Car Troubles

[Big Eggy]

Hello all..

now i could post this on a car forum but i cant be bothered joining yet another forum so i thought i'd run this by you guys.

I have a 2001 focus 1.6 zetec that after a long run for the family holiday started to misfire on Cylinder No.3

I change the coil pack and ht leads (this had happened before) but the problem was still there.

the spark plug in no.3 is covered with black sooty crap.. and after being replaced it soon builds up again.

my mechanic says that it's probably a burnt valve.. and when i hold a peice of paper to the exhust it sucks it towards the exhust pipe and then blows and so on.. so i guess his diagnosis is correct.

But this has me wondering maybe the valve is stuck (i assume open) .. do any of you guys no if a stuck open valve will have the same symtoms as a burnt valve?

and if the answer to the above is yes.. can i add deisel to the crank case prior to an oil change to try and free the stuck valve?

i've thought about a new head but my Mech says that the new head will probably cause the bottom end to go plus the cost of the job will be more than what the car is worth.... same goes for a engine swap.

so i guess i'm hoping the symtoms for a stuck valve are the same as a burnt valve and there may be some hope?

 

[gingerale]

Big, is the motor actually firing #3 spark plug? Pull the coil pack, stick a spark plug in it, then hold the metal (threaded) side of the plug up against a metal part of the engine while a helper cranks it....does it spark? If not, double check the others too. If you're getting spark then next step is a compression check, and idle vacuum test. Can you take a picture of the "black sooty crap"?

 

[Snagglepuss]

It helps to find out why the valve burned in the first place ..Most often it is the exaust valve caused by extreme temperatures ...Bad thermostat or other cooling issues related to the engine...When i have a burned valve ,i just replace the whole head....

Insure that all your issues related to engine cooling are sorted out.Whilst this may cause the bottom end to eventually go...You'll most likely get alot more use from the engine before this may happen.....

Find someone who would help you replace it yourself .....to save you the excessive charges......

"Todays auto tip" .....Adding 1/2 quart of dextron transmission fluid to a tank of gas ,will help clean the carbon deposits on the inside of your engine .......Ladazzzzz...

 

[burns1n209]

Big, is the motor actually firing #3 spark plug? Pull the coil pack, stick a spark plug in it, then hold the metal (threaded) side of the plug up against a metal part of the engine while a helper cranks it....does it spark? If not, double check the others too. If you're getting spark then next step is a compression check, and idle vacuum test. Can you take a picture of the "black sooty crap"?

Good place to start. to soot could just be carbon loosineing up because the cylinder is not firing, and building up on the plug. a compression check with tell you if valve is stuck or burnt. you could also do a vacuum test on the cylinder. if it holds a vacuum, the cylinder is good. How many miles does the engine have on it? If it has under 150k u could get away with just a head job, the bottom will hold on for awhiile longer, as long as your not beating it to hell. while you have head off, good time to replace timing chain/belt and water pump, cheap insurance usually 30 bucks, and belts. Youll have a Strong engine you shouldn't have to worry about. A reasonable shop would charge 1000 to 1300 i would quesstmate. rebuild head is 500/600 alone and then parts and labor. fairly simple job.

 

[burns1n209]

Hello all.. my mechanic says that it's probably a burnt valve.. and when i hold a peice of paper to the exhust it sucks it towards the exhust pipe and then blows and so on.. so i guess his diagnosis is correct.

First id find a new mechanic, no upstanding mechanic is gonna say well its probably... and if its not hes still gonna charge you with a new head, and the price of fixing the actual problem.. A good mechanic would say let me put the compression gauge on the cylinder and see what kinda pressure you get. takes 5mins. or atleast check if you got spark to the plug.

 

[amber666]

i can't help at all, i suck at car stuff. but i just wanted to say how i hate it when cars needs repairing. man do they burn holes in your pockets!

 

[gingerale]

^^ Exactly, all this burnt valve talk is premature....you must diagnose the problem, unless you want to just throw money at it and hope it magically starts running right, like most people do. Rent a vacuum gauge and compression tester from the auto parts store and I'll tell you how to use them.

