Log1call

Don't know if injector cleaner would help or not but it couldn't hurt. That code is set at light throttle settings so anything that causes a miss under those circumstances could cause it. In my experiance, and in the normal course of operation, having the plugs a bit too closed or opened can cause the sort of irregular idle/light miss that could cause it. The sort of miss-fire that you are normaly aware of, like plugs miss-firing under load, going up a hill or accelerating hard say, shouldn't cause the code. The other suspect, to my mind would be an air leak causing a slightly lean mixture. The slight air leak though should really show up more at idle. Under your circumstances though, we would be foolish to disregard the fact it has just had some work done on it. You said initialy that two valves had been done. Was this because the new heads had bent valves too? Did they lap all the valves?

There is a better way to check the operation of the O2 sensor using a voltmeter.

Hi, I'm a mechanic and I don't think a new motor should leak oil or smoke. My motors don't but I build my own. I obtain the parts, ensure the outwork is reliable, assemble them together and fit, start and drive them and guarantee them. The trouble here though was that the customer obtained his own engine, then had to deal with the warrenty issues. If the workshop had obtained the engine they would probably have negotiated that the removal and refit was on the engine builder. I suspect the motor came without cam covers, flywheel, pulleys etc. and that the leaks will be the mechanic that fitted the motor's fault. Also, the difference between a good motor and one that smokes is in the first twenty minutes running. If left idling for any time at the first start-up they can oil the rings and even a very careful "bedding in" drive can not fix it. New motors need to be ready to drive as soon as they start. You should be able to stand next to them and reach in the window and start them. Have a good look under the bonnet to make sure the belts etc all look good and then drop the bonnet and go for a very carefully conducted test drive. Drive moderatly for about a mile and then stop and have a look under the bonnet for anything amiss then head for a highway to bed it in. Following the recommended process of applying steady load from low/medium revs to medium high revs, then throttling off till back down to the low revs before applying a little more throttle than the time before. If this is done correctly the motor is about ninety percent run-in in the first twenty minutes. Done correctly even a bit of abuse in the form of idling for long periods should not hurt the motor. It is however worth pointing out that idling is not a good idea anyway on a new motor. In this case, I'd suspect the motor was possibly idled too long after start-up while the mechanic checked all his work or in the ensuring weeks it was idled too much. Just my opinion, but based on a lot of experiance. Avoid short journeys, avoid idling for long, drive it briskly and it will "learn" to rev freely and will last a long time.

Or a fuel blockage? Vacuum in fuel tank?

Yup, well done Rvac.

The miss in question is probably almost undetectable driving the car. It there is a lean injector it could cause a weak firing just at certain throttle/load conditions and you would not notice. A standard tune and inspection should in most instances cure these codes.

You could try wriggling the main engine connector and, if you are really keen, the wires going into the ecu. Ok, only one code, Hmmm, it could be either the main relay or the fuel pump relay or power supply. It could even be a dirty fuel filter. Recommended procedure is to do a standard tune up and service, including inspection all the vacuum hoses. Then I'd check the fuel pump's connector under the back seat(because it's easy), then I'd probably pull the main and fuel pump relays(which isn't easy) and check them both and/or substitute a known good one.

That code is set because some cylinders aren't firing as strongly as others. The valves, injectors, compression could be suspect, along with plugs, leads, coils, fuel pressure regulator etc. The freeze frame facility of the ecu might help point to it. This code is set as a result of steady driving, it won't get set if you have your foot down or if you are accelerating too much. What this means is that you don't feel the miss like you would if the plugs were missing under load... So the plugs having the wrong gap and just missing at idle or some narrow rev range when there isn't a heavy load on the motor means you may not notice it. Lean mixtures can also cause these sorts of light throttle miss that can be hard to detect. If you could drive and log data it may help diagnose it. I'd start by doing a thorough tune-up and a check of the vacuum hoses.

Wriggle the wires and plugs with the motor idling.

Since it only started happening after the other work I would take it back and give them the option to fix it, then if it turns out to be something serious that they have done they can't blame you for either ignoring the symptom or "messing around" with their work. I'm a self employed mechanic and I always want to hear if there is any hiccups after I've worked on cars, for my sake and the customers.

