? :confused:

Had to stop at 00:30 - Jagwaaar.

So there’s 2 different ECU’s… an 8 CU and 16 CU, does anyone know the difference??

16cu is a later design, less prone to solder cracking and cold solder joints. You have to ensure its from a Lucas distributor car if substituting for the earlier design. Edit: Oh, and also it depends on whether or not the car had O2 sensors. You need to be part number specific when buying a 16CU.

Actually 4; there is the 3CU used on pre HE. 6CU was used on early HE 5.3L, 16CU used on later HE, those two are interchangeable/pin compatible. Then there was a 26 CU…used on 6.0 towards the end of XJ-S production.

Hello AttyDall - check out the “Lumps” section on here - numerous cases of XJS with engine changes - Tex Terry, II - 1991 XJS V12 Classic Coupe, 1986 XJS V12 Coupe - sent 11/18/2020 0827hrs. EST USA.

36CU was the ECU used on the factory 6.0ltr cars.

And don’t get me started on the Zytek ECU used on the XJR-S.

So, there are 6…26CU on late (92 and up) 5.3L. So, 36CU exclusive to the 6.0? Then another for the post XJ-S 6.0 Zytec used for a brief time in MY96.

The Car Wizard did the right thing, swapping in the 16CU. I had all sorts of intermittent stalling and no start issues until I did. I went over my 6CU and reflowed the solder on everything that looked slightly suspicious, but I never trusted it after all the issues I’d had. I know a lot more now about trouble shooting and using a scope than I used to however.

The Zytek ECU was limited to the TWR cars when Tom Walkinshaw was running the Le Mans V12 cars. Later in the V12 timeline, the last of the XJ12 saloons had a Nipon Denso ECU and a coil on plug system.

The Nippon Denso distributorless ignition system was never fitted to the 6.0ltr XJS - it was only fitted to the X300 XJ12 & Daimler Double Six cars in 1995 & 1996.

I know of at least two businesses lumping XJS with v8’s.
Never liked the idea and haven’t been close to one.
I understand the attraction but not certain it solves every issue.

I think the ECU in the early 3.6 was an 8CU. It was problematic in that it didn’t respond well to engine wear. Bywater offered a mod for it to provide a trim for a worn engine.

Uh, no. The XJR-S cars also had a Zytek engine management system. I’m looking at the factory publication on the XJR-S as I write this.

That’s not in dispute. Last Zytek ECU I saw on U.K. eBay was listed at £899 ($1,170) & the last distributor (with the unique pick up) I saw was £1,495 ($1,900+)

I loved the facelift XJR-S that I owned but I’m glad I’m not trying to source essential spare parts at those prices.

I wonder why not, since apparently it worked O.K. with the 6.0 engines in those cars (sedans)? Might have solved a lot of headaches … :exploding_head: