V6 running problems

[windywatson]

Both of my V6's have had rough running, missing and improving once warmed up etc. In both cases the symptoms are as discribed in the initial post and by other owners, it is common at about 10 years old for the HT system to be at the end of it's life and start breaking down. In both cases of mine the investment in HT leads, rotor cap & arm was the cure.
If these last as long as the originals, it will have been worth the price as I bought via the club and got original mazda parts.

Cheers

[mikeWalsall]

My LPG V6 is vastly improved since closing up the plug gaps slightly ..

Even when the temperature is up to normal .. and the heater is blowing warm air .. when initially switching to gas is still 'lumpy' ... when the engine as been running for a time .. it runs like a sewing machine ..!!

I to have put it down to the aged ignition system ..

[windywatson]

If its running smooth on petrol before it switches to gas, and then its lumpy on the gas at switch over that could still mean that it's switching over a little to soon before its hot enough. Get it checked by a good LPG installer as that shouldn't be happening.
Mine switches over very smoothly now but it was initially a little lumpy just after conversion. But it's not unusual to have to do minor adjustments to iron out small problems like this as mine did when first done.
The switch over is very temprature critical as the evaporator for the gas has to be hot enough to get the incoming liquid LPG into its gas form for ignition. As this is usually done by the water temprature passing through the evaporater, the engine has to have got up to the required temprature.

Cheers

[Simon Jones]

Mine switches seemlessly at 40 degrees C. What do other folk have theirs set to?

[windywatson]

Dito, mines at 40 degrees too. Was originaly 38 but needed uping.

[haydn callow]

Mine switches at 40c.....Romano system......it does not like to be ticking over when it changes over at that temp.....I reckon 44c would be purrrrrrrfect for me......must get it adjusted
As long as you are moving it switches seamlessly........just a problem if you happen to be stopped at a junction when it changes over.

[weebrian]

Exactly the same as Haydn although it always seems to wait until the wrong moment to change. Just pulling out from a junction is the classic one.

[windywatson]

Hi,

Some of the switching over just on pulling away may be to do with engine RPM. I recall being told during the set up of my system that switch over was not only temprature related but also engine speed related.
I assume that if the system wants to switch over when its reached the required temprature it also requires to be above a set minimuim RPM. Hence the engine may sometimes be switching when you start to pick up revs, perhaps when pulling off from a junction.
I recall my installer suggesting that the RPM setting be a little higher than the usual setting (what ever that may be) so that switch over would be smoother.
There will no doubt be en expert out there that will comment / know wether this is actually the case.

Cheers

[Glenda]

Richard I found your thread whilst searching for sluggish V6. Mıne has had all the same symptoms
for a good few months now. I have dropped it in at Allan's (Allansvehicles)and he is looking at it for me.
I will report back on diagnosis as it seems to be a common V6 problem.

Checks Fuel Filter, HT Leads, Distribution Cap, Rotor Arm and possibly crankshaft position sensor.

Stuart

Finally got round to picking the V6 up. It was indeed HT leads, rotor arm, distribution cap and coil lead. Now running perfectly again. Allan says the HT leads were leaking so much from around the cap that it was like a mini firework show. Took me half the petrol to drive back as it did to get there.