diesel rattle in D4D Prado

[SWR Banned Find all posts View Profile Close SWR]

Gday Shifter
I believe the answer you are looking for is "How does the ECU know the injector values!).
I will give basic description to the best of my knowledge as too many other sensors in the big picture involved.
When the injector is assembled (wether it be of solenoid or piezo--piezo responds 4-5 times faster than solenoid) they are flow/crack tested (Crack being at the point it opens) and then given a 16 digit calibration (Compensation) code. Impossible for two of the same injectors to give same flow/crack-point hence the compensation code!
The code is so that the ECU knows exactly how much fuel all cylinders are getting and to give accurately and can compensate accordingly.
Now all the above is sorted in a basic manner you can now go one step further!
The ECU measures the resistance feed back from the injector (Combustion/compression load pushing on the injector Vs resistance feed-back on the tip... Not forgetting crank angle and RPM etc.) which will influence the resistance feed-back to the ECU when the injector is energised... This in turn gives the ECU the capability to compensate more or less fuel to each single cylinder to keep the engine running smooth and evenly.
If one cylinder drops in power (for what ever reason) the ECU will make the next in line cylinder work harder by putting in more fuel (If cyl 1 drops cyl 3 will get more fuel) Firing order 1-3-4-2.
If an injector was to start abnormal wear and tear this would show up in the feed back resistance based on the 16 diget calibration code and known fuel rail pressure which is read from the fuel rail sensor switch! Switch is also a fine calibrated resistance feed back. (ECU has incredible call-up maps with equations of variables).
The fuel rail sensor not only tells the ECU its line pressure but inturn the ECU then controls the electronic fuel rail pressure relief valve.
As you can imagine! If rail pressures are changed so is the calibration of fuel to the injectors.
If fuel line pressure is too high or too low The ECU would know this under normal circumstances (No shim fitted to the fuel relief valve and no corrigulation of the fuel sensor switch) and fault codes or limp mode would follow if mapped parameters are not met!....... I would call this a "Safety" feature!
When the injectors are manufactured they are manufactured to work within certain fuel pressure tolerances.
Cheers

[Shifter Junior Member Find all posts View Profile Close Shifter]

Skywalkerrun,

Thank you for the detailed response. I understand now. Certainly a little different from my day when we had slow speed oil engines built by Doxfords, opposed pistons, with a comman rail system built in 1946 up to about the late 70's. All mechanical of course.
Thank you again, most informative. I am continually astonished what electronics can achieve.

[Bushbasher Out of control poster! Find all posts View Profile Close Bushbasher]

Gday Shifter
I believe the answer you are looking for is "How does the ECU know the injector values!).
I will give basic description to the best of my knowledge as too many other sensors in the big picture involved.
When the injector is assembled (wether it be of solenoid or piezo--piezo responds 4-5 times faster than solenoid) they are flow/crack tested (Crack being at the point it opens) and then given a 16 digit calibration (Compensation) code. Impossible for two of the same injectors to give same flow/crack-point hence the compensation code!
The code is so that the ECU knows exactly how much fuel all cylinders are getting and to give accurately and can compensate accordingly.
Now all the above is sorted in a basic manner you can now go one step further!
The ECU measures the resistance feed back from the injector (Combustion/compression load pushing on the injector Vs resistance feed-back on the tip... Not forgetting crank angle and RPM etc.) which will influence the resistance feed-back to the ECU when the injector is energised... This in turn gives the ECU the capability to compensate more or less fuel to each single cylinder to keep the engine running smooth and evenly.
If one cylinder drops in power (for what ever reason) the ECU will make the next in line cylinder work harder by putting in more fuel (If cyl 1 drops cyl 3 will get more fuel) Firing order 1-3-4-2.
If an injector was to start abnormal wear and tear this would show up in the feed back resistance based on the 16 diget calibration code and known fuel rail pressure which is read from the fuel rail sensor switch! Switch is also a fine calibrated resistance feed back. (ECU has incredible call-up maps with equations of variables).
The fuel rail sensor not only tells the ECU its line pressure but inturn the ECU then controls the electronic fuel rail pressure relief valve.
As you can imagine! If rail pressures are changed so is the calibration of fuel to the injectors.
If fuel line pressure is too high or too low The ECU would know this under normal circumstances (No shim fitted to the fuel relief valve and no corrigulation of the fuel sensor switch) and fault codes or limp mode would follow if mapped parameters are not met!....... I would call this a "Safety" feature!
When the injectors are manufactured they are manufactured to work within certain fuel pressure tolerances.
Cheers

