Surging Idle and constant misfire on startup.

Alright, so if you have followed my previous thread I have had the head gaskets done on the 2008 Toyota Tundra with a 2UZFE. The harness was fried so we installed a new harness, fuel pump was bad so we installed a new fuel pump as well, spark plugs as well. We got it started but idle is rough it surges from around 5-600rpm to around 1,000. At start up it has a constant misfire on cylinder 1,2,4,5,6 cylinder 3 and 7 we installed new coil packs and I cannot monitor a misfire on those cylinder. We also noticed while the truck is surging the short term fuel pressure is around 14-20(positive) and it will sometimes go into the negatives like it should but this is not a constant occurance. I am running out of ideas on what to do with it, anyone got any idea of what it could be?

 

What does the MAF read? This could be something simple like a vacuum line that's cracked or not hooked up; a smoke test may be in order. (The positive fuel trim means the truck either is receiving too much air from a vacuum leak or it thinks it's receiving too much air from a funky MAF)

 

MAF reads 16-14.89m/s at rough idle(5-1k rpm) and when it idled correctly around 2k(cold start) it would read 18-17.

 

Have you hooked up a reader to get the codes that are being thrown? post em up

 

p0301, p0302, p0304, p0305, p0306, just basic misfire codes and the engine light is flashing but those misfire codes are also the pending codes.

 

I went ahead and got a smoke machine to see if the intake may have a massive leak in it(will be checking it tomorrow), because it is running really freaking RICH(all we can smell is fuel). Whenever we put it into drive and press the gas it bogs down and almost shuts off like it is getting to much fuel.

 

Is that grams per second?

You should see about 5 grams/second at idle with the 2UZ. Is the throttle body butterfly closing properly?

 

Yeah my bad, it is showing like 16g/s. I am going to check that but I also monitored the throttle position and it was acting funky.

 

My knowledge of the 4.7 is not substantial, but it's possible that the throttle body and the MAF share grounds, 5V supplies, etc., and you could just have just missed a ground or not tightened one all the way (this I know from experience!).

 

I have ran through multiple grounds and all of them are okay. I towed it to two different shops and they checked the grounds I installed a new wiring harness and I forgot one ground and they fixed that. The electrical shop I had it towed to said the fuel pump was bad so I threw a fuel pump in and now I have it back at my shop trying to figure out the other issue.

 

FlexFuel truck?

 

Alright, so I did a smoke test on it and it had a massive leak under the intake manifold. I removed the intake manifold and found out they did not replace the old intake manfold gasket. I installed a new one and that fixed the massive leak. BUTTTTT, I also installed new injector seal and am now having another issue(its going to be a long day for me). I installed the new seals on all the injectors plug everything up correctly and now cannot get it started. It was running after I installed the intake manifold but now after pulling the injectors(they were leaking) I cannot get it started. I checked for spark and it is getting spark. It will not run off of supplemental full(sprayed half a can of it in there) and it will turn over but not crank at all.

 

anybody got any ideas to go from here?

 

Can you verify injector pulses? Some scan tools allow you to manually pulse them.

Did you bleed the air out of the fuel system?

I'm glad you found your vacuum leak. A half decent mechanic would have smoke tested that as part of the diagnosis BTW.

 

Oh trust me I know, I am pissed at that shop but I am dealing with that. It has been a whole ordeal with that shop. How would I bleed the air out of it?

 

Maybe post pictures of the fuel rails if it's not clear. Sometimes you'll see Schrader valves on the rails that you can press with a poker to let the air bleed out. If there aren't any of those, you can try cycling the key to force the fuel pump to run and shove the air into the tank.

 

It is fowling the plugs it is getting so much fuel, i can crank it now but is flooding every single time with no misfire data on the scanner

 

If you haven't reset the ECU, it may be trying to satisfy the vacuum leak still.

 

We connected the battery cable together for 10 minutes and it is still doing the same thing. To my knowledge the timing is fine we have had it running for a while prior and did not hear any abnormal noise through the RPM range (2k-5k). At idle the truck will shake and feel like it is misfiring but no misfire is recorded and eventually when giving it gas or letting off of the gas it will bog down and stall.

 

I would verify that you can pulse the injectors just to be sure they aren't somehow all stuck open or something.

 

Fuel pressure measured at 40psi

 

I could be wrong (I thought I was wrong once, but was not), but I don't think the 4.7 was offered with FlexFuel, only the 5.7.

 

I had similar erratic idle and misfire codes, turns out the wire harness that runs down the front to the crank position sensor and oil pressure sensor had gotten damaged by the fan belt. It was erratic and would be fine at times, but gave me a headache until I dug deep enough to find it.

Since you've done other harness work I'd give that a good check.

I had thought I had fuel issues as well and changed fuel pump, regulator and injectors but pretty sure it was the crank sensor and wire damage all along.

Good luck!

 

I towed it to another shop and they ran through every electrical connection and they said everything checked out to be okay with it. I am heavily debating just put a new,used motor in it and see what happens.

 

Just had it towed to another shop to see if they can give me a halfway decent answer at all.

 

Check ECT and IAT temps and compare to ambient. Cold readings will enrich mixture.