Noob to sr20det, got issues...

[J.bell]

Just got my first 240sx w/ sr redtop swap. Kid before me treated the car like shit and now Im gonna bring her back up to snuff. The one issue thats really bugging me is the acceleration is really sloppy. Once I get to 4500 rpm it really gets sloppy and the car is kinda jerky. Also at times I have trouble selecting 4th or 2nd gear, and I can never down shift to 2nd, and in neutral the release bearing is noisy. So my question is, could these be symptoms of a bad clutch? or could there be multiple problems? I just need sum opinions from ppl who know these cars, so I know what course of action to take.

[420sx]

Just got my first 240sx w/ sr redtop swap. Kid before me treated the car like shit and now Im gonna bring her back up to snuff. The one issue thats really bugging me is the acceleration is really sloppy. Once I get to 4500 rpm it really gets sloppy and the car is kinda jerky. Also at times I have trouble selecting 4th or 2nd gear, and I can never down shift to 2nd, and in neutral the release bearing is noisy. So my question is, could these be symptoms of a bad clutch? or could there be multiple problems? I just need sum opinions from ppl who know these cars, so I know what course of action to take.

bad throw out bearing, possibly slipping clutch. take the tranny off and look, you will need to get a new clutch kit.
also could be this plus tranny failing, but before you toss the tranny do the clutch. if the tranny shifts smooth through gears when its cold generally its probably fine. your priority once again is a new clutch and new t/o, pilot bearing. good luck

[doitsidewayz]

sounds like a bad TOB and clutch... but like he said ^^^ open it up and look inside and see whats up

[J.bell]

kewl, thanx. Funnything, I just blew the slave cylinder on the way home, so looks like Ill be under there anyways.

[doitsidewayz]

Alright man. That could be one of your problems as well!!!
Keep us updated!

[J.bell]

What happend was the spindle and cap for the tranny's input shaft broke, thats why I was hearing TOB noise. Because of that, my cluch fork fell of the bearing and caused the slave to hyper extend. That spindle keeps the TOB centered on the shaft, so my bearing was off center and wasnt engaging the pressureplate properly, which was most likely why I had troubles selecting gears at times. I went to a silvia shop here in calgary and got the parts, ( spindle and cap 20$, stock SR disk 20$, slave 20$, getting all problems solved in one shot PRICELESS!). The guy who runs the shop was saying that these spindles break often because they are only cast aluminium. Im going to see if a machinist can duplicate it from harder metal, which would also help seal in tranny oil better. There may be internal damage to the transmission, because the pervious owner bagged on it. So my next step, for next year is to bolt up a Z tranny, the shop here sells the adapter plate, driveshaft and tranny as a kit for around $2000.

[Sileighty_85]

the break up sounds like inccorect spark plug gaps. Gap should be .028-.030

[J.bell]

Heres pics of what Im talking about:
http://www.bluemelon.com/speedstar/carpics#page-0/photo-1817153
http://www.bluemelon.com/speedstar/carpics#page-0/photo-1817154
http://www.bluemelon.com/speedstar/carpics#page-0/photo-1817155
http://www.bluemelon.com/speedstar/carpics#page-0/photo-1817156
http://www.bluemelon.com/speedstar/carpics#page-0/photo-1817157

[J.bell]

Yeah thats a good point, the guy I got the car from said he did the plugs, and he was a complete dip-shit when it came to fixing things on this car.

[J.bell]

So after a month of tinkering with my 240, and doing tons of reasearch on forums, I finaly got this thing running great, and it shifts better now thans to a cluch and tranny repair, but the trans is on its last legs, so Im going to baby it and replace it in a few months. Ive noticed on alot of forums, people were having issues similar to mine. Jerkey acceleration, power loss, loud hissing during boost, couldnt get past the 5k rpm range, detonation, backfires, etc...(and my car had ALL these symptoms, my first post was a "summed up stab in the dark"). There are alot of possibilities to what is the cause of the problems, and to what the solutions are. And answers were scattered around all the forums, with nothing truely definitive. All of these answers, and how scattered they were made me decide to write this up, so the next kid looking for a solution to this issue, has many of them consolidated in this one post. These were the problems I found:

1. The spark plugs were carbon fouled badly, and werent gapped properly. They were at the .36-.40 range, way off the .28-.32 range. I got new plugs, gapped properly, and the engined idled nicer, but I was still having acceleration issues.

