Replaced more... it's starting to run better!

ECU, Wiring, Sensors
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By teal_dx
- Sat Jun 09, 2007 3:24 pm #10455 I had an idea.....
So my car started last week and ran rough for a min (brand new motor) and then smoothed out for a few mins. This was with the old bad battery, I had jumper cables going to my hx the whole time.

So I figured the bad battery had been charged after a few mins, so I took off the jumper cables. About a min later, the car started to idle crappy and then eventually died in another min or so (just like it still does).

I've replaced everything, and it's still doing this and every time I pull the plugs out they are covered in soot. Like the car must be either running way to rich or not getting spark. Well I know that it is getting spark because I've put in brand new plugs, and tried diffeent dizzy & wires.

So here's my latest guess... When it was idling smooth the first night it ran, the battery started to die when i unhooked the jumper cables. The weak battery gave a weaker spark, which burned less fuel. The plugs became fouled along with the dying battery... there was probably very little spark by the time the battery died and the car stalled. Perhaps when this happened, it was so rich that it could have fouled the O2 sensor or got enough soot in it so that now it isn't able to read correctly (but not damaged enough to throw a CEL). I cleaned it off with a wire brush once, but maybe that wasn't good enough.
So maybe it is not able to get an accurate reading of the oxygen, so it thinks that it needs to tell the ECU to dump in more fuel. This is like the snowball effect because it's running richer, fowling the plugs faster, and then getting the same soot all over the o2 sensor, which would make it read even worse, causing the ecu do dump more gas in to try to keep the car running. :?

I've got nothing else left to try.... might as well give it a shot
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By Skyu_Ivy
- Mon Jun 11, 2007 11:36 pm #10645 Damn, this could drive a person mad!

I know you have good fuel pressure but i was wondering if maybe when you installed your new injectors the wiring might be messed up or something. Not trying to diss your wiring haha but maybe your engine isn't getting enough fuel? and when you give it gas it becomes to lean an chokes the motor? I am not sure just a suggestion. you probably already checked that :?

p.s. Even though it isn't running well it still looks like a piece of artwork! :thumb: Love the walk around in your first video.. love the color!
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By LaMbErT*
- Mon Jun 11, 2007 11:49 pm #10646 Man im fresh outta ideas lol! Hows this getting on now btw ?
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By teal_dx
- Tue Jun 12, 2007 4:55 am #10691 the plugs kept getting black so it was running way too rich. Today I took the plugs and O2 sensor out and cleaned them both with carb cleaner. Fired it up later and it was rough, but after a min and bumping the fuel pressure up to 42 psi... I had a smooth 1500 rpm idle! :woot:
Then it started to fluxuate a bit and I noticed a CEl was on. I shut the car off and checked the code, #5 MAP sensor. My MAP sensor was relocated from the outside of the firewall to the inside, so I relocated it closer to the throttle body and reset the ecu. no code and back to runnine like shit and the plugs and o2 were filthy again :x
I tried some more stuff and it was still fouling the plugs constantly and ready to stall just like usual. Then I put in a different O2, same thing. Then I unplugged my MAP sensor, and it idled nice and smooth (with the CEL on).
So I had a lead... my throttle body is a 1992. 1992's came with the MAP sensor mounted on the firewall with a vac hose going to the throttle body. 93-95 have the MAP attached directly to the throttle body. All this time I;ve been using the 1992 since my car is a 92, my harness is a 92, and the Si I got the D16z6 motor from is a 92. The intake manifold is a 1999 y8, but I used it on my last setpu, with the same 1992 throttle body I had on right now.
So for the hell of it, I swapped throttle bodies with a 93-95 with the MAP mounted to the top, and without the big ugly coolant passage on the bottom. Reset the ECU, cleaned the plugs again and it fired right up and idled smooth around 800 rpm. The loud hiss from the intake is now gone too. It idled for a good 5 mins, but eventually started to bog like it was running rich. The RPM kept getting lower untill it died.

But this was still a huge step :)
Hopefully I'll get the rest solved tomoorrow. Im gonna get some sleep :zzz:
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By ChicagoMike
- Tue Jun 12, 2007 1:25 pm #10720 Dammit teal, just buy my Hondata s100 in a P28 (manual :lol: )

Make the car run the way you want it! :twisted:
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By teal_dx
- Tue Jun 12, 2007 1:45 pm #10728 I've got another P28 chipped w/ CROME. I'm cheap and CROME is free :D
I'm just using this stock P28 to break the motor in.

So maybe there is a difference in the P28's that came in the 92 models vs the ones that came in the later models?
My 1992 throttle body was not jiving at all with the P28 I was using... I would have never guesed that.
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By ChicagoMike
- Tue Jun 12, 2007 1:48 pm #10729 Well keep in mind that the map thats inside a P28 is going to be different if it came out of an Si model. That trim required more fuel. :wink:

Not 100% sure on that, but it makes sense.
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By -EJ1- COUPE
- Tue Jun 12, 2007 7:51 pm #10806 hey teal did you take out your srs system and wires and the wires to the blower and etc. when you took all your shit out just askin cuz i did and wanted to know if my car would start eventualy when its done
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By chnzgoofball
- Tue Jun 12, 2007 9:02 pm #10824
AddictiveAllMotor wrote:Well keep in mind that the map thats inside a P28 is going to be different if it came out of an Si model. That trim required more fuel. :wink:

Not 100% sure on that, but it makes sense.


yeah and don't forget u r running a y8 i/m that could be another problem too... bigger manifold more air... can that be the reason why its running crappy??
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