SOLVED! Post 2853 Leaking Injectors, Dealer Techs Rock! Extended Cranking after Engine Swap 3.4L 5vz

Spring break is around the corner, so don't go putting up your pen and paper yet Jen!

 

The newer, very expensive engine management systems have individual sensors per cylinder Jen.

With our "Oem 1st gen dumb Ecu" stuff, it's just the two or one sensors, however one sees the sampling taken, for a combined overall reading of the gasses exiting the motor.

The "smarter ecu's" that a person could graft into out trucks are big dollars and it's a more aftermarket setup where money is really not a problem. The box alone is just over 1/2(or more) of what you spent for your engine rebuild. Then you add on sensors and gizmo's and wiring and stuff and then get it tuned right. Cubic $$$$.

For example, it could sense your misfire and shut that cylinder down, voiding the spark and fuel delivery, to avoid meltdown or further destruction of that cylinder. A nurse for every cylinder, in other terms.

AS an example,,Ecoboost comes to mind as one of the more spendy modern systems that are a lot smarter than our stuff. The Ford engine management gig that kills 4 cylinders(v8) when not needed,,then kicks them on when the load dictates. For fuel economy basically. Don't start cheering just yet,,they are having some sensor issues with those as well, and oil pressure sensing problems.

Lots of interesting reading out there on the subject,,if you so choose.

 

Thanks Mod! Very informative post! I particularly like your analogy about "a nurse for every cylinder" - you guys know how I love the down to earth analogies - makes the learning process way more fun and also way easier to understand the concepts.

But there's just one thing you're wrong about - its not an ECU, it's a Mr. Brain Dude!

Hmm, so if ECU is Mr. Brain Dude, what are all the sensor's titles? That will be today's assignment - homework due by midnight tonight guys, GO!

 

The thinkin box,,and all it's minion's.

Problem solved,,no pop quiz.

 

Whoa. Just found this article (with excerpt that interested me most copied below link) on the Innovate AFR gauge website, which is the manufacturer of the gauge we have. Don't totally understand everything this article is saying, but some of the points sure sound like they could be related to what's going on with our truck......

http://www.innovatemotorsports.com/resources/electrical-grounding.php

Electronic fuel injection and ignition systems have their own caveats though. Ignition systems create very high current pulses for a very short time. This is especially true for Capacitive Discharge Systems. Those need their own ground wire to the common. EFI systems rely on different sensors in the car. Throttle position sensor, Intake and coolant air temp sensors, Manifold pressure sensors and so on. These sensors typically have 2 or 3 wires. When they have 2 wires, one is typically the signal and the other ground. 3 wire sensors need a 5V supply, signal and ground. DO NOT connect the ground of these sensors to the common ground as described above. The EFI computer, as any electrical device can only see its own ground and references all measurements to that. The EFI computer also switches the injectors on and off. Injectors use relatively high currents, and these currents have to flow back to the battery through the EFI computer’s ground wire. This causes a voltage drop on that ground wire. Were the sensors grounded to the common ground as described above, the ECU would see only the sensor voltage minus the voltage drop of its ground. Instead ground the sensors directly at the EFI computer to its ground. Sensors only take a few mA of current anyway, so the additional drop on the EFI ground caused by them is irrelevant.
Another issue arises with sensors that create a very small signal, like thermocouples for EGT and cyl.-head temperature measurements. In an engine compartment a lot of current pulses from ignition and injection systems flow around. Any electrical current also creates a magnetic field. The two wires from the sensor (signal and ground) create a loop, which acts as antenna to pick up these magnetic fields. To avoid that, either use shielded wire or simply twist the wires together. Each twist creates a smaller loop, which picks up less of that noise, but also adjacent loops pick up a signal that’s inverted from the loop before. This way the induced noise voltages in each loop cancel each other.
Audio systems in cars also need to be connected to this ‘star’ ground. The human ear is the most sensitive organ we have. The difference between the loudest noise (pain threshhold) and the quietest noise we can hear is over 1 million to one. So any electrical noise from inadequate grounding can be amplified by the audio system to hearing level.
Now to the claims of some of the grounding systems regarding 10 times better impedance. We talked about resistance of the wires before. Resistance applies to steady-state current (DC). Steel has about 10 times the specific resistance of copper. So the material must have 10 times the square area of copper to achieve the same resistance. This is not a problem when using the frame as ground.
The material with the lowest resistance known is silver. Followed by copper (a few % higher) High frequency currents (and pulses contain high frequencies) make the wire behave differently. High frequency resistance is called impedance and depends on the frequency of the current. Very high frequency currents tend to flow not evenly in the whole cross-section of the wire, but only on the surface. Therefore multi-stranded wire creates more surface area for the high frequency currents to flow, hence lower impedance. But this effect is only important for VERY high frequencies in the upper radio frequency range. If the electrical system in your car produces high currents with frequencies that high, your car would shut down TV and radio reception for miles around. Frequencies that high are just not normally encountered in a car. The advantage of multi-stranded wire in a car is flexibility and vibration resistance.
As to claims of better performance and lower fuel consumption: The EFI systems injects fuel according to the amount of air drawn into the engine, measured with it’s sensors. More performance can only be had if more air/fuel enters the engine. No electrical system can increase the air-flow, so no more fuel flow either. The only effect a better grounding system can have is if the sensor grounding was so bad before that the EFI computer misread the sensors due to ground offsets. This can be inexpensively remedied by following the grounding guidelines above. Some of the better EFI computers utilize ‘differential’ inputs. They measure both, the signal and the ground of the sensor itself and calculate the difference. This way they become independent of any grounding issues.
As to ignition system grounds, one of the performance parameters in an engine is ignition timing. Timing is derived from sensors on the flywheel or crank. These sensors create reference pulses. A pulse can either be there or not. If not, the car stops. No additional grounding changes that. As to the ignition system itself: as long as there is enough spark energy to light the fire, the engine runs. More ignition energy does NOT increase power, just spark-plug wear. Corresondingly, if the ignition system is adequately grounded no amount of additional grounding will do any good.

