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

Hey Bama! Good to see you! Yeah man, it's been a whole 48 hours, how could you do this? You mean you have to live your life too?!?!? NOT OK! Seriously, hope you got stuff squared away, thanks for coming back!

Thank you, this helps a lot, great analogy - makes it way easier to understand. And now, in typical fashion, I will ask for even MORE details on this topic. I'm guessing to flash the ECM, you'd have to actually take it out of the truck and do some serious stuff to it, right? I know when I told our mechanic we might be able to get another ECM from some kind generous person, he said if certain details (manual vs auto, 4wd vs not, etc) were NOT the same, we could have the other one "flashed" somewhere for $100. Hence, this is why I'd assume "flashing" it has not been done to ours, because surely he would have told us if he'd done that.

But as far as clearing codes vs. resetting - I'm thinking he reset it, is that what you think? I mean, I know that's what he called it (resetting it), but we all know how stuff in this field often has multiple terms for the same thing. Anyway, assuming he did "reset" it, any idea how that is done? Just curious whether it was something simple he did (hook up snap on tool and press a button type, or disconnect battery for a bit type stuff) or if he actually removed glovebox, disabled air bag (not in that order!) and spent a lot of time/effort doing something very PITA with our ECM. I know he said whatever he did would force it to relearn the sensors. We've yet to get a CEL, and Scan Gauge continues to show no codes. That's my other question - if by the time he's back there are still no codes per SG and we still haven't gotten any CELs, I wonder if he'll be able to still retrieve some sort of useful data because the scan/computer tool he's using is so technologically advanced/fancy? I also wonder if whatever he did can simply be redone again, if need be for whatever reason? Not that I'm feeling guilty for monkeying around with stuff or anything....

Yep, you know we're splittin hairs when we're draining the coolant to check the jiggle valve. But ya never know - sometimes it's all in the details, right?

So tell me if I'm understanding correctly - the crankshaft position sensor reports info to the ECM about

#1 ignition timing

#2 timing belt/valves/DOHCs timing

Then the ECM tells the crankshaft position sensor to make adjustments accordingly if anything is off? Sorry, this is fairly confusing to me.

The first time husband checked the timing, he chickened out on doing the jumper wire check, because we weren't sure if that would screw with mechanic's resetting ECM goals. He just did the hook one thing from timing light up to #1 plug wire, right over by coil pack, and other thing from timing light up to battery, then shone light at whatever you call the thing with the number marks that's down sort of below/to the right of the timing belt, and the light wasn't even shining within those numbers. Then we drove it some and he rechecked it. This time he did the jumper wire thing, where he connected to that data port under the hood - DLC1 or 2 maybe? Pretty sure DLC3 is in the cab, so thinking 1 or 2. He didn't tell me he was doing that or I wouldn't have let him, but that's another story. Anyway, this time the light fell within those numbers, so we assumed the ECM corrected the timing while we were driving it, via the info the knock sensor was feeding it. But it sounds like you are saying the crankshaft position sensor would be the one reporting to the ECM to adjust this, as opposed to the knock sensor - is that right? Then just to compare apples to apples, we immediately repeated test #1 method (no jumper wire into DLC1 or 2, just battery/plug wire 1 hook ups) and got the same result of being within the number marks as we did with test #2 method (jumper wires/DLC1 or 2).

From what I understand, it seems to me this is good - means at least our valve timing and timing belt timing are't screwed up after all, and our ECM can't be totally fried if it's capable of adjusting the timing - right?

Thanks, great stuff as usual! When's the next class time?

 

OH NO

You know how I panic when I see these types of diagrams!!

I prefer photos of long blocks vs short blocks!

Seriously, thank you, will review this in detail ASAP, thanks Bama!

 

Usually to do a factory reset you just need a fancy Toyota technical tool and it's done through the OBD II port. I'm sure your mechanics snap on diagnostic tool was used to perform the reset.

Flashing an ECM totally wipes whatever was on it and uploads a new set of firmware for the truck to run off of. As far as I know it can only be done at the dealerships because they are the only ones who have the programming and the balls to mess with the firmware of your trucks brain directly. Think about jailbreaking an iPhone. How would you like it if a mechanic told you he was going to try and do that to your truck lol.

 

OK, just gotta recap where we're at and why we are thinking EVAP - could be way off, but naturally want to bounce off my sounding board...

detailed summary post coming in a moment

 

Just to put my mind at ease, did the mechanic disable the air bag so he could gain access to the ECU? That's pretty normal.

What he has done to the ECU is still a mystery to me. We will have to wait til he gets back.