The knock sensor being faulty won't cause the problems you have but, those codes are intended as an aid to diagnosis. In this case the code could be telling us that the engine is knocking as the problem is occuring. So what can cause knocking? Oil consumption, carbon build-up causing localised hot-spots in the combustion chamber, general overheating, too much boost from a turbo, ignition timing being too advanced, wrong/bad fuel. Do you know what knocking sounds like and have you heard any? Is the motor running hot? Is the motor smoking, using oil? I'd check the cooling system first. You don't say how long you have to leave it after the five mile drive but I assume till it cools off a bit. If you had to wait for the whole engine to cool it could be the thermostat or radiator not working correctly, if it only takes a couple of minutes to cool then it could be locallised heat, like carbon or the water pump not circulating the water evenly.

Good work Guys. First guess would have been camtiming but you have been there. I was just about to say, before Ob99w beat me to it... Don't over-look the fact that those sheided wires are sheilded for a reason; to stop interference. You wouldn't have a bad connection on the sheiding, a miss-routed wire that was too close to a H.T. source, an H.T jumping causing interference? Also, could the temp and the cam share the same earth, or, the temp and the sheiling's earth are shared... but broken/loose?

It can be caused by mixture problems, air leaks into the exhaust, contaminated cat. You should take it back to the dealer and explain that the problem wasn't there before they worked on the car.

Put the volt gauge across the battery posts(not the clamps) and check you have twelve volts. Crank the motor and check the voltage, it should drop to about nine volts. If it goes below nine the battery is crook or the starter is drawing too heavier load, which can be caused by a tight motor. If there is not more than one volt drop then there is a fault with the starter or wiring. Put a volt gauge from the battery positive terminal(not the leads clamp if you can manage it, get someone to hold the test lead on the batteries post)to the starters positive terminal(the threads, not the starter lead) and see what it reads as you crank the motor, it shouldn't read more than a half volt. Note that this is not the same test as suggested earlier. This tests the connectors on the ends of the cables are connected properly. Then connect the volt gauge from the battery negative post to the motor, anywhere there is a good contact will do, crank the motor and check there isn't more than a half volt drop. This checks cable terminals.

Try not using the handbrake overnight and see if it helps. The handbrake may be sticking on slightly.

Good description.

Yeah, nice work guys!

The O2 sensors can be tested with a voltage gauge. An analoge gauge that reads millivolts is best. With the motor running the voltage should range either side of four-fifty millivolts and it should go from one end of it's range to the other several times a minute. All sensors can be tested for correct operation... which is always a good idea before rushing out and buying new parts.

Since it is saying secondary O2 sensor is out of range, but it is not saying the front sensor is out of range, I would conclude that the cat is faulty. If there was a missfire the front O2 sensor would also set a code as well... probably! Having said that, I would check what the oil burning is caused by because the repair might not work of the engine refouls the new cat when you put it on. I'd also check the tune and for air leaks in the hope that the faul is marginal and a cleaner burning mixture will clear the code.

The fact you get an O2 code does not mean the O2 sensor is faulty. If you have a missfire, rich mixture for any reason, air leak, carbon canister full of fuel... anything that can make the mixture too far out of range(either too rich or too lean), can set a O2 code. These trouble codes are an AID to diagnosis only.

Might pay to check the wiring running down to the O2 sensor isn't getting shorted by the water. The water can splash up there easily if there are puddles and it could cause it. If you don't think water would be splashing up there, or, squirting water up there doesn't do it, it could be HT related as suggested previously. Again, get a hose under the bonnet with just a trickle coming out and wet one thing at a time to try and find the place the water is getting in. Run it over the HT system first then any engine connectors.

If it moves at all then it will come. Try more lube and knocking it back up and down a few more times. That will hopefully work the lube into the tight spot.

I have seen similar ones that fit into a bell-housing bolt hole and then pivot in and jamb against the flywheel.

It's not usual but perhaps the clutch plates have broken in half and jammed up into a bunch which is causing the clutch pack to lock-up?

"But the wife is happy, her turbo sedan is back on the road." You'll get your reward!