If, as you say, one cylinder drops power for whatever reason then the ECU increases power to the next cylinder, then the obvious conclusion (according to your reasoning) is that it will send more fuel - in some cases too much fuel - to the next cylinder or cylinders. However, I am not aware of any sensor attached to the engine which can read individual cylinder power output. The 4 cyclinder engine is designed to run on 4 cylinders, not three, not two. Have you ever driven a 4 cylinder car that has dropped combustion in one pot? It shakes like a wet dog. Drop 2 and it most normally won't run at all.
As you say correctly, fuel delivery is based on load which is a combination of throttle position, vehicle speed, engine speed (RPM) and gearing (assuming a warm engine). Based on these inputs the computer then calculates the injector cycles applicable to each cylinder based on timing cycle. If, we lose an injector, you are asking the other 3 to carry more of the load. Where's the safety system for the engine to recognize that one is down? If we put a crack/hole in a piston the computer will still send fuel to that cylinder, and based on load, will send more fuel to ALL cylinders because we are now down in power and your right foot is demanding more. Unless you are very aware and observant and recognize that something isn't right. The computer isn't going to help you here. At some point the engine may stall because it can't handle losing one or two cylinders, remember it only has 4 and has no fall back or ability to operate properly on anything less than 4. (It isn't a hemi V8). If the computer was able to recognize a combustion problem in one or more cylinders then why doesn't it act promptly and either (a) shut the engine down or (b) go into a limp home mode to save us from that catstrophic damage? This would have saved me from 8 weeks of grief.

[tdprado Junior Member Find all posts View Profile Close tdprado]

Last year I purchased a Toyota Intelligent Tester II like the Toyota workshops use to keep an eye on my injectors that were becoming noisy. After following various threads on noisy injectors, and not having a very good experience with Toyota service departments, I decided I would need this tool to program the new injector codes at some stage, also to check that the codes in there now were correct. I also have a Corolla so the tool can be used on that car as well if ever required. Haven't changed the injectors as yet, as I have been doing some extended tests. I am a service engineer and fix electronic things for a living the last 30 years.

The Toyota Intelligent Tester readings for the injector feedback volume are in mm3 (mm cubed) and should be between +/-3.0 mm3 when idling.

Initially I had one injector that read +5.0 on number 4 cylinder - engine very noisy at the time.
Yesterday - number 4 cylinder read +0.4 - engine nice and relatively quiet.

I have been doing some experimenting with running injector cleaner in the vehicle and going for a run on the highway up the coast to a mates place - a 5 hour round trip with an overnight stay and a bottle of rum

After doing this procedure, my injectors run quiet for several weeks. My initial thoughts are that the injector seals have indeed failed as a minimum, they would be the original copper ones, and running the injector cleaner is temporarilly cleaning up a bit of the mess.

I have had all the parts to do this job sitting around for six months, but do not want to do all this work and put the original injectors back in at this time. The vehicle has done 110,000km, oil changes every 10,000km, sump screen looked fine at last oil change. I intend cleaning up the EGR buildup at the same time so this will take me several days as I am pedantic to the extreme.

Will post some further results some time in the future for those interested.

Re intercoolers - I have had a 90 series diesel, a 120 series with the 90 series diesel engine, and now the 120 series with D4D engine. Looked at the 150 diesel but didn't like them as much as my 120. Plus an absolutely horrendous experience with the Toyota Sales team which is another story.
Bullbars were always a nightmare when I got my first 120 in 2003, I purchased this vehicle the first week they came out. This was because when you opened the bonnet, the grill lifts up as well. The grill contains the vents that run the air through the twin skinned bonnet and through the intercooler above the engine, anytime the car is moving forward. This style of setup limited the style of bullbar that could be fitted as it had to sit so far forward to avoid the grill when opening the bonnet.
The 150 Prado's grill stays in place when the bonnet is lifted, meaning the bullbar does not have to protrude as far out. This would have made it difficult to align the vents in the grill with a dual skinned bonnet like in the 120, and hence I concluded that that is why they relocated the intercooler. Not for any other reason.
I prefer the 120 series intercooler setup, as anytime the vehicle is moving forward, there is usually cooler air from outside of the engine bay moving over the intercooler.
These are my thought in any case.