In wiring the electrical system in a car the best way is to run separate ground wires from each system to a common ground point. The common ground point should NOT be just a bolt where lugs from each device are stacked in top of each other. The contact patches between the lugs create their own resistance and ground problems. The very best way is to bolt a short piece of copper bar near the battery to the frame. Connect the copper bar to the battery with a heavy duty ground strap. Drill and tap the bar for each ground return. The heaviest current user in a car is the starter. It can take up to 800 Amps of current. So it should have its own ground strap directly to the battery. So should the alternator. Its wires carry the second most current after the starter.

That bolded audio section - I thought maybe I was asking a dumb question yesterday when Mod mentioned electrical noise and I replied that we hear our CD spin now, whereas we didn't before, and asked if that was what he meant. Now after reading this, I'm thinking maybe that wasn't a dumb question...........

 

Hey Jen, I've been following along like most of TW since this saga began... although I'm not as smart or skilled as those who have been trying to help, I did notice something that might explain what is going on. I was installing my fancy new UltraGuage Mx and reading the literature (surprised?) and they taked about changing the sample rate and said don't crank it up too much, because the guage gets it signal through the same buss that handles the ECU and there is only so much bandwidth available. they set it at once a second. Think of it as a traffic jam and not everyone gets where they need to go on time. So, if your gauge is sampling too often, it would definately affect ECU controlled functions, like starting and running. The sample rate can be adjusted by the user on most of these guages. Good luck and keep plugging away.

 

Thank you! After reading your post, I looked all over the Innovate website (the manufacturer of our AFR gauge) and couldn't find anything about changing the sample rate. If you know of somewhere I can read about what you're mentioning, I'd love to read more about this!

Also, what did you mean in the part I bolded above? What's a "buss"?

Thanks for the info, and thanks for the good luck wishes!!

 

"buss" is basically an electrical highway, with two way traffic...

 

Good bit of informative info there. Toyota and many others (BMW, Mercedes, Cadillac, etc) have actually gone to the smart cylinder for a while on several vehicles. For instance on my 2002 RAV4, if there is a misfire present on cylinder #2 for longer than a predetermined time frame, the computer will actually shut down the entire cylinder for the remainder of the drive cycle.

 

Uh oh, I had a feeling it was something complex like that. That stuff is super confusing to me........

Thanks for the explanation hetkind. Cheers to good whiskey!

 

Whoah, wait a second, there are two things here.

