Engine turns over but doesn’t start on a Toyota Yaris 1.3 Auto 2002 VVTi

[YarisVVTi2002]

Hi everybody, new member and major Toyota owner / enthusiast here with 5 different Toyota models in the immediate family.

I got a Toyota Yaris 1.3 Auto 2002 VVTi as a run around and for the school run over a year ago, except for one problem it has been good runner until now.

I’ve been working on cars for years and normally solve most problems on my own but this one has me stumped.  I have done lots of checks on this problem, listed below.

Car has been running rough for weeks – very sluggish / loss of power, engine vibration etc

Car started one morning and cut out after a few minutes after engaging drive and trying to pull away. It would not restart again despite cranking over normally.     Since the break down I’ve tried many ideas and I got the car started once for about 30 seconds before it conked out. It had been left for a few days and the Battery had been taken out to charge it. Sometimes when the engine is turned over, the turn over speed may increase after 10-20 seconds and it feels like it’s close to starting, but this fades away.

Things done so far:

1. The fuel tank is nearly full, it was filled up with unleaded a few days before.  

2. I tried starting it with the other key, in case of an immobiliser fault- No difference

3. Charged car Battery and tried jump starting the car off a different car- No difference

4.  Used Cold Start spray both in the air inlet and directly into cylinders- No effect
5.  Replaced all 4 pencil coil packs with a working set with the same model number- No difference. The voltage on the 4 pins of the coil leads are 0 & 12v on the 2 outer pins and about 7v on the 2 inner pins. The resistance across all 4 pins of the coils are the same on all coils.  A break down technician had checked the car, plugged in an OBD scanner and said the error codes indicated a problem with the coils or the coil driver circuit on the ECU but I can’t find any faults here.
6. I took out each spark plug, left them connected and cranked the engine – there was a good spark on all 4 plugs. On removal each plug was slightly wet, indicating fuel was getting through.

7. The fuel line was disconnected and the engine turned over, about 100ml of fuel was pumped out in one crank. Indicating the fuel pump is ok and the fuel line & filter are not blocked.

8. The pistons could be seen moving up and down as the engine was cranked. Both the tops of the pistons and the plugs were quite carbonised. The car has done about 58,000 miles and has been serviced regularly. So I can’t see how there can be a problem with the starter motor. I think this model has a timing chain rather than a rubber timing belt.
9.  Compression was tested by taking out the spark plug and putting a rubber valve grinder suction cup over the hole and cranking the engine, a loud popping occurred indicating pressure in all cylinders.
10.  The crankshaft sensor failed about 6 months ago and was replaced. The last OBD check didn’t show any crankshaft sensor error code – which it did before.

11. The petrol had a small amount of diesel contamination about 3 months ago. Since then the car has been filled up over 4 times.
12.  The yellow engine warning light has been on continuously since I got the car over a year ago. The Yaris has been to the garage many times about this issue and I was told it was related to the Catalytic converter. The error can be cleared but comes back again after some time driving; it never seemed to effect starting or performance.

If anyone has any ideas or advice on this problem I would be very glad to hear them.  

[bathtub tom]

I'd look closely at item 12, catalytic converter and be tempted to remove the exhaust in front of it to see if it runs.

[Madasafish]

I can think of ywo possible faults:

1. Blocked exhaust.. either baffles moved  or catalyst blocked.. (Warning code)

2. Timing chain has jumped a tooth or several  - so timing is out. (you should get a warning code)

 

I would start by buying a cheap code reader  or getting someone to read the codes and post them here.

 

The facts that you have a spark and fuel say it is not igniting for some reason .. - which may/may not be giving a fault code. If it has a yellow light - engine fault - you need to know what code is being registered.

 

 

 

[YarisVVTi2002]

Thanks for all the great ideas which I have checked out and it’s time for a long overdue update.

It doesn’t look like it’s an exhaust obstruction. I couldn’t undo the bolts from the front of the Cat but I removed the first O2 sensor so gas could get out – no change.

I took off both Battery earth straps and cleaned up the bolts and terminals, they were quite clean anyway – no change.

Since my original post I got the car working for some time, it’s not clear how. I also got a OBD2 tester and compression meter.