[SWR Banned Find all posts View Profile Close SWR]

Gday tdprado
Welcome aboard to prado point!... Enjoy!!
@ Bushbasher
QUOTE Bushbasher: I am not aware of any sensor attached to the engine which can read individual cylinder power output.
_______
ANSWER skywalkerrun: If you read through the thread again you mite understand it a bit better! (You "Bushbasher" did say that you do understand the closed loop fuel system?) The engine can compensate fuel distribution?... The ECU has a capability of self learning!... hence the 2,000km drive for the engine to settle into its new calibrated mapped perimeters when new parts or re-mapped programmes from OEM (Toyota).
_______
The fuel injector "IF" shown on an Oscilloscope has three wave forms. "One" is switched positive, "Two" is switched negative and the other is that ever revealing current draw at which the ECU looks at and dependant on RPM/crank angle/fuel temp/fuel pressure/engine load etc, etc will call up particular "call up maps" and adjusts the pulse width/duration accordingly and this is then decided by the ECU based on sensor feed-back from the numerous engine components. (All of this goes out the window if sensors of any sort are manipulated or malfunction).... No longer corresponding ECU maps and false sensor reading feed back that the ECU can no longer work with or may no longer know about?.. An error code may follow and be stored in the ECU!..... "If" a really bad conflict with the engine management was to happen then a check engine light or limp mode will be forced!
_______
EG: The ECU knows the exact calibration of the fuel injectors (16 digit code-Maybe more?) it also knows sensor feed back signals from all four injectors and if one cylinder drops in power the voltage feed-back resistance will change on "That" injector (compression/combustion pressure/fouling of the tip/abnormal wear Vs fuel pressure will affect resistance on the injector when it is energised) and the ECU will see this and try to balance it out in what ever way it is mapped in order to keep the engine running smoothly..... I personally did not map the ECU so you need to ask the person who did but that is the basics of it!.... I also did not Design/ Manufacture or Build the engine either?
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QUOTE Bushbasher: The 4 cylinder engine is designed to run on 4 cylinders, not three, not two. Have you ever driven a 4 cylinder car that has dropped combustion in one pot?
_______
ANSWER skywalkerrun: I have driven Trucks/cars (Petrol & diesel 4cyl-6cyl-8cyl & V12) when cylinders have dropped and even completely re-built them!... But I did not design the electronics or engine management!
_______
Hope this makes things a bit clearer for you to understand.... If not grab book as i am not a TAFE teacher!! Lol
_______
I can't explain your dilemma with your engine for which i do feel your pain but i have read the past threads that you have been in and they are a tad contradictive?... Especially when looking at times and dates and i wasn't the only one who picked up on it so i would prefer to let that one go to sleep.Cheers

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

Given my experience and I guess that of others like Bushy I would be insisting that Toyota read the feedback values when the car is left cold for the valve clearance check at the 40k and 80k services. If your warranty is running out ahead of that then I would be getting it checked before time. Same situation for extended warranty.

I was really of the opinion that any changes would be noticeable and that you would be able to note the change and say hey my engine isn't running as well as it should be, better get it checked but actually it is a finer line than that.

I don't know what Toyotas view of the extra fuel filter or catch can is but it would be interesting to know if that would somehow give them an out from warranty.

[pjorek Advanced Member Find all posts View Profile Close pjorek]

i guess 2nd fuel filters, catch cans etc are all good idea but one thing that we need to remember is extra piping, clamps, fittings etc also means possibly more reliability issues/more spares to carry when in the bush.

so all good but there is a down side to it as well

[Bushbasher Out of control poster! Find all posts View Profile Close Bushbasher]

Alright, I get it. The injectors are very clever and quite complicated (at $1150 a piece they'd want to be) but are linked to a not so smart computer that doesn't always know what's happening under the bonnet! And my fuel rail pressure has never been modified.

[AJ120 Out of control poster! Find all posts View Profile Close AJ120]

Last year I purchased a Toyota Intelligent Tester II like the Toyota workshops use to keep an eye on my injectors that were becoming noisy.

Interesting post, could you tell us more about the tester, like what it cost and how hard it is to use? If it was cheap and easy it would be a bloody handy tool, but I suspect its neither.

Cheers Andrew

[Bushbasher Out of control poster! Find all posts View Profile Close Bushbasher]

You can get one from as low as US$260 from tool company in China or pay $450 for a touch screen version or pay $1500 for a really fancy one. Just google Toyota Intelligent Tester. I'm looking to buy one myself.

[tdprado Junior Member Find all posts View Profile Close tdprado]

Interesting post, could you tell us more about the tester, like what it cost and how hard it is to use? If it was cheap and easy it would be a bloody handy tool, but I suspect its neither.

Cheers Andrew

Hi Andrew,

Purchased from here, was $520 when I purchased it: http://www.eobd2.com/wholesale/toyot...th-suzuki.html

Touch screen, easy to use, plugs into the comms port under the dash, very handy tool. Reads all sort of data for engine, gearbox, fault codes, reprogram injectors and spare keys, etc.

Stephen

[AJ120 Out of control poster! Find all posts View Profile Close AJ120]

Thanks for that Stephen, seems like a pretty comprehensive little kit. $330us and I guess shipping on top of that makes it a reasonable price for the peace of mind of being able to check injector values on a regular basis.

