Replaced 6cu with 16cu as upgrade but as soon as the ignition is turned on the injectors continually pulse the car will start and rev but runs rough and will not idle , its a xjs he 1983

 

For some reason the car is overfuelling madly as the injectors should not pulse continually, ignition-on.

• Does it go back to being Ok when the old ECU is put back?
• If so, the new 16CU is faulty
• If not, you have a wiring loom problem.

 

hi Greg if i put the old ecu back on the car start and runs

 

Bob,

As Greg has said, and you have now confirmed.

The 16CU is bad, which is rare.

Petrojet in Kent Town used to repair them, not sure now, its been very many years since I have needed their services.

 

Thank Grant I did try to call you but i only have your land line number and that seems to be disconnected Rob

 

PM sent, stand by, get a beer while the cyber space stuff does its thing.

 

Which version of the16 CU do you have? It could be possible you have a Marelli 16CU If this is the case then the ECU will not recognize the tach pulse correctly.

 

Warrjon,

Do you happen to know the last 16CU for the Lucas and / or first Marelli 16CU model numbers?

 

This might help? From AJ6 Engineering:



16CU Part Numbers and Applications.

All are preceded by DAC.

4118, 4585, 6335 - Lucas ignition, Cat
4119, 4478, 4586, 6336 - Lucas ignition, non-Cat
6337 - Marelli ignition, Cat
6338 - Marelli ignition, non-Cat


Cheers
DD

 

I might be able to help. I have 2 16cu ECUs here...

I don't even know why I have them, lol
JagCrazy...
Help!

Really tho. Where would the numbers with the designation (the ones Warren laid out) be printed on the units? They are old, and IIRC (I'm at work) there are not a lot of clear markings on them. I'll post some photos when home.

 

Thanks, the ECU I fitted is a DAC 4586 non catalytic converter.
Cheers Bob

 

So, from what you now know. Is that the correct one?

I needed this thread today. Thanks Warren. Trying to figure out what to do with these.

This is what I am looking at.

 

84526B is a DAC4118 which is for Lucas ignition; the other I don't recognise the part number. You might have to remove the lid and check which components are fitted and what firmware revision is given on the EPROM.

 

Thanks James...

All of that is above my pay grade... These are what I just have and can offer,,, if its any help...

 

Hi Jay jag jay
The 4118 is for a Lucas car but a catalytic converter model, no good for my car,
Thanks
Cheers Bob