View Full Version : spark blowout/fuel cut???
oLemurs
06-22-2018, 05:02 PM
so recently i did a 1st - 3rd pull on my sr20 like ive been doing for the past few weeks but this time ive ran into an issue, once i hit 3rd gear it started hesitating bad it felt like going through the windscreen, i was driving it home and it was sputtering real bad through 4th gear and eventually i had no throttle response at all. it came back after a few seconds and eventually cleared up pretty good but now when i hit around 4000 rpm it happens. ive checked all couplers and they are all still there, all vacuum lines, and put in brand new spark plugs gapped to .028 and im still having issues, i did notice if i keep it floored it will only happen about one or two more times in that gear so its not extremely bad. any clues what it could be? ive never had these issues before yesterday. here is a video of my problem. https://youtu.be/DtPiYVnMDck?t=58
and a pic of my plugs before changing them https://imgur.com/gallery/VtSm3dv any help would be appreciated even if its just letting me know to check over stuff. btw fpr is working good at 43psi no vacuum
Kingtal0n
06-22-2018, 05:06 PM
whats wideband say
in b4 no wideband
oLemurs
06-22-2018, 05:30 PM
whats wideband say
in b4 no wideband
i didnt think it was really necessary to have a wideband on a stock motor with a stock ecu but yea it would help to diagnose and it is a near future purchase
Kingtal0n
06-22-2018, 06:45 PM
its not the engine that matters. its the application.
if you are doing performance things and taking an engine to redline all the time- you need a wideband.
All that talk above and nothing about fuel pump situation. A racing application is based around fuel delivery since fuel is where energy comes from to make torque and power.
2 big mistakes, both lead to the bad kind of blown engines
oLemurs
06-22-2018, 06:51 PM
its not the engine that matters. its the application.
if you are doing performance things and taking an engine to redline all the time- you need a wideband.
All that talk above and nothing about fuel pump situation. A racing application is based around fuel delivery since fuel is where energy comes from to make torque and power.
2 big mistakes, both lead to the bad kind of blown engines
forgot to mention its a walbro 255 and ISR fuel pressure regulator and i have it wired in to a relay directly off the battery
Kingtal0n
06-22-2018, 07:07 PM
no fpgauge, no wideband. How do you know you have gas going to the engine at all? How can anyone else know?
it isn't what we can tell you on a forum its what gauge you are lacking that could have saved you the trouble of asking questions that nobody knows the answers to (because we don't have widebands or gpguages on your car, only you can do that)
oLemurs
06-22-2018, 07:13 PM
no fpgauge, no wideband. How do you know you have gas going to the engine at all? How can anyone else know?
it isn't what we can tell you on a forum its what gauge you are lacking that could have saved you the trouble of asking questions that nobody knows the answers to (because we don't have widebands or gpguages on your car, only you can do that)
the reason im asking is because there are possibly people here that have had the same issues as me, sure i cant tell the fuel pressure because the gauge is under the hood but at the same time if i wasnt getting fuel pressure around 4k why would it start pulling again all the way to 7k im just trying to figure it out while saving some money. it just doesnt add up as to why this would happen after a pull. i guess i never really got the gauges yet because this just happened yesterday, before then it has been running great. the reason why i posted a pic of the spark plugs is because they look like they have been leaning out.
oLemurs
06-22-2018, 08:01 PM
checked the codes it looks like i have a code 12 so maf sensor, going to check it real quick and make sure there is no debris in it even though i am running a filter.
Kingtal0n
06-22-2018, 08:13 PM
even if putting a new maf in the car "fixes" the "problem", it doesn't guarantee you fixed the problem.
For example lets say the a/f right now at 4k goes to 16:1 and you put a new maf in and now the a/f is 13.5:1 instead and the car runs great.
Well guess what. 13.5:1 at reasonable pump gas boost is going to lead to engine destruction. It just so happens that an engine can run normal and still blow itself to bits. So you don't always fix the 'problem' just by fixing the symptoms. Sometimes we can mask these symptoms with cough syrup. Like catch cans are a great cough syrup for inadequate oil control for any reason.
The real problem here is a basic lack of common automotive diagnostic tools which are considered an essential part of owning a performance vehicle of any kind.
oLemurs
06-22-2018, 08:20 PM
checked the codes it looks like i have a code 12 so maf sensor, going to check it real quick and make sure there is no debris in it even though i am running a filter.
welp i checked the maf and it turns out im missing the little clip that holds it in so it just popped out. i will keep updated because i think i found the issue but i wont know till tomorrow
oLemurs
06-22-2018, 08:21 PM
even if putting a new maf in the car "fixes" the "problem", it doesn't guarantee you fixed the problem.
For example lets say the a/f right now at 4k goes to 16:1 and you put a new maf in and now the a/f is 13.5:1 instead and the car runs great.
Well guess what. 13.5:1 at reasonable pump gas boost is going to lead to engine destruction. It just so happens that an engine can run normal and still blow itself to bits. So you don't always fix the 'problem' just by fixing the symptoms. Sometimes we can mask these symptoms with cough syrup. Like catch cans are a great cough syrup for inadequate oil control for any reason.
The real problem here is a basic lack of common automotive diagnostic tools which are considered an essential part of owning a performance vehicle of any kind.
i agree with you 100% its just i gotta go out and buy those tools which i WILL do.
oLemurs
06-23-2018, 09:34 AM
even if putting a new maf in the car "fixes" the "problem", it doesn't guarantee you fixed the problem.
For example lets say the a/f right now at 4k goes to 16:1 and you put a new maf in and now the a/f is 13.5:1 instead and the car runs great.
Well guess what. 13.5:1 at reasonable pump gas boost is going to lead to engine destruction. It just so happens that an engine can run normal and still blow itself to bits. So you don't always fix the 'problem' just by fixing the symptoms. Sometimes we can mask these symptoms with cough syrup. Like catch cans are a great cough syrup for inadequate oil control for any reason.
The real problem here is a basic lack of common automotive diagnostic tools which are considered an essential part of owning a performance vehicle of any kind.
ok so i have the issue fixed, i will say this right now i am a dummy but the hose clamp around the maf slipped off and there the hose wasnt making a good seal around the maf sensor hence why it only happened at high rpm because it needed to suck in more air.
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