SR20 Breaking up under Boost... I'm an idiot! - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

GoingHam · 07-26-2011, 07:18 AM

so i noticed everyone always posts their problems about there SR20 breaking up, but they never post a solution!

Well i'll tell you what, i had this problem that everyone else seems to have where the car is all good until about 5k-5.5k rpm and then it would start breaking up. I had tried everything from checking the fuel pressure to checking my grounds and reading voltage off of them. this was just rediculous. i was so mad that i couldnt figure it out. so finally on my last string effort i decided to take it to a shop up the street where they would let me use a lift to work on it.

We began to check everything that i had already checked and it was just not showing any results. finally... we checked my battery voltage to ground and it was onnly showing 10.5 volts with the car running.. first off, this just isnt good but before you all get excited.. i took the car for a test drive and this was not the problem

HOWEVER! on that test drive one of my intercooler couplers blew off and needless to say the car was now running worse than ever!! so i limped it back to the shop and as i was revving the car up to get it to move into the bay, we heard a faint whistling noise. So my 3 friends shot up and ran over to the carand found an itty bitty leak coming from a intercooler couple that was not properly sealed, by itty bitty i mean probably the collective surface area size of a ladybug. we tightened that up like it had never been tightened before and VOILA!!! the car ran perfect again.

moral of the story.... CHECK YO' SHIT!

GoingHam · 07-26-2011, 07:19 AM

hence the name of the thread, im an idiot, i should have found this boost leak first thing but i dont think i was able to hear it before the final occurence? and i didnt have a smoke machine =/

s14unimog · 07-26-2011, 07:49 AM

^ that's odd though that a boost leak caused it to break up. My experience with boost leaks usually calls for a rich condition with fuel clouds under boost. If it was my guess I would recall failed coil packs or too much plug gap for the P/R. I've killed two coil packs from heat in the past and now don't run with the factory cover b/c of it. I've also stayed around 0.025" gap for >15psi applications. Glad you got your car sorted. A lot of people fail to ground their swapped SR's well enough; the more grounding the better.

GoingHam · 07-26-2011, 07:57 AM

Quote:

Originally Posted by s14unimog

^ that's odd though that a boost leak caused it to break up. My experience with boost leaks usually calls for a rich condition with fuel clouds under boost. If it was my guess I would recall failed coil packs or too much plug gap for the P/R. I've killed two coil packs from heat in the past and now don't run with the factory cover b/c of it. I've also stayed around 0.025" gap for >15psi applications. Glad you got your car sorted. A lot of people fail to ground their swapped SR's well enough; the more grounding the better.

thanks man! and yeah thats what i thought as far as the boost leak, well its at least fixed now and im getting a D-Jetro Power FC installed and tuned tomorrow so hopefully this will help prevent future problems

s14unimog · 07-26-2011, 08:18 AM

Quote:

Originally Posted by GoingHam

thanks man! and yeah thats what i thought as far as the boost leak, well its at least fixed now and im getting a D-Jetro Power FC installed and tuned tomorrow so hopefully this will help identify future problems

No problem. Let me fix your statement though. GL with the build!

warauto · 08-11-2011, 12:19 AM

I found that boost leak is not the only problem in a case like this. I had the same exact problem and I found out my spark-plugs NGK BKR6E-11 was too hot. I had to go one step colder BKR7E-IX. Before I changed the plugs I did a leak down test and corrected some small leaks I had, which did not solve my problems.

If boost leaks not the culprit try plugs and make sure you gap too.

07-26-2011, 07:18 AM	#1
GoingHam Leaky Injector Join Date: Mar 2011 Location: CREEPER ZILVIA ASKING WHERE I LIVE Age: 35 Posts: 69 Trader Rating: (1) Feedback Score: 1 reviews	SR20 Breaking up under Boost... I'm an idiot! so i noticed everyone always posts their problems about there SR20 breaking up, but they never post a solution! Well i'll tell you what, i had this problem that everyone else seems to have where the car is all good until about 5k-5.5k rpm and then it would start breaking up. I had tried everything from checking the fuel pressure to checking my grounds and reading voltage off of them. this was just rediculous. i was so mad that i couldnt figure it out. so finally on my last string effort i decided to take it to a shop up the street where they would let me use a lift to work on it. We began to check everything that i had already checked and it was just not showing any results. finally... we checked my battery voltage to ground and it was onnly showing 10.5 volts with the car running.. first off, this just isnt good but before you all get excited.. i took the car for a test drive and this was not the problem HOWEVER! on that test drive one of my intercooler couplers blew off and needless to say the car was now running worse than ever!! so i limped it back to the shop and as i was revving the car up to get it to move into the bay, we heard a faint whistling noise. So my 3 friends shot up and ran over to the carand found an itty bitty leak coming from a intercooler couple that was not properly sealed, by itty bitty i mean probably the collective surface area size of a ladybug. we tightened that up like it had never been tightened before and VOILA!!! the car ran perfect again. moral of the story.... CHECK YO' SHIT!

07-26-2011, 07:49 AM	#3
s14unimog Nissanaholic! Join Date: Dec 2003 Location: In a place, near a river, over a lake Age: 38 Posts: 2,415 Trader Rating: (22) Rides Gallery: s14unimog Feedback Score: 22 reviews	^ that's odd though that a boost leak caused it to break up. My experience with boost leaks usually calls for a rich condition with fuel clouds under boost. If it was my guess I would recall failed coil packs or too much plug gap for the P/R. I've killed two coil packs from heat in the past and now don't run with the factory cover b/c of it. I've also stayed around 0.025" gap for >15psi applications. Glad you got your car sorted. A lot of people fail to ground their swapped SR's well enough; the more grounding the better. __________________ Fuking ginger bread man stole my wallet... SHIFT*lock_slide to side d3m3rs0n: if i have a baby im naming it Brandons Fault Emerson

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07-26-2011, 07:19 AM	#2
GoingHam Leaky Injector Join Date: Mar 2011 Location: CREEPER ZILVIA ASKING WHERE I LIVE Age: 35 Posts: 69 Trader Rating: (1) Feedback Score: 1 reviews	hence the name of the thread, im an idiot, i should have found this boost leak first thing but i dont think i was able to hear it before the final occurence? and i didnt have a smoke machine =/

08-11-2011, 12:19 AM	#6
warauto Zilvia Addict Join Date: Oct 2007 Location: GA Posts: 633 Trader Rating: (3) Feedback Score: 3 reviews	I found that boost leak is not the only problem in a case like this. I had the same exact problem and I found out my spark-plugs NGK BKR6E-11 was too hot. I had to go one step colder BKR7E-IX. Before I changed the plugs I did a leak down test and corrected some small leaks I had, which did not solve my problems. If boost leaks not the culprit try plugs and make sure you gap too.