Strange noises, Stuck inlet valve?

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TerryG
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Joined: Wed Jan 05, 2011 1:54 pm
Location: East Midlands

Strange noises, Stuck inlet valve?

#1 Post by TerryG » Tue Jan 18, 2011 11:10 pm

This is a quick clip of what my engine sounds like. Does this sound like a stuck inlet valve?
http://s1114.photobucket.com/albums/k52 ... EO0445.mp4
The story behind it is here: (sorry for being long winded)

For the last 2 weeks I have been having idling problems when warm. For no apparent reason the revs would suddenly drop to almost stalling point then a blip of the throttle all would be normal for a moment then it would start dropping off again. On Sunday night it started "squeaking". It was (is) an engine speed / throttle position high pitch squeak if i accelerated it got worse but if i let off and hold revs anywhere in the range the squeak was gone. I couldn't see anything wrong parked outside the house so i decided rather than investigate at 10pm to risk it as i had to be back in London for work. On the drive back i "booted it" in frustration and the car backfired, started vibrating ALLOT and refused to idle at all. A look under the bonnet in a layby and a lead had come off. I bunged it back on and started up, looking under the bonnet on the side of the A50 in the dark i could see the leads arcing out all over the place (including the king lead to both LT terminals on the coil). It limped home "squeaking" if i used more than 1/3 throttle and vibrating quite a bit but not as badly as with a lead off. Getting to investigate it tonight i can cure the squeak by retarding the ignition a bit but it makes the idle rough but at revs it's ok, when starting after it catches it dies almost immediately, holding the throttle it's fine but let it idle and it dies. It doesn't have the torque it has with the ignition in the "right" place and the squeak there but it is quiet. If i disconnect the MAF sensor then it will catch and idle but it sounds "odd" and if i put the ignition in the "right" place with the MAF disconnected it still "squeaks". I have tried 2 MAF sensors with no difference.
Understeer: when you hit the wall with the front of the car.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.

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Luxobarge
Posts: 1898
Joined: Wed Jan 05, 2011 3:12 pm
Location: Horne, Surreyshire

Re: Strange noises, Stuck inlet valve?

#2 Post by Luxobarge » Wed Jan 19, 2011 8:46 am

My first reaction is that it's a misfire caused by bad HT components - if you've seen lots of sparking when looking in the engine bay during the dark (a very good and easy test for the health of the HT system BTW) then you've clearly got a problem and I'd solve that first before worrying about anything else, especially as it's such an easy test after dark. Another clue that all is not well is that a lead fell off - leads shouldn't just fall off, sounds to me like it's a bit "life expired", perhaps a new set of leads, dizzy cap and rotor might be a good start.

When you've got no stray sparks in the engine bay see what it's like then and take it from there would be my approach, otherwise you could be fighting more than one fault at a time.

Does the car have a cat? If so, another reason to sort a misfire PDQ is that if you run the car with a misfire you run a very real risk of destroying the cat. The normal operating temperature of a cat is only a couple of hundred degrees below the point at which it will start melting/self-destructing, and the unburnt fuel from an ignition misfire will ignite in the cat and quickly raise the temperature above this point, leading to catastrophic overheating, nasty smells, expense and misery. It doesn't do the oxygen sensor any good either.

If it doesn't have a cat then it's not so critical, but I'd still achieve 100% confidence in the HT system before fiddling about further.

All the best with it! :D
Some people are like Slinkies - they serve no useful purpose, but they still bring a smile to your face when you push them downstairs.

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TerryG
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Joined: Wed Jan 05, 2011 1:54 pm
Location: East Midlands

Re: Strange noises, Stuck inlet valve?

#3 Post by TerryG » Wed Jan 19, 2011 9:46 am

Hi Luxo, thanks for the reply, i have bunged a new set of HT leads on and the stray sparks have all gone as far as i can see. I'll scoot to a country road tonight and check. I'm calling my local motor factor to get a set of plugs a cap and arm in for me to try tonight. I have a new ignition amp ready and waiting to fit so i'll do that at the same time. The set that's on there is less than 2000 miles old but as the leads failed i suppose there is no reason to believe any of the other components would be any better.
Thanks again.
Understeer: when you hit the wall with the front of the car.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.

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TerryG
Posts: 6754
Joined: Wed Jan 05, 2011 1:54 pm
Location: East Midlands

Re: Strange noises, Stuck inlet valve?

#4 Post by TerryG » Wed Jan 19, 2011 9:42 pm

Still having troubles (effing car!)
So far i have replaced:
plugs
leads
cap
arm
Plug on the ignition amplifier (one of the wires broke off when i turned the dizzy!)
re-crimped various leads going to the LT side of the coil
fiddled with the timing
tried an alternative idle stepper motor
adjusted the idle air bypass

The only "origional" ignition component remaining is the coil. Nowhere local had one in stock but a new one will be delivered tomorrow so i'll swap it out tomorrow evening.

I did some more videoing with my mobile phone after swapping out the bits:
retarded timing:
http://s1114.photobucket.com/albums/k52 ... EO0449.mp4

timing where it "should" be
http://s1114.photobucket.com/albums/k52 ... EO0450.mp4

Regardless of the setting with the timing the car goes to almost stall when i put it in gear.
if it makes any difference it used to have cats but some cheapskate previous owner has cut the cans open, emptied out the material and welded them up.

Any advice would be greatly apreciated, this is my only car at the moment and i have to drive to bath on friday!
Understeer: when you hit the wall with the front of the car.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.

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TerryG
Posts: 6754
Joined: Wed Jan 05, 2011 1:54 pm
Location: East Midlands

Re: Strange noises, Stuck inlet valve?

