Was boosting, now car sounds like a WRX????

[RMiller]

My car has been running perfectly for a while and it's been really fun. I love it. I boost to .9 bar. While I was boosting the other day, all of a sudden the power cut out and the exhaust tone totally changed. Now it sounds exactly like a WRX with exhaust. I know you all know what that sounds like. Also, it runs super rich now, is slow to respond, and only builds about .1 bar of boost. It isn't rev-happy anymore and feels awkward starting around 5k rpm. If I rev it, it pops multiple times on its way back to idle. The engine runs very rough as well, it shakes the whole car. I have no boost leaks. So to sum it up:-gurgly exhaust note, clear, sudden change-rough engine-slow response-rich-almost no boost-no boost leaks-very weak, obviously due to the richness

My troubleshooting:

I thought it might be running on fewer than 4 cylinders. I then compression tested the motor, which I've been meaning to do just so I would know. The temp. was at 65*C and my numbers were 149/149/150/151. I think my compression is where it should be; maybe it would be a little higher if the motor was completely warm (I was mainly looking for consistent numbers).

I thought the wastegate may be stuck open, but it's not.

I thought the cat. might be clogged (yeah, I run the stock cat cuz I'm a sissy), so I removed it and still the same thing with an open downpipe.

Now I'm thinking an injector problem. Any pointers?

[AmoebAssassin]

Remove your fuel rail, get a rag, and turn the key to "on" but not "start"...the engine should try to prime itself by firing ALL of the injectors for a short while...check if one or more is malfunctioning. If thats all good check your plugs and coilpacks, stick a screwdriver in the end of each coil and rest the plastic end on the valve cover so that no metal is touching. Remove your fuel fuse and turn the engine over...if you're getting a good spark, you'll see arcing between the metal of the screwdriver and the valve cover. Your problem definately sounds like you lost a cylinder, since all your comp tests come back then im led to believe its a fuel or spark problem. Good luck with fixing it.

[rico05]

My car did the same when my dropping resistor accidentaly got jostled. It came slightly unhooked from the harness, and my #2 coil was firing intermittently. Check your coils and ignition system. Coils are easy to kill. But the new one I got from O'Reilly was only like $56.

[float_6969]

My vote is an ignition problem due to the "popping" in the exhaust. This sounds just like what my KA-E did when I broke an exhaust bolt off and I kept melting through plug wires. I would check your resistor pack and coils before the injectors. And I like to start at one end of the system and work backwards, so I'd start with the coils first and make sure they're all firing, then go from there...

[RMiller]

Thanks for the replies guys. Darrell (Cuzan0) helped me out a bit. It's clear it's a dead cylinder, so I'm going to pull each coil and see which one doesn't change the idle. Then I'll check for spark on it, then I'll check for fuel on it. It could be an injector, or it could be the dropping resistor as rico said. Come to think of it, I don't have the metal clips that secure the injector plugs to the injectors. One could have fallen off, although I doubt it.

[themadscientist]

sounds like a dead cylinder, likely a dead plug. You could have popped the head gasket though, be sure to check the radiator for oil and do a compression check.

[iliketocrash]

oddly enough that almost sounds like the exact problem i'm having with my car. only difference is that my compression is a bit higher, but it really doesn't sound like its running on less the 4 cylinders. I hope this problem gets resolved, maybe it'll help me out as well.

[DriftinNC]

well i had a similar problem when i 1st got my engine running, which it sounded like a wrx, lack of power, running rich, and i had to drive around town normal in boost just to keep it going, i couldnt find out the problem so i took it to T88lexus (pretty smart guy) cause he figured it out that nite... the problems were: coolant temp sensor was bad, knock sensor wasnt wired up but he did it, 1 coilpack was bad

not sure iff we have the same problems, but just to give you some ideas

[WeldingHank]

sounds exactly like when a plug wire popped off on another car of mine. said cylinder is not firing. as others have said, check all your coils and the resistor. then check the plugs too.

one more vote for a dead/non-functioning coil.

[RMiller]

Ha ha ha. I really appreciate the help everyone. It turns out...dear God...a fuel injector came unplugged. I don't have the metal clips that hold them on, but I'll put some on from a 13b (apparently they fit).

Yup. Good diagnostics guys. You were all betting on the dead cylinder and you were all right.

I don't think my compression seems low for a used motor. It may have been higher if my temps were up at 78 rather than 65. I'm very happy with the numbers because they are all about the same. You could likely do another test at a different temp and get significantly different numbers.

Thanks again.

[iliketocrash]

crap... well i'm still at a lost. my plugs are new, they're gapped at about 1-1.1mm, my fuel injector plugs are secure, my dropping resister pack plug is secure and my knock sensor is all wired up. my ecu shows a code 55 so everything else should be ok, right? or is it possible to still have a bad coil or injector and the ecu just not know it?

[RMiller]

If it's running on 3 cylinders it will be really rough. A common problem is the engine running rich. That could be due to a boost leak, bad o2 sensor, etc. Only so many things can go wrong. Could be your fuel injectors.

