Thank you Wyoming. Hope you got some good eats! We just took a research break for some cheeseburgers and fries - a nice healthy low cal lunch! : )

It's super helpful to hear your thoughts on IAT readings - sounds like we can rule out a faulty IAT sensor being the culprit.

Mechanic said he put in brand new Denso plugs w/new engine. Think we should pull 'em? Can't hurt, and it's easy enough to do....

Good question about the battery voltage, and also an easy thing to check, so that'll be next. I doubt we've done anything to run it down though - we've contemplated doing all sorts of testing, but really all that's actually been tested is IAC valve by the mechanic yesterday. We have started it a lot (probably ~5+ times per day) and only drive it maybe 1 or 2 of those starts, ya think that might run the battery down? Guess we'll find out soon!

 

The major thing that bothers me is that all the wonky idle does not trip the MIL Has it ever been on with the old engine??

I want to see If I can cause the MIL to trip on mine but forgot yesterday.

Nor the fact that hooking up the scanner did not show like a zillion codes.

One of those things about being a few thousand miles away.

Cold engine starts are fine The engine starts the idle goes up to around 1200 to 1500 depending on the outside temperature and when the coolant temp sensor yells to the ECM getting warm here . idles down to 750 to 650

you then can drive to your hearts content no issues no stalling or carrying on in general.

5 or 10 minutes no problems it is only when it sits for 30 minutes or longer

I am pretty sure this is a electrical problem .

Be nice to know the reading of the coolant temp sensor at the 30 to 60 minute long crank time.

This seems to happen no matter the outside temperature correct ??

Keep an eye on the oil if unburned gas is getting in the oil from all the cranking not good for the bearings.

Either the injectors are not firing or a no spark condition at these times.

Or the ECM thinks the Idle Air Valve is open so the injector pulse is according meaning to much fuel and not enough air. Then your plugs are wet .

This happens it is possible to get deposits on the plugs.

as the Coolant temp sensor is a thermistor and they have been known to do strange things.

Then this is a fresh engine on top of everything else.

 

Wyoming, thank you so much for continuing to try to help us. We're grasping at straws, so the ongoing support from all of you intelligent forum guys is appreciated more than words can express.

CEL did come on w/old engine. Came on 8/6/14 midday while driving - continued driving ~10 minutes to gas station (was lowish on fuel anyway, ~1/4 tank if I remember correctly); filled up, asked attendant to tighten cap good, CEL went away. Never pulled codes. Came on again 8/28/14 while driving in AM, stayed on until arrived at work, then started truck to leave work ~9 hours later, and light came on again while driving. Bought new gas cap, CEL went away. Never pulled codes. In ~12 years we've owned Taco, every time we got CEL (probably ~5-10 times), tightening gas cap turned it off, so we've NEVER pulled codes. So we began taking it for granted that all was fine, just a quirk of our truck that it liked it's gas cap extra tight. DOH! Not a smart move.

But, our lurching followed by engine making strange noises incident (assumed to be the moment the spark plug lost it's center electrode and hole was burned into the piston) was on 11/30/14, and we did NOT get CEL during or anytime before this incident.

Of course now we realize we were total idiots to go for the gas cap and skip pulling codes, and have been so caught up in kicking ourselves over that, that we completely lost sight of the fact that it seems quite bizarre that CEL did not come back on again BETWEEN the August CELs and the November engine failure, nor DURING the November thing.

When 11/30/14 incident happened, towed to dealer immediately. They did not check for codes, nor did we ever discuss w/them that we didn't get CEL during incident. DOH! Perhaps that simple conversation would have alerted us to possible ECU/electrical issues BEFORE we decided to spend $6K on new engine. Chose a mechanic to do engine swap, and assumed codes would be there for him to see, at least from August CELs, since dealer didn't check them. Mechanic said there were no codes. A Taco World guy said they can go away after 5 or so ignition cycles, so assuming that's what happened. Awesome, will never know what they were.

CEL does light up when turning key to "on" position, so my understanding is that proves bulb is good, and also randomly that EFI relay for fuel pump is working. But yes, many the Taco World guys wholeheartedly agree w/you, that the most concerning piece of this puzzle is that we're not getting CEL despite hard starts, weird idle, etc.

