Fuel Issue Or Electrical Gremlin ?? (SOLVED)

[Conker]

Just wondering what i should be looking for...

When the car is stationary, it revs freely and strongly. When driving under load, the car judders when accelerating between 1000 and 2000 rpm, and the higher gear Im in the more violent it is, so in fifth the steering wheel visibly shakes.

Is this a fuel issue, or something else?


N.B.  Not sure if its relevant, but on the motorway when I go past 80mph the rev counter goes bananas and spins around to all sorts of weird numbers.

Any suggestions appreciated...


EDIT:
I've already replaced rotor, plugs, leads, coil, and i've done timing (but not CO2 setting). And its a 1991 16v.

[fused]

Just a guess, gearbox/fly?   does it still judder if you are out of gear??

but I'd check/change fuel filter maybe pump if you suspect it, maybe clean up injectors...

Good luck

[Leon R]

Hall sender on the dizzy maybe. Check the plug on the distributor is ok and not broken off.

[Conker]

Thanks for the suggestions so far...

Leon... I was thinking hall sender but was confused by it only doing it under load - surely the hall sender would affect it all the time?

Fused... Fuel filter is a good idea. Pretty sure its not gears related as the problem goes away higher up the rev range.

[Leon R]

For the rev counter to go bananas it normally leads to hall sender and as far as i know, they can cause very strange faults. As can checking your ECU pins for corrosion. Loads of problems went away by replacing just 2 pins on mine.
 
If you live near north london i have a spare dizzy if you want to try it

[Conker]

Cheers for the offer Leon. I've got a whole new dizzy ready to fit (I was hoping not to have to fit it so that I could get my £80 back!) so I'll just use that.

I betcha it won't sort out the running issue though. Amusingly, I completely killed it yesterday - I cleaned out the metering head (theres a "mini" fuel filter on the main fuel line that I thought might be blocked) and now the car won't even start  :embarassed:  Its prob just lost all fuel pressure and needs a bump start.

[rubjonny]

that mini fuel filter shouldnt be there, take it out and bin it!

[Conker]

THREAD UPDATE:  PROBLEM SOLVED
***************************

I've fitted a new fuel filter and all four injectors have been replaced with brass merc ones. I then re-did the timing which was quite significantly out. After the injectors were fitted, the car pulled better, but it was the timing that sorted out the miss-fire.

The crazy rev counter was sorted by replacing the hall sender, although I unfortunately had to buy a brand new dizzy to do this as the old one wouldn't come apart. There is a silver lining in that the new dizzy comes with a new oil seal, so that should stop oil ingress into the dizzy as well!

[rubjonny]

coolio