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

Just looking at the data and pictures available I have a couple of questions, and some comments. On the cylinders that showed some leakdown, (5 and 6 I believe) where was it leaking to? Intake or exhaust?

IAT of 118ºF is not abnormal after a hot soak. Many times scan tool data uses "raw" data, or the actual value when showing the data on a scan tool, but the internal computer uses calculated temperature for starting, based on the IAT temp, and the external temp sensor. (Just food for thought) In all honesty, having an IAT of 118ºF after a hot run is not high at all.

Fuel leakdown is more that 4 PSI, so that is a definitive problem right there. I would chase down the cause of that and get it fixed before chasing down any other issues. Having that kind of leakdown could be a catalyst of other problems.

Jen, it is VERY common to reuse valves on cylinder heads when rebuilding. When I rebuilt mine I simply lapped the old valves to the new head (Google search: "Valve lapping" to learn more) and set the valve lash.

Now here is a consideration: The Toyota engines have two different valve lash specifications. One is cold set, the other is warm set. If you use the numbers from warm set, and use them to set the cold valve lash, then when the engine warms up you can very possibly have a valve that would be leaking down. My recommendation at this point to the technician would be to fix the fuel leakdown, then remove the valve covers and check valve lash when engine is cold, then compare to specs.

 

Only if a new head was purchased with valves and cams included. On a rebuild, the most common process is reusing the valves, and grinding the seats, then lapping the valves.

 

I am under the impression that they bought a dressed long block to be installed and returned the old motor as a core -- not a rebuild of the same engine. I could be wrong.

 

but it was not a brand new dressed longblock. As I recall it was a rebuilt long block. Rebuilders inspect the valves, and if they are good, then they reuse them. A valve can cost $15 each. There are 24 valves in a 5VZ engine, so this would increase the cost by $360. So yes, even rebuilders will reuse valves if they are still good. Today's valves are built with a good quality hardened steel and rarely "go bad" over the life of an engine that uses an overhead cam design.

However correct me if I am wrong about which kind of longblock was bought. If it WAS a totally new longblock, then I would be contacting the installer for a warranty on a defective unit with those kind of leakdown numbers.

 

I would be concerned with both the loss of fuel pressure AND the leaking valves...we have MULTIPLE problems here and lets see how the current mechanics sorts them out

If the valve lash is good (and I suspect it to be) then we have leaking valves, which normally requires a trip to the machine shop assuming the cam timing is good. Maybe the cam timing is off...

 

Yes, that is what we were told. That a "new" (not our old) remanufactured dressed long block was installed, and our old engine was returned to them as a core.

I assume they obtain lots of 5vzfe's from junkyards, then rebuild them and install them for people. I think a lot of their business is folks with an older/less powerful Toyota engine come to them to have them put a 5vzfe into their Toyota truck or SUV, and make the appropriate modifications to the vehicle to accommodate the different engine type. So naturally, they would always be coming up short on 5vzfe's, so that's why I assume they obtain lots of them from junkyards then rebuild them. But I don't know what their protocol is regarding the valves. A neighbor was just explaining to me the process of "spiffing up" the valves to reuse them in an engine rebuild. I will look back in my notes to see if I ever wrote anything down about their valve protocol.

 

Yeah, I would think that most likely you had the valves simply reseated and lapped. It's a VERY common practice on rebuilds. Otherwise if all new parts were used then a rebuilt engine would cost somewhere in the neighborhood of $6k

 

It doesn't really matter what the published "protocol" is, what matter is that they have delivered and installed an engine that appears to have excessive valve leakage. It is up to the mechanic who supplied and installed the engine to why the fuel pressure is leaking down. It might be an issue with existing parts, check valves in fuel pump, pressure regulator valve, return hoses from rail...but the leaking valves need to be tracked down. It could be poor cam timing, poor valve adjustment, wrong parts like incorrectly ground cams or nothing more than not finding TDC during the leakdown test. I would probably guess, based on my experience, a poorly done, or NOT done valve job.

I have bought more than ONE rebuild head that had every valve ground beyond specs.

Howard

 

I was assuming a rebuild. Finding a brand new 5VZE would probably be very difficult even if you were willing to pay for it.

I got a 20R long block for my Celica from JIS for $700, pretty sure they provided a lot of info on the rebuild specs, including compression and leak down numbers, or at least compression numbers.

 

I have seen and road in vehicles showing a 50%+ leakdown,,and they have ran good for 100's of thousands of miles. Not the most efficient, nor the best engine health,,but they do run for a long time. The 30% is a bit scary Jen, but it might be just a bad valve setting. Lets hope they installed the piston rings the right way, which is the other big part of the picture on leakdown.

Plugs look nice and clean,,so that's always good.

