Erratic RPM Surging

[robtash]

Arrrgh please... On the weekend I changed my Plugs,Cables, Plug Caps, Solenoid, distributor Cap and Rotar arm with a suggested higher performance option given on TVRCC. The issue I am now faces with is erratic RPM in all gears. The car still runs but the RPM is all over the place.I waited for her to cool down , popped teh hood and cheacked that all the cables were seated prperly but still nno change,

PLEASE

Thank you for your help.

[Johnniem]

Is your stepper motor clean? Are there any shorts?

[Johnniem]

Is your stepper motor clean? Are there any shorts?

[nikman]

What was wrong to start with? I mean, what made you change that lot? Oh, and what solenoid are you referring to? Nick.

[robtash]

Hi, sorry spelling was so poor in last post.
Right with a little more time at hand, I needed to change the plugs as they were fouling up and were due for a change. Two of my HT leads were damaged (burnt) and needed replacing. However she was running Fine. I replaced:
HT leads to Magnecor Reds
Coil
Distributor cap
Rotor Arm
Plug extenders
All from ACT.
Starts no problem and runs but the RPM fluctuated around 900 to 1300 rpm on Idle. In 5th gear on the motorway at 2500RPM it fluctuates 2500 to 3100 erratically.

[GreenV8S]

I assume the tacho is the only problem, the engine runs OK.

Without looking into the details I would guess that you have got too much / too little HT resistance (out of plugs, leads, extenders exactly one should be resistive), or the wrong coil.

[V8 Animal]

ACT are very good so i would of expected them to of sold you the right bits they talked me through the parts. I bought the same as you.
My advice is to reset the ECU
V8 Animal

[GreenV8S]

As far as I can tell the symptoms show that the spark itself is good but the tacho is getting a poor signal, which IMO points to a back EMF problem, lack of resistance could cause this.

[robtash]

Hi , Nope the engine is running a little rough, not very smooth, and shudders on Pull off in first.

[robtash]

Update,
well these are two different issues.
The erratic RPM was a result, it seems, of the wire from the Coil being wrapped once around one of the new HTC leads.

The shudder it seems is when the engine was hot,a faulty oil seal caused a fine bit of oil to escape onto the clutch plate.

Cheers

[im]

robtash said:

Update,
well these are two different issues.
The erratic RPM was a result, it seems, of the wire from the Coil being wrapped once around one of the new HTC leads.

The shudder it seems is when the engine was hot,a faulty oil seal caused a fine bit of oil to escape onto the clutch plate.

Cheers

If you don't mind me asking, who sorted the problem out?

[robtash]

I took it to Highgate Motors as it was too lumpy to drive out to my local TVR. Open to suggestions if available.