engine cut under high boost?? Scared...

[killedbydeath]

Alright lads, here's my beef.

I just spent a month and some pulling the engine on my 180, replaced some gaskets and so on...

After all is re installed and running again, it runs great, an issue I'm having is, under fast throttle, I'd say mid 5 grand rpm's, I'm making lots of power and everything, but if I've got it wot, sometimes it seems to cut for a second, buck and s***.. At this point I let off the gas, now under gradual throttle I can take it right to decline with little issues, it almost seems like a heavy misfire, or major fuel cut, there's over a quarter tank of gas, idles fine and drives great otherwise.

Only mode are full 3" exhaust downpipe back, and front mount intercooler, also getting maad compressed surge, but like I said, plenty of power. Also, no aftermarket gauges to monitor, should be running stock boost.

Any help is appreciated guys, please point me in the right direction

[zenki-S13]

maybe a new fuel pump?

[Ca_Silvia]

Is it tuned? or stock ECU?

[fabio240]

I had that exact same problem and I had an exhaust leak around the manifold and turbo

[Ca_Silvia]

I had that exact same problem and I had an exhaust leak around the manifold and turbo

I have a hard time believing that an exhaust leak will lead to bucking and/or fuel cut like symtoms.

[killedbydeath]

Stock tuned ecu, another thought would be leaning out, while could also be a fuel issue, what should my fuel pressure be reading at with stock pump? Testing will be held off till this snow f***s off, just got s*** on.

[fabio240]

I have a hard time believing that an exhaust leak will lead to bucking and/or fuel cut like symtoms.

It did on mine its worth a try. I would have never figured it out if it wasnt for my bro tellin me because you could barely hear it only when I was flooring it. It would make a screeching sound.

[killedbydeath]

Screeching sound eh? I could see lack of back pressure f***ing s*** up, but not to this extent, I'll check it out though.

[fabio240]

but does it make a screeching sound wen ur getting on it?

[killedbydeath]

The only screeching sound sounds kind of like an ungreased release bearing, it's slight and sounds kind of luke metal on metal

[float_6969]

You need to verify that you're running stock boost. It sounds like boost cut to me, but it's hard to tell for sure.

If you find that you are running stock boost, then the next thing I would start looking at is the ignition system. Double check all of your grounds and make sure the ignitor is properly grounded. Don't forget that the ignitor ground via the metal on the back of it, so make sure it's good and clean and use some di-electric grease when you put it back on the bracket.

[killedbydeath]

that sounds promising! I recently on stalled full 3" exhaust with a 2.5" fmic, which should cause a boost creep, right? Where do I find this bracket and stuff?

[boost_boy]

You are running too much boost. I don'tknow what type of boost gauge you have, but they fail or are inferior. But like float says, you are fuel cutting and you need to lower the boost and check the accuracy of your boost gauge.

Dee

[killedbydeath]

this makes sense, and I stated the car currently has no gauges.

[mbmbmb23]

Getting huge compressor surge and possibly overboosting?.... Is your stock turbo overboosting due to faulty wastegate actuator not opening? Is your WG actuator's vacuum source working correctly? Add fuel pressure/boost pressure gauges asap!

[killedbydeath]

Oh f***, totally know what's up, vaccuum leak. I missed a vac hose. I'll fix it and let you all know how it goes.

[RS12Turbo]

Don't forget that the ignitor ground via the metal on the back of it, so make sure it's good and clean and use some di-electric grease when you put it back on the bracket.

Hmmmm, can you elaborate on how to properly ground the ignitor please

[lcw1980]

How does the CA ECU detect boost btw?

[float_6969]

Hmmmm, can you elaborate on how to properly ground the ignitor please

The back of the ignitor serves two purposes. The first is a heat sink. The second is for grounding. The ignitor is basically a set of 4 solid state relays built into a single, enclosed container. If you're familiar with electronics at all, you know that a solid state relay gets hotter the more load it has. This is why Nissan putting the ignitor on the exhaust side of the motor was a bad idea. The extra heat increases the resistance across the solid state relays, and decreases their life.

Secondly, if I understand this correctly, The "coil" side of the relay (there is no coil because it's solid state, but it's easier to explain this way) is grounded via the metal housing of the ignitor. So if in either case, the back of the housing doesn't have a good ground, it won't conduct heat well, and it won't ground well, both of which inhibits the function of the ignitor.

How does the CA ECU detect boost btw?

It doesn't. Not really. It detects mass air flow vs. RPM. And actually, it compares the voltage output of the MAFS vs. the RPM, and then has a chart that says that if at a certain RPM the MAF signal is greater than y, to cut the fuel/timing (I don't remember which, I think it's fuel) until the MAF signal drops below y again.

[RS12Turbo]

Hmmm, interesting. Maybe the ignitor has been my prob the whole time with my cutting out issue. I'll have to double check, but I'm pretty sure when I mounted the ignitor I just bolted it down with the top 2 bolts, and it is mounted on the curved fender well....so the bottom 2 bolt holes aren't even touching anything

[float_6969]

Yea, there is a bracket that the ignitior is supposed to bolt to, and then the bracket bolts to the strut tower.

[RS12Turbo]

Yea, there is a bracket that the ignitior is supposed to bolt to, and then the bracket bolts to the strut tower.

Just checked mine...and yep, held down by the top 2 bracket holes only. Not a lot of flat spaces in the s12 down there....when i moved it over from the s13 front clip, i just put it in about the same location, except it's a little more forward on the the fender well, instead of the strut tower so it would be a little further from the turbo. Where it is bolted down is on the fender well, so the bottom of the bracket is sticking out and not even touching the curved fender well. With it being like this...you're saying it isn't grounded correctly and will cause cutting out issues?? It's been 3 years now, and I can't remember how much slack is in the harness...but is there enough slack to relocate it at all?