Essex 3 Litre V6 misfiring

Essex 3 Litre V6 misfiring

Author
Discussion

Jukebag

Original Poster:

1,463 posts

141 months

Monday 3rd August 2015
quotequote all
I wonder if anyone could help with a problem I am currently having with a Ford Essex 3 litre V6 engine. The engine is originally from my old Reliant Scimitar, which is now housed in a replica E-Type Jag. It's abit of an explanation, but here goes:

Ever since I fitted the engine in the car, there has always been a constant misfiring at low revs. I always put this down to the inlet manifold gasket, which I renewed a few weeks ago, this I did according to the manual after numbering al the spark plug leads. On re-assembly, and on starting the engine up, it sounds as thought it is only firing on 2 cylinders (it sounds very rough and noisy). I've no idea what I could've done wrong, though I'm suspecting something could've gone wrong with the electronic ignition, although I cannot see any wires out of place and all wiring seems OK.

Does anyone know what could be causing this?

Thanks


Steve_D

13,776 posts

260 months

Monday 3rd August 2015
quotequote all
It was working before you took it apart so the most logical is you have gone wrong somewhere in the reassembly.
On that basis there is very little we can guess at.

Back to basics....do you have a spark at all plugs? Do you have a temperature laser gun you can point at each manifold branch and see which one(s) are not getting hot enough? Have you touched the timing? have you had the dizzy out and put it back 180 degrees out.

Etc etc etc

Steve

Jukebag

Original Poster:

1,463 posts

141 months

Monday 3rd August 2015
quotequote all
Steve_D said:
It was working before you took it apart so the most logical is you have gone wrong somewhere in the reassembly.
On that basis there is very little we can guess at.

Back to basics....do you have a spark at all plugs? Do you have a temperature laser gun you can point at each manifold branch and see which one(s) are not getting hot enough? Have you touched the timing? have you had the dizzy out and put it back 180 degrees out.

Etc etc etc

Steve
Hi Steve, thanks for the advice.

I have not disturbed the distrubtor as there is no need to because the inlet manifold goes around it. The inlet manifold new gasket, which I fitted, can only fit one way. I fitted this with sealing compound on the new gasket; the manifold head was reinstalled, gently, and tightened down as per sequence from the manual. With the carburetor installed, and all the other fittings included, including the plug leads (which I numbered one to six and fitted in the correct order), I was expecting the engine to fire up and start gently, nice and quiet. However, it started and sounded exactly as though I had put the leads on wrong, firing on one or two cylinders only. As I said, I have no idea what it could be. Is there any way of checking the electronic ignition (but why should it fail when the engine has not been running?)?. There is power getting to the two terminals on the coil and the high tension lead.

A friend gave me a plug testing device, which fits between the plug lead and the spark plug. On trying this device, on each cylinder, I couldnt get any response from it, but yet, the engine is firing on one or two cylinders. To me this is a mystery. Everything with this car seems to be going wrong, ever since I put the Essex engine in and gearbox; problem after problem.

Any solution would be gratefully appareciated.

Edited by Jukebag on Monday 3rd August 21:20

trumptriple

202 posts

133 months

Wednesday 5th August 2015
quotequote all
Had low rev misfiring on my old Scimitar, very annoying as it was an auto. Turned out to be broken down plug leads. When I shut the garage door, so it was dark, I could see tiny blue sparks jumping between plug leads.

Fitted a cheap new set, same problem. Fitted an expensive new set, problem solved.

Bennachie

1,090 posts

153 months

Wednesday 5th August 2015
quotequote all
Too much gasket goo? Ingested and fouled plugs? Have you taken them out to check etc.
Is the manifold seated correctly and sealing all inlets?

paintman

7,714 posts

192 months

Wednesday 5th August 2015
quotequote all
I'd be inclined to do a complete static re-time of the engine starting from physically checking that No1 piston is at TDC on the compression stroke and that the rotor arm is in the correct position AND the plug lead is in the right hole in the dizzy cap.
Then check that the rest of the plug leads are fitted in the correct positions.
That eliminates the chance of disturbance or mix up of leads.
I appreciate you say you did it all by the book & labelled all the leads. I've been told that by someone who had a misfire after working on a LR V8 & was certain all was in order. After much persuasion he finally did what was suggested & cured the misfire. Which had been caused by wrongly connected plug leads.....