Stock s14a engine issues - help!

Hi guys, having a bit of trouble with my car

basically it revs out fine in neutral and at low throttle but as soon as i go past like half throttle the car accelerates really slowly and sounds like its misfiring

it seems to get worse at higher revs, around 4k and up.

also when at full throttle it accelerates slowest of all, if i let off a bit after being at full throttle it backfires and then accelerates better.

any ideas on where to start? its a stock s14a with a questionable past so I'm slowly going through replacing everything i can afford to,
but i'd like to solve this asap as it doesnt sound healthy. new spark plugs are on the way mainly as i dont know when they were last changed,
but the fact it is fine when not in gear makes me think it may be something else.

Cheers

Sounds like a boost leak bud. Standard you say? Original side mount intercooler are known to crack with age.

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Sounds like a boost leak to me. Check the air intake and inter cooler pipe work and joints

Definitely doing the right thing by changing the plugs first. When I first got my car it was spluttery under load and turned out to be the plugs.

Could also try running it without the MAF plugged it and see it stays the same or not.

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Replace your plugs and gap them properly, if it still continues it sounds like the coil packs are breaking down under load.

Without seeing/hearing the car it is only a guess.


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cheers guys, i'll try make a diy smoke tester for it and i'll have a look at the intercooler.

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Originally Posted by jj205mi16

Replace your plugs and gap them properly, if it still continues it sounds like the coil packs are breaking down under load.

Without seeing/hearing the car it is only a guess.


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ive ordered a set of BKR7EIX, what do i gap them to? im a bit of a noob

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Originally Posted by skint14a

ive ordered a set of BKR7EIX, what do i gap them to? im a bit of a noob

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Leave them gapped from factory for standard power. I'm running the same plugs and I'm at 1 bar and they work fine

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Quote:

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Originally Posted by finnnerz

Leave them gapped from factory for standard power

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cheers man :)

I'll end up chasing power like everyone else eventually but for now i just want it to run so i can fix all the boring stuff

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Originally Posted by skint14a

cheers man :)

I'll end up chasing power like everyone else eventually but for now i just want it to run so i can fix all the boring stuff

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Yeah that's understandable haha, might have to close the gap a bit if you're running more boost then but I'd only start gapping then when you feel it blowing out.

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Don't gap the plugs, fit VAG coil packs. It gets rid of the weak old coil packs and gives you a solid spark regardless of gap.

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Originally Posted by CrazySx

Don't gap the plugs, fit VAG coil packs. It gets rid of the weak old coil packs and gives you a solid spark regardless of gap.

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sounds pretty neat, is there a kit for that?

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Originally Posted by skint14a

sounds pretty neat, is there a kit for that?

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You can buy them, or make your own, its not that hard of you are confident with wiring and a solder iron ;)

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Quote:

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Originally Posted by CrazySx

You can buy them, or make your own, its not that hard of you are confident with wiring and a solder iron ;)

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I could probably do it but usually when i try my own electronics it ends up as a functional eyesore blob that has no place in an engine bay lol
I'll see what kits i can find

Listen to this guy :nod:

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Originally Posted by CrazySx

Sounds like a boost leak bud. Standard you say? Original side mount intercooler are known to crack with age.

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There aren't many 200SXs still running with their original wing mounted intercoolers. They were fragile and usually broken within a few years from new. Your initial symptoms sound to me very boost leak related.

Thanks Jon,

I have had all of the above. A failing coil pack, a failing fuel pump and then my favourite, a leaking DV (boost leak!)

The symptoms defo sound like a boost leak.

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lol are these the original plugs?

i may be a noob but they dont look fantastic, will report back later on whether the misfire is solved or not..

also car is very slightly over filled with oil i just discovered, changing it today along with filter but just wondered if that will have been messing stuff up? previous owner was an idiot thats for surehttps://uploads.tapatalk-cdn.com/201...b5c25d56c2.jpghttps://uploads.tapatalk-cdn.com/201...e60a69a087.jpghttps://uploads.tapatalk-cdn.com/201...0f5f2dabf2.jpg

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Originally Posted by skint14a

lol are these the original plugs?

i may be a noob but they dont look fantastic, will report back later on whether the misfire is solved or not..

also car is very slightly over filled with oil i just discovered, changing it today along with filter but just wondered if that will have been messing stuff up? previous owner was an idiot thats for surehttps://uploads.tapatalk-cdn.com/201...b5c25d56c2.jpghttps://uploads.tapatalk-cdn.com/201...e60a69a087.jpghttps://uploads.tapatalk-cdn.com/201...0f5f2dabf2.jpg

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They look like they're burning okay tbh, good colour. I had that amount of blow-by after a year of my ngks as well

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Originally Posted by finnnerz

They look like they're burning okay tbh, good colour. I had that amount of blow-by after a year of my ngks as well

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this is why i like forums lol i wouldnt really know

but hey atleast they are changed.

more worried about the oil, its almost 1cm above the gauge on the dipstick

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Literally the same as mine after filling up the recommended amount. Spooky stuff hahah

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As said above, those plugs look OK if a bit sooty around the perimeter.
1 cm above max on dips tick won't do any harm. I did many S14 oil and filter changes and 3litres of new oil generally ended up at the max mark. The book says 3.2litres.

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The electrodes look a bit fooked if you ask me/always worth trying new plugs for the sake of £30


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to update this im a spaz and managed to not see a crack in the intercooler

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The plugs shown are standard platinum plugs designed to be changed every 100K miles. I see nothing wrong with them other than the soot that Jon pointed out which is probably symptomatic of a recent boost leak.

Most people replace them now with iridium plugs. As long as you stick with NGK, you'll be alright. EIXs are pregapped and iridium are hard to gap with a feeler gauge especially if they have a v-groove ground electrode. They normally have a smaller gap than coppers.