Very poor mpg 2zz

[MrChris]

I did replace the cam cover gasket when I did the valves. Maybe I didn't seat it perfectly? It was done at Ding Day (good times). 

But I have to say those sparks look as good as they ever did.

I actually did this on the 1zz because the rocker/cam cover gasket had a visible leak. I think the problem was coming from where the blobs of sealant are needed which, as I understand it, are a known weak point of the valve cover. I don't think it was anything wrong with the installation, just past its best.

[MrChris]

Update:

I've been out and inspected the rest of the spark plugs. All look exactly like the first one I took out.

I then scanned the O2 readings with some revs applied:
O2B1S1 - between 0.8 and 0.1 - I believe this is okay.
O2B1S2 - between 0.5 and 0.2 - I do not believe this is okay.

My LTFT1 reading is -20% and lower, possibly even -25/-30%.

My STFT1 is between 5 and -5 - which is good.

Picture of these readings is attached.

What I have done so far:

Driven around in normal road conditions - fuel is noticeably dropping in a way it shouldn't in my opinion.

The MAF has been cleaned.

Inspected all spark plugs - all appear "perfect" (despite oil on the threads).

Based on the condition of the spark plugs, it would suggest that I don't have a problem with injectors. I do not have black smoke, misfires or anything like that.

I do have a slight exhaust leak at the exhaust manifold.

Some additional context: the air intake is from a 1zz. I can't hear any vacuum leaks, but should I be looking at a different intake?

What I think I should do next:
Change the manifold gasket.


Bit stumped at this point as people have mentioned that the tiny exhaust leak should no be causing the fuelling issues I'm experiencing. Appreciate any further thoughts on this.

[shnazzle]

Stft -5/5 is not necessarily good given that your LTFT is maxing out. You're a few percent off a dash light coming on.

It still means it's measuring running severely rich on that cyl 1/3 bank such that it has to reduce fuel by 25% there.

It is good I guess that the fueling strategy is keeping it all in spec and running. Which could be the reason why there's little to no evidence on the spark plugs. The issue is within the range the ECU can "fix"

O2 voltage readings are next to useless other than to verify they're working ok.
Taking it back to Carolyn's earlier comment:
There's something causing massive amounts of fuel to be dumped into a (or two) cylinders. If you can be bothered, swap injectors 1 and 3 with 2 and 4. Reset ECU and see if the ltft issues move to LTFT2

[MrChris]

Stft -5/5 is not necessarily good given that your LTFT is maxing out. You're a few percent off a dash light coming on.

It still means it's measuring running severely rich on that cyl 1/3 bank such that it has to reduce fuel by 25% there.

It is good I guess that the fueling strategy is keeping it all in spec and running. Which could be the reason why there's little to no evidence on the spark plugs. The issue is within the range the ECU can "fix"

O2 voltage readings are next to useless other than to verify they're working ok.
Taking it back to Carolyn's earlier comment:
There's something causing massive amounts of fuel to be dumped into a (or two) cylinders. If you can be bothered, swap injectors 1 and 3 with 2 and 4. Reset ECU and see if the ltft issues move to LTFT2

I will do this, but it's just started chucking it down so I will have to wait.

Could anything else be causing me to lose fuel? I suspect not as that's basically a fuel leak and would be obvious.

Thanks for the insight though, it does seem like it's too do with injectors after all. Do you know if it's worth sending them off for refurbishment or just replace?

[Carolyn]

In addition to the manifold gasket, why not swap the O2 sensors around and see if the odd reading moves to the other bank, or not?

If it does - it's a sensor issue. 

One variable at a time though!

 

[shnazzle]

I will do this, but it's just started chucking it down so I will have to wait.

Could anything else be causing me to lose fuel? I suspect not as that's basically a fuel leak and would be obvious.

Thanks for the insight though, it does seem like it's too do with injectors after all. Do you know if it's worth sending them off for refurbishment or just replace?

You're not losing fuel anywhere other than inside the cylinders (as per the massive fuel "cut" in ltft) and there's only one source for that. If it were leaking outside the car you'd smell it and it'd likely be running very lean and you'd have positive LTFT.

If an O2 sensor is duff it's usually reading lean, not rich. But you never know.

[MrChris]

Nothing is ever simple is it. Pulled the fuel rail, 3 injectors stayed in and needed pulling out. Second from left fell and has fallen into a pit of doom between engine and air intake manifold. Any tips on how to get it out from there? Could the fact it just fell out point to my original problem?

