Author Topic: P12 QR20DE 2l engine problem  (Read 933 times)

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Vet88

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P12 QR20DE 2l engine problem
« on: 10 October, 2015, 11:33:10 PM »



grim_reaper

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Re: P12 QR20DE 2l engine problem
« Reply #1 on: 11 October, 2015, 01:13:33 AM »
Sounds like more like spark, maybe fuel.
With the stretched chain, they throw codes related to a miss match between cam & crank sensor.

more_fasterer

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Re: P12 QR20DE 2l engine problem
« Reply #2 on: 11 October, 2015, 10:01:53 AM »
Can you please confirm whether it's a QR20DE or a QR20DD?  The DD's are the ones with direct (read: high pressure) injection and suffer from issues with the pump and timing chain as a result.  I don't think anyone has posted up on this forum before with a stretched timing chain on a QR20DE.

When you say the rev counter is flicking up and down, can you go into a bit more detail?  i.e. does it bounce wildly with no reference to actual RPM, or does it flutter by a couple of hundred RPM while the engine is running rough?

These engines are really reliant on a good o2 sensor reading under normal operation, so if the o2 sensor is giving some really odd readings it may cause the engine to lean out and run like you've described.  Tellingly, the engine computer ignores the o2 sensors when you're flooring it.  I suggest starting by fixing what you know is wrong (the o2 sensor) and going from there.
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Vet88

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Re: P12 QR20DE 2l engine problem
« Reply #3 on: 11 October, 2015, 11:43:42 AM »
It is a QR20DE engine. This car is one from the UK, not a jap import.

The rev counter flutters by a couple of hundred RPM at idle when the engine is running rough and in tune to the engine running rough (if that makes sense). When the engine is running normally it is steady.

The O2 sensor fault only occurs when the engine is running really badly and only intermittently. For example: engine doing it's bad thing for the last 5 minutes, I pulled into a car park that had a slight uphill to it, the engine had no power as I tried to gently accelerate into the car park, I held the throttle steady revs around 1800, the car slowed right down and almost came to a stop then there was a backfire, the O2 sensor fault activated and then I pumped the accelerator quickly 4 times and the engine gained power again.

Are you suggesting I start with replacing the O2 sensor to see if that fixes things?
.

pTen

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Re: P12 QR20DE 2l engine problem
« Reply #4 on: 11 October, 2015, 08:29:26 PM »
Unplug the o2 sensor, it will throw a code but ecu will run basic fuel maps (I did this with my p12 trying to find a fault). If the problem is still there it will be something else.

more_fasterer

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Re: P12 QR20DE 2l engine problem
« Reply #5 on: 11 October, 2015, 09:04:01 PM »
Are you suggesting I start with replacing the O2 sensor to see if that fixes things?
.

Yes. pTen's suggestion is a good one too.
Kieran: thank you for being amazing... Have my babies.

Vet88

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Re: P12 QR20DE 2l engine problem
« Reply #6 on: 12 October, 2015, 12:13:37 AM »
Thanks, I will try this tomorrow or Tuesday when I get some time and let you know the result.

pandap10

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Re: P12 QR20DE 2l engine problem
« Reply #7 on: 12 October, 2015, 07:02:37 PM »
Check for air leaks also.

Vet88

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Re: P12 QR20DE 2l engine problem
« Reply #8 on: 13 October, 2015, 12:35:30 AM »
OMG pTen, you are godsend. Unplugged both O2 sensors and drove a regular route where I could previously draw on the road where the problems would start. There and back, around 20 minutes each way, and not a fault. Will drive it tomorrow for another 2 hours in a start stop environment but at this stage it looks like an o2 sensor. Can anyone recommend which brand to get for this car and from where? I've read lots of different opinions as to what to buy and lots of it conflicts.

I've found an engine with 100k on it for a good price so I'm most likely going to buy it and hold it in reserve given the km's the current engine has. I have the manual and it says to drop the engine / trans to get it out. I don't have that capability at home so can anyone say if the trans can be disconnected whilst it is in the car and the engine removed upwards?

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Re: P12 QR20DE 2l engine problem
« Reply #9 on: 13 October, 2015, 12:18:41 PM »
If it says drop it out the bottom, that's probably the easiest way. Just drop it onto a garage creeper or something. Then jack the car up really high and slide it out the way.

On p11s you can lift it out the top I think. Not sure about P12s.

Quote from: Cameron
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Vet88

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Re: P12 QR20DE 2l engine problem
« Reply #10 on: 13 October, 2015, 04:58:09 PM »
Ok, I'll give some thought as to how I can lift the front of the car high enough. Not keen on using a jack, might have to rent a lifter from hire pool for a morning.

For those in the know about the O2 sensors, until I get one is there any chance of damaging the engine whilst they are unplugged? I assume gas might be slightly heavier in use, any other side effects? Does anyone remove them permanently? I assume you must do something with them if you remove the cat?

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Re: P12 QR20DE 2l engine problem
« Reply #11 on: 13 October, 2015, 11:13:08 PM »
I admit I haven't had a lot of experience with the QR engines, but most of us here haven't.

In the SRs, you can remove the O2 sensor no problem, and the engine goes into open-loop mode 24/7 (as opposed to closed-loop). It runs slightly richer in order to be on the safe side of stoichiometric. It might wear out your cat converter 0.0000000001% faster, but who cares about that anyway.

They are only narrowband sensors anyway. Just a "rich" or "lean" signal. In open-loop the computer makes it so it is most likely "rich" most of the time.

I can recommend that you don't do the following ;D


Quote from: Cameron
Darryl, what would it take to RWD SR convert my QG18 bluebird? Ive got a mate with a angle grinder and stick welder, surely it cant be too hard

jevans

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Re: P12 QR20DE 2l engine problem
« Reply #12 on: 14 October, 2015, 12:06:09 AM »
I admit I haven't had a lot of experience with the QR engines, but most of us here haven't.

In the SRs, you can remove the O2 sensor no problem, and the engine goes into open-loop mode 24/7 (as opposed to closed-loop). It runs slightly richer in order to be on the safe side of stoichiometric. It might wear out your cat converter 0.0000000001% faster, but who cares about that anyway.

They are only narrowband sensors anyway. Just a "rich" or "lean" signal. In open-loop the computer makes it so it is most likely "rich" most of the time.

I can recommend that you don't do the following ;D



That is literally the most dangerous but most artistic jacking I've ever seen ;D

jonathanhogdahl

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Re: P12 QR20DE 2l engine problem
« Reply #13 on: 26 August, 2019, 07:20:11 PM »
Sorry this late but:
I had the same problem last week after cleaning the throttle body.
After hours of frustration I decided to check all the intake areas including manifold for leaks by spraying WD Throttle Body Cleaner with engine idling at 2000-2500 rpm.
Last resort - I sprayed into the oval intake behind the nearside head lamp.
The engine slowed down to 700 and then more, until it stalled.
I restarted and it idled at 650rpm!!!!!!!!