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

Not gonna freak out with excitement YET, lesson learned......

 

But, WHILE WE WERE ON THE PHONE, he goes "I just found a fuel leak"

 

Said he repeated his test of the pump with the gauge closed, and it started right up.

Then repeated test again with gauge open, and it started right up. So thinking it's not the pump.

 

He said there's a leak in a return hose that runs off the FPR and ultimately back to the tank, it's a fuel line that's ~1/4" in diameter above driver's side valve "something" (I missed the last part of what he said)

 

Said the hose is $3, he's going to replace it. I could visualize what he was talking about, thanks to Mod's helpful linked article this morning!

His words were, "this could be good news, you might not need a pump" and I said "pump was sounding good, I've been thinking ECU all morning, this would be unbelievable news!"

 

He's saying he'll replace that hose and repeat his test again. If all checks out, then perhaps we'll......

FINALLY be done? Not going to freak out yet.....but cautiously hopeful! He asked me again, "so you thought you smelled fuel you said, right?" and I said "YES!"

Crossing fingers.....more news later.....

 

Guys, does this sound like it could be the real true for sure culprit, or does it still leave lots of room for doubt?

Koditten? Mod? Please be honest......really......cuz as great as this guy has been thus far, at some point it may be in our best interest to take the dreaded last ditch effort drive to the dealer for the $110 diagnostic assessment......so if this doesn't clear up all suspicions for you guys, please, seriously, tell me!

Would a leak in that return hose fit logically with great starts cold or super hot, but horrible starts warm?

 

This makes sense. That hose is kinda in a position that could be damaged by the removal/insertion of engine. It is also kind of hard to see when engine is installed.

Do keep us informed. I hope it really is something as simple as a split hose. That would explain the off and on smell of gasoline that I think I remember your hubby meantioned.

 

Thank you!

Would a leak in that return hose fit logically with great starts cold or super hot, but horrible starts warm?

 

It goes back to my initial statement of the truck starting just fine before engine change out and it being something stupid and simple cauing all the issues.

I still am having doubts about the illumination of the CEL when the previous engine grenaded.

Is there a chance the battery was disconnected or ran so dead that the CEL's were cleared? I dunno. There is just no way a that the ECU would not have turned on that CEL when you got your first miss fire/hole in the piston. Some data is missing. Maybe the same person that was filling your powers steering resivior, was also clearing your codes?

 

Sure would. Fuel line would not lose pressure on short duration hot starts, but would depressurize over the 45 minutes or so. Must be a pretty small leak if it was to lose 30psi over 45 minutes, but not lose any pressure during short durations. I'm betting the leak was no more than a couple of drops of gas over that 45 minutes.

Remember, liquids are non compressable, but they can be pressurized.

As much as I'm enjoying the thread, I have to admit that I want to see the end of it.

 

Thank you for your input! I agree, can't wait to see the end of this damn thread!

Yep, it's true, this still wouldn't clear up the lack of CEL during piston hole. I suppose a dealer diagnosis on that might be a worthwhile next step if we find the fuel issue to be a $3 hose though, so we could still be on a positive path here!

 

HELL NO !!!!

not until we hit the 1000 post count at least

besides we need to do the bearings before we let you go anyways

 

Oh good grief Keakar. If we hit 1000 posts, I am buying a mountain bike and we'll have a contest on the thread for you guys to win a free Tacoma with just a few minor issues........

Shit, just realized what I said. Will now start editing every post to add onto it, instead of writing a new one.......1000 is not far off.......

Not going to respond to that comment you just made below this. Stop posting man! I was in spaz posting mode yesterday and today, cuz I wanted to get all the Taco World input as fast as possible on what the mechanic had told me, and it was faster to get the info out there that way, instead of writing a huge long summary then hoping/waiting for folks to log on and see it and give their thoughts......

 

well this time yesterday we were at 650 posts, and now we are at 800 so by friday we should hit 1100

 

99.9% sure but not 100%. You know what happens when you assume. If your truck was in my shop I could verify it pretty quick.
Engine control module or unit. Different names for the same thing. Yes it's behind the glove box but the wiring goes all over.

I don't see how, smell yes, fire hazard yes but not the running of the engine.
The pump is capable of delivering near 60 psi of pressure. The FPR, located downstream from the injectors "regulates" this pressure between it and the pump to around the 43psi the injectors like by allowing some of the fuel to sort of leak past and "return" to the fuel tank via the return hose. I would love to be wrong here and get my 1 mistake for the year out of the way but I don't think so.

 

OK, with regard to the concern over lack of CEL during piston hole event, some of you might remember a few days ago we pulled the MAF and started Taco to see if we'd get a CEL. We did. We jumped for joy. However, we really had no idea if this actually proved our ECU was fine or not. I posted that info to a guy on Yotatech, and his response was:

"With the MAF sensor unplugged the ECM does not see the signal telling it the engine is drawing in air .
So if it is all working like it should it turns off the COR*** shutting off your fuel pump.
The ECM just no longer sends the voltage to the COR"

What is a COR? Can anyone decode his post for me, I didn't really understand it...

EDIT: Also, what is that hose/fuel line made of that was found to have a leak? Just curious......

 

Your test only proved that the CEL worked in that particular case. There are a bazillion other cases.
No CEL when the engine misfires (for what ever reason) is strange. I guess I wasn't following the thread closely enough when that was discussed.
The COR is the circuit opening relay, the one that turns the pump on and off at the request of the ECM. I have no idea if the ECM would shut the pump off due to unplugging the MAF but it should set a CEL.

 

Thanks DP. Don't suppose you have any ideas about why no CEL during initial engine incident? I posted a summary of some CELs we got in August, but how we didn't get one during the piston hole event on 11/30. Post #757.

It's seeming like that's the most concerning factor here to a few people, so its concerning me too - it really doesn't make sense. Really don't want to replace ECU. And really don't understand the electrical stuff at all.

 

The return hose is just a hose, nothing special other than being rated for gasoline, it carries little to no pressure. It's bought by the foot at any parts house. Some sections of the fuel return "route or line" are steel tube for cost and ease of assembly reasons. The rubber portions, one near the engine and one back at the tank are just there to allow a little "flex" as the engine shakes/vibrates.