This is a last resort... i've run out of ideas here. I had some help from other members in some other threads, but no luck.

Got the motor setup and put it ~9months ago... sat for a while cause i had my permit, i've put around 3000miles on it so far.
Setup is a sr20de motor, t25, MR tubular manifold, 370s, tuned ecu + safc, 3" dp test pipe and exhaust.
Im looking to solve the problem, not hate on the sr20de/t. (which sucks at this point.)

Problem: it has slowly died since i started driving it consistantly. After it got done, and when i drove it occasionelly when it was sitting.. it pulled real hard, at 7psi just like a regular det would, spun first no problem, drove easy, no bucking and bullshit, good mpg.
Now, it idles crappy until warm, definately doesnt have the power it used to have. Has something wierd between ~2000-3000rpm when it feels like the clutch is slipping, or something is holding it back, like a lean spot, but its not running lean there. gas mpg is absolutely horrible. It pops, backfires, and bucks during shifts and sometimes at partial throttle.
I've run a wideband on it, and partial throttle in 3rd, 4th and 5th gears is too rich, around a 11.8, but wot is ~12.0

It just doesnt pull like it used to, i've checked ignition, fuel, wideband, turbo etc etc etc

Looking for any idea that might help, thanks.

Timing?

Sounds like a timing issue.

I've run a wideband on it, and partial throttle in 3rd, 4th and 5th gears is too rich, around a 11.8, but wot is ~12.0



That doesnt sound "rich" to me. thats where i think you should around. even lower if you have stock pistons and stock rings... WOT is a bit too lean for my taste.

Providing that the wideband is giving you an accurate reading....which kinda seems like it. Those AFRs will not be casuing the problem.

I really doubt timing got messed up unless you messed wih and didnt set it right.

I would check your spark plugs and see if they need to be changed. If yuo are getting those AFRs *** means there is fuel flowing through. Maybe your spark plugs are fouled. Make sure they are gapped properly. Check your spark plug wires and Distributor. Maybe new cap and rotor.

And to br sure check your timming as well.
Who did the ROM tune for you?

PauL

for a ~70mph... 13% throttle in 5th 11.5-11.8 is rich, and it drops too 10's too
plugs are new and gapped right, wires are new as well.
The wideband is an lm1, and when my friend dyno'd, we compared the two readings side by side, it was remarkably accurate.
Yea, 12.0 is a little lean, i agree...i did knock it down to 11.7-11.8, forgot to mention that
The rom tune was done by my friend, the fuel map is from a sr20det.. he's made his own maps for his 11 sec sr, and 500hp 300zx, so i dont think its too far off.

What kinda plugs are you running?

What's your timing set to?

Is your timing chain tensioner in good shape?

Check compression in your cylinders?

Turbo on its way out and is starting to seize and not able to spin freely?

Vacuum leak?

Faulty MAF?

Any codes on the ECU?

ngk iridiums, heat range 7 (enjuku carries them)
timing is slightly advanced... it used to be waaaaay advanced, could having the timing super advanced make more power? (doubt it)
yes, the timing chaing is taunt
I do need the check compression - i said that above
No vac or ic leaks, i checked that ~week ago
MAF needs checked.. im using an alternate redtop maf tomorrow to check
ECU is #55 :)

Does anyone know what the voltage readings should be for the injectors, o2 sensor and MAF sensor? I checked the TPS, and according to numbers posted on here, they were spot on.

ngk iridiums, heat range 7 (enjuku carries them)
timing is slightly advanced... it used to be waaaaay advanced, could having the timing super advanced make more power? (doubt it)
yes, the timing chaing is taunt
I do need the check compression - i said that above
No vac or ic leaks, i checked that ~week ago
MAF needs checked.. im using an alternate redtop maf tomorrow to check
ECU is #55 :)

Does anyone know what the voltage readings should be for the injectors, o2 sensor and MAF sensor? I checked the TPS, and according to numbers posted on here, they were spot on.

Having your timing way advanced will hurt the bottom end power, and possibly risk having detonation due to it.

As for voltages and all that, I'm sure you can refer to the FWD SR20DE values as they should be the same.

I think i figured it out...
with the help of my friends expertise, we're pretty sure its the knock sensor.

A lot of people suggested it was a timing issue, and a bad knock sensor will pull timing, and wont set off and ecu code.
The other reason is becuase, after some research, most ecu/rom tune companies will pull out the knock sensor signal at wot, because it cant handle the noise. I dunno if this is just something nissan knock sensors do, or maybe other companies as well.

Im gonna get the base time set right at 17* and pull the knock plug, see if that helps. It better damnit.

IIRC, the Nissan ECU ignores the signals from the knock sensor beyond 4000rpm anyway because there are too many noises up above that rpm that it would throw off the reading.

Anywho, on the Z32, the ECU will pull up to 4 degrees of timing (that's it no more) to try and save the engine once it detects knock, however, the knock sensor only works up to like 4000rpm as I said before (IIRC).

So what you said could be true.

We want reports :)

^4k sounds right... everything after that is where the engine feels like its being held back

Im trying to find where the damn plug is on the block lol... do you know if theres a plug uptop on the intake manifold i could undo instead?

Yup, right underneath the IACV plug.

The actual knock sensor itself is on the block, just below where the head bolts to it, underneath the intake manifold jungle fever.

^this guy is my hero...
out driving right now :)

edit: nm... i'll get back to ya'll tomorrow

ohs nos! i aint no hero! hahaha

well... that didnt work either.
I pulled the knock sensor, took it for a spin.. maybe a slight difference.
Pulled the water temp, no difference, pulled the o2 no difference.
These were all just quick neighborhood runs, i didnt drive around like this for any period of time.

I guess im back to getting my timing dead on at 15* and ill start all over again from there.

thanks again though sosideways

No problem.

I thought you reset the timing FIRST out of anything you did! hahaha

Report back with any findings!

No problem.

I thought you reset the timing FIRST out of anything you did! hahaha

Report back with any findings!

lol... timing is reset... and the car runs tits again :D
it was wayy to far retarded, no idea why... but i think i need a new maf as well. Cause when we pulled the tps (the ecu runs of the maf then) it had a crazy miss, and made it mad hard to time.

We got it as close as possible (the orange dot, 2nd in from the left is 15 correct? lol)
And its back to pulling like it should. I dont think the knock sensor had anything to do with it. Its fuckin fun to drive it again though :) :)

next upgrade... new coolant temop sensor, new vac lines, and i'd like to get my ecu done right with JWT or Calumsult.

The 15* BTDC mark is actually the 2nd one from the RIGHT.

2nd mark from the left is the TDC mark, for when you go to tear the engine down or when you go to stab the CAS into the head.

well thanks for telling me now damnit!
:laugh:

either way, the car is running soooo much better, even at 0* timing lol
Ill make sure and post up once i get it set on the RIGHT mark

You get the car timed to 15* yet?

If you did, what are the results?

oh yea.. my bad
yea i got it timed up las sunday.. another improvement over the 0* lol
i ripped it sideways and surprised the shit out of me when i banked second and tires kept spinning :D