Hello I have a 2004 manual with a engine I rebuilt about 3 months ago and put about 1000 normal miles on it and 3 drift events on it where blow by started so I tore it apart and replaced a very torn up side seal luckily everything else looked good, so I reinstalled the engine and did a heat cycle making sure everything was good and then went for a drive and it hesitates at 5k will continue to rev but it’s very slow and lots of backfire, it got new plugs coils and plug wires when I did the first rebuild, I’ve bought a new crank angle sensor and that didn’t help. I do not have a cat and I have an AEM intake, omp off to side of engine as I premix. I have codes for P0037 ( Heater circuits low voltage bank 1 sensor 2) P0661 ( intake manifold tuning valve control circuit low) and the intake valve all move freely, P0138 ( O2 sensor circuit high voltage bank 1 sensor 2) and P0302 (“cylinder” 2 misfire) I’ve done quit a bit of searching on here and have not been able to find anything the same some things close and the suggested fixes were not wrong that I could tell, any advice is greatly appreciated I’m really not sure at this point so maybe one of you knows or can point me in the right direction. Thank you

 

So here are the fuel trims at idle and the air flow and load of the car after it has hit 180f, I am not sure what’s normal but I was advised to show these

 

Anyone have any ideas?

 

Wait the only thing you replaced in the rebuild was a side seal? What was replaced in the first rebuild?
There's a difference between "looks right" and "in spec", and that side seal got torn up on something...

Is it possible the valve solenoids were mixed up when reinstalling the engine? I.e. the SSV is connected to the APV and vice versa?
Ditto for injector wiring, it easy to mix primary and secondary and it would give you weird problems.

Need more info to diagnose further, ideally fuel trim values on a warmed up idle.

 

The first rebuild was all seals and middle and rear iron, reused housings, my best guess is my side seal wasn’t correctly clearances and it expanded too much that’s my best guess. I didn’t unplug the injectors I left the harness attached to the intake manifold so I didn’t need to worry about that, it is possible that I maxed them up but I had the wires marked that I unplugged to make sure they went back where they should have, I will give that a check though. I posted a picture of fuel trims when warm and it said it had to be looked at before it could post. I’ll try again after this post.

 

 

Hmmm. Your car is running in open loop, when idling fully warmed up should easily be closed loop operation. That would also be why the fuel trims are 0'd out -- they're not being used. It says distance since codes cleared is 0, does that mean you haven't moved the car since the battery was disconnected? That might explain it, you need to put drive cycles on it.

Airflow for 850rpm looks good though so there's not an obvious vacuum leak or anything.

I think the next step would be to log the same data when the issue occurs and look for clues there. And make sure the intake valves are all correctly connected and routed. The issue kicking in at specific rpm makes me think it's related to one of them. The APV opens at 6000, so if for whatever reason it's not opening, you'd see about what you see. The VFAD opens at 5500, but you don't have a VFAD because of the AEM intake. Possible the VFAD line was somehow routed somewhere else?

 

I’ve driven the car about 10 miles in two different times since the battery was hooked up and it hasn’t been disconnected, I will look at the valves and make sure they are hooked up properly and move freely tomorrow after work. I do recall seeing a small hose I didn’t know what it did and it had been blocked off when I got the car, it may have fallen off it the plug came out so I will look at that as well. Where does that hose come from? Upper intake manifold?

 

I will also log the data scanner when driving at high rpm’s when it’s not running properly and post them up.

 

You might have to be more specific about which hose you mean. Could be the VFAD, but there are others.

 

Yes sorry, I meant the VFAD hose and can I just plug it off?

 

Yep just plug it or remove entirely and cap securely the nipple under the UIM.

 

Okay, thanks for all the info so far, I’m hoping to get it going before this weekend for a drift event.

 

Okay so I did have a bad SSV silo pie but I had a spare and changed it, all the vaccine lines and wires are routed right on the UIM drive it and nothing changed, it did accrue to me that I do not have one I’ve the airbag sensors I belive mounted on the underside of the front crash bar I’m not sure if that could affect it but I lost it during the rebuild, I also learned that my exit has some water in it so I let it sit in rice over night and it didn’t change, that could definitely be it I would think but I’m not sure. I drove it and kept it steady at 40 in second and here is what the data reader said

 

I also got a lean code but this went away after I started driving I imagine from having the fuel line unhooked from start up

 

I see the 02 sensor is reading 0 v. Maybe look into that.

 

That's bank 1 sensor 2 though, the postcat which I think was removed?

Hmm. Nothing looks terribly out of place here except the fuel system still running open loop. Maybe it needs more time to learn, but that's weird without other codes present and holding steady speed.

You said the OMP is off to the side? That's usually a 3000 rpm limp mode, but perhaps something else plays into it. OMP codes don't always show up on non-Mazda scanners. If the CEL is on but no codes are stored, that might be a clue. Why is it off to the side anyway, you can premix and run the OMP without trouble. Best of both worlds.


Couple of other things:
- is there oil in your intake and does the exhaust puff oul clouds when the issue occurs?
- do you have flow straightener screens in your intake before the MAF? Not sure where the AEM puts them exactly but you definitely need those.

 

Yes I belive it just has the one O2 sensor, it does have two screens in the intake to swirl the air. The omp is off too the side and I have tried switching it with another that I have and even checked the pins to make sure they were good but still nothing changed. I just personally thought it easier to not run it so I know for sure it’s getting the amount of oil I put in and should be plenty lubed and then I can run whatever oil I like without adding or worrying about carbon build up

 

Sorry I forgot to reply to this question, the intake has a tiny bit of oil in it but I believe this to be from the blow by before the engine was reinstalled. Yes the car smokes on start up it has since I’ve owned it never really been a big concern to me as I figured it was just a little oil rich and that didn’t really bother me. Is there a bad reason for it to smoke on start up (and to clarify it’s not a huge cloud just some smoke until it’s warm)

 

Is it oil smoke or coolant or condensation? Oil and coolant should stay in the engine, there's no "oilrich" condition. Condensation can totaly be that smoke though if you're in a cool humid climate.

 

I live in Washington and it’s been fairly warm and it still smokes on start up, it’s not coolant, doesn’t smell sweet and isn’t white and I don’t think it’s condensation but this is also the first that I am hearing that can happen. I believe it’s oil smoke but it’s not very blue

 

I found out that the injectors were wire up wrong and I found out the correct order and wired them up correctly went for a test drive and rolled my car a few times…. Here’s a few photos

 

Well that sucks !!

 

But you solved the issue right?

 

Sorry been gone a while, yes it did fix the problem