Thread: Unfixable problem??

This has been going on as long as I can remember. I feel it has something to do with the timing. When I set it at 15* where it belongs, it runs like crap... detonates like a banshee, stumbles under acceleration, poor throttle response, just has no get up and go. This remains true backed all the way down to about 8 or 10*. If i put it up to 19*, it runs great, the stumbling goes away, and its got good throttle response, but obviously it's still detonating like a pig.

Only CEL i get is that damn knock sensor one that everyone els claims they get, but I don't here anyone els complaining of a problem.

Mods to the engine... CAI, 2.5" header, exhaust, jwt s4s.

Now I know someone here is going to blame it on the mods running with stock ecu, but i've already put everything completely back to stock, except for the catback exhaust, and the same problem is still there.

I've changed... ecu, maf, o2, plugs, wires, distributor, tps, fuel pump, tried 3 different fuel rails/fpr, knock sensor, fuel filter, cleaned air filter.

I'm not running egr. On or off, it doesn't make a difference. I've tried 3 different egr systems.

I've checked under the car to see that the fuel line hasn't been smashed that its pinching the fuel supply. The fuel pressure has also been checked. The pump has been checked to make sure its getting proper voltage. maf and tps have been back probed and checked okay. All vacuum hoses have been taken off and pressure tested.

What's next? I'm ready to sell the car..

Get a freaking knock sensor.

/Thread

A lot of people run stock ECU's with those mods. Infact buck per HP gain in ECU is not all that great, unless you get it tuned for your setup.

When your ECU see's a failed O2 sensor it starts backing off on timing. To avoid knock. Go on eBay and get a genuine Nissan knock sensor for like $80, then reset your ECU after you install it.

how are you checking timing. I've read somewhere that you have to make sure the timing is okay mechanically and electronically. Timing light on crank pulley and then see if the ecu is see the same timing. Like using nissan datascan. Did you degree the cams? This, i've read is more of a safety measure than anything. Just some other ideas.

I've replaced the knock sensor. Still get the code.

Checking the timing by disconnecting tps, starting car, connecting to cylinder 1, get her hot, set timing, reconnect tps, set idle.

Who did your cam install and I bet your mechanical timing is off a tooth

I agree on the possibility of being off one tooth.

Did you reset ECU or at least clear all codes with OBDII scanner? Try that see if that helps get rid of the code.

By the way that is not the correct way to check timing. I can go through the long FSM way, but I will mention the short way that is form SE-R.net

1. Start the car and let it warm up, driving it will help that.
2. When the car is fully warmed, disconnect the TPM
3. Rev up the engine 3 times to 3k rpm, this is so the timing would be consistent
4. Hook up the timing light to cyl 1 and check the timing. Adjust it via distributor
5. Reconnect TPS, turn off car and start it back up.
   

wiring to the knock sensor?

^ i was thinking the same thing, also dont drive that car with it detonating like that by the time you fix it , it wont be for ****

I was thinking about the knock sensor wiring. Is there a way to backprobe to check that the ecu is getting a signal?

Btw it's a 96 se-r.