Most likely your AFR gauge is NOT tied into the ECU or vehicle communication bus. It is a sensor tied directly to the display gauge, with only power coming from the vehicle (power and signal/bus wires are different). The only issue would be if they wired some kind of OUTPUT from the system into your vehicle's ECU. Not very likely, but possible. And in that case it would not be reading anything FROM the bus, it would be putting a sensor value ON the bus for the ECU to pick up and do its thing with.

Your ScanGauge is what you need to check for sample rate (similar to an UltraGauge). It connects to the vehicle bus in order to display the information that is flying through the wires and ECU. I have one in my '12, and I have not messed with the sample rate, and it has no detrimental effects, but the bus on a '98 may be slower (think of how computers have changed since '98) and more susceptible to the gauge's sample rate.

 

Ah, I see. Sort of. All this electrical stuff is still new to me, so until I reread your post more slowly, I'm a bit confused. And headed to the store right now - dropped hubby at work so I could have a car today. But, as far as Scan Gauge goes, I very seriously doubt it plays any part whatsoever, because we had the excessive crank issue immediately after the engine/AFR gauge. We didn't add the SG til ~2-3 weeks later - can't remember the exact date, but I know it's on the thread somewhere! Anyway, there was no change with the addition of it, for better or worse, so I'm thinking it's not doing a thing. But that AFR gauge is - that I am certain of.

Called our angel mechanic this morning. He's wrapping things up in Florida - he said his brother (who passed away) and his brother's wife were married for 48 years!! Wow. That is so super sad. She must really be freaking out. I would be. Anyway, it sounds like he's going to try to get back here this weekend. Hurray!

 

Bummer. 1/2 century mark,,that's some time put in together.

He just might want to dive right in asap. Good therapy sometimes.

 

Really??
We had a 01 rav4 that lost a coil, wife decided to drive it home that way and it ended up eating the cat conv. I figured it was because it was dumping fuel in the cylinder.
Damn thing also popped a head gasket at 100k, took it apart and found two of the back head bolt holes were stripped out. Then tried to remove one of the other head bolts and stripped the head off having to drill it out... Royal pita.... Ended up having to drill, tap and install inserts in all 10 bolt holes.... Took me 20+ hours just to get the holes done.... Not including time for tear down and reassembly... Had enough aluminum chips when I was done to fill up a kids sand bucket.. Cured me of ever thinking about buying another 1az or 2az powered toyota.

 

A friend picked up a really beat down 2006 Rav4 about 3 years ago. Best $500 he has spent,,so he says. All it needed was a alternator. No room in there behind the wheel for me,,not gonna happen. Easily drive with my knees,,lol.

 

01-05 were plagued with transmission problems as well as the head bolts pulling out of the block
06 weren't bad, that's the year they actually corrected the problem with the head bolts.
around here you cant touch an 06 or up for less than 9 grand

 

Anybody have thoughts about this? It's an article about the do's and don'ts of grounding from the Innovate website, which is the manufacturer of our AFR gauge.

http://www.innovatemotorsports.com/resources/electrical-grounding.php

You’re Grounded Young Man

From March '04 issue of TPR magazine, by Klaus Almendinger

Recently a spate of new products have come to market that improve ‘grounding’ in cars. Sometimes the claims of what these products do are fairly broad. The usual claims of horsepower improvements and lowering fuel consumption are pretty standard for all automotive aftermarket products, including seat-covers, floor-mats and cup-holders.

Let’s look at the issue these products try to adress. Every electrical system in the car (excl. alternator) uses electrical power. Electrical power is defined as voltage (the ‘pressure’ in the line) times current (the flow volume of electrons in electrons/second). Electricity flows from the plus side of the battery through the device back to the negative side of the battery. The negative side of the battery is also connected to the chassis or frame. This is called ‘ground’. In a lot of cars the negative side of a device is connected just to the nearest hunk of metal in contact with the frame. This can cause problems under some circumstances. Here’s why:

Ever been under a nice hot shower while somebody else in the house flushes a toilet? The nice warm water stream suddenly changes to scalding hot? The reason for that is easily explained and the same principle applies to grounding issues. When water flows through a pipe there is a certain pressure loss along the pipe. The pipe creates a resistance to the water flow. The smaller the pipe, the larger the resistance. This resistance lowers the pressure at the end of the pipe (shower head) from the original pressure where the water main enters the house. If another outlet on the same water pipe also uses water, the flow in the pipe to both increases and more pressure loss results. So now your nice balance of hot and cold water is upset because less pressure is available on the cold water side of the shower valve.