[themadscientist]

pull the injectors one by one with the engine running. When you pull one that doesn't make the engine run worse that's the bad cylinder. On a lot of cars I pull the plug wire but as anyone who has been hit by a direct fire coil pack can attest, IT FRIGGEN HURTS!

once the bad cylinider is determined you can test for a bad injector by listening for the solenoid clicking, luckily Nissan squirts tend to be real noisy. When in dobt swithc the injector to another cylinder and see if the problem follows it. The same can be said for the coil packs.

[biosehnsucht]

Remove your fuel rail, get a rag, and turn the key to "on" but not "start"...the engine should try to prime itself by firing ALL of the injectors for a short while...check if one or more is malfunctioning.

Just listening for injector tick or seeing if the fire by removing them from the intake in 'run' vs 'start' w/o starting is meaningless, ECU DOES prime the pump but not the injectors, injectors only fire when it sees movement on the CAS. Now, you can listen for tick or watch for squirt after having removed the CAS and turning it by hand, while in 'run'.

If thats all good check your plugs and coilpacks, stick a screwdriver in the end of each coil and rest the plastic end on the valve cover so that no metal is touching. Remove your fuel fuse and turn the engine over...if you're getting a good spark, you'll see arcing between the metal of the screwdriver and the valve cover.

On a lot of cars I pull the plug wire but as anyone who has been hit by a direct fire coil pack can attest, IT FRIGGEN HURTS!

And that, kids, is why NOT to ghetto test the coils with a screwdriver! They can easily output in excess of 80,000 Volts on direct fire coil systems, not something to risk getting arc'd from.

[float_6969]

It's not the volts, so much as the amps... Heheheh. Don't worry, it'll only make you steril!

[WeldingHank]

yes, i can attest to the pain. i got a hit from a coil on a neon once. holy crap i almost fell over. and i'm not a small guy.

[RMiller]

Unbelievable. That sounds so painful. I'm sure many of you have gotten a little electricuted during the holiday season putting up lights. I do every year, usually from a broken light on those icicles. The funny thing is I get shocked, then say something like, "hmm that was weird, probably a spider bite or something." The I touch it to confirm, get shocked, think of another possibility, then touch it again. This year it took 3 tries to realize I was getting shocked like a mother. Weird. I think it's because I'm nervous being up on a 20 foot ladder.

[biosehnsucht]

It's not the volts, so much as the amps... Heheheh. Don't worry, it'll only make you steril!

Yeah but the volts are a more dangerous sounding number!

[float_6969]

Yea, if I tell you that you just had 50,000volts travling through your body and lived, it's not as cool as if I tell you that you had 5 amps travling through your body and you died. I love electricity...

[iliketocrash]

Yea, if I tell you that you just had 50,000volts travling through your body and lived, it's not as cool as if I tell you that you had 5 amps travling through your body and you died. I love electricity...

i agree, cool stuff. i love it so much i'm in school to become an electronic engineer.

[float_6969]

I would say that I only have an intermediate understanding of it. I work for a pool and spa company and so I mess with a lot of electrical concerning those area's. I also do automotive electrical, but I don't have any real "training" in it.

your electrical > my electrical

Hehehe

[iliketocrash]

your post whoreness > my post whoreness

[float_6969]

Thank you!

[AmoebAssassin]

And that, kids, is why NOT to ghetto test the coils with a screwdriver! They can easily output in excess of 80,000 Volts on direct fire coil systems, not something to risk getting arc'd from.

I'm sorry, i was assuming most people on this board were intelligent enough to stay away from firing coilpacks. It's not like the arc is a hard thing to see. You dont have to hover over the screwdriver to see it.

[themadscientist]

my boy got picked up and thrown when he arced an Optima redtop. That beats my CA coilpack hit. I did however hit myself in the head with a mallet once so I should get some style points!

[KaZ (VaBch)]

It's not the volts, so much as the amps... Heheheh. Don't worry, it'll only make you steril!

Ha! I've done that on my old CA18ET... was testing the coils and shocked my dumb ***... lol... house current hurts more than that did... was just a bit of a shock (pun intended) and just scares you a little more than anything...

Steril... that's a good one. =)

[RMiller]

I melted 2 10mm wrenches unbolting my battery terminals. I'm so stupid. The wrench connected the two and left an indentation on the tip of the wrench. Luckily it barely shocked me, but it did burn me some. When will I learn.

[shawya]

I'm having a similar problem. The thing with mine is that the car starts fine the first time, and drives fine for a little while, but as soon as I drive it in the city for a little while or drive it on the freeway and stop at my first offramp, the damn thing goes to three cylinders. Once I park it again and let it sit for a while, it'll start up fine and do the exact same series of events all over again, like clockwork. I took out and tested all my coils, the coil harness, ignitor module, and resistor pack. The only thing that didn't come out kosher was the last ignitor module test (if your looking at the FSM) where you test just the 5-prong plug, which showed resistance where there should've been continuity, if I read it correctly. I'm guessing that since just part of the ignitor tests didn't come out good that maybe it's only in the process of going bad, but isn't completely dead yet. Any help would be a lifesaver, since this is my only ride.

[RMiller]

Try replacing that part. That does sound weird though.

[shawya]

I also forgot to mention that once the engine goes to three cylinders it starts backfiring almost everytime I let off the gas after putting the engine under load. But I tested the new ignitor and it tested exactly the same and the engine still does the same stuff. Starting to get frustrated, so any help would be...mmm...helpful.