BTW I absolutely would NOT recommend pouring any kind of oil into your gas tank, not even ATF, because your fuel injectors were not designed to pump fluid as viscous as oil and it could clog them. If you ever want to clean your injectors, the product to use is Sea Foam, either poured in the tank or sucked through a vacuum hose while the motor is running.

 

[kongbud]

One question does this car have one of those noisemaker mufflers?

And as a follow up I have to question the mechanic who says replacing the head will cause the bottom end to fail.

 

[izzybud]

ur gonna find urself throwing money in a whole that doesnt fill up. it keeps getting deeper!

 

[usda101]

^^ Exactly, all this burnt valve talk is premature....you must diagnose the problem, unless you want to just throw money at it and hope it magically starts running right, like most people do. Rent a vacuum gauge and compression tester from the auto parts store and I'll tell you how to use them.

BTW I absolutely would NOT recommend pouring any kind of oil into your gas tank, not even ATF, because your fuel injectors were not designed to pump fluid as viscous as oil and it could clog them. If you ever want to clean your injectors, the product to use is Sea Foam, either poured in the tank or sucked through a vacuum hose while the motor is running.

What he said .

 

[knucklehead bob]

^^ Exactly, all this burnt valve talk is premature....you must diagnose the problem, unless you want to just throw money at it and hope it magically starts running right, like most people do. Rent a vacuum gauge and compression tester from the auto parts store and I'll tell you how to use them.

BTW I absolutely would NOT recommend pouring any kind of oil into your gas tank, not even ATF, because your fuel injectors were not designed to pump fluid as viscous as oil and it could clog them. If you ever want to clean your injectors, the product to use is Sea Foam, either poured in the tank or sucked through a vacuum hose while the motor is running.

What he said .

Ditto , a proper diagnosis will save mucho dinero .

 

[knucklehead bob]

i can't help at all, i suck at car stuff. but i just wanted to say how i hate it when cars needs repairing. man do they burn holes in your pockets!

That is why EVERY vehicle on the road has what is called a "maintainence schedule". While it is still a little costly , it is a drop in the bucket compared to actual repair when all you really have to do is make sure your levels are maintained and changed in a timely fashion.

 

[EASTCOASTSEEKER]

A Vac guage will tell you all kinds of things about an engine if you know how to read it. Have your mec hook a vac guage up to the manifold. Did they do a leak down test or a compression test on that cylinder ? Have you replaced the wire to that plug ?

 

[EASTCOASTSEEKER]

Could also be an onjector that is stuck paftiallly open. Get a wooden dowl or long screw driver place one end against your ear & the other end touch the injector body. You should hear a distinct licking sound. Sharp clean sound. See if that injector sounds dull compared to the others. A noid light set for chevking injector rlevtrical pulses are available at any auto parts store. A Good mech will havd thrm on his tool box.

 

[Wild1]

Two word test. "Leak Down". Only for sure method of determining what and where the problem exists if it is indeed mechanical. If the shop your at does not have or know what a leak down test is, run.....

 

[supermanlives]

if its fully insured have it stolen lol. newer cars aren't as fun to work on as older rides

 

[PizzaMan5000]

I am an avid zetec fan, but I never had this issue on THAT motor but try this for an easy experiment, get new plugs if you havent already, suck WATER yes water into a vacuum line like you would sea foam. Theoretically the water won't compress so it will be forced into the pores of carbon build up, do it slowly or you will trash the motor (this is really pretty hard to do, don't be a pussy.. use a pair of pliars and remove the brake booster line and use the pliars to pinch off the hose and control the flow. Do a couple spring water sized bottles and take it for a ride, this COULD free a piece of carbon IF one were stopping a valve from closing. After this, swap the spark plug wire from the bad cylinder with another one. The water probably caused misfires and now that we have swapped the wire it's time for an experiment... Unhook the battery to clear the codes, now run the codes again. If the misfire is gone completely, it was carbon, if the misfire is present on cyl 3 it's an injector or valve (or possibly an ignition control module, which controls the coil packs- and they fail upon heating up sometimes so take them to an autoparts store and they will stress test it) I don't know if your engine has one but I assume it does. NOW, if the misfire is on the cylinder that has the plug wire from cyl 3, the wire was bad.

 

[stoned-trout]

run resistance test on wires ..no guessing needed.. multimeter