The car had been sitting with the Battery removed for a few days. I cleaned and re-gaped the spark plugs. With a freshly charged Battery I tried cranking it and as before it picked up cranking speed before fading away. I kept cranking the engine with my foot to the floor and it picked up again and eventually sparked into life. I kept my foot on the gas / accelerator pedal to give fast idle for a while before driving it. Since then it started and drove quite well and interesting the engine warning light had gone out since it was started. The OBD tester showed no error codes at first but after driving it for a while it showed a pending diagnostic trouble code DTC (mode 07): PO302 - cylinder 2 misfire. After clearing it, it never came back again. After driving 20-30 miles the DTC Catalyst System Efficiency Below Threshold error came back as the engine warning light came on. There is a minor bit of blowing near a joint on the exhaust which may cause the error. Both O2 sensors readings on the OBD tester were 0-1V.

There was still a minor tappy sound from the engine- more noticeable when cold. I was still worried there may be an issue with the valves and I checked the compression on all 4 cylinders: 1 = 11 bar, 2= 9.5 bar, 3 = 11 bar, 4 = 11 bar. I took the plugs out again and checked the compression after a few weeks and they were about the same. When I repeated cylinder 1 there was some blow back out of the loosened air intake pipe and since then the car has not started again. The compression readings are all about 3 bar on all cylinders. No trouble codes have come up on the OBD tester. It feels and sounds the same as when it first didn’t start and again the plugs are producing sparks and it won’t start on cold start spray. There is no pick up of speed at all when cranking. 

So I'm back to square one and run out of ideas. Any ideas anyone?

[YarisVVTi2002]

This problem has a lot in common with this one: http://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/strange-problem-no-compression-sometimes-wont-start-2389750/

[Madasafish]

I suspect a blocked catalyst. Or EGR valve. Or MAF sensor. Or air filter...The latter three will give no warning codes.

 

but clean the MAF sensor carefully first - using Carb cleaner.

Check air filter

Clean EGR valve..

 

If all that fails, as Bathtub Tom, Remove catalyst.

[YarisVVTi2002]

Thank's Madasafish, I've checked the MAF sensor and air filter both look very clean, will give the MAF a blast with carb cleaner when I get some new stuff.

My Yaris is a petrol VVTi (variable valve) does it have an EGR valve? I couldn't see it anywhere. https://axleaddict.com/auto-repair/Bad-EGR-Valve-Symptoms-and-What-to-Do-About-Them

It still wouldn't start even with the first O2 sensor removed to allow exhaust gas to escape without going through the cat. 

The main issue that doesn't look right at the moment is the very low compression. Clearly it won't start with compression down at 3 bar. 

[Madasafish]

Sounds like cam timing may be out. Or the crankshaft sensor is fubar,

[YarisVVTi2002]

I got the car going again about a week ago. At the end of my last update I mentioned that there was low compression (about 3 bar) in all 4 cylinders.  I realised that during the last compression test when I was turning the engine over I had not disabled the fuel system and I guess the unburned petrol was washing away the oil around the piston rings and reducing the compression. All I did then was dribble about 10-20 ml of engine oil into all 4 cylinders through the spark plug holes and the compression went back up to normal.  It started easily after this and it ran reasonably OK for about week.

In the last few days the car has started to lose power and run rough again, error codes came up on the OBD tester.  PO300 – random / multiple cylinder misfire detected and PO301 – cylinder 1 misfire detected. This morning it started but the car hardly moved when accelerating, it then cut out and wouldn’t restart. I checked the compression again and all cylinders were 3-5 bar, so no chance of starting. As before all cylinders are getting a spark and fuel. When I was checking the spark there was a small explosion inside the engine like a large pop and some small amount of smoke came out from the front of the engine and from the oil filler cap. Perhaps this was unburnt petrol inside the engine igniting as perhaps the piston rings don’t seem to be doing their job at the moment?  

I was thinking that the piston rings can’t be worn out (car has only done 58,000 miles) and the compression can be normal when the car is working. Perhaps something is wrong with the oil supply so that oil is not getting to the piston rings intermittently?

Some articles mention vacuum line problems with these error codes. I wonder if anyone had a similar problem and got to the bottom of it?

I don’t think that the problem is with the ignition system as I have been around that loop a few times, swapping coils and plugs around.

@ Madasafish,  I can’t see how cam timing or crankshaft sensor problems can be the problem as this seems to be intermittent and can it explain the low compression?

[bathtub tom]

Going back to your original post: " I got a Toyota Yaris 1.3 Auto 2002 VVTi as a run around and for the school run over a year ago "

Does it get started and run for a few yards and then stopped again?

Has it just been used for short journeys?

Both the above can result in fuel washing oil off the bores leading to premature ring and bore wear. I wonder if this could be the problem?

[craggle]

As it's a VVT-i model could the variable valve timing be playing up and holding the valves open at the wrong time or for too long? This would result in reduced compression.

When was the engine oil last changed?

Craig.

