my j bod has a few issues, and i think it needs a major tune.

i bought this car, after having some car issues with previous cars...i now proudly own a 2000 z24 with the ld9 i do believe. (kid said motor was a swap from a auto trans z24)

he put a header on it, cheap cold air intake (which is F***ed, ill explain in a sec) E3 plugs supposedly and a straight through performance "farty" muffler.
that's what i know of.
now my problem...
I can feel the power drop off in low RPMs, like 2nd gear from about 1.5k- 3k it seems to lag. i can feel it pick up and drop off around 2-2.3k and pick back up at 3.1+k

i can hear a farely loud rattle (over the loudness of the car)...no its NOT piston slap/engine knock. but SOUNDs similar. just is not rpm consistent ( sound drops off when power picks up)
to my knowledge..i do believe this is spark knock

now the cold air intake on my car...the kid before me must not have had patience or common sense to use the internet as of i've fixed a few of this kids f**k ups.
but the MAP/MAF sensor that plugs into the intake pipes, is in a custom drilled hole, that he did not bother sealing, he just kind of stuck the sensor in it. also there was pre drilled holes for the sensor, one was left open AFTER the sensor, and of course the filter... (yay).

i fixed this the best i could with some electrical tape around the sensor and over the unplugged hole. seems to have not done a thing

the exhaust...the header is i think a 2.5" or 3", without a cat...but the kid also decided to leave the stock piping after where the cat would be, along with a nasty looking newb weld to seal and hold it on.

now could i be having a sensor problem? or is it the lack of a cat that could be screwing with this...

i have noticed the car runs WORSE in the warmer weather, since it is winter in michigan, and we've been having crazy temp gains and losses. it does love the 20 degrees or lower weather. but also runs like a pig cold...

how could i fix this? i'd rather do it myself/ learn how. any help or suggestions are much appreciated...thanks..

That sensor in the intake is not a MAP-MAF. It is a IAT. Incoming air temperature.

I would start with new spark plugs. Go to the parts store get NGK 3951 (stock number), should be about $1.60 a plug. Run those the engine will like them.

See how it runs then.



FU Tuning

okay, i'll start off there.

where would the MAP/MAF sensor be then? i have a loose plug/connector, and i dont know what it pertains to. i do believe its from the same harness location as the IAT.

today it was rainy and around 35-40 degrees. the car ran like @!#$ all day. i got a trip to virginia comin up and i'd like it to run half way better than it is now.

Our cars have a map sensor. It's stock location is on a black bracket off the front passenger side bolt on the Throttle body. It has a hose that runs to the front of the intake manifold.

Picture of the plug not connected to anything?



FU Tuning

well im having trouble posting them all, ill try individually. but heres one.

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another (side view obviously ;p)

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and the wire colors

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tomorrow i'm doing all 4 wheel bearings, and installing new mirros because some idiot took my drivers side mirror out last weekend.
so tomorrow as well, i'm gunna try the spark plug idea, and i'll give updates to that as well.

Also, out of my own curiosity. is there a performance chip out there, that is not cheap, chinease made, piece of junk. or are they just worthless crap?

now by perforemance chip, i mean a variety of things..i.e a bulldydog programmer, like fore diesels, or maybe just a chip that reflashes the ECU? and where could i get directed to, to look for these. ebay just has a bunch of what looks like junk on there.

And cause im a noob, i keep seeing WOT, and other lingo, someone maybe wanna clarify some of the more regularly used abbreviations?

There is no "chip" for our cars that actually does anything.

HPTuners will allow you do do everything you will need to do to the pcm.

WOT=wide open throttle

Philly D wrote:There is no "chip" for our cars that actually does anything.

HPTuners will allow you do do everything you will need to do to the pcm.

WOT=wide open throttle

thank you, thats great info to know, however. costly im assuming?

and how worth it for a daily driver, that i want a little nuts.

plus i have issues with the timing it seems already as stated above, and what about meth's idea on the plugs, i have e3's in them supposedly right now but i havent checked them yet and couldnt get to them today. the bearings were a bitch.

chris meyers wrote:thank you, thats great info to know, however. costly im assuming?

It's costly but the harder part is finding someone who actually knows what they're doing with our cars. Being NA there's definitely less concern, but still you need to find someone who has tuned these cars before. They're nothing like cobalts, mustangs, camaros, etc.

chris meyers wrote:and how worth it for a daily driver, that i want a little nuts.

It's always worth it IMO. There have been documented cases of bone stock cars gaining 10hp out of just a tune.

chris meyers wrote:plus i have issues with the timing it seems already as stated above, and what about meth's idea on the plugs, i have e3's in them supposedly right now but i havent checked them yet and couldnt get to them today.

Get rid of those plugs. Run stock Delcos or the NGK equivalent.

Lastly, fix your intake issues before getting a tune. They should be decently cheap ebay options. As long as it's the correct plumbing with the correct holes for sensors and doesn't leak, you're golden.



Edited 1 time(s). Last edited Monday, March 24, 2014 7:03 AM


"In Oldskool we trust"

As long as it's the correct plumbing with the correct holes for sensors and doesn't leak, you're golden.
yea if only the kid before me would have had some common sense lol.

and what about the sensor, you know what it is yellow?

and another, does HPT work for other cars? or specifically designed for the jbods.

odds are the noise you are hearing is a spun rod bearing, unfortunately. very common problem in the 2.4. mostly stems from people not maintaining the full oil level.



RIP silver car. You will be missed.

it's not rpm consistent, and the noise quits, its mainly only if im puttin around, if i get on it though, the car runs beautifully. and the noise isnt there. im pretty sure its spark knock, because its also very faint over the noise of my car itself.

the spark plugs seemed to help quite a bit, but i still think the car may need an actual tune, or maybe some new ignition parts.
but i put the NGK 3951's in, and like i said it's better, and it was rainy today. both before and afterwards. still a little bit of spark knock i think.

but there was e3's in the car and they looked like cheap junk ebay crap. 3 prongs, that had a base at the bottom of the plug, and it just looked like a cause of issues the way they are designed in my opinion, but im no expert.

however thank you guys it is better, but now were to go? still a bit of a studder in power then pick up. not as bad as before, still wondering about that loose plug? any ideas.