 

For anyone new to the thread, the issue is difficulty starting (excessive crank time) when truck is hot. This problem didn't exist before the engine was swapped, which was in mid December. Since early January when the problem was first brought to our attention by the engine mechanic, the following has been done to try to fix it:

1. Fuel pressure regulator - replaced w/new, denso or bosch, I forgot
2. Fuel pump (no rust found in tank) - replaced w/new denso
3. All 6 Injectors serviced/replaced as needed/rebuilt otherwise
4. IAC valve replaced with known good used one
5. TB cleaned, its reading on Scan Gauge appear to coincide w/normal operation
6. MAF cleaned/tested per FSM
7. 3 new aftermarket coil packs
8. NGK new plug wires
9. 6 new denso spark plugs
10. Tried a different aftermarket EFI relay, no change, so put old Denso back on
11. New aftermarket cam sensor
12. New aftermarket crank sensor
13. New OEM thermostat/replaced coolant, jiggle valve installed per FSM, used green coolant (no lectures please, we know about the red thing and made a conscious choice on this)
14. Timing belt set correctly - verified at home last night
15. I know I'm forgetting some stuff - help me out here guys - what am I forgetting?

Anyway, our mechanic is getting to the point of thinking it's gotta be our ECM, and there's certainly plenty of times that we have NOT gotten a CEL that it seems we should have by most people's opinions, so there's reasons beyond just the hard start issue to think it could be this. And we are fortunate enough to have a donor ECM if it comes to that. But my husband and I are scared about that - we want to be 10000000000000% sure that we have 100000000000% exhausted ALL possible other causes before swapping the ECM. For some really strange unknown reason, we are just a wee bit gun shy about swapping a major organ on the truck again. Obviously if it has to happen, we'll do it. But I've yet to really hear anything about what has SPECIFICALLY been checked regarding EVAP on our truck by either mechanic, plus these 2 factors (to me at least) seem EVAP related:

• per our mechanic, when TB held open, starts during normally hard start time

• when hood is up, starts during normally hard start time

And I'm pretty darn clueless about our EVAP system at this point. Still not 100000% sure which components of EVAP our truck does/doesn't have. Thinking maybe that should be our next goal - to try to use neighbor's garage for a full day, spread out all FSM EVAP related documents/diagrams, and teach ourselves the ins and outs of what's on our truck EVAP wise.



OK, now you're all filled in - fix the truck now please!

EDIT: I'm going to go clean my kitchen - when I come back, I will be reading how to fix my truck, right guys? No pressure though

 

I'm back, where's all that brilliant stuff at guys?

Seriously though, if anyone has questions about anything at all, ask away. I'm thinking about googling mechanics in our area that specifically test for EVAP issues, and have one of those smoke machines. Not necessarily taking that step just yet, but thinking it could be a good first step in helping me understand how to test for EVAP issues at least.....

Also, one question I have is whether testing our MAF per FSM is enough to rule out an issue with the IAT sensor that (from my understanding) is inside the MAF? What we did to test MAF was:

- per FSM, while hooked up to volt meter, blow on it - if volts fluctuate, it's working properly (truck was not running during this test - per FSM)

- per FSM, using an ohmeter, measure resistance between terminals THA and E2 - our result was a resistance of 1.7 - then you look at the temp range chart next to resistance value, and ours fell between 68-104F, which correlated roughly with the approximate temp of the MAF itself (truck was warmish when we did this) - results seemed normal

Here's the PDF of what we did, as it likely describes it better than I just did! Should also mention we used neighbor's nice Fluke 25 tool to do this, not a Harbor Freight, and neighbor was with us doing these tests, so I'm fairly certain we can trust the results.

 

On a side note, take one of the used coils you replaced that is still functional and leave it in your glove box. Super simple to replace on the side of the road.
One quit on our rav4 and wife drove it home on 3 cylinders. The excess unburnt fuel ended up taking out the catalytic converter which was $300 aftermarket (part of the exhaust manifold).
If your truck starts missing and you get a flashing cel that says a cyl is not firing the spare coil could save you a tow bill. + your scan gauge will tell you exactly what cyl to look at.
I have a spare in every vehicle I own.

 

Her AFR gauge will also show if a pack goes completely sideways. Dumping fuel down the exhaust makes things a little rich .

 

Man, I go exploring for a few days and now my eyes hurt. Your mechanic should have left you with a sitter.

As far as the jiggle valve and temp. The overwhelming majority of folks report an average 10 deg decrease in ECT reading when swapping the position from 12 to 6.
In itself, 10 deg is nothing but combine it with a ECT sensor reading that's a little off and the cumulative error could be significant enough to cause fuel delivery errors. That's the whole reason I initially mentioned it. Did you guy's get to replacing the ECT sensor? I thought you bought one.
Check out this thread and the included link to a YotaTech thread. Read all of both threads.
http://www.tacomaworld.com/forum/1st-gen-tacomas/276678-thermostat-replacement-question.html

As far as your timing issues, along with the factors BamaToy mentioned, the ScanGauge reading should be more accurate than a timing light. The SG number is the value generated by the ECM. All kinds of factors can influence the accuracy of a timing light.

