2zz Flat Spots / No Power

[andibell]

Finally got the opportunity at the weekend to take the car for a really good drive, from Dorset up to Gloucestershire and back again and discovered it seems to be really struggling to make any decent power around the midrange, far beyond the difference I'd expect to see (and feel) between being on and off the VVTL.  It seems to be really struggling to get past about 3500-4000 RPM, (in any gear).  You have to absolutely bury the throttle into the floor and hold it in to get past the flat spot and then it struggles to get up to 6000+ RPM after which it picks up reasonably quickly until the lift kicks in around 7500, at which point, it's almost time to change gear and the whole charade starts again...

I've had a trawl around the internet and there seems to be a few reports of similar issues, but I can't find anyone who's conclusively located the source and a cure - hoping those people on here with experience of this engine might have some ideas I can try.

[m1tch]

Have you changed the lift bolts?

[andibell]

Have you changed the lift bolts?

They came up a few times on the internet as a possible issue but I've not looked at replacing them, mostly because I have no idea what they are or how to change them!   s:lol: :lol: s:lol:

[m1tch]

Have you changed the lift bolts?

They came up a few times on the internet as a possible issue but I've not looked at replacing them, mostly because I have no idea what they are or how to change them!   s:lol: :lol: s:lol:

Basically if they havn't been replaced they will be the original ones which are know to fail (sheer off) and mean that the lift mechanism doesn't work properly - lift should kick in at around 6K I believe.

Here is a guide I found:

 m https://www.youtube.com/watch?v=kKsyhAa7zlU m

And

 m http://www.newcelica.org/forums/showthread.php?t=314525 m

Worth checking out.

[1979scotte]

Even if it isn't the lift bolts get them changed if you haven't.
It's usually advised when you are doing the swap.

[MilesH]

Also clean the vvtli oil filter, located above the gearbox on the left side of the engine when looking from the back. It can cause all sorts of issues coming in and out of lift if it gets clogged.

Do a search on cleaning vvtli filter and you should get a few hits.

[MilesH]

Also clean the vvtli oil filter, located above the gearbox on the left side of the engine when looking from the back. It can cause all sorts of issues coming in and out of lift if it gets clogged.

Do a search on cleaning vvtli filter and you should get a few hits.

[JoeCool]

It won't be lift bolts or VVTLI actuator filter if lift actually works. Neither would impact the engine performance below 6,200 rpm.

My money is on knock sensor. If it's not the right kind or hasn't been wired up properly, it causes all manner of running issues.

This sounds like a more general fault, not a 2ZZ specific thing. Start trouble shooting from first principles. Sounds like a fuelling issue, so start there.

[Carolyn]

I'm with Joe on this.  There are several earths for sensors, any of which could be a culprit, especially the crank sensor (at the bottom of the timing cover).  Check them all by undoing, cleaning and doing up again.  Also MAF could be part of the problem.  Tedious, but probably not serious or expensive.

[andibell]

Thanks everyone - looks like a long list of things to be fiddling with over the weekend!

[JoeCool]

That's a point - the 2 maf wires got swapped, yes? (can't off the top of my head recall which 2 of the 4 need swapping...)

[andibell]

That's a point - the 2 maf wires got swapped, yes? (can't off the top of my head recall which 2 of the 4 need swapping...)

No idea as I didn't have anything to do with the conversion, I bought the car with it done.  I know that there was a similar problem before I bought it and that a lot of time and effort went into fixing it, but don't have any details. I've messaged the guy I bought the car from to see if he can find out what his mechanic did before.

When you say swapped do you mean replaced with something else or swapped as in position?

[JoeCool]

Just swapped in position.

[shnazzle]

Do you mean the tps ground wire?
Wasn't aware of any MAF wiring changes.

[andibell]

Just swapped in position.

Found this on Spyderchat:  "You will also have to change the polarity of the TPS on the 2zz throttle body. You MAY be able to use the 1zz tps and it work ok. The pins that need to be moved around are posted in the library. Ιt is the brown with the red striped one. 1 with 2. Just take the pin out of the connector and swap it. This is done on the connector side" - Is that what you mean?

[m1tch]

There are some photos here:

 m http://www.mr2oc.co.uk/forums/200/162290.html m

[Alex Knight]

I'm presuming it has a primary lambda sensor wired and plumbed in?

[andibell]

I'm presuming it has a primary lambda sensor wired and plumbed in?

I assume so, I believe the conversion was originally carried out by Rogue who know what they're doing - that said it needed a lot of work to get running before I bought it as it had a similar problem then. - How would I check on the sensor?

One other thing - I swapped the exhaust & manifold a couple of weeks ago, I moved the O2 sensors from the old one over; are the two sensors different and if so might it be that I have them in the wrong places?

[Alex Knight]

I'm presuming it has a primary lambda sensor wired and plumbed in?

I assume so, I believe the conversion was originally carried out by Rogue who know what they're doing - that said it needed a lot of work to get running before I bought it as it had a similar problem then. - How would I check on the sensor?

One other thing - I swapped the exhaust & manifold a couple of weeks ago, I moved the O2 sensors from the old one over; are the two sensors different and if so might it be that I have them in the wrong places?

A 2ZZ ECU only needs 1 lambda input, despite the fact that there may be 2 physically present.

Do you have any ECU fault codes?

[andibell]

I'm presuming it has a primary lambda sensor wired and plumbed in?

I assume so, I believe the conversion was originally carried out by Rogue who know what they're doing - that said it needed a lot of work to get running before I bought it as it had a similar problem then. - How would I check on the sensor?

One other thing - I swapped the exhaust & manifold a couple of weeks ago, I moved the O2 sensors from the old one over; are the two sensors different and if so might it be that I have them in the wrong places?

A 2ZZ ECU only needs 1 lambda input, despite the fact that there may be 2 physically present.

Do you have any ECU fault codes?

There's no lights on the dash, I don't have a reader though so can't check if there's anything in the computer.

[MilesH]

Where are you andi I have one that will read it?

[mikek]

You should have said. I've got a reader. It was in the car when we swapped the exhaust!

[Chipstix]

Resurrecting this old thread as I have a similar issue, a noticeable flat spot that you really have to push through from 5k to 6k until lift comes in at 6200rpm. Hesitation seems worse when the engine is cold and at partial throttle input.

Once it's in lift, it goes like the clappers! Pickup below 5k is fine (except when cold)

I'll check the things above.

Wandered if it could be to do with the MWR swap header which looks a bit a restrictive. It has the MWR intake system. No warning lights, no fault codes. I've already cleaned the MAF. Full recent service including spark plugs.

@andibell did you find out what it was and fix for it?

[Alex Knight]

Do you have a CAT?

Have you reset the ECU?

Not entirely sure why you're revving up to and past 6K RPM on a cold engine?

[Dev]

Hesitation when cold with part throttle input like it's bogging is due to running lean caused by a un calibrated intake like what you find with the MWR set up.

As for the other issue of having a flat spot between 5k-6k or before lift could be a restrictive exhaust if you are using the cat that is made for the 1ZZ.