Gas "too rich" when cold.

[Ando81 2,949]

Hi all, just wondering if anyone can shed some light on my 91 cross flow powered xf ute running terribly rough and smelling of gas from cold. After 5 mins or so it is fine and idles great. I'm wondering if it could be a sensor that changes the timing when the engine is cold or is it something else playing up. I can't smell the gas once it has warmed up. I thought of adjusting idle mixture on the gas but thought it would play up once at operating temp. Any thoughts?

[Ando81 2,949]

Sorry about the multiple posts lads, bloody phone is playing up. Anyone know how to delete the unwanted copies?

[Thom 6,650]

Sorry about the multiple posts lads, bloody phone is playing up. Anyone know how to delete the unwanted copies?

 

Done

[Ando81 2,949]

Thanks Thom, I felt like a real dick for a while there

[tpak addict 1,909]

what type of system is it.... got pics?

[Ando81 2,949]

No idea of the system but I can put some pics up tomorrow.

[gerg 10,871]

Where is the gas coming from? Is it coming out of the vent on the converter? Could be a holed diaphragm.

[Ando81 2,949]

Haven't really been able to source the smell as it won't idle without holding revs on it. Might get a mate to help me tomorrow.

[tpak addict 1,909]

Could be just running rich on startup and may just need tuning but depends on the system.

Impco systems tend to do that....

 

Will wait til I can see what system it is tho

[deankxf 20,286]

could be all gummed up, waxy stuff. vacuum opens the gas valve inside then the waxy shit holds it open and most times it floods the engine and stalls and the converter freezes..

you could test that theory by pouring hot(not boiling) water over the converter before starting the engine.. if its good, then it needs cleaning.

[Ando81 2,949]

Cheers for the help fellas, I will try these things tomorrow and see what happens.

[Ando81 2,949]

this is the converter and gas mixer. Not sure if it helps to determine what type of setup it is. I'm not really switched on with gas as you can probably tell.

[XFChris 126]

That's a complex converter, simple mixer setup. Opposite to impco setups .

 

I have the same converter as you, omvl r90e. I have seen rebuild kits for them .

 

sadly, I don't know enough about lpg to help with your issue

[deankxf 20,286]

that converter is better at not getting gummed up than the LANDI(or nimrod copy etc) but i haven't successfully cleaned one once they play up.

give the hot water a try before starting it, if it makes the difference it will be due for a clean.. probably cheaper to replace with a new one and then would have a warranty as not many gas places would waste thier time cleaning one anyway.

(the landi ones are easier to clean, but gum up more often.. i was cleaning mine out once a year and it was in the colder month like now ish.)

[gerg 10,871]

Strange, I had a Nolff's set-up on my Corty and apart from a little tweak to the mixture now and then I never touched it in the 6 years I had it. Turned over winter, summer, rain, frost whatever with a bump of the key. The needle adjustment on the mixer (it rides with the venturi needle) was shitloads better than the Impco ones that are just a bypass port. None of those i've seen have ever worked. I don't know if anyone's heard of Nolff's but it seemed like a very good system.

[Ando81 2,949]

I will try the warm water trick when I knock off work later. I've never had the converter freeze up but I had a converter the same as this one fail and let gas into the cooling system which was a pain.

[deankxf 20,286]

I will try the warm water trick when I knock off work later. I've never had the converter freeze up but I had a converter the same as this one fail and let gas into the cooling system which was a pain.

what was the outcome with this?

[Ando81 2,949]

Did the converter water test and no change. I changed the timing a little as it seemed way too advanced and it seems to accelerate better and idle smoother. I think I might need to take it to a gas expert for a proper tune.

[matt_lamb_160 252]

What is your idle speed? If it is a bit low just bump it up a tad and don't worry about the rough cold running. It's likley no big deal??

[gerg 10,871]

If it's just idle speed, that's unfortunately something you can't change without some sort of idle speed solenoid. Problem is there's no getting round the fact that cold engines are inefficient. Instead of the heat being used to turn the crank, a lot of it gets absorbed trying to heat up the cold block and head with lots of water in there too. If you go adjusting the idle speed to suit cold running, it will be too high once warm.

 

Maybe a little canister purge solenoid off a jap car could be used to bypass the throttle using a switch, just as you'd use a fast-idle on your choke