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

By the way, earlier today I posted the following on here and on Yotatech:

The IAT (intake air temp) readings on Scan Gauge are typically in the 40s when we have a good cold start, which makes sense cuz temp outside will be right around the same, and I assume engine is receiving extra fuel, due to being cold. But then IAT will jump up to ~80-100 F ~20-30 min later, and that's when the hard start happens. Does it seem normal that IAT goes up to 80-100 F in 20 min while truck is just sitting there? I know IAT goes down when driving, due to more airflow coming in (right?), therefore I assume the opposite is true, that when you're sitting w/engine running, the engine's heat coupled with the lack of airflow should either make IAT rise or stay put, right? But should it go up that much that quickly?

The guy on Yotatech said "your IAT readings are fine; if it is open or shorted the readings are like minus 40F and like 248 F" - so sounds like we should rule out fault w/IAT sensor.

He also asked "What kind of voltage are you getting at the battery?? With all this cranking and testing are you keeping the battery charged??"

We haven't checked battery voltage, so if we get a break in the rain we'll do that next. But the only testing we've done is the mechanic testing the IAC valve yesterday, so I'm guessing the battery isn't part of our issue. We have been starting it a lot (~5 times per day) and only driving it 1x or 2x per day, so who knows, maybe that's causing some weirdness?

I thought I read somewhere that battery needs to be reset after anything at all is done to fuel system - could that be something, like mechanic forgot to reset it after swapping FPR? Or would they have had it disconnected for that anyway?

 

Koditten, you'd suggested this - Look for fuel pump relay in fuse box under hood. Swap it with one that looks like it or get a new relay. There is a diagram on underside of the cover.

And we did/said this - Husband listened w/stethescope at the EFI relay, while I turned to "on" position. He heard 2 clicks when I turned to "on" then heard 1 click when turned off. Repeated this 3 times, same results all 3 times. Truck was semi warm from starting/idling a bit earlier.

Do you know if that means that relay is all good? Should we swap it anyway, since easy enough and seems harmless?

Seriously thinking our best next step is to have a dealer diagnostic inspection, and hope like hell they can identify the cause of the issue, AND can tell us it will be very little $ (better yet, free!) to fix.

Thanks for the ongoing support guys.

 

https://www.youtube.com/watch?v=sonu_Vio0BQ&feature=youtu.be

Yes, because you guys haven't seen enough of my exciting videos of starting my truck, I thought I'd be kind enough to share another, for your Saturday evening viewing pleasure.

One of the worst starts yet. Seems like problem is getting worse. And I'm hoping you guys (well, anyone who actually watches it) can hear the engine making sort of a loping/revving type sound. I see the RPMs fluctuate on SG when this happens, but it's tough to tell if they're moving in rhythm w/the sound or not. Will be taking this video for dealer tech to see, definitely.

 

Idle looks fine to me. Its common for it to jump around a bit.
I still say replace the fuel pump......

 

Thanks for watching Knuckle. You have any popcorn with it?

We called a dealer, and asked who their best guy is for diagnosing engine/fuel issues, and who ideally is most familiar w/our engine type and older Tacomas. They gave us his name, and said he's got openings early Tuesday morning. Planning to call mechanic to verify he's fine w/us going this route, then taking it to this guy Tuesday. With a giant stack of service history records, notes describing what's going on, and videos. Wonder how long it will take before this poor dude is sorry he ever met us?

Still certainly seems very possible the pump is the problem, but all of this circuit stuff is looking possible now too. It is very weird to me that no CEL w/all the issues we're having. Don't really understand what the heck that would mean in terms of the big picture costs, but will keep hoping for the best and praying the Toyota tech is a freaking genius with a lot of patience.

 

It sounds great,,,just finiky hot starts. 3-4 revs it should start, hot or cold.

If you can mute that crazy focus sound,,that would help a ton. You might be shooting in to much dark surround, around ya.

 

Mod! Thanks for watching my exciting video! Will try to clean up video and post another - hell, it's free, it's easy, and it's about the best I can do to move forward at the moment.

Husband is researching accessing the circuit opening relay - looks like it's above ECU behind glovebox. He found a thread where some dude's circuit opening relay was f'ed up, so the guy jumpered it and it solved his problem (a problem identical to ours).

