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

We'll take it Keakar! Wrong call = GIVE ME YOUR TRUCK NOW!!!!

Exactly what you said regarding the engine mechanic. I still believe they did a fabulous job on our engine, and would recommend them to anyone that needs AN ENGINE ONLY. To be fair, I suspect the majority of their customers who have them do labor on a swap are coming to them NOT because their old engine had issues (like ours did), but because they want to swap our engine type into their older Toyota truck - going from a 3.0L to ours, etc. It appears they gave us a damn good engine, for which I am truly grateful and glad we spent the extra $ on. But, because (I think) they don't do a ton of diagnostics to figure out why an old engine failed, they probably just aren't as experienced at that part as others are. The part that bugs me is I wish I would have been better informed of that up front. I asked lots of questions about that up front - will you diagnose the cause of piston hole BEFORE new engine goes in, will diagnostics cost extra, what diagnostics will you do, etc.....and essentially was given all positive answers, not necessarily full complete thorough accurate answers to those questions. Even said, that's one of the big reasons we want to come to you guys, because it's "one stop shopping" - you can diagnose the cause, provide a great new engine, and do the swap. I was assured that yes, exactly, that's how it is.

It's a pride in your work thing, like you said Keakar. At least have the courtesy to point us in the right direction on how to resolve hard warm starts if you can't do it - don't patronize me about it, and trivialize the issue. If we'd let this go (like they somewhat implied we should), who knows what kind of havoc that might have wreaked on our very expensive new engine. But, like I said, I would still recommend them to others shopping for a reman for THE ENGINE PART ONLY. I'm sure they are skilled at basic diagnostics, but there's a line between basic diagnostics and super f'ed up stuff - and it seems the f'ed up stuff requires really expensive tools, and tons of experience and patience. So I get it - when your passion is building beautiful engines, and maybe you're lacking those fancy diagnostic tools as a newish youngish business, I can totally see how a bunch of pain in the ass diagnostics are avoided as much as possible. Bottom line, go to them for your engine; get your diagnostics elsewhere.

 

So, there's still the burning question that even our new fairy godfather admitted he doesn't know the answer to, and also that my buddy Matt said is strange -

Why good cold starts if fuel pump is failing? Does anyone know the answer to that?

Trust me, I'll go with whatever our new guy says, as it's obvious he WILL NOT take a "throw parts at it" approach, period. He's all about correctly diagnosing the problem, then rechecking those tests a billion times - he made that very clear to me today (music to my ears!). So if he says it's the fuel pump, and still can't answer that question, that's A-OK by me.

But does anyone have a logical explanation as to why that is?

 

well when it sits for a while the gas in the tank creates fumes which fill the tank and "pressurized" it slightly so maybe this small amount of pressure is enough to give it just enough fuel to keep the fuel lines filled with gas and be easier to startup cold as opposed to having been running where the gas being drawn from the tank kinda creates a more neutral pressure situation since the pump has been sucking fuel from the tank.

if this "guess" were correct then this should also make warm weather starts easier then during colder periods because warmer weather creates more fumes in gas

NOW WHERE IS MY COOKIE !!!

 

I like it, I'm going with what he said! Thanks Keakar!

Now, don't disappear on me guys, after this, we'll have wheel bearing questions, rack & pinion questions, and shocks/struts questions!

Experienced forum guys, what's the proper forum etiquette for that - should I start new threads for each topic, or how does that work?

EDIT: Also, anyone have theories as to why no CEL when piston hole occurred? Would failing fuel pump have played a part in the piston hole ya think? Anyone have suggestions as to other diagnostics we should request to determine why no CEL during piston hole incident?

 

step 1 - open hood

step 2 - remove radiator cap

step 3 - replace truck

step 4 - replace radiator cap

job done enjoy your truck

 

seriously girl, now you know why so many of us kept insisting you get a salvage yard engine or sell your truck for parts and just get another one.

other then the education, it has been a money pit and adding it all up you might have bought a nearly new truck by now for that money

 

My guess would be-
On a cold start the pcm cycles the fuel pump for an extended period when cranking to deliver more fuel to prime the system for the extended cranking a cold start can cause.
If the pcm knows via the coolant temp that the vehicle is warm it will start the vehicle in closed loop ( which means when the truck is warm its uses feedback from all of your sensors to make your engine run at peak efficency) while warm its not triggering the fuel pump to cycle longer and having a bad pump thats allowing the pressure to bleed back into the tank is causing your engine to crank until the pump cycles enough to pressurize the lines and feed the injectors.
Thats my theory but i dont know enough about toyota engine managment to give a definant answer.
Hoping bama will chime in on this and possibly learn me something

 

C'mon Keakar, don't go there. Was just about to post, thanks to all the used engine vote guys for never saying "I told you so." That's just mean dude! Was gonna send truck cookies, but not now......unless you gimme your Tacoma!

