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About YarisVVTi2002

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    Yaris VVTi
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  1. @ bathtub tom & Gerg I used 10W40 semi-synthetic oil. I noticed the previous oil had turned quite red and the new oil I used is starting to go a bit red too - maybe the colour is leaching out of the baked on deposits? I've started by spraying carb cleaner (I don't have any Redex left) into the cylinders and leaving it overnight - there little improvement in the compression. I've been cleaning around the camshafts and VVT unit but still no compression improvement. I'm thinking the next step is to take the head off to look at the valves. It would be nice to open the VVT unit up but it has pentagon shaped nuts holding the cover on. .
  2. Thanks for that Furtula. It's proving to be very useful, especially in planning the next steps.
  3. Another 2NZ-FE engine which I have which has done similar mileage is completely clean under the rocker / cam cover. So sticky baked on oil is highly suspected somewhere. The problem I have with the idea of sticky valves or piston rings is that it would have to switch from a sticky state causing low compression to a non sticky state with normal compression on an intermittent basis and it would have to happen across all 4 cylinders together. Maybe there is a threshold temperature at which this occurs? What is the chance of that?
  4. Thanks for that Furtula. I just registered and it says 19 correction bulletins are available. The only one that relates to the 2NZ-FE engine is repair manual RM749. It doesn't say what they contain - are these comprehensive repair manuals or just field remedy bulletins? I already have the Haynes manual for this car which has quite a lot of detail on removal and re-fitment of parts.
  5. Currently about 63,000 miles, the full service history goes back to 36,000 miles (2011). I have no reason to doubt it was fully serviced before that. I'm tempted to unbolt the inlet camshaft and see if I can get the whole camshaft (with the VVT unit) off without removing the timing chain. Has anyone tried this? Has anyone had a no start problem due a faulty VVT? I'm guessing that if a 15 degree advance would never cause a cranking no start condition, checking the VVT would waste time?
  6. On my 2002 1.3L Yaris the rear O2 sensor wire goes through the car body (through a rubber cover) and the connector is under the carpet on the right side of the hand brake. You might have to unbolt the drivers seat to reach under the carpet to get to it.
  7. This intermittent Cranking No Start problem has been going on for years in my 2002 Toyota Yaris 1.3 VVTi Auto. The cause of the problem was never identified. You can read up on the history here: The Yaris has been laid up not working since last year unused. About a month ago it started on the first attempt this year and was running fine. I took it for an MOT and it passed without problems. I was using it every day on short journeys and it started easily. The Yaris was parked up for a week fully working and when I got back to it and tried to start it the old Cranking No Start problem returned. I have already previously done lots of checks on the Yaris which failed to find the cause of the problem. So I thought a new approach would be more successful. The most comprehensive method of testing I've found is FASTTEC, which is described here: https://www.youtube.com/watch?v=LuRI8bjjNho&t=106s So I thought I would work through each system below systematically and get your opinions on the results and what to do next. The details are here: Fuel Air Spark Timing (Ignition / electronic) Timing (Crank / Cam shaft) Exhaust Compression 1. Fuel I don't have a fuel pressure gauge. I had previously checked out the fuel pump which seemed OK. I loosened off the 4 fuel injectors out of the inlet manifold but still connected to the fuel rail and turned over the engine, all the injectors produced a noticeable spray. Removing an injector from the rail produced a noticeable release pressure as fuel jetted out. I connected an injector wire to an oscilloscope and the injector pulse width was about 33ms over a 0.4 sec cold cranking cycle (cranking speed was about 150 rpm). From what I can see online this may be a bit long and means the car could be running rich (please see photo 1). I tried disconnecting the injectors and spraying quick start spray into the air inlet but there was no sign of the car starting in this case. 2. Air It has a new air filter and the MAF sensor was cleaned. The 5 pin MAF sensor has 2 resistors and a ground. The resistors seem to have normal resistance. The 5 pin connector to the ECU had a correct +12V and +5V signal and some grounds. I removed all the vacuum lines to the inlet manifold and air supply and blocked up the holes. I replaced the throttle body (complete with a TPS sensor and Idle Control Valve (ICV)) with a known working one- the car still didn't start. I tried starting with no air inlet pipe to the throttle body – still no start 3. Spark The 4 coil packs were removed and inline spark testers were added. On cranking all 4 sparks testers lit up in sequence. Previously the coil packs were changed and it didn't make any difference. 4. Timing (ignition / electronic) I connected an oscilloscope to both the Crankshaft and camshaft sensors (please see photo 2) and they both produced cranking signals that seem reasonable. I disconnected the temperature sensor and it still didn't start – I saw some report that if it produces a faulty low temperature reading it can trick the ECU into making the fuel mixture too rich as a cold start situation. I've taken the ECU out and looked inside, it all looks clean with no corroded contacts etc. I've checked and cleaned many earth wires on to the block and fuses. 