HC emissions too high.

Unburned fuel probably from a faulty spark or general engine fault. Valve clearances, cam timing, plugs, leads, dizzy cap etc. Just general service items.

Dave Baker - Puma Race Engines

I'm not at all sure why women like men. We're argumentative, childish, unsociable and extremely unappealing naked. I'm quite grateful they do though.

Burning a little oil as well? Check the ignitions spot on & the plugs or good but You can always lean it off slightly to pass .

Before I got the CO down to 2% it was running very rich which obviously blackened the spark plugs up a fair bit. Although I've cleaned them up best I can, they might still not be firing quite as reliably as they should. Pretty much all the other ignition bits and bobs are pretty new so should be OK. Might be worth chucking some new plugs in.

Hope I'm not burning oil, its got new valve stem seals on it; and a compression test seemed OK so piston rings aren't knackered. Maybe the slightly sooty plugs are the problem.

CO level is easy to measure with my CO tester, but there doesn't seem to be any affordable devices for measuring HC?

Check the fuel-pressure-regulator. I'm not familiar with the Pug injection setup, but there's usually some vacuum-link between the fuel-pressure-regulator and the manifold [in some cases it's a vacuum-line between the warm-up-regulator and the manifold]. This compensates for changes of manifold-pressure as seen by the injectors at different throttle-openings. If the vacuum-line has come disconnected/got blocked or is leaking, the regulator sees what it thinks is wide-open-throttle and so does the additional-fuel-thing, with the result that the engine will run rich.

Also worth checking the spray-patterns of the injectors; if they're not atomising the fuel properly into a fine spray it won't burn cleanly and you'll get unburned HC in the exhaust as a result.

The ignition distributors have a common fault on these cars. The centrifugal advance system either sticks in one place or only operates over part of it's range. This will have a marked effect on the engines ability to burn fuel. Regards Mike

When I was originally running rich (9% CO), this was one of my suspicions, so I swapped over the FPR, but it made no difference. I got the CO down to 2% by adjusting the spring in the air-flow meter in the end. Not an ideal solution given the AFM was fine before I overhauled the car, but it seemed to do the trick.

That's a good point, I will have some spare injectors soon anyway, so I could try swapping them over to see if that improves things. Do you recommend a good way of checking the spray patterns?

Oh dear. That's an expensive item to bodge.

Did you check the fuel pressure first? And the coolant temperature sensor?

Any injection specialist should be able to do this; they can ultrasonically clean the injectors to remove any gum/tarnish etc. They should do a leak- test and check/record the opening pressure too.

Also check the cold-start injector: if this is weeping it will affect fueling, and the effect will be greatest at idle/small throttle openings.

What did this overhaul consist of?

Regards, Graham L

Wonder if it's got a non standard cam?

They're pretty common on eBay these days, so not too expensive ;) There's not a lot to them really, can't understand the price they justify. I wouldn't really call it a bodge, more of an adjustment, and I've marked the original position, so it's easiest to put it back to how it was.

I did check the coolant sensor and it was fine (around 300ohms @ full temp). Haven't had the chance (or tool) to check the fuel pressure, something which I wanted to do, but was hoping replacing the regulator might cover this one. Still would like to do so though.

Thanks for that, I'll get my strobe out and have a look. I did replace the vacuum unit a while ago, so the centrifugal part might still be iffy. Hopefully got a spare distributor on the way soon.

I would say its running too lean, but a CO of 2% rules this out, so therefore check for reasons of a poor burn- secondary HT components, valve clearances, and poor compression. Also check the Throttle switch is indicating idle position to the ECU.

Tim..

A decent tyre pressure gauge will work ok if you can make an adaptor. I bought a pressure gauge and suitable pipe adaptors from my local engineering suppliers for under 30 quid. But I checked it against a good tyre pressure gauge.;-)

Its all standard on there. The overhaul was mainly bottom end stuff, new big-end & main bearings, etc. The only thing done on the head was some new valve stems seals, which I did as it seemed a useful thing to do even though the head was fine before I removed it. All the ancilleries (ECU, AFM, injectors, etc) are the same parts as before the overhaul, when the engine ran fine emissions-wise (until the bearings gave up the ghost!).

I wonder whether if any of the ancilleries 'went off' while they were sitting around doing nothing for many months?

I might get my colourtune plug in there, then I can see if all the cylinders are burning the same. Maybe the 2% means lean on 3 cylinders and rich on another, instead of 2% equal on all four?

If you changed the inlet manifold gasket then double check you fitted the correct one. Many head sets for the Pug 205's include 2 inlet manifold gaskets. One for carb equipped engines and one for injection equipped. IF you have fitted the wrong one then the injectors are partially blocked via the gasket and it results in very poor running.

Just pull the injector rail off and make sure the holes the injectors fit into are completely clear and not "masked" by the gasket.

Regards, Graham

I'm fine with that one; heard of that problem in the past.