 

Thanks Knuckle and Keakar for the explanation. Makes sense, I like it!

Now the only unresolved question I can see is why no CEL when piston hole occurred. Will ask our new super awesome mechanic that one tomorrow, and I suspect he won't rest til he has an answer (and might even already be puzzling over it), cuz it seems like that's just how he rolls.........wonder if he needs a secretary!

 

Ah, I found it! It was you Knuckle! Solder and splice, that's what our new mechanic said he could likely do if we even have this issue. Good call once again buddy!

 

Any why do you think a different used truck or engine would be any less of a problem?

This is back to the old saw about frying pan and fire

Howard

 

This was my Yotatech guy's response to the news yesterday - he doesn't think it's the pump, and he strikes me as one of the sharper tools in the shed on that site....and is echoing the same sentiments/concerns as lots of you.......

"The minute the spark plug broke the MIL should have tripped.
The fuel pump is either on or off
Turn the key it should be at full pressure in theory if there is nothing wrong your fuel system should always maintain pressure.
This is why you have a fuel [FONT=inherit !important][FONT=inherit ! important]return [/FONT][/FONT][FONT=inherit !important][FONT=inherit ! important]line[/FONT][/FONT] to allow excess fuel to be returned to the tank
I am waiting to see the end results I don`t think it is the fuel pump although it could be in the control circuit."

I have an enormous amount of faith in our new mechanic to solve the mystery though, so I'm not going to stress. Found a Denso pump & strainer kit locally for $115. Only place that had the gasket/seal thingy locally was my fave local dealer - you know, the one that diagnosed a spun rod bearing - and shockingly, the dealer OEM (Denso?) is same price as the Denso on R.A.

 

Been thinking this the whole time as well. I'm awaiting results.

kirk

 

OK guys.......here's my theory about the no CEL during hole in piston event.....everybody whip out your crystal balls and tell me what you see...

1) Got CEL on 8/6/14 (I know this from combing back over Visa statements - went to Petsmart that day!) - perhaps that was the first misfire at #3? Got some gas while it was on, asked attendant to tighten cap really good, CEL went away.

2) Husband got CEL on 8/28/14 (good ol' Visa, it's like a diary) on his way to work in AM. ~9 hours later, drove home, light came on again. Bought a new gas cap on his way home, CEL went away. Maybe that was the second misfire at #3?

3) 11/30/14 - I was driving on the interstate, Taco started lurching/hesitating, got to my exit within 2-3 min of this, heard the nightmare knock/tap noise, parked - NO CEL immediately before, during, or after this event. Maybe the lurching was the center electrode finally giving up and taking off to spark plug heaven, and maybe the knock/tap noise was the plug (with no center electrode by this point) literally drilling a hole into the piston? By the way, I've always been convinced that the VERY SUDDEN/UNUSUAL temp drop to freezing cold temps that day somehow played a hand; coupled with, that was probably the first time Taco had driven at interstate speeds in quite a while, at least days, maybe weeks. And I basically floored it out of the driveway the second I started it - you know, cuz that's what you're supposed to do, especially when it's unusually freezing cold, right? Why warm it up, it's just an engine?!

4) First week of Dec - started Taco a handful of time for seconds each time, to see if awful noise magically fixed itself, or helped us determine something helpful about WTF was happening under the hood. NO CEL each time - but it's not like there's a compression sensor (right?), so why would it?

IF either/both CELs in August were related to piston hole/plug electrode, that is really remarkable and scary at the same time - because we drove A LOT during those 3 months between August & December. We did a Labor Day trip of ~800 miles round trip, most of which was in a remote area! Not to mention 3 months worth of daily errands, park w/the dog, etc.

Is it possible the initial misfires (the key events that SHOULD have set a CEL in all of this, right?) happened way back in August, but that piston was still moving up and down correctly all that time til November? Is it possible that cylinder was still firing with only the two side electrodes intact all that time?

It raises the questions of "how exactly does a spark plug work?" and "define misfire" (those will be the google mission of today! but assistance from you guys is always a helpful lesson supplement too!) Does it need both side electrodes AND the center electrode to properly create spark? Or can it still fire/create enough spark to keep that cylinder functioning with only the side electrodes to rely on?

I plan on asking our new mechanic what he thinks about why no CEL during the knarly event, but in the meantime it's driving me a bit batty, considering it's the last MAJOR stone that hasn't been turned over yet. I am determined to prove to myself that my Taco doesn't have some kind of brain damage! All input appreciated, thanks guys!

 

EXACTLY. No guarantee when you buy a used engine or a used truck - could have traded this set of problems for potentially an even worse set of problems. Had to gamble on something, this is the route we chose to gamble on. Moving forward on that route is all that really matters now, no point in looking backwards.

No more "I told you so's" please!

