240SX Need Help!

[bilracer]

I have ran my 89 240 in ITA for 2 seasons with very few problems that I call "serious".
During my winter teardown, I noticed that #1 piston was actually starting to burn. I rebuilt the engine, checked everything that I could think of and started this season off.
At VIR in may I burned #1 completely through. I was having some fuel pressure problems so I changed the pump and had my injectors cleaned and blueprinted to be safe. After installing a spare engine, I went to another race last weekend and now have the same problem. The spark plugs show that the engine in NOT lean and I watched the fuel pressure very carefully - that was not the problem. Does anyone know of a distributor or ecu timing problem that exists here. ANY HELP AND INPUT WOULD BE APPRECIATED.

thanks

[ITA240]

bilracer,
email me at [email protected] or lets figure this out.

Jim Cohen

[This message has been edited by ITA240 (edited June 26, 2003).]

[Tristan Smith]

Billy, Jim please share with all of us. Thats all I need this season is a problem like that. Would love to prevent it before it happens.

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Tristan Smith
Buffalo's Southwest Cafe
ITA Nissan 240sx #56

[Joe Harlan]

Billy, The first thing is to check the TDC mark on the balancer is correct. #1 seems to be the first to go in the 3 valve when they burn pistons. I have found in the past the timing marks on the balancer to be off by as much as 5 degrees. You mentioned fuel pressure issues? Pump? Injectors? Do you run a cell or a stock tank? Also what fuel are you running? What Pistons early 89?

[This message has been edited by Joe Harlan (edited June 26, 2003).]

[ITA240]

Tristan,
I shared with Billy a little personal experience resulting from a crappy wiring harness. The harnesses on these cars seem to deteriorate quickly and I didn't catch a bad injector clip on #3 prior to Sebring race a couple years ago. The clip was vibrating. At idle, it ran fine. Under race conditions and rpm, it intermittently lost contact. It expanded a piston too much and beat a rod bearing to death.

I don't know if this is Billy problem or not.

Billy,
I failed to mention that I ALWAYS run a mix of high octane race unleaded and 93 street fuel just to be safe. Bob Stretch and Doug recommended I do it, so I just listened and spend the money when it is fill up time.

Jim
ITA240 for sale
(or going back to Daytona in august)

[bilracer]

Good thoughts from Jim and Joe. Thats what I need - some input!
No I can't say I have checked the TDC mark, and Jim, I've always ran 93 octane. Thats what JWT recommended for the ECU settup they gave me.
I am runing a fuel cell, with an aftermarket pump from NAPA designed to pump fuel for a fuel injection system standing alone (designed not to need a secondary in tank pump). I tried to run a bosch pump like a VW runs but they give up after awhile because they don't have a prepump. I learned that this year. I'm 95% confident (don't know if your ever 100 % sure) that I don't have a pressure problem anymore. The first time I burned a piston it was with the bosch pump. This pump is for people who put a fuel injection system on a car that was formerly a carb. model and is designed to "pull" the fuel out of the tank. The bosch pump is designed to "push" fuel because it has a prepump in the tank to deliver fuel to the pump. I've heard rumors that excessive heat will cause the distributor to go nuts. I can say that I've never had this problem when its cool weather. The only thing about this theory is why is it always #1 or #2 piston. Seems like if distributor was going faulty , it would be all cylinders. Anyway, thanks again guys! Any more thoughts are welcome. Like I said, I did not have these problems for 2 seasons - why now?(Don't misunderstand - I had other problems - just not this one)

[dpc]

Joe talk to us more about the timing mark being off, how did you check that. I have a JWT computer and it seems to produce real high advanced timing at 4000rpm. thanks for any help. dave

[Tristan Smith]

I run 100 octane unleaded. Not because I think the car needs it but purely for the "cooling" factor that all that unburnt gas can help provide. I am sure it is actually robbing me a bit of power, but again, provides just the tiniest safety factor.
Jim, what are you planning to run after you sell the 240sx?



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Tristan Smith
Buffalo's Southwest Cafe
ITA Nissan 240sx #56

[Joe Harlan]

<font face=\"Verdana, Arial\" size=\"2\">Joe talk to us more about the timing mark being off, how did you check that. I have a JWT computer and it seems to produce real high advanced timing at 4000rpm. thanks for any help. dave </font>

Dave use a dial indicator to find TDC #1... Look at timing mark and make sure it lines up. I have seen these mis-marked and also the rubber in the balancer gets old and the outer ring turns.

The other thing is when using a fuel cell with out a surge tank. Could you be drawing a little air into the system from time to time in different corners. This could cause a temporary lean mixture that would not show up in the EGT or O2 sensor...If my memory is correct on the 3 valve the number 1 injector is the first inline to get fuel so any air is going to go through that injector first? Just more to think about. I know on the stock tanks you need to run them on the top side of 3/4 to keep them from drawing air on the S14's. The S14 has a knock sensor so they don't seem to burn pistons from lean but they do eat the aluminum out from behind the exhaust seats when this happens. I have 2 really nice 4 valve heads that are junk from this. We call it a lean extrude hone job http://Forums.ImprovedTouring.com/it/smile.gif

[dpc]

Thanks Joe, will check my marks. I now run a surge tank.

[erlrich]

Billy, did you ever figure out what the problem was? I for one (and I'm sure I'm not the only one) would like to know if there's anything I should be watching out for.

Thanks

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Earl
ITA 240SX in process

[bilracer]

So far so good. I was told that when the distributer gets hot, sometimes if causes the timing to go haywire so I put in another one. I also put a heat shield between the distributor and the header. I am running 100 octane now instead of 93. I set timing down to 13 degrees. I put new connectors on the injectors so that they can't short out. I ran at Road Atl. last week and it seemed to be ok. Time will tell I guess.

[ITA240]

Bill
sounds like a little bit of everything. And sounds like maybe it is fixed..I hope so..

Jim