Author Topic: Very strange idle problem - Movies. (Read 5585 times)

dinu.negrean · « **on:** February 19, 2010, 12:12:50 PM »

Hey everyone!

I'm all out of ideas here.

Start
My original engine started knocking something like piston slap or crankshaft knock. Just the work of the mechanic for any of the cases was a minimum of 300 Euro. So I found an engine for 200 Euro without intake or exhaust or any electronics. The engine had been sitting for two years, so I had little hopes for it.

Simptoms
I made the engine swap and surprisingly it started up on the first try.The engine revs great and pulls hard as hell, the consumption is very good, better than the old engine, it does not consume any oil, but the idle ...is terrible.

When it starts in the morning the revs go up... then they fall almost causing the engine to stop, it shakes very strong.. you will see it in the movie below:

http://www.youtube.com/watch?v=nu5KTkDQHho&feature=player_*****ded

After ~2min it "settles" down, meaning the idle will not jump anymore, but on the exhaust you can hear continuos backfire/misfire I'm not sure how to say it, but the movie below is the best explanation.The shaking continues though.. you can feel it in the whole car.

http://www.youtube.com/watch?v=W46uUEFKNg8&feature=channel

What I have tried:
- the first thing was a compression test [all good for number the numbers 2, 3, 4 were equal 10.5bar and cyl onw showed 10bar, but I reapeted it and it came equal 10.5bar]
- vacum leaks, replaced all hoses and all gaskets.
- idle control regulator
- MAF or VAF..
- Checked camshaft sensor [ok]
- Checked crahnkshaft sensor [not ok, it registered 580 ohms, when it should register 1280+- 10 ohms. But I don't think that that can be the cause, because I checked my old sensor and it indicated 470ohms and the engine ran smoothly except for the knock]

My idea:
My next thought is on the valve lifters. Because every morning when I start I can hear them very loud for about 2-3 seconds. I believe they may not be holding the oil anymore. But this is just my thought, I'm not very good at this.

So what is your advice on this on guys? Has anyone had a similar problem? I could really use some help inhere.

Thanks everyone in advance.
Dinu

flyinglizard · « **Reply #1 on:** February 19, 2010, 08:53:54 PM »

Pull the valve cover. If the lifters are junk, you can push them down. VW uses a small pry bar , same lifter here.
Check the cam timing by the book. As the engine wears the chain and guides, the cams get later. Verify that the timing is close. The holes on the cam squares should be flat with each other. RE to the TDC mark on the crank. A quick check of the TDC mark is good also., as the pulley is in rubber, and some have come apart and moved the mark.
HTH. MM

dinu.negrean · « **Reply #2 on:** February 21, 2010, 02:35:28 PM »

Thanks Flyinglizard, will look into it sometime next week.

Has anyone else ever experienced a sound like that in the exhaust? Any similar exeprience?

TheDutch · « **Reply #3 on:** February 21, 2010, 02:40:28 PM »

Quote from: dinu.negrean;88036

Thanks Flyinglizard, will look into it sometime next week.

Has anyone else ever experienced a sound like that in the exhaust? Any similar exeprience?

The two things which caused my poor idle were a split vacuum hose to the brake servo and the timing being slightly off, the latter making a huge difference.

dinu.negrean · « **Reply #4 on:** February 23, 2010, 02:45:01 PM »

Finaly took the valve cover off, and found the following:

1. Exhaust sprocket seems really bad set.From my knowledge, the bolts of the camshaft sprokets must be set in the center of the hole. As you can see in the pictures below, the exhaust is in the left end of the bold channel.

What is the solution for that? Following the bentely procedures...take the chain off, set the exhaust sprocket in the center ... that means one tooth behind right? If I pull it on tooth behind what are the risks?

2. As you can see there is a good amount of rust on my cams, this engine had been sitting for a year and a half before I bought it. What do you suggest? how does that affect the engine? I touched it and you can't feel the difference on the rust spots, it is smooth as on the other side where there is no rust. Can that affect anything?

3. I have opened up my old engine also, and the sprockets look as good as these ones. Are they ok? They seem ok to me compared to these ones: http://www.esatclear.ie/~bpurcell/wornsprkts.jpg

Please comment and give advices. Any help is welcome and greatly apreciated.

All the photos can be bound in this album:
http://www.flickr.com/photos/47779682@N05/4382330269/

DesktopDave · « **Reply #5 on:** February 23, 2010, 03:01:12 PM »

Your crank sensor is OK. The manual is wrong, it should be around 600 ohms.

Check your coolant temp sensor and the air temp sensor in the AFM/VAF. Also double check the ICV. I know you replaced it, but I had a new one DOA once.

Choking Hazard · « **Reply #6 on:** February 23, 2010, 03:07:18 PM »

Don't move the cam gear from the current chain alot. Just loosen up the four bolts on the front of the exhaust cam gear, grabe the cam down by the firewall end on the square part with a a pipe wrench or even some large lockjaw pliers and rotate the cam itself until it is centered in the gear. Get a new timing chain tensioner. I guess you could maybe compensate for chain length growth moving a link, but it is like a band-aid on a collapsed lung. If the chain tensioner is at the full extent of it's expansion (probably), it will need a new timing chain eventually regardless. OR
Drive it with the stereo up loud, keep train fare in the glovebox, and be ready to walk if it self-destructs. That may be the most practical solution...