Plug wires and coil pack firing.
I think I read you replaced the plug wires. There is a specific routing/placement for each wire with intentional crisscrossing. Denso wire kits usually come with a little chart to go by but here's one just in case.


As you have seen, the coils fire 2 plugs each. Lesser appreciated is the fact that both plugs fire at the same time and in series. This happens once with every crankshaft rotation. Thus a complete (no fire) ignition fault with any one coil shows up as a misfire in 2 cylinders.

As can be deduced from looking at the plug wire routes here's a handy reference to the "brotherly plugs".

This and the injector pulse issues your mechanic was seeing still seem to be the "hot leads" to pursue, pun intended.

BamaToy also mentioned the igniter module and the IGF or "firing confirmation" signal to the ECM. This is the only "part", short of the ECM that has not been talked about, yet. Short of swapping in a "test" igniter there is not much you can check. There is a voltage/open/short test for the IGF circuit but it's not conclusive and best left to your guy. Your guy's reader should be able to confirm the signal and check the circuit if he hasn't already. If you have a tachometer and it does not move during the bad start, that might be a clue but not 100% on that.

 

The "holding open the the throttle and starting while hot" has me intrigued. What is telling the ECU to close the throttle when hot? The throttle should be open(choke off) when warm I would think. Temperature sensors tell the ECU if the engine is hot or cold and they should be telling the ECU that it is hot and no choke is needed. I know I'M simplifying.

Just thinking out loud here to generate some responses.

 

DP, I never said you were allowed to go exploring for a few days. You are in serious trouble!!!

Glad you're back, dissecting your post now.

Did you have some fun?

 

Thanks for the input K. Here's a dumb question -

Our mechanic told us if we push the accelerator to the floor for a few seconds then let off before turning the key when we anticipate a hard start, it would decrease the cranking. We were confused by that, because we thought pressing the accelerator down meant fuel delivery, not air delivery. I can't remember for sure, but I wanna say we asked him that right then and there, and he said, no, doing that is allowing more air in.

Don't quote me on the above, totally possible there were miscommunications there.

I guess the dumb question is, what the heck does it do exactly when the accelerator is pushed down?

 

Your '98 actually has a throttle cable. when you push down on the gas, you are opening the throttle, thus helping it get air to ignight the fuel/air mixture. Pretty similar to your mechanic holding open the throttle.

Refresh my memory, when you experienced these long cranks to start, did you ever smell gasoline? I'm betting yes.

 

Could very well be communications, the above seems to conflict with "when TB held open, starts during normally hard start time".

 

Thanks K. That makes perfect sense with what he told us then.

I don't remember ever smelling gas during hard cranks. Its sure possible we missed it, although seeing as how many times we've experienced them, it does seem as though at least once in a while we would have smelled it.

The only smell I've noticed is sometimes after we shut the truck off, we smell something - a strong odor. I thought it was fuel, husband thought it was oil, mechanic said he didn't notice it. That was all on the night we first took it to him. Then the night we brought it home from him about 1 week ago, we noticed it again when we got home from his house - and that time, husband though it smelled like burning rubber. We called mechanic and told him about it, and he said not to worry, probably just the bearing oil or something.

So does a lack of sufficient air seem EVAP related at all?

 

Yes, I'm not sure if he wanted us to let off then turn key or keep floored while turning key. That's the part I'm most suspicious of a miscommunication.

 

OK, now I'm really wondering about that - seems at the heart of the issue.

Is that right guys, that the ECM should tell the throttle to be open when the truck is warm?

If I'm remembering correctly, the TPS is ~10 when we start it, whether during a hot start or cold start.

WAIT! Could we have an f'ed up TPS??????

 

If we got no codes to work with, we got no real data. I know codes are not the answer to all engine issues, but they give the skilled mechanic a very good location to start.

From experience, I've had emission issues and have never had a hard start problem, but I have ALWAYS had a check engine light when I've had emission malfunctions. In almost every situation, even the smallest issue with the emission system will trigger a CEL. In my opinion it is the most prone to failure, with the electrical system being first. In fact, many will say our emission systems on our trucks are too sensitive.

If you don't have a CEL, then we almost have to assume the evaporative system is intact. I wish I could offer more

 

Going by memory here, but when we go to start our trucks, the ECU must detect 2 full revolutions of the crankshaft in order for start sequence to initiate. If that is correct, with you holding open the throttle while cranking, the only thing you are doing is allowing more air into the intake. The ECU won't inject any fuel until it senses the crank has made 2 revs. Again, I'm thinking out loud and will be happy to be corrected.