Noticed that I'm getting very bad mpg on my 2zz at donington this evening.
I will need to check wiring on the loom etc. But does anyone have any general pointers as to what I can check?
My exhaust has a fairly strong smell coming from it and it pops and bangs which I was not expecting.
Oh and my rear offside caliper was sticking which obviously won't help, but this can't be the sole reason for getting really bad mpg?
Clean the maf. Take out the plugs & check their condition. Any codes/pending codes.? Check for exhaust air leaks.
Quote from: Gaz mr-s on September 10, 2024, 00:30Clean the maf. Take out the plugs & check their condition. Any codes/pending codes.? Check for exhaust air leaks.
I'll go through these thanks. I did have an EML come on when it came back from MOT but I had the battery disconnected and it cleared before I could read it.
Quote from: MrChris on September 9, 2024, 22:46Noticed that I'm getting very bad mpg on my 2zz at donington this evening.
I will need to check wiring on the loom etc. But does anyone have any general pointers as to what I can check?
My exhaust has a fairly strong smell coming from it and it pops and bangs which I was not expecting.
Oh and my rear offside caliper was sticking which obviously won't help, but this can't be the sole reason for getting really bad mpg?
Can you please quantify what 'really bad' is?
What's bad in your opinion, may not be bad in another's.
Quote from: Alex Knight on September 10, 2024, 14:37Can you please quantify what 'really bad' is?
What's bad in your opinion, may not be bad in another's.
Good question!
1 tank of fuel - maybe more (went from just under half full to full then back down to quarter/half).
70 regular road miles.
About 15 track miles.
Went out and checked the exhaust and found two very slight leaks from the left two pipes right where the PPE manifold meets the head.
Will be checking coils and plugs when I get a chance. But does anyone think these two tiny leaks can make a big difference to the fuelling? Also, what is the best way to resolve this? Tighten up? Does it need a gasket?
I'd give it a new gasket. But I don't think that will be the major cause of fuel consumption.
I'm thinking leaky injector.
@MrChris said:
Does it need a gasket?
I might have misunderstood your question but a gasket is required between the cylinder head and the manifold.
That being an aftermarket manifold you may have used the gasket supplied with it. From my reading on here these are typically less than optimal and an OE gasket is recommended.
Quote from: Joesson on September 10, 2024, 18:47@MrChris said:
Does it need a gasket?
I might have misunderstood your question but a gasket is required between the cylinder head and the manifold.
That being an aftermarket manifold you may have used the gasket supplied with it. From my reading on here these are typically less than optimal and an OE gasket is recommended.
I didn't do the install, but presumably a standard 1zz gasket would work from what you are saying?
Quote from: Carolyn on September 10, 2024, 18:34I'd give it a new gasket. But I don't think that will be the major cause of fuel consumption.
I'm thinking leaky injector.
Presumably this means they're letting too much fuel in and need replacing?
Quote from: MrChris on September 10, 2024, 18:58Presumably this means they're letting too much fuel in and need replacing?
If it is an injector, it will only be one of them. By pulling the spark plugs you should be able to see which one is running rich, by looking at the tips.
Quote from: MrChris on September 10, 2024, 18:53I didn't do the install, but presumably a standard 1zz gasket would work from what you are saying?
Even more likely that the gasket supplied with the manifold was used then. As said, reportedly less than it could/ should be and could be a contributory factor on the low mpg, but a dodgy injector is more directly related to that problem.
Last sat at blyton in mine. 125 miles just under 40 litres
Quote from: MrChris on September 10, 2024, 14:46Good question!
1 tank of fuel - maybe more (went from just under half full to full then back down to quarter/half).
70 regular road miles.
About 15 track miles.
Do some pure road miles. Too many variables on track.
Do a circa 50 mile motorway run and measure your fuel consumption (60-70mph).
If your value is around 35MPG or more, you don't have a fuel consumption issue.
For reference, when both me and my car were competitive.
In dry conditions - 40 litres (8.8 gallons) would do me about 60-70 knockhill laps (1.26 miles so 75-85 miles) - so I get under 10mpg. That's a mix of maybe 75/25 on hot to cool laps.