I can see them getting a bit of business, you might need to hit them up for a commission

Cheers Andrew

[tdprado Junior Member Find all posts View Profile Close tdprado]

Thanks for that Stephen, seems like a pretty comprehensive little kit. $330us and I guess shipping on top of that makes it a reasonable price for the peace of mind of being able to check injector values on a regular basis.

I can see them getting a bit of business, you might need to hit them up for a commission

Cheers Andrew

Yes, it does give some peace of mind that's for sure. At that price, it is definitely a bargain in my opinion.

[Steve-Kylie 120 Junior Member Find all posts View Profile Close Steve-Kylie 120]

Hi Andrew,

Purchased from here, was $520 when I purchased it: http://www.eobd2.com/wholesale/toyot...th-suzuki.html

Touch screen, easy to use, plugs into the comms port under the dash, very handy tool. Reads all sort of data for engine, gearbox, fault codes, reprogram injectors and spare keys, etc.

Stephen

Before i clear the moths out of my wallet and find $400 could you be as so kind as to give us all a brief run down on what you do with the device.

Reason i ask is the way the add has worded something

Notice:
There is no memory card in this device. please dont insert the memory card ,also dont insert two card at the same time when you using this item,please pay attentions,because the memory card will slow down the running speed of the device.

Im guessing instruction come with the device, im not very IT savy so alot of this stuff comes in 1 ear and out the other.

[Graceilyons64 Lurker Find all posts View Profile Close Graceilyons64]

Hi Andrew,

I want to just add to your statement - I'm quoting you below

If you want to work out statistically then you need a large sample group, so lets look at PP as a large group of D4D owners. OK now how many on this forum have had issues costing over 10 grand, a few, not sure how many but a few. OK now statistics need to have anomolies removed, so anyone who joined the forum because they had a major injector issue, such as Sharon needs to be ignored, the reason they need to be ignored is because there are a number of other "Sharons" out there that have not joined because they have not had an issue, hope that makes sense.


Andrew - you cant make a statement basing statistic on the PP Forum. You are missing a wider group of people who havnt found PP, for one reason or another. Up until I had my problem I didnt know PP existed. My reasons below:

Since I have had this problem
I have spoken to many people, and quite surprisingly the response is "I know someone who has had the same problem or that's happened to me". The cost to those people ranging from 50/50 split with Toyota or owners having to pay over the $10,000 baseline; whether they are in warranty or out of warranty. Those few lucky ones who have been able to catch the problem before the injectors have blown through the cylinder- have had a cost of $4,000 + labour for replacing all 4 injectors or 8 (which ever Toyota Vehicle you have). Other people who are mechanically minded have repaired the vehicle with their own skills (cost of parts + their own time = how much did it cost them all up?). The point is Andrew - there are alot of people out there who have the problem, but get sucked into Toyota's Australias spiel on FUEL problem. Toyota owners either - fix the car without getting a second opinion, dont question Toyota (because they trust them) Or they get sick an tired of fighting Toyota that they give up a pay for the repairs themselves!

I'm being brutaly honest here, and no disrespect to members on PP - but you guys are a minority who take 4x4 driving seriously. Most of the general population have other interests. My Toyota was brought for me to use on my property, to tow my horse float, to use for camping. I reckon I've used my 4 x 4 wheel drive half a dozen times in 3 years.

What you also have to keep in mind is there are alot of people, like me who are not mechanically minded. But who take care & pride in owning a Toyota, we save up or take out loans to buy one . We have them regulary serviced, we take out insurance to protect them. But that's the extent.



Here's some statistics - a Company who employees 10 people - out of those 10 people, 2 people had injector failure. One was stuck up in Darwin (Car was still under warranty) he fought Toyota for 9 months, gave up and paid to get his engine rebuilt. The second person had a hilux, out of warranty 120K, Toyota blamed it on fuel + wear and tear etc.... in the end that cost him $8,500, plus he had to hire another vehicle to get him to and from work, Toyota met him half way with that costs. So in total 2 x $8,500 = $17,000.


My other point Andrew is - there is a manufacturing problem with the injectors. So as a [B]Consumer[B]dont we have the right to know? Talktotheroos statistics - are derived on how many vehicles he has had to repair. So if he's had 32 vehicles and 3 have been over $10 grand = 3/32 x 100 = 9.375% (rounded 10%). If you base his statistics on just the 32 cars been through his work shop with injector failure = 100% , I think you need to disregard the cost. Because it's the injector failure as a whole that needs to be accounted for, don't you think?

DOESNT IT MATTER THAT ONE PERSON has had this problem? Isnt it the responsibility of Toyota Australia to make it right????

I agree, there needs to be accurate statistics on documenting every case, but it should be categorised or identified per mechanical failure. Because regardless of cost - the fault should be fixed free of charge by Toyota.