ecu hotwire

rscob · Post by **rscob** » Tue Jan 05, 2010 7:22 pm

need some efi expert to help with this one,i have a 3.5 hotwire wiring loom and ecu,and i was wondering if this will run a 3.9 that i am rebuilding,or if not can i just get a 3.9 ecu and plug it into the 3.5 loom,also i need to know which wires i need to run this in my cobra,before i start butchering the loom. rob

Post by **katanaman** » Wed Jan 06, 2010 1:20 pm

Loom wise I think they will all be the same and you will need all of the loom for it to work. ECU wise I am not sure as I have never seen a 3.5 hotwire. Chances are that you can change the tune resistor though, hopefully someone else can confirm this. The ECU wont run a 3.9 though if that isnt the case.

kiwicar · Post by **kiwicar** » Wed Jan 06, 2010 3:52 pm

I think, from posts I have read in the past, where people have wanted to run a hotwire set up on a 3.5, the conversion is done by an eprom in the ecu, ie you want a 3.9 eprom. However someone was on here last week wanting to run a hotwire 3.9 set up on a 3.5, it may be worth looking in recent posts on here and arranging a swap with whoever it was, then you both will have the right ECU for the job.
(3.5 hotwire set ups were on late 3.5 discos)
Best regards
mike

rscob · Post by **rscob** » Wed Jan 06, 2010 5:35 pm

hi mike,so let me get this right if i get a3.9ecu it should plug straight into the hotwire loom and work. rob

Teesdale_landrover · Post by **Teesdale_landrover** » Wed Jan 06, 2010 11:54 pm

you can run a 3.5 on hotwire no problems, they run very well on the stock 3.9 ecu

rscob · Post by **rscob** » Thu Jan 07, 2010 12:44 pm

but will a 3.9 run on the 3.5 hotwire setup if i just change the 3.5 ecu for a 3.9 ecu. rob

rscob · Post by **rscob** » Fri Jan 08, 2010 5:05 pm

Come on guys there must be some hotwire experts out there,even if its to tell me to stop being a kn-b and try something else. rob

Post by **katanaman** » Mon Jan 11, 2010 1:34 pm

if you change the ECU for a 3.9 one then yes it will run why shouldnt it since its a 3.9 engine with a 3.9 ecu.

rscob · Post by **rscob** » Mon Jan 11, 2010 3:20 pm

I thought so but wanted someone with a bit more efi knowledge than me to say its okay before i go any further. rob

CastleMGBV8 · Post by **CastleMGBV8** » Mon Jan 11, 2010 4:53 pm

Rob,

If you want a 3.9 ECU try Alan Coote at Range Rover Heaven, his prices are usually reasonable.

07711 369785

Kevin.

rscob · Post by **rscob** » Mon Jan 11, 2010 5:45 pm

Cheers kevin,i will give him a bell tomorrow. rob

Teesdale_landrover · Post by **Teesdale_landrover** » Mon Jan 11, 2010 9:05 pm

for sure it will 'run' but how well, half the rover v8's on the road have bad camshaft wear, uneven compression amongst other problems.
i wouldnt take on le mans in it, but it will run