Thanks H

 

Page 2 and 3 is interesting,,if this PDF link works. General type info, but it answers some of your questions. The whole thing is a good read and worthy of saving.

http://www.lovehorsepower.com/ToyotaPDFs/42.PDF

 

Thanks Mod! Reading now.......



EDIT: apparently reading for a while, 23 pages man?!??! JK, thank you!

OK, so we have the RETURN kind, not the RETURNLESS, right?

VAPOR LOCK! I CALLED THAT FIRST! Now my money's on that........it would help explain why tightening gas cap always got rid of CEL, wouldn't it? Wondering if we have a failing pump and some kind of vapor lock situation, what do you guys think?

How does one check for that exactly, and not in a half assed way (supposedly this has already been done by SOMEONE, not naming any names)? I've read about some crazy smoke machine - is that the only way, or is there some kind of pressure gauge? Will ask mechanic if this is something he can check, but would love to get input from you guys about methods of checking, so I'm not a tard when I ask him about it.....

Article says:
An outlet check valve, located in the discharge outlet, maintains a residual fuel pressure in the
fuel system when the engine is off. This improves starting characteristics and reduces vapor-
lock. Without residual fuel pressure, the system would have to be pressurized each time the
engine was started and this would increase engine starting (cranking) time. When a hot engine
is shut off, fuel temperature in the lines around the engine increases. Keeping the system
pressurized increases the boiling point of the fuel and prevents the fuel from vaporizing.

 

Yah, grab a fresh cup.

 

with the salvage yard engine, yes its a gamble for the purpose of saving money and if properly checked to see its running good before buying, there is no reason to think it wouldn't go another 100k plus miles issue free and outlast the truck.

in your case the truck itself has the issues besides what you did with the engine so im speaking in terms of not having gone through this whole learning process but that in itself was quite fun and rewarding to you I would imagine (even though there were often times of worry and great concern).

it comes down to time and money for most things and yes you are better off today but having been through all this and getting a chance to start over at the beginning, anyone would have second thoughts if they did the right thing, so it comes down to what each individual is looking for.

for you, keeping your truck was worth it but there was a devil on my shoulder that had to point out the obvious that second guessing if you did the right thing is normal.

and for the record:

feel good about your decision, I think you did do the right thing rebuilding your engine, maybe not the cheapest route to go but its going to be way more reliable and ensures the trucks engine will last you another 200k miles for sure.

I wasn't trying to say I told you so but more to show you the reasons why so many of us were giving you the advice to go with salvage yard engine instead of getting into a situation where you get in too deep and find yourself trapped into a truck you may not think is worth the money you have to put into it which again is not true in your case. in a way I wanted to remind you that we all had your best interest at heart even if we had different ideas of the best way to go with it.

 

OK, so we have the RETURN kind, not the RETURNLESS, right?

VAPOR LOCK! I CALLED THAT FIRST! Now my money's on that........it would help explain why tightening gas cap always got rid of CEL, wouldn't it? Wondering if we have a failing pump and some kind of vapor lock situation, what do you guys think?

How does one check for that exactly, and not in a half assed way (supposedly this has already been done by SOMEONE, not naming any names)? I've read about some crazy smoke machine - is that the only way, or is there some kind of pressure gauge? Will ask mechanic if this is something he can check, but would love to get input from you guys about methods of checking, so I'm not a tard when I ask him about it.....

Article says:
An outlet check valve, located in the discharge outlet, maintains a residual fuel pressure in the
fuel system when the engine is off. This improves starting characteristics and reduces vapor-
lock. Without residual fuel pressure, the system would have to be pressurized each time the
engine was started and this would increase engine starting (cranking) time. When a hot engine
is shut off, fuel temperature in the lines around the engine increases. Keeping the system
pressurized increases the boiling point of the fuel and prevents the fuel from vaporizing.

Also, do we have the 2 speed or 3 speed fuel pump control?

That part on page 10 seems relevant:

"When the engine is OPERATING AT HIGH SPEEDS OR UNDER HEAVY LOADS, the ECM turns off the fuel pump control relay. The relay switches to contact A and the current to the fuel pump flows directly to the pump bypassing the resistor, causing the fuel pump to run at a high speed. The fuel pump also runs at high speed WHILE THE ENGINE IS STARTING."

We hauled ~2-3 very heavy loads of rock this fall (drainage project - you NW guys know what I'm talking about! good times!), as well dragging a very heavy trailer load this summer (taking old concrete footings from fence posts to the dump), and quite a few trips loaded down w/lumber & concrete for fence project. It's always seemed too coincidental to me that we've really never hauled that kind of weight, at least not so frequently, like we did over the ~4 months immediately prior to piston hole. I'm still confused as to how it all fits together, but there's something to this......

EDIT: I keep rereading that part I just bolded over and over - is it saying it could be as simple as a bad EFI relay under the hood? Or that our ECM is short a few brain cells? Or neither?