5. Timing (Crank / Cam shaft / mechanical) I took the rocker cover off and checked the timing chain by rotating it around with the starter. There was no sign of any excessive wear or damage and the chain seems to get lubricated as the engine is turned over. When the white timing mark on the crankshaft pulley is lined up with the TDC mark then the marks on the camshaft cogs are at the top (after second rotation of the camshafts). This would suggest that the timing chain hasn't jumped any cogs (please see photo 3). 6. Exhaust The Catalytic convertor was removed and I inspected it internally with an endoscopic camera (please see photo 4). There is no sign of the honeycomb structure breaking up or showing signs of damage. I could see some light coming through the honeycomb at some angles. I checked the O2 sensors in a gas flame and they produced voltages between about 0 to 0.9V. The car still didn't start with the exhaust and Cat removed. 7. Compression The readings from the compression tester were: Cylinder 1: 7 Bar / 100 psi Cylinder 2: 2.25 Bar / 35 psi Cylinder 3: 2 Bar / 25 psi Cylinder 4: 2.25 Bar / 35 psi I added a cap full of engine oil to each cylinder and retested the compression: Cylinder 1: 8.5 Bar / 125 psi Cylinder 2: 11.25 Bar / 165 psi Cylinder 3: 10.25 Bar / 155 psi Cylinder 4: 11 Bar / 160 psi These reading seem to be more in line with what they should be and I put the spark plugs back in and it started straight away but it cut out after a few seconds. Lots of smoke was produced. I checked the compression again and the first few compression reading were Cylinder 1: 5 Bar / 85 psi Cylinder 2: 2.5 Bar / 35 psi Having burnt off the oil which was sealing the piston rings or valves, the low compression has returned. I also noticed that when the engine was turning over but not starting that exhaust gases were venting out of the top of the rocket cover vent hole (with pipe removed). Quite often the cranking revs would increase after about 5 seconds of cranking. Maybe fuel is being burnt but the combustion is not fully contained in the cylinders? Many people thought that the Cat was blocked as the Yaris was giving a DTC Catalyst System Efficiency Below Threshold error. Since removing the Cat and checking that nothing is breaking up inside, that possibility can be eliminated. I had considered whether the engine was running rich and even flooding during starting. This could cause low compression if excess petrol washes away the oil seal around the piston rings. I'm guessing that an engine running too rich could cause the Cat error? There are also signs that the top of the engine has got hot in the past as there is sticky baked on oil and carbon deposits under the rocker cover. One idea is if the fuel injectors leak when the car is not used and flood the cylinders. I never noticed any fuel sitting on top of the pistons when I have checked in the past. Another idea was if the VVT unit was stuck in an advanced position, could this cause the low compression? I heard that the maximum advance is 15%? The VVT solenoid was changed before and it had no effect. The VVT unit uses oil pressure to operate, so if an oil way was blocked or a moving part was stuck in the advanced position, I could see how this could be intermittent. If adding oil to the cylinders restored compression could we eliminate this option? The only clear fault I have found is the low compression. This is an intermittent problem and sometimes the Yaris works fine and has good compression. This would eliminate worn piston rings. If the valves or piston rings are intermittently stuck by sticky oil deposits, that would have to occur on all cylinders together, could this happen or produce the observed compression problem? I have another engine ready to swap out if needed, if the problem is not an easy fix. I'm open to any ideas and comments.
  8. Hi Gerg Many thanks for taking the time to go over the history of this problem and for your kind words. It does seem logical to suspect the catalytic converter given its history of producing an OBD error. As you noted I had taken out the first O2 sensor on the catalytic converter to improve exhaust venting but it didn’t make it start. On my posting on the 18th Nov 2017 (first one) I had disconnected the catalytic converter inlet pipe completely from the exhaust manifold downpipe. Exhaust gases can now escape without going through the catalytic converter but the Yaris still didn’t start During the last summer, the car started and was running OK, whereas before then and now it doesn’t work, this intermittent behaviour indicates something changes Perhaps something is wrong with the engine which has been producing unburnt fuel which then caused overheating of the catalytic converter and damage to it? There is some evidence of engine overheating under the rocker cover. I am confident that the fuel and ignition systems are working, does that leave timing as the most likely cause of the non-starting problem now? Is the catalytic converter problem a consequence but not a cause of the non-starting problem?
  9. I forgot to mention that I had recently cleaned the throttle, inlet manifold, and IAC valve. I still can't find an EGR valve, is there one on a 2002 1.3 petrol Yaris? If there is one I would be really grateful if someone could post a picture with its location on it. I took the plugs and coils out and left them on a radiator overnight and tried to start it with warm dry plugs - it still didn't start. I've connected a heavy duty car battery and tried to start it with that. Thinking that the cranking speed may be too low as the cold would make the oil more viscous and reduce the battery current. The cranking speed was still about 200 rpm and still no start.
  10. 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.
  11. Thanks, Alan333, it's an interesting idea but would worn piston rings cause intermittent non-starting? Its only done 58k miles too
  12. 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?
  13. 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.
  14. 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?