Misfire problem?

[HowardB]

Just had a Kenlow fan fitted to replace the seized viscous coupling, but now it coughs and splutters when I accelerate hard above 4000rpm. Engine pulls & runs fine at lower revs - has anyone any suggestions where I should start looking?

[jclay (RIP 2018)]

Fuel pump or fuel filter.

[Hasbeen]

Howard, where are you drawing the power for the fan from? Could be a
problem there.

Have you tried disconnecting the fans power supply, & giving the car
a run?

Probably it has nothing to do with the new fan, these things often
just pop up to fool you, so after the fuel supply, check all the
ignition bits, & connections. It does sound like something braking
down at high load.

My recent starter failure was due to the fact that I had moved an
electrical cable with my elbow, while head down, & tail up, in the
footwell, playing with the ventilation controls.

Hasbeen

[busheytrader]

The electric fan wouldn't cause these problems unless something's been tugged or unplugged whilst fitting it.

My 2.0L engine used to behave like yours about 4,500 miles after servicing it. The points needed adjusting or the condenser replacing. The breather pipes to the carb also cracked up and leaked causing erratic running.

Have you replaced your fuel tank yet? They rust from the inside out clogging up the filters and carbs with fine orange silt. The fuel bowls get enough petrol at low speed running but can be starved at high revs. I replaced mine last year because of this.

Adam





TR7 V8 DHC Jaguar Solent Blue. 9.35cr Range Rover V8, Holley 390cfm, JWR Dual Port, 214 Cam, Lumention, Tubular Manifolds, Single Pipe Exh, 3.08 Rear, 200lb Spax & Solid Bushes, Anti- Dive, Granada Vented Discs & Calipers, Green Stuff, 4 Speed Rear Cylinders, Uprated Master Cylinder & Servo, AllyCat 5 Spokes. No Door Stickers.

[bmcecosse]

As above - if you have taken the supply for the fan from the coil feed - it's through a resistor wire and so you may be starving the coil of volts! With any problem that suddenly 'appears' - best to take a step back and undo whatever has just been done!

[HowardB]

Found the problem - it was a loose HT lead on the coil. Thanks for the suggestions which were appreciated.