3rz Fuel Pressure and Rough Starts (solved)

Not throwing any codes? If I remember correctly you just had your engine rebuilt like last year right?

I'd start by doing an ohm reading on the injectors ... in the heat of summer you don't want more than 16ohms

 

what would the OHM test indicate? would a bad injector show higher than 16 or an OL?

and yes you are correct i did put a new rebuilt engine in last year and it has been nothing but trouble. what ever killed my last engine was a bolt on part and i had the same rough starts on the new engine, that eventually cracked the head and blew the head gasket on the old engine. i had bad pinging also and an overheat that warped the head and sent it back in to be re-bult again. dude i'm like 8k in on this engine and its still off a little. slight ping still, blow by past the rings and fuel in the oil. a new IAC and MAF fixed the really bad cold start rough idle i had but trying to track down the fuel in the oil.

I just did a compression and leak down test today and good compression (180-190) but bad leak rate....which explains the blow by out the oil filler cap. leak rate was 15% on 1 and 2 and 18% on 3 and 4

that's still within acceptable limits (barely) so i am hoping the fuel in the oil is an injector and i can live with the blow by, but if i'm diluting my oil that is a bearing failure waiting to happen and id rather it be an injector lol

I must have Stockholm syndrome with this truck because it is torturing me yet i still love it..

 

I thought it was you! We both installed rebuilt motors in our trucks about the same time I remember asking you about where you got your motor from when you posted pictures dropping it in. Thankfully I haven't had any motor issues since then... sorry you've been chasing your tail

So take my example with a grain of salt because my knowledge on these 3rz motors is based entirely on what I've run into.. back when the 3rz was in my 4R I had very hard start issues with no codes. Found a cracked manifold and bore scoped to see a crack in the head at cyl 3. Rebuilt it and reinstalled the stock injectors. It started much better but still not as easy as I figured a rebuilt motor should


Long story short 3 of the original injectors tested at 14ohms and the 4th tested at 280 something! Put in 4 other used injectors from a different 3rz and it fired up exactly as I felt it should.


Now I don't know how a "leaky" injector would ohm test out but if you reused old ones its a place to start. After that I would get a fuel pressure test kit to see how quickly it's bleeding off ... im bot sure what else would be suspect causing fuel in the oil (be warned the test kit sucks balls for our motor cause there's no test port to thread into)

 

I bought a pressure guage kit from lce; it helped solve the issue letting me know how long it took for the pressure to bleed off.

 

Is that in all the time? That's really cool

Since you've got one, do you think it would be possible to make a bracket with hard lines and leave it in all the time?


I just like gages that do stuff lol

 

Dude, can you walk me through how to do a leak down test?

 

While we are at it I bet I could screw in a pressure transducer with some Bluetooth capabilities

it is in all the time; directions said to not leave it in. I don’t see an issue.

 

here is a great video on how this test is performed.

i like to pull the EFI relay and the connectors to the coil packs just in case i want to do a compression test as well and also just for extra safety.

https://www.youtube.com/watch?v=og9nXfXSaoY

 

I have the same gauge installed on my truck and i leave it in also with no issues . mine is odd i have seen it leak down to 20 almost immediately than take 30 min to drop to zero, i have seen it hold full pressure for 30 min than leak to zero and i have seen it hold for days full pressure. i literally quit looking at it because its so inconsistent. but i have heard from other guys here that if it hold for 30 min its fine. what have you guys heard whats acceptable for a leak rate? i haven't found a Toyota spec for this myself.

 

I’m really curious what is acceptable for fuel pressure to bleed off. I would guess it’s an all or none situation but I would need a diagram of the system to say for sure. I’ve since had the motor rebuilt like you guys. Found what I believed was coolant leaking into a cylinder due to a leaky head gasket. Could have been leaky injector the whole time. It was enough of a leak to start causing misfires on startup. I’ve been sending off my oil changes to be tested since the rebuild and nothing abnormal yet but I’m not out the clear until the 3rd change at 7,500 miles. Yota1 said the orginal head had a few cracks which I can not see with the naked eye (I asked that they send my original back, the newer one is definitely of poorer quality based on a visual observation). In fact I was just at the Nissan motor museum in Yokohama and the raw head casting looked similar to what came on my new head but I am no expert.

also I still have the same amount of blow by, none of my other Toyota engines have much blow by and they all have over 175k. One is a V6 and one is a V8.

I think I might ohm the injectors, use the bore scope to see if I see any liquid in the cylinder, etc.

Curious on any updates from you two.