If you get a sec to do whatever you were going to try on your truck and let us know, we'd love ya for it big time. We've been researching how to test our CEL, and husband found a forum saying to disconnect MAF, then it should trip CEL. Any thoughts on this? No reason it'd hurt anything, right?

Correct to all of your statements. Engine coolant temp (WT reading on Scan Gauge) doesn't seem to impact hard starts - had a horrible start last night, and WT was 150; this morning's hard start, WT was 179.

Ambient temp doesn't seem to matter either, as temps hover between 45-55 degrees constantly throughout the time this issue's been going on.

RPMs are ~200 when choking/cranking through a hard start, then shoot to ~1100-1200 as soon as it turns over. They decrease to ~800-900 gradually over next 5 min or so.

The ONE FACTOR the hard starts seem to correspond consistently with is the IAT (intake air temp) readings - they are always 76 or higher when hard starts, and it seems the higher that number, the longer the crank time. Last night's hard start was our worst (longest crank time) yet, and IAT was 83; this morning's hard start (crank time definitely too long/abnormal but not as bad as last night), IAT was 76. It seems it's just coincidence that it takes IAT ~30 minutes to rise enough, as opposed to the time frame actually being the factor that means something.

Thanks for mentioning this, wouldn't have thought about that. Although, not sure how to handle it exactly, as engine swap mechanic put in special bearing oil that we were told to change at 500 miles (we're at ~300 now).

Agree. This is now becoming the consensus on Taco World also. From a bit of research on ECUs and electrical stuff, praying this could somehow be some silly chaffed wire, or blown relay, as opposed to a dead ECU.

The post RW made, listing the 3 circuit items (starter, fuel pump, fuel pressure) as what to check for 'difficult to start, hot engine' in FSM - we're now really thinking it's one of those things. What do you think? You wouldn't happen to have the '98 FSM pages that explain how to check these items, would you? I emailed RW asking this, but no word yet. We're considering getting alligator clips to test starter relay and EFI - think it's worth a shot? Also thinking about testing coil packs - mechanic says he did that already and all were fine, plus he said issues we're having now don't sound coil pack related, but, see #5 below....

FWIW, other history regarding engine/CEL light/possible electrical & ECU stuff:
1) Clock has been fading past couple years, would come back if tapped on, now totally dead
2) Power passenger window occasionally refuses to go up, but eventually always does
3) CEL in ~2007 in FREEZING cold temps - we'd just finished a long day of snowboarding, started truck, idling and taking off wet gear while parked, CEL came on. Pretty sure it was the 1st time it ever came on since buying truck in '03. Panicked, called a nearby dealer, they said tighten gas cap (and that's how that brilliant idea began). Tightened it, CEL went away.
4) June 2007 - Dealer replaced starter assembly w/reman'd (husband says we had sticky solenoids and wouldn't start, just heard clicking)
5) July 2007 - reported to dealer "when pulling a hill engine cuts out and sputters" - they found #3 spark plug, plug wire, and coil carbon tracked; replaced plugs, wires and #3 coil, and also cleaned injectors. NUMBER THREE IS SAME CYLINDER THAT WAS CARBON TRACKED AND THAT HAD PLUG W/MISSING CENTER ELECTRODE when hole in piston occurred recently.
6) April 2008 - wouldn't start - towed to dealer - they found & removed an aftermarket alarm we didn't even know we had
7) July 2009 - reported to dealer "growling noise from engine area" - they found A/C clutch causing noise, replaced it; also replaced leaking valve cover gaskets.
8) September 2010 - temp gauge raised to hot very quickly while driving up a mountain in freezing cold temps, and we also reported recently noticing low idle at stop signs and lurching - towed to dealer, they said radiator clogged. Husband replaced radiator/thermostat. ONE MONTH LATER, we took back to dealer and reported "temp gauge will match RPMs, meaning needle will move; hesitation at idle when accelerating, really low idle, this is all when vehicle is warmed up or has been under stress" - they found "chaffed/loose engine ground wire (that controls multiple ECU functions) on manifold." That visit's cost was $108 - praying for same outcome now.

Really sorry for the novel, just want to be sure I give ya everything and anything that could provide clues. Appreciate any input Wyoming, even if just scratching head due to not being able to put your hands on our Taco. Thank you, especially if you actually read this far.

 

Try this on a cold fresh start after sitting all night or day how ever it plays out.

