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

This was one of those old posts I was referring to, where I mentioned the hood being up while starting it....

 

Here's that other post I was referring to about the hood being up.......

 

Maybe it could be as simple as the wires to that TPS getting too hot or pinched when hood is down or something? I don't know, so confused........like a story problem from hell!!!!!

EDIT: Just called dealer parts - guess who's throttle body assembly is an exact match with ours, based on cross checking VIN numbers??????? Did I mention who's my bestest friend in the whole entire wide world?????

Obviously hoping we don't need that, and rather all we need to do is something simple, like grab a new TPS sensor and put it in, or fix some weird wiring/connection issue, but I'm very glad to know those are a match, because I'm guessing K's price on that whole assembly will be lower than the dealer's price of $1146.29!!!!!!! He said that whole assembly comes with new IAC valve, new TPS sensor, etc. And so far the 2 local stores I've asked about getting the whole new TB assembly have told me they can't get it from their suppliers, so it's looking like if we DID need the whole thing, our only choices would be dealer or my bestest TW buddy

Funny, the dealer price for the sensor by itself is only ~$10-20 more than the local stores selling the aftermarket version. Seems worth the extra couple bucks to get that one if we can somehow verify it's the key to ending this damn thread

Hmmm. Not sure how to proceed here, testing, or put in $75 dealer TPS knowing we can't return it, or...............

K, I took your tip about buttering up the parts dude - it's the same guy answering every single time I've called there over the past 2 months. He doesn't even have to ask me the stats on the truck anymore. Told him I was going to bring him some brownies after it's all fixed for all the trouble he's gone to helping me. Immediately followed that statement with, "would you mind running multiple VIN #'s for me to check something?"

EDIT: Just thought of one other thing here guys - I remember someone (I think on here maybe?) telling us the TB and IAC valve gaskets should be REPLACED, not REUSED when cleaning them. So I asked the engine guys which they did, and they said they reused ours. Ya think it could even be as simple as that? We did have the hard warm start issue BEFORE they were cleaned, but maybe cleaning them helped, but then not replacing those gaskets made the problem persist? Gaskets are cheap....would be great to just pick some of those up....

 

well i'll throw this out there, with the hood up the engine cools off a lot faster so timing on things related to engine temp will certainly be altered when the hood is up vs closed

 

One other thought, then I promise I'll shut up.......for a little while anyway.

It seems to me that perhaps a faulty TPS sensor or faulty TB *could maybe* have contributed to piston hole. And now with new engine, it's just manifesting itself with different symptoms? Can you tell I'm still desperately trying to wrap everything up into one nice neat little package, to be put away forever?

Thoughts?

EDIT: I'm gonna go turn key to "on" and see if I can retrieve any saved data from Scan Gauge, just in case its helpful, like what TPS reading is, temp readings, etc.

Looks like it might be taking new readings, rather than showing the old ones. TPS says 12 right now. Temps are all ~ the same as ambient, ~60ish.

 

PHEW! While I had the hood up to take some pics of the TB/IAC area, I looked at the routing of those plug wires. After seeing DP's post on that, its been lurking in the back of my mind "did he route those correctly? surely he did, he never just wings it with the truck, but I always thought 1 + 2 matched up, 3 + 4, and 5 + 6, just based on what seemed logical. Guess what, they're routed correctly! 1 + 4, 2 + 5, and 3 + 6. Don't tell hubby I doubted it, it'll be our little secret, OK TW?

Will upload pics I just took....

 

Photos probably not worth much, but to me it looks like everything in that area is routed funny, like there's a shorter path for some of that stuff to take but instead it's all wrapped up together.......although I have no clue how the heck it's supposed to be routed....

Know what I mean though, like maybe some wires are being stretched unnecessarily or something? Also, in looking at our hood liner, it looks like there's burn marks on it. I realize it gets hot as hell under there, so maybe that's to be expected? Thinking we should take that thing OFF. Like NOW.

 

Did you run through that diagnostic procedure you posted? The first two steps can be done by yourself with your scanner and a simple multimeter. The third step may require a brick or something to hold the accelerator down, if you have to go that far. It's a good procedure to narrow things down.

 

Stretched wires are not good. Could be looking connection. Inspect those closely.

