Sierra 1.8 CVH (ESC Hybrid) Misfire under high load at low revs.

[swinster]

Hi,

This problem has been bugging me for ages. I have a 1.8 CVH that exhibits a misfire problem and high load conditions at low revs. (E,g pulling up a steep hill in second, or even just flooring it on the flat in third with the engine at about 1500 rpm). It's like the advance is way off, coughing and spluttering with the occasional loud backfire. Releasing the throttle and reapplying sometimes clears the problem and when she picks up she fly’s (as best a 1.8 CVH can fly!)

I have bypassed the fuel separator, changed the ESC module and crank sensor (albeit with second hand parts), checked it over on some crypton tuning kit (which checks out fine), even changed the fuel pump push rod.

Anyone have any ideas?

The car has intermittently died on us a few time in the past, only to be able to start some 10 minutes later, but this hasn't happened for a while - possibly through one on the changes mentioned above.

[swinster]

Well, the consensus for on other forums was that this is an HT fault, so even though I thought the HT had been looked at sometime ago by our garage, I toodled off down this road.

I flipped off the distributor cap and there were some hefty build-ups on the contacts so I scrapped these off and cleaned them with a bit of fine sand paper and did the same for the rotor arm. No joy, in fact it seemed to make things worse!

So I went off an bought a new rotor arm and dizzy cap and installed, but only after making the basic mistake of pulling all the leads off and not remembering the firing order or rotor arm rotation (moppet). After this was looked up a a local garage opposite the motor factor’s we back in business, but still with a misfire.

Therefore, that leaves plugs, leads and coil. I was sure that the leads were replaced by our garage but even so, I had limited tools with me to thought that that would be the next move. One set of leads latter (this time carefully replaced one at a time!) and bingo – no more misfire.

It just goes to show that servicing does not always pay to be done a garage! Thanks for every one who suggested HT side of things. At least it has saved me the cost of an diagnosis at the Ford dealers next week.