Feeling like a real tard right now. Realizing many of you guys kept saying right from the start, its strange you didn't get CEL during initial engine incident. I was so focused at that time on beating myself up over not pulling codes on the CEL we got in late July, then again in September, that I completely lost sight of the point I now think everyone was trying to make. Even though we were tards to ignore the intial CELs, the truck tarded out when it didn't give us another CEL as a hole was being burned in piston - right? Obviously our engine decision would have been different if we'd recognized a potential failing ECU at that time - or at least we would have done diagnostics to determine BEFORE $6K new engine. Also, our clock gradually faded over past few years and doesn't work at all anymore. Til now, I thought, who gives a shit about a clock, but now.....chasing this wiring stuff, not so sure its insignificant. Passenger window gets a bit goofy now and then. Had a chaffed, loose engine ground wire on manifold, which controlled multiple ECU functions found/repaired in ~2009 by Toyota tech, that had caused crazy sudden rise in temp gauge to look like overheating, plus low idle. And now, these funky warm starts and funky idling stuff and no CEL. All electrical/circuity/ECU type stuff - totally over our heads and potentially quite expensive from a bit of research. Thinking we've either got some wacky wiring stuff or bad ECU (and maybe bad fuel pump too Knuckle!).

Haynes manual says to check ECU, take glovebox off and "tap on side of ECU vigorously w/fingertips while engine is running" - sounds potentially damaging, yet coming from Haynes manual (a conservative approach usually), almost tempted to do this. Says if engine stumbles or stalls and displays glitches on the engine data stream, could be bad ECU. Says if ECU fails this test, check electrical connectors, then if no signs of damage there, see a dealer. You think we might seriously screw something up if we tried this? Guess that's kinda hard to answer, seeing as you have no way of really knowing how tarded we are, right?

 

Both taken at the beach, on an extremely rare hot, sunny day at the Oregon coast. Normally the best ya get, even in summer, is warmish and cloudyish. My girls Dolly & Patty asking why we are so cruel to put them all the way back there And of course the Taco, chilling on a sunny beach. There's a handful that allow you to drive right out there, which is pretty darn fun. Yeah, I'm ready to have a repeat of that day.

C'mon Toyota tech on Tuesday - but no pressure or anything, right?

 

Slow worn relay could definitely make it act up like this, They do fail on occasion.

Not a bad relay to replace, since it sees constant type duty and it needs to snap closed extra fast to get the pump in motion, then pressure up. Test and replace as needed. Easier on the wallet for sure,,and definitely a do it at home thing.

 

Thanks Mod. Calling around right now to see who's got this relay in stock, and also checking on who has alligator clips. Trying to decide whether to start w/getting clips and testing, or just buy new EFI fuse instead. With clips we could check other relays to, like starter.......waiting for Radio Shack to open to see if they have clips (our fave standby, Harbor Freight, is out!).

It's kinda funny, last night while we were totally engrossed in all the Taco stuff, our super nice neighbor w/boat canopy and 2.5 car garage came over and asked if husband could come help his daughter start her Explorer - apparently it was having a hot soak start issue (what are the odds??). I encouraged him to go help, thinking, this way we won't feel as guilty begging to use his garage or borrow his canopy. Husband reappeared a few minutes later - got the Explorer started by pulling air intake sensor out, cooling it, and reinstalling it. I really don't understand why we went from simple designs for vehicles to everything being controlled by computer/sensors. I'm sure there's a good reason, but not seeing it at the moment. Neighbor said he's still got canopy, borrow anytime, and we're probably gonna go knock on his door in a few to see about testing some relays in his nice giant heated/lit garage - hell, maybe he's even got some clips around, they're one of those super nice older couples that own 5 of everything under the sun. Lucky us!

 

This. Surely Toyota tech will do this Tuesday. Wondering if there's a point in testing starter relay now though?

Found stuff saying CEL wouldn't light up when turning key to "on" position if EFI relay is bad (plus clicked the way I think it's supposed to when turned to "on" then off), so now questioning whether to bother replacing that.

EDIT: Does anybody have access to this page from FSM for a '98? Obviously the dealer will, but curious to see it in the meantime....please and thank you!

 

We got a CEL!!! disconnected MAF, 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 as far as ECU, right?

