MISFIRING

[yaad]

Hi guys

need some help again

finally got my rocker cover and inlet manifold blasted. it has now been put back on but the 5th cyclinder is not firing so the car is running on 5 cyclinders. i changed 3 injectors and all 6 spark plugs. the car is still misfiring. it was misfiring prior to being blasted.


any ideas as to what the issue could be? should i check the air flow meter? change the injector? or could it be a wiring issue?


any help would be appreciated.

cheers
yaad

[ah]

Ive just roughly the same fault,
1,have you found which plug is not firing
2,if so check the lead out to make sure it’s not corroided.
3,HT cap ok.
4,if this doesn’t sort it, the best advice I can give you is give Brianmooore a shout.

[Brianmoooore]

First thing to establish is whether the misfire is fuel relate, spark related, or even compression related.
Connect a spare spark plug to lead 5, lay it on the rocker cover, and run the engine. Does it have a good, healthy spark? Stop the engine and remove plug 5. Is it wet with unburnt fuel? Have yoou performed a compression check?

[BristolE30]

Haha why did you tell us about the blasting if it was misfiring prior to this. Get your multi meter out, a Bentley manual and start testing!

[Cypriotgeeza]

Have you had a look at the distributor cap / rotor arm?

I'd go with what brianmoooore said as it sounds electrical to me..

[yaad]

Hi

Compression levels came within the range. My mechanic recommended changing distributor cap? Best to get these new? Looking online theres alot of different companies making these, any company to go for or avoid?

Cheers yaad

[paultv]

Please! Follow Brians advice...it will save time money and the famous wind pissing.

Check sparks on no.5 same time condition of plug...if plug is wet then its getting fuel and not firing...

If the compression is good and the plug is wet then you need to check the distributor cap and the cable and socket to numbet 5 assuming no spark after you've pulled the plug to test it and give it a visual.

Don't start throwing money about on random items...just do a logical diagnoses, this will reveal the root cause.

Ps. Don't stand in a bucket of water whilst testing the HT to the plug!!

Paul

[yaad]

Okay compression check was clear, we removed the spark and there is no spark out of the plug at all, it is all dry and a brand new plug but used two different plugs and both didnt work. So not sure if the lead is gone to the spark?

[Brianmoooore]

Okay compression check was clear, we removed the spark and there is no spark out of the plug at all, it is all dry and a brand new plug but used two different plugs and both didnt work. So not sure if the lead is gone to the spark?

The one on the rocker cover didn't spark, and the one in place didn't get wet? That would be two unrelated faults, either of which would cause the same problem.
Somewhat unlikely!
Measure the resistance of the suspect lead, and compare it with one of the others. Should be the same.