My rule for fueling for a race was was 600ml per lap + 4.5 litres (to stop risk of fuel starvation and contingency). Call it 500ml per mile.
My car isnt road legal and is a fully stripped out race car. I'd expect a more road spec car, on more road going tyres to be getting between 10 and 15mpg on track in the dry. Maybe up to 20mpg in the wet.
As Alex says there are a lot of variables but 250-500ml of fuel per track mile would be, in my opinion, normal.
First thing I'd check is all of the spark plugs. They should give a clue to what's happening.
Just pulled a plug and it's pretty slick. Presumably this points to injector replacement or refurb? Appreciate thoughts on this as it's something I've not dealt with yet.
(https://i.ibb.co/HTNPGd5/20240912-163343.jpg) (https://ibb.co/HTNPGd5)
(https://i.ibb.co/5jbvMGx/20240912-163417.jpg) (https://ibb.co/5jbvMGx)
Edit: A quick go on ChatGPT and some Googling seems to indicate this could be either piston rings (not good?) or the valve cover gasket and spark tube seal letting oil in... if so, easy fix. I guess it would be the valve cover gasket as there is no oil on the tip where the spark is made.
Edit Edit: I still need to check my MAF but using stock 1zz airbox on 2zz seems like a bad idea from what I can tell?
The electrode is a perfect colour - so it's not oil in the chamber, i.e. not rings.
Oil on the threads indicates the plug was not properly seated. Oil on the ceramic indicates cam cover gasket.
Spark plug oil seals I would imagine.
One of mine went on my 2ZZ, so I replaced all of them. About £15 each from Toyota.
Quote from: Carolyn on September 10, 2024, 19:11If it is an injector, it will only be one of them. By pulling the spark plugs you should be able to see which one is running rich, by looking at the tips.
Just on the leaky injector side, is it worth getting my injectors refurbished or getting new ones? I'm guessing they're needing
something as they've been in for a while (years).
If all the electrodes on all plugs look like the one in the pics, I'd probably rule out a dodgy injector.
Totally agree with Carolyn, that spark plug looks pretty much perfect. The oil on the thread isn't something I'd be "too" concerned about either.
As a side, in 5yrs within the 2ZZ community, I've seen few reports of injector issues. I don't think that's injector related and I'd even say (going by spark plug) your engine appears fueled correctly. Too much fuel would leave a sooty deposit.
Could this problem be pre-injector?
Could a fuel line be frayed and opening when under pressure/heat? Tank leak? Faulty fuel gauge/sender?
I am 99.9% sure that this is spark plug oil seal. It's fairly obvious from the picture, and the name of the part I think has failed.
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.
Quote from: shnazzle on September 13, 2024, 20:36I 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 don't know about the 1ZZ, but on the 2ZZ then spark plug oil seals are not part of them cam cover gasket. They are a separate part.
Quote from: Alex Knight on September 13, 2024, 22:57I don't know about the 1ZZ, but on the 2ZZ then spark plug oil seals are not part of them cam cover gasket. They are a separate part.
Sorry wrong car haha. It's late
Quote from: shnazzle on September 13, 2024, 20:36I 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.
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.
(https://i.ibb.co/1Q5P9YR/Screenshot-20240915-113711-Torque.jpg) (https://ibb.co/1Q5P9YR)
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
Quote from: shnazzle on September 15, 2024, 12:23Stft -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?
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!
Quote from: MrChris on September 15, 2024, 12:29I 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.
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?
Quote from: MrChris on September 15, 2024, 17:17Nothing 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.
Quote from: shnazzle on September 15, 2024, 17:47Feel 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.
(https://i.ibb.co/ynn8tP5/1726421883254111795474978241832.jpg) (https://ibb.co/ynn8tP5)
Quote from: MrChris on September 15, 2024, 17:17Nothing 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 ©.
Quote from: MrChris on September 15, 2024, 18:38Holy 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.
(https://i.ibb.co/ynn8tP5/1726421883254111795474978241832.jpg) (https://ibb.co/ynn8tP5)
Time for new rubbers and O rings.
@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!
Quote from: MrChris on September 15, 2024, 19:19@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
Quote from: shnazzle on September 15, 2024, 19:23While 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?
I recall one of our members having the kit to do this.