Got engine up to full temp (ECT ~200) and began testing coil packs, and #3 (our problem one in 2007, where #3 plug, wires, and coil pack was found carbon tracked at dealer, they replaced all plugs/wires and #3 coil pack, and cleaned our injectors) was above specs! One of the values (I forget if primary or secondary) was normal, 13.28 (the one that is supposed to be between ~9 and ~16 if I remember right), the other one that's supposed to be between 0.67 and 1.05 tested 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. 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. Hoping this is good news?????? Coil packs are cheap, relative to where we are now cost wise!!!!!!!!!

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

Back in a few, husband's out there tinkering around, I gotta hold umbrella over hood in case rain starts back up....had to tell ya ASAP about CEL and coil pack, praying this is good news!!!!

Just got back up to really nice and hot, ~202, then immediately retested that coil pack - this time it read 2.2!!! That is way above specs according to manual! Could it be that a faulty coil pack is the culprit?

EDIT: Husband and neighbor are messing w/batteries in tester to be 100% sure it's taking proper readings......I'm calling every auto parts store under the sun to see if any have Denso coil packs on a Sunday night in stock......

Crap, looking like our tester is no good. Just borrowed super nice fancy tester from another neighbor (whole neighborhood's out there now, at least it's not raining) and his is showing a reading of 1.2, 1.1 when truck is hot. Sorry to waste anyone's time that read this.......

Focus now will be writing up a clear, concise summary for Toyota tech that we'll hopefully be able to get in with Tues AM.......grateful to have this thread to reference to make my notes sheet!

 

Still wanting to triple check that this coil pack was within spec.

Haynes manual says primary resistance should be between .67 and 1.05. Doesn't list spec ranges for cold vs. hot truck.

A 2000 Taco FSM manual (found on web for free) for same engine type (5vzfe) says when hot, should be between .85 and 1.23, and when cold, should be within .67 and 1.05.

We got readings of 1.1 and 1.2 on #3 when engine was fully warmed up (ECT ~200F).

Anyone have more accurate data (than Haynes manual or FSM for different year truck), to tell us if primary resistance readings of 1.2 on a coil pack from a fully warmed up 1998 Taco 3.4L is within specs?

OK, I realize it's another long shot, but just realized, each time we tested coil packs, we never did it when IAT (Intake Air Temp) was up in the range where the hard starts occur (~60F or more), we only paid attention to ECT being fully warmed up to ~200F. And so far, IAT is the only value that definitely correlates with the hard starts. So, even if that coil pack's readings seem within specs, it's just barely within the very tippy top range of spec - so thinking about allowing IAT to raise up to crap range then retest that coil pack.

 

Actually melted fuel pump wires at the fuel tank are quite common. I have replaced at least 80 fuel pumps over the past 15 years because the fuel pump wires got hot over the years and started melting and corroding.


OP, I still say after reading more of the posts and such that you need to replace the fuel pump and strainer. HOWEVER if you think you need to replace the ignition coil(s) then let me know. I have I think 3 spare coils that I will happily send to you if you need them. Just let me know and I will dig through my parts shipping box.

 

OK, just rechecked primary resistance readings on all 3 coil packs with neighbor's super nice fancy OHM meter (a Fluke 25 brand - we're confident this tool works properly, I promise), when our IAT (Intake Air Temp) was up there in the range of what it is with shitty starts and ECT (Engine Coolant Temp) was between 120 and 130 - here's the results:

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, so that would mean all are in excess of spec if that's true.

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, Bama & Knuckle? Wait, I know what you guys will say!! Seriously though, does this sound like a symptom of a FP that's dying/dead to anyone? 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 wondering whether a faulty fuel pump could cause these signs?

EDIT: Bama, just saw your post. Thank you so much!! Wow, that is incredibly generous. Thank you x a million billion trillion. May very well take you up on that. Our tinkering testing today was really more just to pass the time (can't think about much else til this is solved!) and to gather any additional info we can easily put together to provide to Toyota tech. Still planning on taking his 7am Tues appt. So before replacing coil packs (especially based on retest results all being same, even if they are out of spec, see above), I want to see what the tech thinks. But may very well take you up on your offer, so thank you x a million again! And thank you for reviewing the thread - you guys giving us input is such a mental boost for us through a long crappy journey. Thank you!

 

Means to me that you need to replace the fuel pump. lol. Seriously tho, I am still mostly inclined to believe the fuel pump is bad. Opinion, yes, but based on what you have posted including the videos, and years of experience.