#5 Post by TerryG » Fri Jan 21, 2011 8:40 pm

OK, i played truant today and limped the car all the way to Derby where my friendly trusted land rover garage is.
2 hours of mucking about and:
it's not a stuck valve, 158-161psi of compression across the board
New distributor,
another new cap, arm, plugs, leads, etc, etc.
new ignition amp
long story short we have replaced everything electrical and it STILL runs on 7 cylinders.
I've left it with them to investigate as even the garage is stumped.
I'll post back and say what bizarre faulty component is causing the problem
(i hate cars!)
Understeer: when you hit the wall with the front of the car.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.

cooperman
Posts: 2
Joined: Sat Jan 22, 2011 3:41 pm

Re: Strange noises, Stuck inlet valve?

#6 Post by cooperman » Sat Jan 22, 2011 3:48 pm

Hi
Could the squeak be an air leak on the inlet somewhere,possibly around an injector this would cause a missfire ?

Grease Monkey
Posts: 106
Joined: Wed Jan 05, 2011 1:14 pm

Re: Strange noises, Stuck inlet valve?

#7 Post by Grease Monkey » Sun Jan 23, 2011 12:12 pm

cooperman wrote:Hi
Could the squeak be an air leak on the inlet somewhere,possibly around an injector this would cause a missfire ?
I was thinking an air leak as well, and agree it could be a leaking injector seal, run the engine and establish which cylinder is not firing by pulling off each of the plug leads in turn, then when you know which cylinder is not firing, try squirting some WD40 or similar around the affected injector or manifold port and if the revs rise then your problem lies there.
Let us know how you get on.


John.
1964 Sunbeam Rapier IV
1966 Sunbeam Alpine V GT
1981 Mini City
1983 MG Metro
1997 MGF
2003 MG ZS
2004 MG ZT T

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TerryG
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Joined: Wed Jan 05, 2011 1:54 pm
Location: East Midlands

Re: Strange noises, Stuck inlet valve?

#8 Post by TerryG » Tue Jan 25, 2011 3:14 pm

Well, the garage "can't get to it until next week" as they have so many staff off sick so i collected it and limped the 25 miles home. It was running on fewer and fewer pots the whole way, under 1500rpm it refused to run on more than 3/4. I Parked it on the drive and went inside. Came back an hour later and it won't start at all.
It fired on the odd cylinder while turning over but won't catch. It was doing the same trick on gas and petrol with the added bonus that when on gas if i put my foot down it backfired and blew the air box lid off!
Ignoring the sneezing / squeaking noise for the moment there must be something electrical up the creak. When i am up next weekend i am going to try bypassing various bits of electronics and seeing what has died. I'm thinking the most likley culpret is one of the leads from the dizzy to the coil but i'm sure than an hour with a soldering iron and some bits of wire will get the old girl started even if it doesn't cure the other problem.
In the interim my focus decided to suffer catastrophic rear wheel bearing faliure on Saturday. Had a friend come out to give me a hand changing it, we broke an impact socket trying to beat the old bearing out! I must buy myself a press!
Understeer: when you hit the wall with the front of the car.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.

User avatar
TerryG
Posts: 6754
Joined: Wed Jan 05, 2011 1:54 pm
Location: East Midlands

Re: Strange noises, Stuck inlet valve?

#9 Post by TerryG » Sat Jan 29, 2011 8:23 pm

Several more hours of mucking about (and a new battery), no improvement.
I had a mechanic helping me out for a couple of hours and we can get it to "almost" run.
I have removed the LPG kit to eliminate the posibility of that not allowing the injectors to fire correctly, checked where TDC is on compression and found that the marks the garage put on for me are perfect, checked the ignition timing 2300 times and that is is as close to correct as possible without having a running engine. Tried the leads the other way round just to make sure we hadn't got exhaust and compression mixed up.
There is voltage at the coil both with and without the engine cranking over, the ignition amp is pulsing as it should. The coil produces regular sparks when resting the king lead on top of the block and cranking the engine, putting plugs on top of the block when connected to any HT lead and they spark. (The mechanic says they aren't the biggest sparks he has seen but should be adequate)
It sounds like it wants to start, with the starter turning you can hear the engine firing on a few pots, let go of the keys and it keeps firing on a few for a couple of moments but dies.
With all electrical avenues exhausted tomorrow's job is to take the rocker covers off and make sure the valves are opening / closing as they should. I suspect these are fine as it has compression so the next job after that is to take the front pannel off and see if the static timing has slipped.
Sorry for posting jibberish but i have reached the end of my patience! Does anybody have the number of a good scrap man if all fails? ;)
Understeer: when you hit the wall with the front of the car.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.

User avatar
TerryG
Posts: 6754
Joined: Wed Jan 05, 2011 1:54 pm
Location: East Midlands

Re: Strange noises, Stuck inlet valve?

#10 Post by TerryG » Sun Jan 30, 2011 5:31 pm

I definitely have a problem with the inlet on cylinder "3". It doesn't explain why the other 7 don't work but at least I have found one problem.
Turning the engine over with the plenum cover off and holding a hand over each trumpet one at a time one sucks and blows where as the rest only suck (no rude comments please ;) )
Anyway, rocker covers off and all the valves are opening and closing as they should, putting a wooden spoon in the plug hole for "1" and turning the engine over by hand the valves open at the correct times (as described on the interweb) after 2 hours of mucking about i ran out of patience so got my brother in law to tow it to a local garage (read man who has a shed in his garden and fixes land rovers). Now I have new wheelbearings in my focus i am mobile again so i'm not worried about leaving it there all week. fingers crossed all it will need is a new valve or probably cheaper a couple of 2nd hand heads then i'll be back on the road again.
That leaves me free to replace the PAS pump on the focus and work out which tyre is making a racket.
Why aren't cars simple?!?!
Understeer: when you hit the wall with the front of the car.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.

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