In electrical systems it works the same way. Anything that conducts electricity has a certain resistance to the electrical flow. The electrical flow is measured in Amperes (A) or Amps. 1/1000th of an Ampere is a milliAmp (mA). In electrical formulas the symbol for current is I. The electrical pressure (equivalent to water pressure in a plumbing system) is measured in Volts (V). Resistance is measured in Ohms (formula symbol R) The bigger the resistance of a supply wire, the more voltage builds up along that wire (V = R*I). But because there is only a fixed supply voltage available from the battery, the resulting voltage available for the electrical device is less. Bigger wires have lower resistance and therefore lower losses.

If multiple devices share the same electrical return path (for example the frame), the currents of all the devices add up on the way to the battery and there is less voltage available for each, depending on the total current between the ground point and the battery.

Returning to our plumbing example above: If we would run a separate pipe from the water main to each water faucet in the house, there would be no scalding in the shower because the pressure losses from any faucet would only affect that faucet. Of course the other solution would be to run 3” pipes all through the house to minimize pressure losses. This of course would be much more expensive than running only pipes as necessary. It also only minimizes the shared loss effect, but does not eliminate it, like separate pipes would. The grounding systems on the market are the equivalent to that 3” pipe.

In wiring the electrical system in a car the best way is to run separate ground wires from each system to a common ground point. The common ground point should NOT be just a bolt where lugs from each device are stacked in top of each other. The contact patches between the lugs create their own resistance and ground problems. The very best way is to bolt a short piece of copper bar near the battery to the frame. Connect the copper bar to the battery with a heavy duty ground strap. Drill and tap the bar for each ground return. The heaviest current user in a car is the starter. It can take up to 800 Amps of current. So it should have its own ground strap directly to the battery. So should the alternator. Its wires carry the second most current after the starter.

Electronic fuel injection and ignition systems have their own caveats though. Ignition systems create very high current pulses for a very short time. This is especially true for Capacitive Discharge Systems. Those need their own ground wire to the common. EFI systems rely on different sensors in the car. Throttle position sensor, Intake and coolant air temp sensors, Manifold pressure sensors and so on. These sensors typically have 2 or 3 wires. When they have 2 wires, one is typically the signal and the other ground. 3 wire sensors need a 5V supply, signal and ground. DO NOT connect the ground of these sensors to the common ground as described above. The EFI computer, as any electrical device can only see its own ground and references all measurements to that. The EFI computer also switches the injectors on and off. Injectors use relatively high currents, and these currents have to flow back to the battery through the EFI computer’s ground wire. This causes a voltage drop on that ground wire. Were the sensors grounded to the common ground as described above, the ECU would see only the sensor voltage minus the voltage drop of its ground. Instead ground the sensors directly at the EFI computer to its ground. Sensors only take a few mA of current anyway, so the additional drop on the EFI ground caused by them is irrelevant.

Another issue arises with sensors that create a very small signal, like thermocouples for EGT and cyl.-head temperature measurements. In an engine compartment a lot of current pulses from ignition and injection systems flow around. Any electrical current also creates a magnetic field. The two wires from the sensor (signal and ground) create a loop, which acts as antenna to pick up these magnetic fields. To avoid that, either use shielded wire or simply twist the wires together. Each twist creates a smaller loop, which picks up less of that noise, but also adjacent loops pick up a signal that’s inverted from the loop before. This way the induced noise voltages in each loop cancel each other.

Audio systems in cars also need to be connected to this ‘star’ ground. The human ear is the most sensitive organ we have. The difference between the loudest noise (pain threshhold) and the quietest noise we can hear is over 1 million to one. So any electrical noise from inadequate grounding can be amplified by the audio system to hearing level.

Now to the claims of some of the grounding systems regarding 10 times better impedance. We talked about resistance of the wires before. Resistance applies to steady-state current (DC). Steel has about 10 times the specific resistance of copper. So the material must have 10 times the square area of copper to achieve the same resistance. This is not a problem when using the frame as ground.

