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

http://www.customtacos.com/tech.old/files/tsb/04-EG05204-HardCrank.pdf

YOU GUYS! This is a Toyota service bulletin on extended cranking in '04 Tacos and Tundras, including 5vz's. Look on pg 2, about halfway down - it says this:


Tacoma (2RZ–FE, 3RZ–FE, 5VZ–FE)
1. Confirm customer’s complaint.
2. Check fuel pressure and residual fuel pressure. Refer to the Technical Information System (TIS), 2004 model year Tacoma Repair Manual: SFI (2RZ–FE) or (3RZ–FE) or (5VZ–FE): Fuel Pump: On–Vehicle Inspection.
3. If fuel pressure falls to zero after the engine is turned OFF, proceed to replace the Fuel Suction Tube Sub–assembly. Refer to TIS, 2004 model year Tacoma Repair Manual: SFI (2RZ–FE) or (3RZ–FE) or (5VZ–FE): Fuel Pump: Removal.

I realize this doesn't make sense because we have a 98, but still, it's a weird coincidence. Maybe other years had similar problems sometimes?

 

Worth reading, if you haven't already!
http://forum.ih8mud.com/threads/fuel-rail-pressure-when-starting-real-time-help-please.102573/

 

Thanks trx. I know, this guy's symptoms were extremely similar to ours, and I read this one right before we were doing the fuel pump. And I was freaked out that we'd have this guy's problem in addition to needing a pump (charred wires to pump). But then we heard about soldering/splicing wires. And if I recall, the mechanic that changed our pump said no charred wires, and no rust in tank. But still, it's weird that so much matches otherwise....

 

Same mechanic that originally installed the motor? Still might be worth lifting the bed and having a second look. I went down the same rode with my 2.7l, I finally gave up and installed another pump, problem solved.

 

Tacoma fuel pump current and voltage with engine running

 

Nothing odd there. Every rotation of the pump armature shows load and unload. Volts a solid 13.7 or so.

 

No, mechanic #2 did the pump in mid/late Jan, after engine guys did FPR and it didn't fix it.

That's great that the pump fixed it for you. It's shocking how many people have some version of this problem, even with different engine types! It's weird!

We're totally open to whatever these smart guys working on it recc. as far as the pump........seems like we are getting some wacky fuel pressure results that don't really point to a clear pattern, so hard to tell what the heck is going on.

 

Would there be current and voltage during cranking, or not until the engine starts?

 

lots of things are strange on these trucks such as the a/c clutch has no power unless the engine is running so its hard the test for a bad a/c clutch without using a jumper wire.

a lot of stuff wont work unless the truck is running

 

Looks like if we had a problem similar to that TSB, we'd need a new fuel pump bracket instead of what is called a fuel suction tube sub assembly on an '04 Taco. You guys think the test results so far indicate this being a possibility (that there's a problem with the fuel pump bracket)?

PS: Thanks for all the great posts everyone!! Appreciate all the continued input and hard work everyone is doing!! Thank you! : )

 

TW should sponsor a contest - whoever figures out what it is first gets $20K towards the Taco of their choice!

 

There should be current and voltage present as long as key is on. There should not be much of an amperage change regardless of running or just key on. The fuel is always flowing, just what is not going to injectors is sent back to tank.

Something is screwing up the air to fuel ratio. Did the 02 sensor itself get checked? Did the wires to 02 sensors get checked. That sensor and wiring would be prone to damage during an engine change out.

One thing to check. The 1998 trucks had a 3 wire sensor and newer trucks had a 4 wire sensor. I don't know why they are different, but they were changed for a reason. I would like to know the difference.

Later
Ko

 

How much am I in the hole?

 

Gonna have to stop posting, I'm grilling and drinking...again.

 

Uh oh. We all know what happens when that's goin' on....

Time to start advising us on all sorts of wacky stuff to do to the truck time!

Seriously though, we tested both O2s at home and they were within spec, but both were nearish to the end of the range, and I believe the one before cat was more near to end of range. They have at least 130K on 'em, seem like a possible culprit to me!

 

The rear 02 sensor doesn't do much in relation to telling the ECM how to run the engine. The front 02 sensor plays a pretty big part. You have to wonder, with that front 02 sensor being so close to the engine if it is getting heat soaked, thus sending fucked up feed back to the ECM.

 

Makes sense to me. And there was question on the thread a while back of whether that front O2 could have sustained damage from when the AFR O2 was installed VERY VERY close to the stock O2, I think speculation about the welding fumes maybe?

EDIT: Should also mention, one of the two bolts on that front O2 was broken off/missing when we got the truck back from the engine mechanics. We had a mechanic replace the bolt a few weeks ago.

 

I don't see how welding fumes would make trouble. I'm more worried about that sensor receiving physical trauma while that AFR was being installed.

While a fume is defined as vaporized metal, there is the possibility that some foreign metal could have attached to the 02 sensor. Who knows. I don't.

 

Agree about possibility of physical trauma! Was just adding this to my last post:

EDIT: Should also mention, one of the two bolts on that front O2 was broken off/missing when we got the truck back from the engine mechanics. We had a mechanic replace the bolt a few weeks ago.

 

I know, it's been bothering me for some time. I have that "Y" down pipe if you think you need one. Only cost you a couple of drinks