 

[YarisVVTi2002]

I've changed the oil and oil filter now but it still doesn't start. The old oil is just over a year old and was surprisingly clean and red coloured. I tried pouring a little bit of new engine oil into all 4 cylinders but still no luck starting and the compression is still very low (2 bar).

@bathtub tom yep the car's mainly used to go a mile to school and back a few times a day. It does normally get a longer run for about 30 miles once a week. I'm not sure about excessive ring and bore wear as the compression has been good sometimes (11 bar). It seems like an intermittent problem. Why should the compression be 11 bar one minute and 2 bar the next and return to 11 bar again sometimes? 

I've taken off the vacuum pipes from the top of the rocker cover and cleaned them. One had a small amount of mayonnaise in it but not enough to block it. 

@Madasafish would a faulty camshaft sensor not show up as an error on the OBD scan? I've cleared all the errors (misfire and cat) and nothing new comes up. 
@Craggle a problem with the variable valve timing sounds like an interesting idea. How could I check the VVT system?

Something has to explain the low compression.

I'm thinking of taking the rocker cover off and checking the tops of valves and the timing chain as the next step.

The weather in the UK has been really cold this week, with a hard frost at night (below 0C), which won't help the starting conditions, as the car is outside on the drive.

Keep the ideas coming thanks, this is a real puzzle.

[YarisVVTi2002]

I have taken the rocker / valve cover off now. 
First impressions are the timing chain is fairly slack but I doubt it's enough for it to jump off the cogs. It is a VVTi so I'm not sure how to check the correct chain slackness?
There is quite a lot of water under the rocker cover. The car has been outside unused in the cold for weeks. 
Some photos of it: 

[Bod&Hammie]

Sounds to me very much like a VVTi issue due to the coming and going of compression. Either the actuator or the hub on the end of a cam. 

https://m.youtube.com/#/watch?v=WnbJ6-nc6Oo

 

https://m.youtube.com/#/watch?v=WY5Nlwhb6Zk

This second video is of the VVTi valve location. I know it's on a Lexus but it'll be in the same place.

Hope that helps.

[YarisVVTi2002]

Won't low compression be due to either a problem with the cylinder pistons rings or the inlet or exhaust valves ? 

I've taken out the VVT oil control valve & solenoid and tested the resistance across the 2 pins - it was 7.1 Ohms, which is normal for this one according to online info. The piston in the valve slides back and forwards ok and the spring acts normally. I can't see any obvious problems with it. I've cleaned it and sprayed it with carb cleaner in case anything is sticking. I haven't opened up the cylinder at the left end of the forward camshaft which contains the VVT gears- I'm worried I might not get it back together again. 

I took out the camshaft sensor as well (to the right of forward camshaft) and cleaned it, it had a resistance across the 2 pins of about 2k Ohms, which is normal for a Hall Effect sensor according to online info. Visually it looked ok. The rotor on the right end of the forward camshaft has 3 cylindrical tabs on it (magnets?), which I guess provide magnetic timing pulses to the camshaft sensor. 

@Bod&Hammie Thanks for the Youtube links, I couldn't get them working directly but I cut and pasted into youtube search, the part of the link starting v= and the top searches were about the VVT oil control valves. I noticed that they had OBD errors in the video, I have never had any OBD errors relating to the VVT oil control valves or system so far. As I understand it the VVT system adjusts the valve timing so that it holds more exhaust gas in the cylinders at higher revs to improve fuel economy. I'm assuming that at starting conditions the VVT system is not active unless it's stuck somehow?

I've turned the engine over for short periods with the rocker cover off. The tops of the valves seem to go up and down normally. The timing chain is normally tight but in some positions it is slightly slack (droops down in the middle as in photo). 

Everything inside the cover is covered with slightly sticky baked on oil deposits, which I've cleaned off as much as possible. Part of the cam lobes (the short radius part) has a baked on yellow coating which indicates that they are not running in contact with the tops of the valves. Is this normal? Also the sides of the cam lobes had carbon deposits, so they must have been running hot to carbonise oil. The cam lobes in this video at 21 min are all shiny all around the lobes: 

 

I'm starting to think that the oil supply to the top half of the engine has been insufficient? Perhaps there is a small inline oil filter for the VVT oil control valve? It's mentioned in the Lexus video but is it on a Yaris ? 

[euphoria]

Hi YarisVVTi2002,

did you get to tthe bottom of your cranking not catching engine?