I agree, Fuel pressure issue at the top, then a cold engine valve lash check. A person can set those exhaust valve settings a bit tighter cold,,it only extends the life of the valve by way of extra heat transfer to the valve seat once it gets super hot during operation. Don't get crazy,,just a couple thousands tighter.

It looks like you are in well educated hands on the wrenches.

 

Wow. Lots of new thoughts rattling around in my head. Seems like the compression/leak down findings and potentially the valves could be key factors in this thing. All I can say at this point is, I agree, Mod, we are in well educated hands on the wrenches, for which I am beyond grateful and will continue to watch all of these brilliant minds come together to form some conclusions for us....thank you everyone for your support and for offering your input and hard work, especially Noahpete!!

 

While I don't like the 30% leakdown, I do NOT feel it is related to the symptom we are tasked to find. (My opinion only)

 

Regardless of the relationship with hard warm starting and poor leakdown, it is a problem that should NOT occur on a VERY expensively rebuilt and installed engine. I have seen vehicles coming in with burned valves, still running, but that is NOT what Jen paid for.

Howard

 

Agreed.

 

My belief as well. A leakdown I do not see causing a hard start after hot soak.

 

I concur.
A previous Tech in the chain noticed the relatively high running fuel pressure (claimed it was the wrong pump). That, combined with the erratic residual fuel pressure deserve investigating, the FPR "should" be "regulating" down closer to the factory spec. Most important with that issue would seem to be "where is the residual pressure going". A possible scenario is the high running pressure is causing excessive drip from most/all of the injectors when the engine shuts down resulting in a super rich restart. (beyond the Toyota spec of 1 drop in 12 minutes per injector)
Maybe take the FPR out of the equation by "pinching" the return at engine shutdown and see if the quick bleed down continues. Then disco and plug the fuel supply line (with pressure gauge plumbed in it). Let it pressurize while cranking then observe the drop. This will limit leakage to the pump check valve. If these 2 checks test good, all that is left is the injectors, where hot start problems could result.

My Taco runs at 45-47 psi and bleeds off to 20psi after around 1.5 hours and stays there. I have a fuel pump cut out switch (as anti theft) and if I mistakenly leave it off the engine will still start and run for maybe 4-5 seconds after sitting over night.

I feel for you guys on making a call when pretty much everything has been replaced. Go by the facts and your findings.

FWIW here are some shots of a Taco OEM pump. It is strikingly similar to the Bosh cutaway.
It's notable that there are 2 check valves. One for "back flow" (yellow arrow) and one set up in the opposite direction (red arrow). I can see 2 possible reasons for the latter, over pressure relief and/or providing some "minimum" flow thru the pump for cooling. There is also a pinhole in the pump body itself (no valve).

 

Sounds like most agree it is not likely related to the extended crank time symptom. Makes sense to me. But now I'm kind of worried/wondering about whether the compression/leakdown issue is something worse than the starting issue? How big of a deal is it?

EDIT: We wouldn't be comfortable going back to the engine mechanics to address it, so it makes me nervous because I'm not really sure what the heck we'd do to correct an issue with the engine itself. Yikes.

PS: Eric should be heading out that way in the next hour or so.....he got tied up at work later than he expected, but emailed and said he'd leave right around now, and will be coming from the Bridgeport area......

 

Eric thinks he'll get there around 2:45 or 3, he is making a delivery downtown now and will come straight there afterwards

Got a chance to talk to him about things more, and he likes the approach of diagnosing the likely fuel related starting issue as originally planned then looking into the possible valve/compression issue later, since it seems like that is kind of the consensus. So I am feeling better about that approach too.

Ultimately we both just want to do whatever you guys think is best! Thank you so much for working on this for us!

 

I wouldn't worry about the leakdown right now -- you have some really good cylinders, some OK ones, and some not so great ones, but consensus is that it is not contributing to the starting issue. If it runs fine once started, I would just drive it once this starting issue gets resolved. What needs to be done depends on where it is leaking, and that is serious work that can wait until it is truly causing an issue.

Anyway, if you are in Portland, go get some BBQ from my buddy Rodney at Podnah's Pit.

PS: I am still betting on a leaky injector. I don't think it is a heat issue, just an injector that doesn't close all the way. When it doesn't, the fuel pressure goes down and it is hard to start due to the fuel leaked into the intake. When it does, fuel pressure goes down more slowly and it starts OK.

 

I have to agree. Those numbers are not deal breakers. This is a case where too much info is really not a good thing. I know you want numbers that are perfect, but it is not realistic.

If you picked 10 vehicles with 50000 miles on them, I would bet at least 2 would have similar numbers And they will be running and starting just fine. Even hot.

I may have forgotten, but do you get a raw fuel smell out of the tail pipe when were these hot starts. I don't think a cat converter can scrub all the fuel vapors if you are super rich on these starts.

I won't judge if you are caught sniffing tail pipes.