Engine won’t turn over/start

Thanks Mauro. Is the relief valve the one thing on the right side the fuel rail?

 

[QUOTE="There is an engine ignition fuse in the cabin fuse block under the drivers dash. Think it's a 15amp. Outside of that specifically, check fuses for continuity at least.[/QUOTE]

I strongly recommend you check this before digging any further, I have seen your condition replicated and it was this fuse blowing due to a shorting spark plug wire harness connector (near the suspect ground). the fuse box in question is under the passenger side dash board. Check those fuses.

Following that, if you disconnected that ground, clamp a wire from it straight to the battery negative. I did that to prevent future problems as I would only get a problem when the engine was running.

 

Thanks for encouraging me that way big_dill. I know where those fuses are (though not sure which of the few 15V fuses is the ignition fuse...) but I was lazy and didn’t feel like trying to get them out I’ll check tomorrow.

What is the advantage of disconnecting that ground and connecting it directly to the battery negative?

 

I wouldn't focus on only 15A fuses, unfortunately I cannot remember which one, but I recommend you check them all with a multimeter.

IF you want to confirm if this is the case: pull out at least one spark plug, attach it to your coil and touch the plug to metal on the car i.e. valve cover. Then crank the engine and look for a spark on the end of the plug, just keep your hands away from the tip of the plug.

I recommended you run a ground to your battery because, although you may have confirmed you have a ground, it may not be consistent. When I re-installed my ground, car would run, and once it started warming up, it would not respond very well to throttle and eventually die and not re-start, just crank until it cooled down again. Running a wire to the battery ground was just a way for me to guarantee that the coils have a good ground. I recommended it so you don't have to worry about any intermittent issues with that problem area.

 

Ok, I tested all of the fuses and one 15A didn’t have continuity (the one with the red circle in the photo). I replaced that fuse and there was no difference. I tested the new fuse after trying to start the car and it was still fine.

I did notice one of the slots doesn’t have a fuse in it but looks like it should (yellow circle). Does anyone know what that’s for and what amp it should be, or why someone might just take it out?

I didn’t get a chance to run a wire from that one ground wire to the battery but I’ll try that tomorrow.

 

According to a quick google search, the missing fuse is for rear wiper. It is likely for the Mazda6s that come with rear wiper. would not have been populated from the factory. Pins may be there because its cheaper to produce the same box for all variations. On that note, I forgot this isn't a speed 3, layout is quite different.

Have you pulled a spark plug to verify you are getting spark?

 

Thanks for the info!

I’ll check for the spark tomorrow, or maybe later today if I get a chance. I might be able to get access to #1 without taking the intercooler off which I dislike doing if I can avoid it. (I replaced the intake manifold a while back and it has studs, and my intercooler has a metal curved portion to the throttle body rather than a curved hose, and that combination makes it a real pain to get the intercooler on/off. The former intake manifold used bolts instead of studs which was 100X easier to get the intercooler off.)

 

Ok...

I tried to check for the spark with and without a ‘bolstered’ ground wire from the HPFP to the negative battery but it wasn’t sparking. I had a hunch that I just wasn’t getting a ground to the spark plug itself so I put the plug back in and tried to start it.

Now it’s definitely trying to turn over. My guess is that I’m back to the P2138 code troubleshooting. Even though it’s not fully turning over it’s definitely trying, just a worse version of before, and I’m getting the fuel-rich exhaust smell again.

Attached is a video of it trying to turn over.

 

So no ground, not sparking, you put the plug back in and it started sounding healthier?

If you are getting no spark, you should try to figure out why. The engine turning sounds like it has low compression in a cylinder (as if you left a plug out).

Just grab any copper wire and run it to the battery negative and to that hpfp bracket. When my ground went bad on me, I cleaned all the surfaces really well and it still did not work for me...

I am assuming you only pulled plug #1. I know its a PITA, but I would check if there are any plugs firing, by pulling them all. This will be very helpful for you to diagnose the issue. In addition, You won't need to put the plugs back in the engine until you get them to spark.

 

Thanks big dill. Sorry if I wasn’t clear.

I did run a wire from the HPFP to the negative battery terminal. Previously the starter would just keep trying with no signs of turning over. Now it’s almost about to turn over and start running. So I see this issue as fixed. I will reply to you on my other thread just to keep these issues separated.

 

Hey man, not sure what you did (if anything) before this issue popped up, but I had a lot of similar issues after I built my motor and it was that I had misaligned the crank pulley to the crank pulley sensor. The engine would crank all day, and I would show super low HPFP readings, so I bought a stupid relief valve for 125 bucks just to find out thats not the issue. Just a thought

 

Thanks! I’m learning a lot but still don’t know many things. I did have the timing cover off and therefore also the crank pulley last December. It was running for several months until the P2138 issue. If the pulley changed position to that extent wouldn’t it also likely result in the crankshaft getting out of timing with the camshafts?

 

On these engines, your timing gear is on the crank pulley. It can be fastened independent of the crank chain sprocket. In essence, the crank and cams can be in sync, but your ECU will be reading timing differently.

If you had your crank pulley off, how did you re-align it to the crank?

 

If it were misaligned when I put it on back in Dec wouldn’t it have not been running since then? I had been driving it a few days a week up until Mar/Apr.

Honestly I can’t remember exactly what I did. I know I had the little bolt in the hole to keep the pulley in place (before fully tightening it) and something about counting teeth from the top... I just assumed it was fine since it started up and ran after the work. Maybe it is out of alignment though. What would I be looking for?

 

Sounds like you timed it correctly. The little bolt that holds it in place, also holds it in time, assuming you didn't move the cam or crank while the pulley was off the engine.

An engine can still run out of timing. Typically poorly and would likely throw all sorts of codes that you aren't seeing.

There is a washer behind that pulley (and 2 more between the oil/timing chain sprockets) that are critical. Depending how much you removed, if you didn't replace them, torque the bolt correctly or at the very least cleaned the mating surfaces (usually a no-no), I would put that on the list, even if that isn't your problem.

 

Ok thanks, that’s good to know I did use the timing tools, the one for the camshafts and the bolt for the crankshaft.

 

Late to the reply, but those two fuses are R.Cigar (15A) and Rear wiper (10A). When I had issues, the one directly above the rear wiper was blown for me. Doesn't hurt to remove it and inspect it. It may have continuity but it could still be a spotty connection. Also, I can upload a pic of the fuses if needed. Had to buy a fuse cover because my 6 didn't come with one lol/

 

Thanks Binary Assault! I was able to get it fully started today after cleaning the spark plugs so I’ll move back to my P2138 thread.