Hi everyone...

Maybe someone here can shed some light on this subject.

My ex cab EBII (dual fuel), converted from 4 to 3 speed years ago, is now gutless when the base timing is set to -10 degrees. it just slugs up the tiniest hills, and the only way to give it any guts is to set the base to a whopping -20 degrees!

It is also running like a dog on petrol (but a lot worse), so I'm asking anyone if they know what might be going on in the eec to stop it from advancing to the required mark at wide open throttle etc? the engine running test throws a MAP sensor error, but the map sensor has been swapped with a known good one, and the problem persists.

Another question - Does the EB have a Limp mode that it can enter?

Any suggestions! Really not wanting to get ripped off by Ultratune etc, only to have them say "Sorry - its not factory - here's your bill, but we still can't help ya!"

the map sensor code does not always mean the map sensor is fualty.
it means there is a problem some where between the ecu and the map sensor. that includes wiring.
there could also be a split in the vacuum hose for the sensor.

also check you balancer has not moved. the outer ring can some times move
causing the timming marks to not line up where they should

Thanks for the reply

The balancer shifting was my first thought on the weekend - I did a rather crude test to see if it had made an obvious shift - the old coat hanger down the spark hole It seemed pretty much spot on. I had the map hose off today and checked it - no leaks there. No cracks in the MAP sensor plastic pipe either - or on the manifold. I'm getting quite baffled at this.

The other problem with this is as follows - this is probably the 6th or so time i've done the timing now in 2 weeks. I reset the computer by disconnecting the battery and shorting the leads for a while. I then set base timing as per manual, and a week later, its retarded by 6 or so degrees and running like a dog again. I replaced the dizzy a few days ago, so hopefully that had something to do with it.

Another question: How much does the map sensor contribute to the timing curve? In old vacuum actuated advance systems, the vac advance was apparently there just to "tweak" the economy and not much more. Does the MAP and TPS do more than this? I haven't been able to find any docs on this anywhere. Also, since it use to be a 4 speed, can the Learn throttle procedure still be performed - as the gear position sensor no longer exists, and whoever put in the 3 speed connected the M51 inhibit swich to the starter relay instead. Which one does the computer use to determind the gear position in a 4 speed for the learn procedure?

Thanks...

the ECU uses the MAP and TPS to calculate the load on the engine.
and from that the ECU refers to an ignition and fuel map. to work the fuel and spark needs.

the old mechanical/vacuum dizzy realy only has a fixed curve to use. the mechanical side is sensitive to RPM and vacuum side to you guessed it vacuum.

you need the MAP and TPS to be working properly to get the right performance from the engine.



i'll leave the auto stuff to some one els as they are not realy my thing