Engine problem... can't idle update with pic...

[Mr X]

Hi all... got a bit of a strange problem.

 The car blips down, loosing rmp and then goes back up to the set idle (when cold or hot) every second or so. It does this on idle or part throttle (not tired WOT).
I have uploaded a video to help show whats happening (see below) the 2 readouts on my tablet are left and right bank fuel trims.

Things I have tried:
No error codes are stored (checked before and after battery pull).
Cleaned MAF. Also ran the car without it plugged in with the same result.
Cleaned Idle control. Car tried to idle at the correct RPM so didn't think this would do it.
Cleaned throttle body (while its out).
I have checked the spark plugs and all fine (i change them every 9k anyway).
I have pulled the plugs to the coils individually while running to see what happens and all result in stall.

Could it be fuel supply fail... maybe knackered fuel pump??
Not sure if it would be a injector sticking as wouldn't this throw an error code?
I do have a 2zz engine with injectors in the shed. I think the injectors do fit the 1zz head but would there be any other issues as i could swap them to see if that solves it...

Also (maybe related) If you look in the longer video, you can see the engine changing the cam timing. The LEDs in my dials flash when it changes timing... also set a graph showing timing on my tablet. This is normally not done at idle...

Short video:
http://www.youtube.com/watch?v=jp8Nl0Pcnj0&

Longer video:
http://www.youtube.com/watch?v=JTLjg7zAb_g&

Thanks in advance for comments/ideas
Mark

[FGrob]

You need to list your mods first.

[Mr X]

De-precat and exhaust I made, that's it.. Engine has ran like a dream up till now.
Mark

[mrzwei]

You've checked more than the obvious  but if you haven't already done it, check any vacuum hose connections around the intake system. (no 2 at the moment so not sure if or where they are. Had this problem with my Saab and a vacuum hose was disconnected). Worth a check just to eliminate the issue.

[Wabbitkilla]

How old is the car?
What mileage has it got to now?
Where are you buying your fuel?

1. Could be an indication that your maf needs replacing now (mine has lasted 100k miles)
2. Myself and other have experienced problems when using Shell petrol, not just cars ... seems the qulity has hit rock bottom.
3. Check your air filter isn't clogged / get a new one.
4. Run some injection cleaner through the system.

See how it goes.

[Mr X]

ooops... forgot to add that to the list of checks. I made sure there wasn't any cracks or blockades in the pipes. I knew cracked pipes could case loss in rmp but I kinda did disregard problems with pipework as a possible cause as the drop is so well timed. Also, the drop in revs does increase in frequency with increase in throttle.

The car is 51 plate with 55k on the clock.
My fuel normally does come from shell but the garage is being rebuilt so for the last 4 weeks its come from tesco.
MAF sensor has been cleaned. As I understand it, MAF isn't used when cold. Running the car with it unpluged to force default map made no change to the way it is running.
Air filter is 6 months old and a little but dirty, new one is coming in tomorrow.
Injector cleaner was used 6 months ago too but also worth a shot. I will get some tomorrow.

Thanks for the input guys
Mark

[mrzwei]

Having listened to the first video (which I should have done to start with   s:lol: :lol: s:lol:  ), that really is a very regular 'pulse'. Just thinking aloud really but it sounds like it's overfuelling / throttling and then correcting which would rule out dirty components.
As you say, MAF / injector / or possibly O2 sensor as these directly control (via the ecu) the mixture.
The Maf is an outsider because you wouldn't get such regularity.
The O2 sensor if it was switching slowly enough is an outsider but would throw a cel.
I would agree that you need to eliminate the injectors.
A problem here is more likely to result in a misfire though.

As said, just thinking aloud.

[Anonymous]

As an outside thought if the maf is dead then you would get the same result if it plug in or not surely?

[Wabbitkilla]

As an outside thought if the maf is dead then you would get the same result if it plug in or not surely?

MAFs tend to not just go "dead", but wander, just like a lot of O2 sensors just start behaving "lazy".
I have this problem a little bit too, but once closed loop kicks in it settles down which suggests it's something other than the MAF or O2 sensors. I did replace the MAF and air filter which improved the situation but it's still there to a lesser degree. My engine has done 101000miles in comparison though.

[scipio]

When I started reading this, it was as if I had written it...I had the exact same problem....turned out to be 02 sensors.
In fact, every time the CEL light has turned on it has been 02 sensors.
I have had 3 fail on me and have gone the resistor ''fix'' route.  s:D s:D  
This has gradually happened over a period of 3 years (the sensor failures).

[Anonymous]

Does your CEL light up with all the other lights on the dash just before you start the engine when you turn the key to the notch just before start up if you know what I mean?

[Mr X]

As an outside thought if the maf is dead then you would get the same result if it plug in or not surely?