 

thanks

 

 

[YarisVVTi2002]

Hi everybody, I'm back! I never got to find the cause of the non-starting problem in my Yaris last year, so I left it over the winter. I changed the VVTi solenoid / actuator in the spring and tried to start it and it worked almost immediately, I tried putting the old one back in (as I couldn't see anything wrong with it) and the car still worked. I've run it intermittently over the summer with the new solenoid in without any problems. I don't think the cause is the solenoid.  I didn't use it for while but now that the cold weather has started the Yaris is back to the same problem as before and doesn't start but turns over OK. Nothing was done on it between when it was starting and when it was not.

I put in some cold start spray into the air inlet and it almost started for a second. 

I've checked a few obvious things: there is a decent spark on all the plugs, fuel is getting through but the compression is low (5 bar / 75psi) . The Battery is fully charged. It's had new plugs, air & oil filter and new oil. 

I've plugged in the OBD and no error codes show up. 

We never solved the problem last year and the current symptoms are the same. My best guess is something temperature or fuel related. 

Any ideas anyone? 

[Madasafish]

Blocked fuel filter

Failed fuel pump.

 

The clue is in "I put in some cold start spray into the air inlet and it almost started for a second. "

 

So ignition works, ignition timing works.. but no fuel in cylinders...

[euphoria]

Exhaust  could be blocked, are there o2 sensors on the outlet manifold u could remove to allow venting? Be careful doing this mind.

[YarisVVTi2002]

I've checked out the fuel system at last.
I took out the fuel pump and sender unit (located under a cover under the back seat). The fuel filter was clean and pump ran fine when connected to 12V. I then took out the complete fuel rail with injectors connected and turned it over with just one injector connector plugged in at a time - they all had a good stream of fuel shooting out of them. So it doesn't seem to be a problem with the fuel system!!
I'm waiting to get some new injector gaskets before reconnecting the fuel rail - it's really hard to find any for sale. Does anyone know a good source in the UK?
Perhaps I'll start looking at the inlet manifold, and clean throttle, EGR valve, IAC valve etc?

@euphoria I don't think it can be a blocked exhaust, I tried the idea of removing the rear O2 sensor in a previous post and it didn't make any difference then.

[YarisVVTi2002]

This has to be one of the craziest problems ever.  I still can’t find any cause for the Yaris not starting. 
In summary:
When the engine is cranked:
1.    There are good sparks produced on the spark plugs
2.    There is a good spray of fuel from all 4 fuel injectors

I have cleaned the PCV valve and disconnected the catalytic converter inlet pipe but it still doesn’t start. No DTC errors come up on the OBD module but I have enclosed below a screenshot of the OBD live data screen when the engine is turned over. I notice that the air flow rate during cranking is between 0.2 -1.43 g/s, this seems quite low? We now know there is no blockage in the exhaust and even if the air filter is removed it won’t start. 
Last autumn the car stopped starting but started again without doing anything major to it this summer, now it’s stopped starting again as before. 
What do people think? Is there anything that should be checked?  Timing, ECU? 

[alan333]

If it's any help... a guy at work has a 12 plate (or maybe it's a 14 plate, can't remember) diesel Yaris, IIRC with 70k on it, which was running rough.  Toyota did some major work to the bottom half of the engine under warranty.  I'd need to ask him again but I'm pretty sure it got new piston rings etc.  Perhaps your low compression could be a similar problem, and the cold temps and therefore bigger tolerance gaps exaggerate the problem?

[Madasafish]

Check the crankshaft and camshaft sensors. If either has an intermittent fault - failing windings ) the car will not start/may occasionally start..

[YarisVVTi2002]

• Thanks, Alan333, it's an interesting idea but would worn piston rings cause intermittent non-starting? Its only done 58k miles too

[YarisVVTi2002]

Thanks, Madasafish  I checked the camshaft sensor last year (Dec 6). The car has hardly done any miles since then. This is what I wrote then:

"I took out the camshaft sensor as well (to the right of forward camshaft) and cleaned it, it had a resistance across the 2 pins of about 2k Ohms, which is normal for a Hall Effect sensor according to online info. Visually it looked ok. The rotor on the right end of the forward camshaft has 3 cylindrical tabs on it (magnets?), which I guess provide magnetic timing pulses to the camshaft sensor." 

The crankshaft sensor was changed a few years ago.When it failed it produced an OBD error. There are no OBD errors at the moment. 

Am I right in thinking that a fault in the cam and / or crank sensors may result in a mismatch in the pulses that go to the coil pack and fuel injector? 

I take on board your point that it may be an intermittent sensor fault and not producing an OBD error code. Is there any easy way to check this?

I am thinking of trying to display the coil and injector pulses on an oscilloscope to check if they are simultaneous.