Hi,

 

I recently had my '87 Ninety (2.5L 5-speed) re-powered with '96 Disco

engine and trans. I've got a few little teething problems with it and I

have found some similarities with problems listed in the archives here,

though nothing conclusive. Perhaps someone can help.

Symptoms are:

1.        Stalling often when slowing for intersections.

2.        Surging at idle in neutral and eventually cutting out.

3.        Missing under load (towing up hills etc) at about 2600 RPM.

I guess I have close to a NAS D90 V8 but without the luxury of the

Diagnostic Display that some posts refer too and other niceties like a/c

(left in the Disco). We ended up with a lot of wires on the loom not

connected after the transplant as the Ninety has very few connections

compared with a Disco, being much more basic. I've got no Speed Sensor,

that having been replaced by my Speedo cable in the same socket on the

transfer case (Speedo still reads accurately). There is a sensor of some

sort on the l/h side of the Transmission which has no connection any

more. Is this supposed to tell the ECU what gear I'm in? I've bought a

Haynes manual #3016 and am going to try and find which wires should be

connected that aren't. Meantime, if anyone can shed some light, that

would be great.

Ray.

_______________________________________________

You are missing the speed sensor input, which is what the empty socket

on the loom near the tranny is for. This may be why you are stalling at

intersections, symptom #1. That sensor tells the ECU if you are moving

along or at an idling stop. This would influence your stepper motor and

your idle.

The other issues sound to be a problem with the stepper motor. Perhaps

not plumber correctly? I'm just guessing here, but the symptom #2 would

point to issues there.

You may also need to check the coil, ignition amp module and dizzy

connections. Are your O2 sensors intact and functioning? These may

influence #3.

Good luck on what sounds like a fun and worthy project. One in fact we

are considering for my friends 84 110.

Regards,

Michael

 

Michael, thanks for the response. I will try reconnecting the speed

sensor and go without my Speedo for a while to see how it runs. The

little problems aside, I can say that the truck is awesome to drive, so

much more power. Can recommend the conversion as being worth the little

bit extra compared to a 3.5 Carby conversion which I originally

considered. I paid NZ$7,000 for the 3.9 complete with tranny and

transfer case. That's about US$3,000.