The car wouldn't run well between the blips if it was the MAF. When you start the engine from cold the o2 sensors aren't warm enough to work so it uses it's last saved results on o2 and airflow plus a bit to be safe. So it uses these until it is warm and flips over.

Engine cold  Throttle > fuel = Saved results + a little in a loop

Once cars are warm they use o2 and MAF sensors to work out fuel.

Engine now warm Throttle >  MAF > FUEL > O2 > Adjust.

If you do an engine reset and then run the car from cold it will use toytas settings from the factory as it has learnt nothing. so MAFs/o2 can be tested buy a reset it should run ok (ish) and then as soon as its warm it will run like crap.

Does your CEL light up with all the other lights on the dash just before you start the engine when you turn the key to the notch just before start up if you know what I mean?

Yes, the light does come on with ignition and then out. I'm still not getting any error codes either...
It really is strange!

After work tonight i will look at the cam position sensor and the oil control for the cam. the car shouldn't be trying to adjusting timing on idle.

Thanks
Mark

[Mr X]

Cleaned the cam position sensor contacts and checked the oil control valve, all seems ok.

Did a reset, car runs fine until warm then starts doing it again. I have a replacement MAF from GTSChris on the way, il try that then replace the o2 sensors.... just seems very strange to be a pulse and not rough.
Mark

[Anonymous]

Just clutching at straws really but what is your battery/alternator condition? As I have known batteries with low power to cause weird issues with components and with the strange pulsing it does seem electrical related.

[Mr X]

12.5 and 14v so that's normal. Worth a shot to mate, thanks...
I have the MAF, GTSchris always on the ball and got the part to me next day! Unfortunately, didn't fix the problem. Going to order new o2 sensors tomorrow. Kinda hoping one is a little off so 2 cylinders are in flux. After that, I only have the injectors on the list.
Mark

[Mr X]

I've removed my last post... I tried new o2 sensors last night and then it was running fine, jump in this morning and it's doing it again! grrrrr!

[Mr X]

ok, I think I have found why it's doing it....


rusted crank sensor.
But I now have a more serious problem! (other than a new sensor being £93+vat)



how the chuff am I ment to get that out   s:scared: :scared: s:scared:

[Mr X]

looks like I'l have to remove the chain cover :/

[Anonymous]

If its just a broken stud use a helicoil kit,I think they are only about £10 on Ebay.   l viewtopic.php?f=11&t=37224&p=444104&hilit=helicoils#p444104 l

[Anonymous]

There is quite a bit of stud protruding. Ive had some success with pipe pliers or aligator grips as the yanks call them. Not mole grips! The pipe pliers constantly tighten their grip as you apply more torque. You need to grip to follow the thread as it unscrews. Plenty of plusgas as usual.



I know there are special tools sold to the trade, but these grips are an economic solution for those who dont need this function every day. There are some good clips on Youtube of pro mechanics using these to pull broken exhaust studs, one of their least favourite jobs.

[Mr X]

I normally get my locking pliers on bolt heads that snap off or mig weld a nut on the end of it but the sensor is just far enough up to not have enough room! Typical! haha
I have half the components off to take out the chain cover but then the heavens opened. Knowing our weather ATM, it will be 2 weeks before i get it off. Once she is back on the road, it will all seem worth it again.
Mark

[Anonymous]

Can you drill it out using something like this?   m http://www.aldi.co.uk/uk/html/offers/sp ... _25439.htm m

[Anonymous]

I normally get my locking pliers on bolt heads that snap off or mig weld a nut on the end of it but the sensor is just far enough up to not have enough room! Typical! haha
I have half the components off to take out the chain cover but then the heavens opened. Knowing our weather ATM, it will be 2 weeks before i get it off. Once she is back on the road, it will all seem worth it again.
Mark

If you have welding kit, could you push in the sensor, then tack it to the block?

[Mr X]

Can you drill it out using something like this?   m http://www.aldi.co.uk/uk/html/offers/sp ... _25439.htm m

How cool is that! Still not sure there is enough room for it under there but I think I will get that just to have it  s:) s:)

If you have welding kit, could you push in the sensor, then tack it to the block?

huh.. Never thought of that. If i do struggle getting the bolt off, a quick clean up and a short blast with the welder hopefully would hold it on and wouldn't melt the plastic surround of the sensor. Have to see once the cover is off... Also a good time for a coolant swap and see what the pump is like.
Mark

[Mr X]

Hi guys,
I have taken the cover off now. I got the broken bolt out by welding a nut to it then heated up the cover to expand it.... job done! Cleaned it all up and painted half the engine.
 Upon putting it back together (installing the tensioner) I noted every 1/4>1/2 clockwise turn crank of the engine the chain slackens and sags down a little. then after another little turn it goes back to being tight??? surly this can't be normal?? anyone had any experience with this while checking valves etc??
Thanks
Mark