Help troubleshooting?

[7anshin8r]

Hello, I'm trying to figure out what's going on with my car and looking for some help. I have a '96 240sx, still has the old KA24DE. I'm getting what I can only describe as a kind of stutter around 2700 to 3000 RPM. Sometimes it's when I'm cruising, sometimes it is during acceleration. Power drops for .5 to 1 second about three to four times in a row. When I say power drops I mean I can push the pedal and the car does not respond. Today it did it for about 2 seconds three or four times and during that time I had nothing.

I replaced the MAFS about a year ago. I checked the TPS after someone suggested that and it was fine.

It is throwing codes P0325 Knock Sensor and P1145 Purge Volume Control Valve.

[OutToWinPAHC]

Check this, most likely that valve motor.

http://www.asashop.org/autoinc/feb2006/techtips.htm

[OutToWinPAHC]

Here

http://www.nicoclub.com/FSM/240sx/1996/ec.pdf

[7anshin8r]

Thank you very much for the links. Would that cause the random bucking during acceleration?

It has gotten to the point it is both embarrassing and a little painful, I have a titanium plate in my neck.

Now that I think about it I used to have a pontiac with a carbureted V8 and it felt the same way whenever it would have junk in the carb. So that is a better description. Like fuel is getting cut or blocked.

[Hoffman5982]

Start the car. Pop the hood. Start pulling on the wiring harness in different places to see if you can get the motor to start bogging. I had this problem with both of my ka's and they both turned out to be a break in a wire. If it starts bogging, start pulling on like 5-10 wire groups in the area and continue until you find the problem wire. To find where the break is, I just ran my fingernail pressed into the wire until I felt it. Took all of an hour and a half, maybe longer. I would try that first and foremost.

good luck

[coolbone28]

My 95 would do this when I first got it. Check out your dist. cap and rotor for build up. Also check for cracked/cut/ripped plug wires. my problem went away after i got new cap and rotor.

[zenkistic]

I am throwing 3-4 codes with one being the knock sensor and the other 2-3 related to the evap system including that P1145. However, my car idles and drives fine (10k miles with the codes on, 110k total on engine) and I don't experience any bogging or hesitation. However, for my case I suspect open circuit or plugged valve since I got the CEL after body work under the hood.
Good luck finding the issue, please report back when you do.

edit: OutToWinPAHC, very nice link.

[OutToWinPAHC]

I think something is wrong with the emmisions that is causing the knock . Start with the basic and use the FSM tips.

[7anshin8r]

Well I've been sick so I haven't been able to do much. My wife helped me change the knock sensor since it was throwing a code and I know it had not been replaced as long as I had owned the car. We did that yesterday and what a PITA, but I am glad we did because it was all cracked up and rusty.

I've pushed and pulled all along the wiring harness looking for a short but cannot find anything. The only thing I found was a loose plug on the MAFS.

I just found out I have to have neurosurgery again so I'm stressed to the max. It's made following the FSM impossible as I just can't focus. It sucks bad.

Tell me your not thinking it might be the EVAP canister purge volume control valve as it looks like I will have to pull the intake manifold to get to that...

I really want to get this fixed before I have my surgery as my recovery will be very long and I'll need the car for my wife to drive me (almost as scary as neurosurgery) to the doctors and physical therapy.

[7anshin8r]

Now it's idling like crap. It idles ok around 1k rpm for about 5 or 6 seconds, then down to very rough at around 500 - 700 rpm for about 5 or 6 then back... Thought I had a short in the wire that goes to the MAFS but can't get it to do it again. Tried another MAFS but it is the same. Did a tune up but no luck.

Strange though when I unplug the MAFS it idles real nice. Can't run like that but odd.