2. Wiring. One of the previous owners gave this car a *decent* backyard paint job, but didnt sand down to metal at the ground points. So ground resistance was high. In fact, it was so bad Im amazed anything worked in the car. By some means from above, it ran still. After cleaning up ground wires, and the ghetto battery relocate, things were improving. The car no longer wanted to stall when clutching and coming to a stop, but still dropped to scary low rpms sometimes. And I now have speeds on my blower motor, not just "4", weird but beliveable. But still, accel issues...

3. Drity MAF. There was an improperly installed HKS suction kit, which the bolts would back out from vibration and the car was sucking up un-filtered air. So the MAF and piping were disgusting. Using MAF cleaner, and A VERY soft fine bristle paint brush, I gently cleaned it, and cleaned the piping while I was in the vecinity. I also switched to a cone and adapter setup and tightend all the silicone couplers along the way to eliminate boost leaks as the problem. The car became quicker, but still bogging, hissing, and backfiring when I give it gas.

4. BOV's, my goodness there alot of opinions on what is good or bad for your SR. In my case, mine came with a PROF Sheepdog. My perticular model of BOV is a semi-recirculating. But the previous owner had capped off the port on the greddy intake tube for the re-circ, and left the BOV pure atmospheric. THIS IS BAD, without proper mods to support it, or a MAP sensor. I tried adjusting the hell out of it with no prevail, so I picked up some 1" heater hose and rigged the recirculation back up. WAY better, smoother acceleration, less hiss coming from under the hood, and danm, in my opinion these BOV sound really nice. Not to loud, but still a unique agressive sound. But, I was still getting boost spikes that would make the acceleration messy. Onto the next trial...

5. Vacuum tube routing. Of my 2 Vac ports on my throttle body, one was to the FPR, the other ran my BOV, boost controller, waste gate, and boost guage, T'd off consecutively. Definately not the way it should be...:facepalm:
So, being a machinist, I made a threaded Vac outlets on my charge pipe, one hot-side, one cold side. Hot, going to the MBC and waste gate, and cold to the BOV. By doing this I got way better response out of the componenents. My boost guage now has its own port at the TB for acuracy, and isolated sources for the rest. No more boost spikes, smoother acceleration, but still.... it was still hesititating in the 3k-5k rpm range. At this point, im getting just a little frustrated... but Im used to it, I was a VW tuner for 7 years before owning this car.

6. Ignition timing and CAS sensor. After seeing this come up in alot of forums, I figured hey what the heck, off with the valve cover and lets check it out. Thanx to FRSports simple method, I found that my ignition timing was out by just a few degrees. So using FRSports method, I reinstalled the CAS, and made sure it lined up perfect. Now with everything installed again I started the car and did the "timing lock in" procedure.( Rev to 3k, shut down, unplug TPS, start it, give 3 3k revs, then plug the TPS back in. Now for a Test drive... and BAM, problem solved, FINALY!

These are just the problems I encountered and how I went about solving them. There were a few other possibilities as to the cause of this problem. At the time I was waiting for consult port software, which makes diagnostic work much easier, so I had to do the trial and error method. Just a few other possibilities I found for these symptoms include: Bad fuel system ( pump, injectors, FPR.), faulty IACV ( Idle air controll valve), Manifold leaks ( boost/vac leaks), bad compression, and faulty TPS or Water Temp sensors. All of these have methods of testing, which I didnt seem to have problems in those areas.

All in all, Im thankful for this journey with my SR, although frustrating at times. Ive become more attached to the car, knowing I made Sugar out of shit. And Im the most thankful for the knowlageable members of the various Nissan forums. I PROBABLY couldnt have done it with out you guys, because really,who wants to jump into the octogon and scrap without any advice on how to fight?