@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..
I had mine done by someone on here...I can't remember who! I'l have a peek
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.
I just checked my O ring stash and I have the correct Viton ones. I'm happy to send you four at no charge.
No worries.
Erm... That's a bit strange. Can you share a pic of this?
Quote from: jvanzyl on September 15, 2024, 20:03No 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
Quote from: Carolyn on September 15, 2024, 20:03I 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.
I have spare injectors you can have fpr nothing
Quote from: KRAMSNEHPETS on September 15, 2024, 20:49I 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.
I love this place.
Corolla 2ZZ ECU over fuels like a pig, mine was doing exactly the same with LTFT at -20. I tried everything from injectors, to intake but nothing worked. In the end I got an Apexi PFC and tune that sorted the over the fueling, car runs like a dream now with AFR's spot on.
It's still special, isn't it?
Quote from: JB21 on September 16, 2024, 08:26Corolla 2ZZ ECU over fuels like a pig, mine was doing exactly the same with LTFT at -20. I tried everything from injectors, to intake but nothing worked. In the end I got an Apexi PFC and tune that sorted the over the fueling, car runs like a dream now with AFR's spot on.
That's interesting but I don't quite understand why the Corolla ECU specifically would cause overfuelling? Also a brief search indicates that getting an Apexi PFC and a tune is not exactly a cost-effective solution..? :-\
Quote from: MrChris on September 15, 2024, 19:55Brilliant 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.
O ring at the top and a thicker rubber 'donut' at the bottom. The bottom one keeps air out and the top one prevents fuel leaks.
Quote from: Carolyn on September 16, 2024, 08:56O ring at the top and a thicker rubber 'donut' at the bottom. The bottom one keeps air out and the top one prevents fuel leaks.
Yeah so that's 2 "seals", but the kits appear to have a third seal per injector, that's the one I'm confused about.
Quote from: MrChris on September 16, 2024, 09:12Yeah so that's 2 "seals", but the kits appear to have a third seal per injector, that's the one I'm confused about.
That's all there are. Two.
I've had a peek on the old interweb.. The other bits aren't seals, they are replacement fittings for each end of the injector. One is a new bottom cap and the other is a replacement filter. I've never messed with either of those.
@JB21 Another one on the ECU side of things... is it possible to use a Celica or other ECU that's not a Corolla ECU?
Quote from: MrChris on September 16, 2024, 10:56@JB21 Another one on the ECU side of things... is it possible to use a Celica or other ECU that's not a Corolla ECU?
I'm sure I heard ages ago that you shouldnt use the Corolla ECU and to use a Celica one when doing the 2ZZ swap so it's definitely possible.
No idea why, just know when Mulaz did his swap using a Corolla engine/car he had to use a Celica ECU.
Quote from: tricky1138 on September 16, 2024, 11:54I'm sure I heard ages ago that you shouldnt use the Corolla ECU and to use a Celica one when doing the 2ZZ swap so it's definitely possible.
No idea why, just know when Mulaz did his swap using a Corolla engine/car he had to use a Celica ECU.
Similarly I recall vaguely that there's a particular Corolla ECU that does work well and has higher lift points etc.
But it wouldn't run the dash so you needed to "piggyback" it on the stock ECU or have the magic box of tricks.
Celica is the easiest
@tricky1138 @shnazzle So I'm working and have limited time to look at this but initial reading suggests that I need a JDM (no OBD2) or US ECU due to issues with the immobiliser or is that not an issue and I can get around it easily? My initial thought was I can just buy the appropriate Celica ECU from this country and as long as the pin-outs are correct on the harness I should be okay?
Quote from: MrChris on September 16, 2024, 12:17@tricky1138 @shnazzle So I'm working and have limited time to look at this but initial reading suggests that I need a JDM (no OBD2) or US ECU due to issues with the immobiliser or is that not an issue and I can get around it easily? My initial thought was I can just buy the appropriate Celica ECU from this country and as long as the pin-outs are correct on the harness I should be okay?
If you don't have an immobiliser currently they yes you'd want the JDM or US.
Also the JDM has the bonus of no post-cat 02 sensor. Makes things easier.
