missing performance

cabbydave · June 25, 2015, 21:57

If you want any engine parts im going to remove a knocking engine that was pulling well before it went bang any sensors on the engine you can pull off and try on your car save you going and buying things to and its not that, all it will cost is your fuel money over to Stockport

wallzaveerz · June 25, 2015, 22:00

It's looking that way Meeerrrk, I can't believe the difference it makes unplugging them, and obviously I was expecting the OBD codes relating to them. Will the ones in the manifold do their job properly without the pre-cats?

Anonymous · June 25, 2015, 22:07

Yes they will do fine with no precats, they are before the precats. If it were me and I suspected them as faulty i would 100% change them before tying to fault find other phantom problems

wallzaveerz · June 25, 2015, 22:07

Cabbydave, you sir are an absolute legend. I will definitely take you up on your very generous offer, even if it just rules out the O2 sensors. I am back in work from tomorrow until Tuesday evening but I then have 12 days off. Would some point then be OK? Are you scrapping the engine and all bits are available or is it a case of trying any easy to get at bits before I buy new ones?

Ardent · June 25, 2015, 23:46

Wallz

This is already on the net so can post freely here. m http://www.mr2.com/files/mr2/techinfo/R ... S2zz-6.pdf m
Have a read through from page 7, sheds some light on things vvt-i.

2 more things.
1, If it helps I can send some other pdfs that relate to fault finding the vvt-i system.
2, Bit random but, what you describe reminds me of myself when I first got my 2.
The sense of a complete lack of power, I was also convinced issues with OCV and vvt-i.
Turns out I was simply expecting too much, tested, ocv and vvt-i working just dandy.

Conveniently, found a Toyota specialist with access to proper test kit. Ran the the ocv test and engine died instantly. Confirming ocv and vvt working fine.

wallzaveerz · June 26, 2015, 00:09

Ardent, thanks again for your invaluable help. It's not a case of expecting too much, as I've said previously I was a spanner monkey in a previous life, just pre variable valve timing days. It's not that I'm hoping for a vtec style step in power. Something is "wrong". The more I talk to you guys and the more I look into it the more I'm now convinced the cam timing is out. Now I just need to ascertain whether or not that is because it has been rebuilt incorrectly or because something is stuck or broken on the variable bit. Your help is massively appreciated. Thank you.

Ardent · June 26, 2015, 09:24

Not really sure if this will help or not. Just thinking aloud.

Do you have an andriod tablet? If you do get an app called torque. Free version will do and a bluetooth obd dongle.

With this set up you will be able to see the timing change as you drive. How much adv etc.

The bit I dont know is.
Is it showing what the ecu is requesting or what it is actually doing.

I am about out of ideas now.
But I can say there are very few reported issues with the head or vvt-i system
Things point to it being set incorrectly. Chain driven and good for 100K.
Jumped a tooth?

You may find someone local with a tablet and dongle in the owners with obd scanner thread.

I suspect you are on the right lines.
Have extracted the following from a pdf. It goes on and happy to send it. But the key is in this bit.

It's vitally important that you cover basics before
tackling any VVT-i trouble codes. For example,
the ECM needs valid inputs from the throttle
position, airflow, engine coolant, camshaft and
crankshaft sensors in order to adjust valve timing
accurately. Understandably, the cam sensor is particularly
important because it monitors changes in
camshaft position for the ECM. If you have a
combination of a specific VVT-i trouble code and
another code or codes, you must correct the
cause(s) of the other code(s) first.
Likewise, you must fix fundamental engine
problems such as a botched timing chain replacement
before chasing down any VVT-i trouble
codes. You can't expect the ECM to control intake
valve timing accurately if the basic valve timing
isn't correct due to an improperly installed
timing chain.

wallzaveerz · June 26, 2015, 10:17

Thanks again Ardent. I'm going to have a bit of faith in myself, like I've said i earned my living many years ago on the spanners and at the end of the day it's still just an engine. When my mate brought the code reader round yesterday I said to him if I didn't know the car and you just plonked me in it for the first time and asked me to diagnose the problem I would say the timing was out. It's looking like that's going to be the issue. Would also explain why it got sold on immediately after a rebuild. It had clearly been loved and still had its private plate on. Looks like they've paid for a rebuild and when it still didn't run right it was a bridge too far and it got binned. I bought it with "known issues" due to the failed cats which has obviously hidden the timing issue. I've done about 10000 miles with it like this (slowly) over the last two years so it's perfectly useable but I have got the car looking amazing and it's a shame it can't deliver its full potential. After a bit of google-foo there appears to be a reputable and cheap Toyota specialist in chadderton which is about half an hour away, they are called Toyotech if anyone has heard of them. I'm going to stick a couple of new O2 sensors in and give it to him. It's coming up to 100k now so I will get him to stick a timing chain on for me and let him know I think the cams are out of kilter before he does. Money i didn't want to spend but the car warrants it and I'm not planning on parting with it any time soon. I was planning on an engine swap to something a bit fruitier at the end of next year so didn't really want to spend on the original lump but hey Ho. Maybe with a healthier turn of speed i'll be happy just with the original lump working properly.

Ardent · June 26, 2015, 10:43

Sounds like could be a simple fix.

Amazon doing correct sensors for £55 ea. Breakout your spanners and do this bit yourself. Easy access and removes the chance of being over charged for sensors. Not saying they would but removes the opportunity.

Keep us posted

wallzaveerz · June 26, 2015, 11:17

Thanks for the heads up on the cheap sensors, I was never not going to change those myself, i've got the correct socket rattling round in the bottom of my box somewhere, five minute job. Only thing stopping me tackling the chain myself is a lack of space. Cheers. :-) :-) :-)

wallzaveerz · June 26, 2015, 18:42

Well that's scuppered my plans. The highly spoken of Toyota specialist doesn't want to do the job. Says it's an engine out pain in the a**e job and is too busy to do it. Ready for finding someone with an empty container and just parking the bloody thing up for now!

cabbydave · June 26, 2015, 18:57

If I didn't have so much on I would come over and do it for you. If you haven't done it by the end of July give me a shout.

wallzaveerz · June 26, 2015, 19:34

Cabbydave, I'm uncertain of getting it sorted before the end of next month, I was pinning my hopes on the recommended specialist
who has knocked me back. There WAS one garage locally that I would trust with my pride and joy and i unfortunately got my fingers burned by him last year when I trusted him with swapping a gearbox. Took me longer to put all the bits and pieces right after the job than it would have to do the job myself. You would be an absolute life saver if you could help me out, i'd rather give the business to a fellow owner who loves the cars, obviously I will be more than happy to pay for your time, alternatively I would be more than happy to return the favour with some other aspect. I've tackled most other MR2 related jobs! I just don't have the room to do this where I'm currently located.