Ok, ive been searching like crazy trying to find the location of the Knock/Detonation sensor harness. I checked this forum and others and all I get is the writeup for the TT or garbled jpgs. I've looked high and low and am going nuts trying to find it, plus the fact its raining outside and I have to do this in my dungeon a.k.a. garage.

I already checked the ECU harness, pristine. Been walkin through ALL the connectors I can grab a hold of, all the connections look good though half of them cracked as soon as i touched them(stupid plastic!)

Its 95 NA M/T OBDI

any help PLEASE!!

 

woops, think i found it, somehow looked at the pic on the TT writeup wrong!!??

 

Yep, its official, bad Knock Sensor..

 

Aren't self-help programs great?

 

he he, yeah. But get this, apparently the ECU knew about the bad knock sensor but the car never showed signs of detonation. I ran it hard and it ran great, though it felt like it had a bit more power to give, but got stuck somewhere in the system. SO I go and check a few things, mostly connectors and such, and tightening that banshee screaming alternator belt, when I go to turn the car on, it gurgles like a drunk prostitute and cuts off.

Another thing too, before it cut out, I ran a diagnostic of the O2 sensors and it reports lean on both sides. That wouldnt explain why i BARELY got 270 miles out of this last tank. I always put premium in, and shes running iridium spark plugs. She past the emissions test BEAUTIFULLY!!! but man this 250 ish mpg sucks. Any ideas?

 

250 - 270 doesn't seem too bad to me. It depends on when your refilling. At 12 gallons to refill, 250 miles would be almost 21 mpg.

In you pic, the r/f wheel is on the wrong side.

 

... I wish I was getting 250 miles per gallon... that'd mean I could drive about 3,500 miles on a tank of gas (assuming I fill up every 14 gallons).

I think you mean 250 miles per tank, which is normal for a 300ZX.

And Canyon Carver is right, your wheels are backwards.

 

yeah , i meant miles per tank. I found out the wheels were backwards(never looked that closely) and have changed them since, just gotta update the sig pic.

 

im gwetting 28 to 34 miles per gallon test pipes straight thew exhaust running 92 and up octan with octan booster in my 1993 300zx 2+2 n/a/ ...

 

are you dividing the number of miles driven on a tank of gas by the actual amount that you use (determined by filling up again and watching the meter when it tells you how many gallons you've pumped) or the entire 18.7 gallon capacity of the fuel tank? I've never heard of anyone getting more than ~25mpg on a 300ZX, and normally the people who think they do don't actually realize that your fuel gauge will read E after only 14-15 gallons. (Just checking.)

 

That I highly doubt.

 

well...mabye he pushed the car some parts of the trip. or got a honda motor swap.

 

That's an understatment; unless he found the longest downhill run on the planet...

Maybe with the very rare VG16DE motor...I've heard that thing got some great mileage.

 

If it's reporting lean, then that would mean you should get better mileage. Detonation usually occurs under lean conditions; which could explain why you got the knock sensor to kick out a code.

Lean=not enough fuel
Rich=too much fuel

 

Well its wierd, I tuned everything I could. Found out my alternator belt had about a 13mm deflection, wich made it SCREAM like a school bus full of kids running down a mountain. Replaced every tune up part I could get my hands on, still says i'm lean. But now the Knock Sensor isnt reported in the ECU? I've never felt anything resembeling detonation, and the engine has ALWAYS run smooth. But I have noticed that it seems to be holding back.

One thing I found was the drain plug for the tranny was loose enough to turn with my hand and only about 1/2 a quart(my edumacated guess ) of gear oil came out. I had about 1/4 inch of FINE metal and a few shavings, promptly replaced diff/tran oils and runs even better. But still lean(not like that had anything to do with it)

So now im stumped. Any ideas why it would run lean? As of now now no ECU codes coming back, and the only one that did before was 34.

 

If the ECU was reading a code it is not because it it sensing knock. Its because there is a short or error in the system. Your system can run great all day and ever feel knock but still have a 34.

Could it be the O2 sensors themselves? An improper readin across the o2s could tell the ECU to run lean. Have you checked your timing?

 

Yeah I checked the harness and everything seemed fine. I did notice the timing was off by 1*. Within tolerence but i adjusted it back to 15. Other than that everything is within spec. I was thinking 02 sensors, but how often does both of them go at the same time. Granted I never checked the ECU (only had the car for a few months) Any other ideas why it would run lean?

 

It seems to me that if one sensor is bad, both would suffer. I dont know if anyone else has any insight into that on here. I dont know if the ECU can lean out one bank vs the other.

 

I read somewhere that its supposed to adjust them independently. Any comments?

 

last time I checked there is only one Knock sensor and I believe is right under the intake manifolds (the lower one) so it will be a misssion my friend... Remove the top and lower intake manifolds u might wanna take advantage of this to block out the EGR, and AIV systems. reroute the coolant lines while you are at it. it will be fun. I gurantee it.

 

We were talking about (2) O2 sensors. He doesnt have AIVs or an aftermarkerI ECU, so the AIV and EGR wouldnt work sfor him.

 

Damn that is still fun but not as fun as the knock sensor. butstill fun. he's gonna have to remove the brake Master cylinder to get to the Driverside Sensor. passenger sensor is not too bad. just teh driverside is hella fun. oh yes!

 

Thats exactly what I didnt want to do. Bu eh, if thats whast causing me to run lean its worth it. I still have to check out the O2 sensors to make sure they are registering the right resistance, but the weekend is right around the corner so yay for me.

 

yah you don;t necesarly gotta take the whole cylinder out. just gotta be able to move it so if you take out the the 2 14mm bolts and it comes right out. just leave the lines hooked up to it so you don;t gotta bleed it just make sure you don't pinch the lines. and get the 02 censor tool from Autozone, kragen, partsamerica, Napa etc... and have fun

 

Do the relocation - http://www.twinturbo.net/net/viewmsg...&msg_id=786419