Those sprockets look pretty worn. I've read that the more pointed the gear tips are, the greater the wear.

B318M42W · « **Reply #7 on:** February 23, 2010, 06:48:22 PM »

the greyer sprockets look brand new. if they are in your engine, don't worry about sprockets but more about the chain. inspect the chain for missing rollers.

flyinglizard · « **Reply #8 on:** February 23, 2010, 07:43:26 PM »

Check the cam timing by the book. Not where the cam wheels are set on the bolts. As the chain and the slide get worn, the cam wheels will need to be set off center. Of the two done in the last month, the slide was worn more than the chain was loose. Place a flat bar, across the cam flats( holes up ) for a quick check.
For a better check, clamp the flat bar to the index flat,on the side of the cam and fix them straight up RE to the head surface Verify TDC on the hub and in the hole if you want to. This can make for a rough idle,IMHO.
If it still idles rough use a stethoscope on the injectors.
Listen for an" Off" one. Pull the plugs, etc. MM

dinu.negrean · « **Reply #9 on:** February 24, 2010, 04:26:04 AM »

So let me see if I got this right.

If one has a car with the timing chain off and has no marks he must:

1. get the engine at TDC
2. lock the flywheel
3. set the cams with the circle marks upwards and lock them with the upper side parallel to the head and with the first two lobes of the camshaft up an pointing at eachother.
4. put the chain back on and set the sprockets so that the chain fits right, if possible with the bolt in the center of the hole.

Is this what it takes to set it correct?

flyinglizard · « **Reply #10 on:** February 24, 2010, 07:39:34 AM »

yes, You dont have to remove the chain or usually the bolts.
Just loosen the bolts.
After rebuild and no oil restart.The engine will run so bad that you will be sure that something is very wrong . The lifters have no oil and wont lift the valves enough to run that cyl. other lifters have extended and willhold open the valves. This may take 3-4 minutes of running for all the clatter to go away . Run the car at 2000rpm so that the cams dont slap the chain and the tensioner gets plenty of oil .
The book says to roll the engine over by hand a few times to settles the lifters, wait 45min before starting.
Many german cars with hydro lifters do this. as the lifters are all the same.
Some VWs/Audi set off the knocksensors and quit also.
Maybe this is what has happened.?

TheDutch · « **Reply #11 on:** February 24, 2010, 10:34:03 AM »

Quote from: dinu.negrean;88277

So let me see if I got this right.

If one has a car with the timing chain off and has no marks he must:

1. get the engine at TDC
2. lock the flywheel
3. set the cams with the circle marks upwards and lock them with the upper side parallel to the head and with the first two lobes of the camshaft up an pointing at eachother.
4. put the chain back on and set the sprockets so that the chain fits right, if possible with the bolt in the center of the hole.

Is this what it takes to set it correct?

Well yours seems to be roughly right so you don't need to go through the whole procedure. If I were you I'd get the timing as correct as you can before opting to do anything more drastic; it's quite simple and worth doing whilst you have the top of the skull removed.

1. Stick a locking pin in your flywheel to get it at TDC.
2. Check whether the squares at the end of the camshafts are parallel with the head and each other, as shown below:

3. If they are not perfectly oriented, loosen the camshaft sprockets and rotate the camshafts using the squares at the opposite end to get it set as best you can.
4. Tighten up any bolts you've loosened, remove the flywheel locking pin and manually rotate the engine to settle. Re-lock the flywheel and check all is as you left it.

Obviously if you find it all looks OK there's something else amiss but, as I said earlier, my exhaust cam was off a little like yours looks to be and sorting that improved my idle hugely.

Choking Hazard · « **Reply #12 on:** February 24, 2010, 12:12:09 PM »

Great picture!

I spun mine through by hand a few rotations just last night. The first time, I had the cams 180 off and, well, it would only turn about 1 revolution before hanging. I'm so glad I did the hand test. I also intend to spin it with the starter with fuse out for fuel, plug wires off a few times before I start it up. I am a bit concerned. While replacing head, I replaced chain, deleted the cooling hose mess, and added Mustang injectors. Several opportunities for failure...

TheDutch · « **Reply #13 on:** February 24, 2010, 12:41:32 PM »

Quote from: Choking Hazard;88296

Great picture!

Not mine, credit where credit is due - http://www.esatclear.ie/~bpurcell/318istimingchain.html

dinu.negrean · « **Reply #14 on:** February 25, 2010, 04:33:25 PM »

Ok, so the next step will be to adjust the timing. I brought the drawings to the workshop and by tommorow or monday I will have the camlocking tool done and the locking pin, both for 25 Euro.
I have heard that the M8 bolt doest the job, but I have tried it tonight on my spare engine and the bolt will move in the hole on the block and will allow the flywheel to move at least 1cm untill locking, because the hole on the engine is 11.8mm.

I will post some pictures I have managed to gather in my research, it may be useful to some users in future. [but since i don't know why it will not upload my pictures even if I respect the size alowed and will not give a reason why, we will use flickr] You can see some good information in the album below:

http://www.flickr.com/photos/47779682@N05/sets/72157623508983272/

I also have the tehnical drawings of the tools in pdf format but it fails to upload my documents anway. So if anyone needs them just PM me and i'll mail them to you.