 

Not doing this alone. Thanks for the input though! The most I'll do alone is take pics, post on forum, research stuff, and look at things......otherwise I don't trust my "mechanic" skills!

Here's a hood liner pic and a much better shot of the wires, and how I think they look stretched....doesn't it look strange how stuff is wrapped around each other, instead of routed on a more direct path from point A to point B? Or is that how it's supposed to be?

EDIT: if a pic from a different angle would be helpful let me know, i can take pics all day, I'm very good at that!

 

uh oh. like whole new wiring harness not good? not just a quick little swapping of the sensor?

 

This thread moves to fast.

Back to the TPS and the recent P0120.
Earlier koditten had mentioned the "10" number on your SG as a % value of throttle position.
I came back to say I thought it was a degree value. With a little remedial study it turns out the SG reads out in percentage and it should be at 10% with engine warm and at normal idle speed. By chance, the throttle plate is adjusted to a 10 degree angle when fully closed, hence the confusion on my part. At this point put any thought of fooling with that adjustment out of your mind.

What can you do about the P0120 until your guy gets back?
Check that 3 wire plug. Unplug, inspect and plug it back in. Make sure it latches or clicks securely back in place. Give the wire harness a good visual check for damage, to the extent possible.
Take a look at page DI-180 in your book. In your case, the whole bit with the initial Toyota or OBD2 tool checking for throttle position values, is the same thing as reading the value from your SG. That value should go from a steady 10% to what ever they said (75% I think) smoothly and at the same rate as how you are stepping on the pedal (opening the throttle) without skipping or jumping around. Note how they say if the those values are good to look elsewhere for other issues.
I mentioned earlier about the SG sampling rate. I'm just not sure if the SG gives a constant reading or it checks the value at some interval. Obviously if there is a significant interval, smooth and consistent values with respect to the actual movement of the throttle would be hard to judge. The other tests can be done with the Fluke. Of course replacing it is an option with the $'s as the only drawback.
After any investigation, plug wiggling, value reading etc, you will not know if the initial issue that set the code has been resolved until you go thru the correct number of drive cycles for it to clear and that varies between codes IIRC.

Now the dilemma. You could clear the code with the SG and see if it comes back but you would also clear any other stored data your mechanic wants/needs to see. I say don't do it.

 

Yes, believe it or not I DO actually have to work and have some free time. Hahaha. Sorry Jen! Yesterday was a BEAUTIFUL day in the 70s so I had to get on my bike and ride as much as I could!

Now as to what you posted that I put in bold. I will help you out a HUGE amount so that you can understand a lot of other things. A SENSOR is a part that simply reads information, and transfers that information to the ECU. An ACTUATOR, solenoid, coil, or a VALVE are parts that can send information to the ECU, and do active changes. So a crankshaft position sensor can only do ONE thing, and that is send information to the ECU about the position of the crankshaft. The ECU then determines what needs to be adjusted, and uses actuators or valve to make these adjustments. The ECU will take all of the data that it receives, then based on the program specifics, it will control other parts.

NOW!

Misfire diagnostics:

The ECU is constantly measuring for misfires, while the engine is running. So just how does it know that the engine is misfiring, and how does it know which cylinder is misfiring?

Well, an ignition coil does one thing: It creates spark when it is told to do so. Obviously this means it has no idea when a spark does or does not occur. For example, your job is to push a button, and on the other side of the wall a lever will move every time you push the button. You can't SEE the lever, so you just simply do your job: You push the button when you are told. That is the coil. So the ECU doesn't find out about misfires from the coil. (but it does use information from the coil for other misfire things, more on that later) Another thing that can cause a misfire is lack of fuel. So we have an injector that can cause a misfire. Just like a coil though, it is only capable of doing one thing: letting fuel go by. It doesn't KNOW if fuel went by. It just opens the injector. Incorrect air volume can cause a misfire. But again we are talking a mechanical issue here usually, with a valve in the head not operating correctly. So no way for the ECU to know that way.

So how? It is simple. One sensor, and one sensor alone is responsible for misfire detection: The crankshaft sensor. The crankshaft sensor measures engine rotation, thus it knows engine rotation speed. The ECU watches the crankshaft sensor and looks for sudden, erratic changes in the signal. When a cylinder misfires, the crankshaft itself will slow down a small amount because the cylinder that fires will not apply power to the crankshaft. The ECU looks for this drop in rotational speed, and classifies it as a misfire.