Reposting this pic as it shows the circuit for your specific engine, and how the circuits are connected for operating the fuel pump.



If you want to energize the fuel pump manually, you can connect a 20amp fused wire across the circuit opening relay. (Make sure you connect terminals 30 and 87) This will force the fuel pump on as long as the ignition switch is turned on. This should only be used for test purposes of course.

 

Thanks again Bama! Your opinion carries a lot of weight with us - will see what tech thinks first, but will likely do fuel pump regardless (assuming what he says instead of/in addition to fuel pump doesn't require going bankrupt!).

Thank you!!

 

Morning guys. Thanks to anyone who's still hanging in there with us.

Today's project is working on a long list of very specific questions for the mechanic, formulated directly from going back through every single one of your helpful posts. Then hubby gets to be the one to make the call this time! Really though, ya never know, sometimes just simple miscommunications being cleared up can fix a problem. So I figure I'm the details freak of the 2 of us, so I'll do a better job than he would of reviewing the advice you've all given and summarizing it into specific questions, and maybe he'll be able to do a better job than I've been doing at communicating with the mechanic to find some hidden clue that solves everything!

Or maybe it's just today's false hope. But worth a shot!

 

All your symptoms have always fit a failing pump but and that is a big "but", your guy said he checked it with a gauge again and again. Should it be the fuel pump, it's not going to reflect well on him. There is nothing magic going on here.

I still call the burnt wires a freak. That one fellow is the only case I have seen in specifically monitoring Toyota Truck forums since forums began nearly 20 years ago. No Tacoma owner goes into a fuel pump r+r with a new in-tank pump harness in hand might be a better way to put it. But anything is possible and opinions are opinions. Just watch, having said that, your harness will come up burnt.

That diagram for fuel pump control /\ is a diagram of "theory of operation" not an actual wiring diagram. Below is an actual wiring diagram for a 99, or at least the pertinent half. I'm 99.9% positive it is the same for 98, at least for the fuel pump control circuits. Notice it's just a tad more detailed having terminal #'s, wire colors and shows numerous places for potential "circuitus interuptus".


It sounds like your resolved to the dealer diagnostics as the next step. In your position I think it's a good idea. Make sure the service writer puts all your concerns on the ticket before you sign it. You don't want some vague "customer complains of poor starting when warm" BS. Don't accept any excuse like "they will know what to do". Make sure they are specifically checking the "start circuit" as it relates to start up fuel delivery and pump pressure in all situations along with the rest of the usual stuff. It might not be a bad idea to write/print up your desires and concerns to be stapled to the ticket. Remember, service writers are usually not techs. Edit, I see your already doing this.

 

Neighbor just told me he has a mechanic buddy that has the factory toyota scan tool!! He's gonna see if guy can come over today.......cross all your fingers and toes for me!

DP, thanks for the post! I gotta admit, the wiring diagram is over my head at the moment, but I suspect will be useful for us as we continue through this journey, as many times that's what has happened. You guys post some scary looking thing/suggest some thing to check that my initial reaction to is: , but then I keep going back over and over all of your posts, and eventually they all wind up making sense to us and being helpful, even if just to better understand what the heck could be happening inside our truck's brain! Which allows me to ask better questions of the mechanics, and understand their answers soooooooooo much more than I would've otherwise. Thanks guys!

We're counting the appt tomorrow as sort of a last hope (unless neighbor's buddy has some insight before that - one can hope, right?) This poor Toyota tech is going to have some serious pressure! I've verified by calling them 2x which of their techs is most skilled/experienced, based on a brief description of our situation. And they gave me an email address I can send links for our videos to, so that's super helpful. And I asked if we could get face time w/tech for even just 5 min at the beginning and again at the end of our 1 hr appt, since our situation is so f'ed up (well, I said it a little differently than that), and they said no prob, they'd make a note of it. So we've got the best tech at the best dealer in our area looking at it for 1 hr, and he'll have all the info we can provide, typed up in as concise yet detailed of a summary as I can possible crank out today.

Even if the news is bad, I'm ready to hear it, as we can't take the not knowing anymore. For me, the only truly bad result of that appt would be if he comes out scratching his head. So if you are a praying person, please say a little one for us that he is a true diagnostic genius. Otherwise, please cross all fingers, toes, arms, and legs for the next 21 hours (appt is from 9:20 to 10:20) - not that I'm counting down to it or anything....