major missing issue

[disco stu]

Hello,
I am the proud new owner of a '96 Disco, 4.0 GEMS with 140K. I bought it @ auction because, well.. it looked cool , ARB bumper, winch, 3" lift big wheels.

OK, so I've been working on it for about a week, I fixed the windows, heater, changed plugs n wires, changed fluids but I can't solve my driveability issue. Starts up great, idles smooth(ish) and can rev it all the way no issues. But....try to drive it and it falls on it;s face. It will act like it is starving for fuel or lost spark, then if you gun it it will take off. Over 2KRPM it will run, but under 2 it bucks like a mule.
Checked TPS, checked rail pressure, changed fuel filter (pressure was good but you never know), unplugged MAF, no change, cleaned IAC, unplugged VSS, speedo quit but it still ran the same. Here's the kicker, no MIL light but the light does not come on when you go to pos 2 on the ignition and I can't establish coms with the OBD ii
any clue???

AS I have no MIL light could my ECU be KAPUTT?


I checked my o2 sensors, checked good, ran 2 gum out treatments thru and using 92 RON fuel.

UPDATE....
MIL light now works, some clever soul removed the bulb.
Removed the GEMs mod, water, dirt and crude has ingressed onto the muti-ribbon cable and the PCB, cleaned it up, no change (might even be worse) so I'm buyin' a new GEMSmodule.

Anyone got any ideas on the missing issue?? or why I can't read the codes?

 

[joey]

Can't read the codes? does it even power up the OBDII scanner? Does is attempt to connect?

 

[disco stu]

It syas that it is connected but when you try to establish coms it gives an error. i sold my scanner whan I sold my shop, so I was using Auto Zones scanner, that didn;t work so i went over to o'reilly, same deal.

Oh, I unplugged my cam sensor, my rig ran a lot better, make sense that the missing issue could be related to cam sensor? timing advance maybe?:

 

[joey]

cam sensor could be the issue, as you found.... the OBDII issue could very well be a bad plug or dirty connection to the ECU.

 

[greg409]

Stu, did you download the rave cd? (bottom of my or joey's post)

It can/will detail the functions & default modes of the sensors.
read -- workshop, 4.0, description, SFI fuel,

As I recall, if you disconnect the cam sensor, the fuel inj. goes to safe mode.

It's not easy to wade thru' but it's good stuff.

luck,greg

 

[disco stu]

I down loaded it, took some reading but , I m an Engineer so it was a good bed time read!!!
Still can't read the codes, cleaned up th connector, cleaned up GEMS unit, what a daft place to put the ECU!! thing is rusty as heck!

I found a knock sensor that had been damaged so I'm changing it on principle, any who I have the interior all torn out, so I can fix the sunroof, the rear window regulator, central locking, dash lights. My rover makes me proud to be British...Like POSH spice does.