Now we go on to tell how the ECU knows WHICH cylinder is misfiring. Well, the crankshaft has 34 teeth on a gear, that passes across a sensor.(crankshaft sensor) The ECU will also check with the camshaft sensor at this point and it will know that when the camshaft sensor triggers, that the engine is at TDC of the compression stroke for #1 cylinder. Well once it knows that, then as it receives the next 68 signals from the crankshaft sensor, it will know when each cylinder will now be on THEIR compression stroke. So this is how the ECU knows WHICH cylinder is misfiring.

Well now we are going to get more complicated. The 3.4 uses a waste spark system. This means that a single coil fires 2 cylinders. (I know you know this, because we have talked about it on the phone!) So if the spark plug for #1 goes bad, it affects the spark for #4. So why do I not get a misfire for #4? Well, the ECU also measures resistance, and "dwell" of a spark. Dwell (in laymen description) is the amount of time the coil is given to energize to maximum voltage before it fires. (this time is in milliseconds) A bad spark plug will have either too high, or too low of a resistance. This will affect dwell build-up time, and the ECU can detect this.

So how can this information help you? Well, if the computer detects ONLY a #1 misfire, then most likely the coil is good, but the spark plug in #1 is bad. But if you have a code for misfires on COMPANION cylinders, #1 and #4, then you GREATEST odds are that the coil itself is bad, and is incapable of creating enough spark for either cylinder.


So there is your lesson for today Jen!

 

By the way, on a little side note: Something that can drive some techs crazy. You have a misfire while cruising, and the computer detects this, and shows "random multiple misfires). However when looking at the engine while it is running in the shop, or under a power brake load, the tech can't see a single misfire. So scratching his head he thinks, WTF?

Well, a transmission can actually cause a multiple cylinder misfire. For example a bad spring in a clutch, when under load, can cause the crankshaft to jerk a little, falsely making the ECU think it is a misfire. I am telling you when I was at the dealer everyone except me hated engine misfire codes. lol.

 

Whoah, holy crap! That thermal barrier under the hood is not attached very well, and it looks like it is tearing up where the throttle cable is. I could be wrong, but that is what it looks like.

You need a new one of those, or somehow get that thing to attach better and not rest on the engine. You don't want that thing interfering with the throttle mechanism.

 

You're right, its hardly attached at all. Thinking of just removing it - I've heard it serves no other purpose than sound barrier and I could care less about that. This way we'd at least take it out of the picture just in case it has any tiny little bearing on what's happening.

Good grief, cannot WAIT for husband to get home so we can start testing!!!! Dealer parts is holding a TPS sensor for us til 8pm, said we can't return it even if not installed since it's electrical. Damn! Hoping we'll be able to accomplish any testing before 8 so we can grab it if we find we need it!! Is it 5 yet, is it 5 yet, is it 5 yet????????

Gonna call neighbor and make sure he'll be around to lend us that Fluke 25 thing.....and hopefully supervise our testing methods as well, always better to have more sets of eyes/hands........

 

Thanks DP!!! Emailing to husband, let the testing begin ASAP!!!!!!!! Cannot wait for him to get home, good grief! This will be the longest afternoon of my life

 

Thanks Bama!! Will reread this more than once, but I can already tell you took the time to explain it in analogies I'll understand, really appreciate it!! thank you!

 

http://www.tacomaworld.com/forum/1st-gen-tacomas/303757-hood-insulation.html

Really tempted to rip out hood liner, this TW thread is filled with guys who did and seem glad after the fact.

Has anyone else ripped theirs out?

 

no, actually it works as a heat shield to protect the hood from the engine heat drying out the paint.

once its gone on days where moisture collects you will have a pattern on the hood shaped like the hood braces where the heat only dries some spots first.

not having it is no big deal the way I see it, so while I wouldn't go out and buy a new one to replace it, if I had access to a free replacement I would sure go get it and swap them.

if you have one in bad shape then that's better then not having one at all so its better to resecure it somehow rather then just take it off, since it does help protect the paint and if you ever have a small fire under the hood it could means the difference in needing a new paint job or not.

if its tattered and hanging down then trim off the bad spots or just take it off completely because if it hangs loose it might get caught up in the fan belts