The material with the lowest resistance known is silver. Followed by copper (a few % higher) High frequency currents (and pulses contain high frequencies) make the wire behave differently. High frequency resistance is called impedance and depends on the frequency of the current. Very high frequency currents tend to flow not evenly in the whole cross-section of the wire, but only on the surface. Therefore multi-stranded wire creates more surface area for the high frequency currents to flow, hence lower impedance. But this effect is only important for VERY high frequencies in the upper radio frequency range. If the electrical system in your car produces high currents with frequencies that high, your car would shut down TV and radio reception for miles around. Frequencies that high are just not normally encountered in a car. The advantage of multi-stranded wire in a car is flexibility and vibration resistance.

As to claims of better performance and lower fuel consumption: The EFI systems injects fuel according to the amount of air drawn into the engine, measured with it’s sensors. More performance can only be had if more air/fuel enters the engine. No electrical system can increase the air-flow, so no more fuel flow either. The only effect a better grounding system can have is if the sensor grounding was so bad before that the EFI computer misread the sensors due to ground offsets. This can be inexpensively remedied by following the grounding guidelines above. Some of the better EFI computers utilize ‘differential’ inputs. They measure both, the signal and the ground of the sensor itself and calculate the difference. This way they become independent of any grounding issues.

As to ignition system grounds, one of the performance parameters in an engine is ignition timing. Timing is derived from sensors on the flywheel or crank. These sensors create reference pulses. A pulse can either be there or not. If not, the car stops. No additional grounding changes that. As to the ignition system itself: as long as there is enough spark energy to light the fire, the engine runs. More ignition energy does NOT increase power, just spark-plug wear. Corresondingly, if the ignition system is adequately grounded no amount of additional grounding will do any good.

I tried to bold/italicize/underline the sections that seemed like they might be relevant to what we are experiencing, but would love to get thoughts from TW! Thank you for reading!

EDIT: Wanted to point out again what I wrote when I posted this yesterday - That audio section - I thought maybe I was asking a dumb question when Mod mentioned electrical noise and I replied that we hear our CD spin now, whereas we didn't before, and asked if that was what he meant. Now after reading this, I'm thinking maybe that wasn't a dumb question...........

EDIT 2: I should also mention - that electrical place I took Taco last Friday afternoon (before we were suspicious that the AFR gauge was the culprit) checked our starter - they hooked something up and had me start it repeatedly, ~5 times, ~5 min apart each time. They said the results of whatever they were checking (I'd assume voltage?) were normal, although the younger kid said something on the start that cranked just a wee bit longer about that reading being a tad off, then the older guy said, nah, not enough to explain our problem. I asked them if we should wait 30 min for a hard start interval then repeat whatever they were checking, but they said nah, wouldn't make a difference.

 

Never had a head gasket issue, but my daughter did run it low on oil and locked up a connecting rod on it.

I read it, and while some of it makes sense, some of it is off past third base. For one, if there is a starter that is drawing 800A of current, then your battery would smoke and your cables would melt! There is not a single production vehicle today that I know of that draws even CLOSE to that kind of current. The Tacoma starter typically draws less than 200A when cranking a cold, northern engine. Hell, even the 3500HD Diesels I worked on at GM only drew 200-250 amps when ice cold! So he is full of it there.

Also he talks about using a copper grounding bar instead of a common ground point because each lug connecting to another has some resistance in that connection. Well, you have the same thing on a common grounding bar. The advantage to a grounding bar is that each ground is separate, so if there IS a problem, then it would be localized.

Oh, and congrats on 100 pages, and almost 2k posts!

 

Thanks for reading Bama. So you don't think our issue could be from improper grounding then? I am so confused.

Thanks for the congrats on the 100 pgs, although its not exactly something I'm proud of or happy about. When I started the thread, I definitely did not expect to it to continue into this many pages/posts, discussing new problems that began during the engine swap. Great learning experience, but would have rather skipped the learning and gotten my truck back in proper working order. But here we are.

 

I think grounding could still be an issue, although going the grounding bar route is a little overkill and unnecessary like Bama says -- I don't think he was meaning to eliminate grounding as a possibility, though. There are probably not that many grounding points, and the fact that you had a CEL code that indicated a signal dropped out kind of points to a wiring or grounding issue. That is why I suggested going through and making sure all the ground points are clean and tight.

The fact that unplugging the AFR gauge makes it run normally is a little strange. It makes me wonder if somehow the additional O2 sensor, when powered, is messing with the signal or reading from the main sensor and confusing the ECU.