[shnazzle]

Nothing is ever simple is it. Pulled the fuel rail, 3 injectors stayed in and needed pulling out. Second from left fell and has fallen into a pit of doom between engine and air intake manifold. Any tips on how to get it out from there? Could the fact it just fell out point to my original problem?

Feel your pain. Been there. Never did recover the item

The injector being loose wouldn't make it fire more into the cylinder I think. 

[MrChris]

Feel your pain. Been there. Never did recover the item

The injector being loose wouldn't make it fire more into the cylinder I think.

Holy crap I got it. Managed to use my endoscope and did some poking and extracted from under the car.

Pic of the injectors before, I would say that the rubber is quite hard on all of them.

Actually on closer inspection they are brittle and cracking.

[Joesson]

Nothing is ever simple is it. Pulled the fuel rail, 3 injectors stayed in and needed pulling out. Second from left fell and has fallen into a pit of doom between engine and air intake manifold. Any tips on how to get it out from there? Could the fact it just fell out point to my original problem?

Could be a job for my Stickystick

From 14 Nov 2021 : Thoughts for the day:

Thought I would post this on here and resurrect this thread as it was about to fall of the edge of the "page".

@Carolyn said, in a post about possible exhaust leaks:
"Tape a piece of tissue to the end of a suitable screwdriver and pass that around all joints.  When it flaps, you've found a leak"

The regular reader will be aware that previously Carolyn has suggested the use of a Stickwith a tissue appendage, (FlappyStick © )this I guess is an example of the continuous development essential for progress in this modern World.

I will take this opportunity to remind the Reader of the StickyStick © of my invention, used for retrieving small items from hard to reach places.

These are still freely available by writing your name, address and post code on the back of a £10 note and sending to me.
NB: Special offer for this week only, old stock FlappyStick © included with StickyStick ©.

[Carolyn]

Holy crap I got it. Managed to use my endoscope and did some poking and extracted from under the car.

Pic of the injectors before, I would say that the rubber is quite hard on all of them.

Actually on closer inspection they are brittle and cracking.



Time for new rubbers and O rings. 

[MrChris]

@Joesson Fantastic 

@Carolyn so if the injectors are working and I sorted out the seals, this could be the source of my high fuel consumption?

I've just tried putting it back together and the o rings are particularly bad at the top. They bend when I try and insert them in the fuel rail and one of them is letting fuel pour out when I crank the engine... Not good!

[shnazzle]

@Joesson Fantastic 

@Carolyn so if the injectors are working and I sorted out the seals, this could be the source of my high fuel consumption?

I've just tried putting it back together and the o rings are particularly bad at the top. They bend when I try and insert them in the fuel rail and one of them is letting fuel pour out when I crank the engine... Not good!

While they're out and unusable, could send them out for cleaning. Usually comes back with new seals as well
I think it's about 70gbp

[MrChris]

While they're out and unusable, could send them out for cleaning. Usually comes back with new seals as well
I think it's about 70gbp

Oh that's not bad, unless it is per injector. Any recommendations?

[Carolyn]

I recall one of our members having the kit to do this.

@jvanzyl ??

[jvanzyl]

I don't have a kit to clean injectors.. I do have a lot of o rings that go into the fuel rail.

This is the place I used many years ago:
Simtek (UK) Ltd
Unit 1, Daniel Street Ind. Estate
Whitworth
ROCHDALE
Lancashire
OL12 8BX

Telephone: 01706854857
sales@simtekuk.co.uk

You can get new proper o rings (the fat ones that go at the bottom) from Toyota..

[shnazzle]

I had mine done by someone on here...I can't remember who! I'l have a peek

[MrChris]

Brilliant thanks @jvanzyl - I've noticed my injectors have an o ring and one seal. Whereas the kits online I've seen have 3 seals per injector, so I'm confused.

[Carolyn]

I just checked my O ring stash and I have the correct Viton ones.  I'm happy to send you four at no charge.

[jvanzyl]

No worries.

Erm... That's a bit strange. Can you share a pic of this?

[MrChris]

No worries.

Erm... That's a bit strange. Can you share a pic of this?

There's a picture further up in the thread of my injectors. I can't see where a third goes

[MrChris]

I just checked my O ring stash and I have the correct Viton ones.  I'm happy to send you four at no charge.

That's very kind of you, I'll PM you my address.

[KRAMSNEHPETS]

 I have spare injectors you can have fpr nothing

[MrChris]

I have spare injectors you can have fpr nothing

Ah that's very kind of you! I'll PM you. Hopefully can get this sorted and then I'll be booking track days again.

[Ardent]

I love this place.