Pinouts I THINK are slightly different on Corolla. So if you have a Corolla ECU now it might not be plug/play.
I'd have to do some digging. I wrote a 2zz conversion guide on here many many moons ago and I think I may have had some ECU/wiring infon in there
Quote from: shnazzle on September 16, 2024, 12:29If you don't have an immobiliser currently they yes you'd want the JDM or US.
Also the JDM has the bonus of no post-cat 02 sensor. Makes things easier.
Pinouts I THINK are slightly different on Corolla. So if you have a Corolla ECU now it might not be plug/play.
I'd have to do some digging. I wrote a 2zz conversion guide on here many many moons ago and I think I may have had some ECU/wiring infon in there
Took an early lunch and actually checked the ECU I have in there. I think it's actually a Celica one: 89666-20150... so that makes life much simpler!!
I've got an exhaust manifold gasket on the way and hopefully the seals from
@Carolyn and potentially injectors from
@KRAMSNEHPETS may see me right... will swap the O2 sensors too just to be sure.
Celica ECU still has an immobiliser but if the car is starting then it must be working.
Usually the key barrel has an immobiliser ring which links to the ECU and the key fob to disable it. On a swap the ring is usually just put somewhere near the key barrel so the key can still read it.
But as I said, if its starting then the immobiliser is working / allowing the car to start.
Hopefully Shnazzle will be along soon with more useful help.
Quote from: tricky1138 on September 16, 2024, 14:21Celica ECU still has an immobiliser but if the car is starting then it must be working.
Usually the key barrel has an immobiliser ring which links to the ECU and the key fob to disable it. On a swap the ring is usually just put somewhere near the key barrel so the key can still read it.
But as I said, if its starting then the immobiliser is working / allowing the car to start.
Hopefully Shnazzle will be along soon with more useful help.
Shnazzle will not. Shnazzle has been out of the game too long LOL
Quote from: tricky1138 on September 16, 2024, 11:54I'm sure I heard ages ago that you shouldnt use the Corolla ECU and to use a Celica one when doing the 2ZZ swap so it's definitely possible.
No idea why, just know when Mulaz did his swap using a Corolla engine/car he had to use a Celica ECU.
Corolla ECU will run the engine, but not the dash. That's the reason.
Best ECU to get is an early Celica 190 (not T-Sport) if you want to retain the immobiliser.
If you're not bothered (I would be) about the immobiliser, go for a JDM Celica ECU.
Posted today. Cost will be a bacon sandwich if you make Blyton park 5th Oct!
Quote from: KRAMSNEHPETS on September 17, 2024, 20:18Posted today. Cost will be a bacon sandwich if you make Blyton park 5th Oct!
If I make it there, how about some tuition (not from me, I'll pay for a session ;D )?
Edit: Bugger it's sold out :( Might get on the 9th November. Will fix the 2 first!
Popped out this morning to see if I could get the exhaust manifold gasket installed and almost got there. I stopped because looking at the picture attached, I'm sure there should be 2 studs and not one. I.e. one on the right and one on the left. If this is right I need to order one before continuing, would anyone know the specs and torque values for these? Thanks.
Edit: found this https://www.eliseparts.com/shop/exhaust-system-1/toyota-2zz-manifold-stud-and-nut/
Edit 2: I'm getting ahead of myself this morning by posting this. Forgot I had a repair manual in the paperwork I got with the car which was packed well away... anyway, found a diagram that answers my question that there should indeed be two nuts with studs, so I will order up two new sets just in case the existing one is stretched (though unlikely)...
(https://i.ibb.co/5Lvcv53/20240918-090246.jpg) (https://ibb.co/5Lvcv53)
(https://i.ibb.co/6n65bJ6/20240918-092758.png) (https://ibb.co/6n65bJ6)
@Carolyn and
@KRAMSNEHPETS O-rings and injectors have arrived today. Again, thank you very much for helping me out. I've got a wedding to go to over the weekend but hoping I get some time after to install and will provide an update here. Hopefully with the new gasket and studs for the exhaust manifold, the items you've provided and an ECU reset I should be back to normal.
Just for reference. Mallory Park today in my 2ZZ, 104 laps. 126 miles , 49 litres just under 12 MPG!!