What I did was disconnect the cam sensor it is right there in front of the engine on the right side.

The engine will start and in 30 seconds or so the MIL will come on or it should if every thing works like it should.

I shut off the engine plugged the connector together read the code P0340 then cleared the code.

See what happens??

then we will go from there.

I can`t stress the importance of clean and tight battery terminal connections ground cable connections . The one for the ECM ground you had issues with before.

These things should have all been done with the engine swap but it seems far to few take pride in doing things.

The battery being fully charged.

Yes I know working outside is not fun been there done that way to often.

 

We got a CEL!!! disconnected MAF, we were too chicken to disconnect the cam sensor - CEL came on as soon as we fired up, gave us 2 codes on Scan Gauge that both correspond w/MAF! This is good news, right?

Checked battery - cleaned terminals, hooked back up, everything looks good there, checked voltage, within specs.

Got engine up to full temp (ECT ~200) and began testing coil packs, and #3 (our problem one in 2007) results were: secondary was normal @ 13.28, primary was in excess of spec at 1.8, then they checked again and it was 1.2, then 1.1, but engine temp was obviously dropping as hood was up and it's coolish outside. Got back up to full operating temp of 202, them immediately retested that same coil pack, this time the primary was 2.2, and even registered 2.8 at one point. Mechanic that did engine swap said they checked coil packs, but we wanted to double check as weren't sure if they checked when truck was full operating temp.

EDIT: After this, we doubted the accuracy of the OHM meter we were using, so we borrowed the neighbor's super nice one (a Fluke 25 brand), and the readings were within spec, but the primaries were on the very tippy top high end of spec, ~1.2.

But then we checked primary resistance when IAT value is high enough to produce the crappy starts (~70ish and up), just for kicks, and here's what we found....

Coil at Cylinder 1 when IAT was 73 and ECT was 119: 1.3

Coil at Cylinder 3 when IAT was 82 and ECT was ~130: 1.3

Coil at Cylinder 5 when IAT was ~80 and ECT was ~125: 1.3

My understanding is that the max spec reading is 1.23 when engine is hot on our truck, so that would mean all are in excess of spec if that's true. And I assume when FSM says spec range for "hot" or "cold" engine, they're referring to ECT, not IAT, so that would mean we're way in excess of spec, since our ECT was not even close to fully warmed up when we took these readings, right?

Being that they all 3 tested at exactly the same number, it seems unlikely that 3 faulty coil packs is the ROOT of our problem, but it also seems this could be (hopefully) another valuable piece of info.

Mean anything to you guys? Thank you.

Also - when we unplugged MAF and started (to see if it triggered CEL, it did), when we stepped on accelerator, the engine started cutting out - bad - like it was going to stall. Sound like fuel pump dying? Also, we noticed the coil pack boots smelled strongly of fuel to us, and the exhaust stunk pretty heavily of gas too, during/after all of our starts and tests today. Hard to say if it was excessive compared to normal, but curious whether a faulty fuel pump could cause these signs?

 

For those that followed this thread It seems like it might now be at long last finished.

It is early to tell but seems like a lot of things they were told by the engine installers were out and out fantasy so leave it like that for now.

Seems like the cause of all the extended cranking times were traced to leaking injectors getting the plugs to wet to fire till they dried off with several cranking cycles.

Thanks to a Toyota Tech that went far beyond what I have ever seen in my life.

Even so far as to pull his own injectors out of his engine to make sure that was the fix.

 

Well said Wyoming. Thank you for updating the thread, for anyone it might be helpful to. Been meaning to do it myself and just now got around to it. Our new injectors and new FPR and new fuel filter are going in today. We are very excited and beyond grateful to the incredibly kind, talented Toyota techs that have helped us get our truck back to proper working order. I think the biggest lesson we've learned is if you really love your Toyota and are not able to do major repairs yourself, then do your best to make a connection with someone who really cares about doing great work at a dealer, and never let go of that person, because you might REALLY need them someday if your Toyota tries to die on you like ours did. We went elsewhere for the engine swap, and were promised dealer quality at a lower cost. Sounded too good to be true, and it was - in a very big way. Our local dealer has rescued our beloved Taco, and us in turn. They are the best!!

 

I dont know the 3.4 but did enjoy seeing how you guys went about troubleshooting it.