Built KA24 won't run longer than 3 minutes - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

treydeal · 05-03-2002, 08:13 PM

I have a 95 240SX SE that had around 120k on it, and I decided I wanted some more power. Turbo seemed like the way to go, so I built the engine low compression using the shortened Arias piston/lengthened Carrillo rod combination. The block was bored .020 over and cleaned up, and all parts that are normally replaced during an engine rebuild (bearings, seals, gaskets, timing equipment) was replaced with brand new parts. Also a full 3-angle valve job was done on the head. The engine cranked right up and runs great, but only for about 3 minutes or so. We hooked up a timing light and the timing retards to the point of the car just cutting off, regardless of throttle position. Even at WOT, the best we could do is keep the car at 2,000rpm. By the way, we also took the knock sensor off of the side of the block and held it away from the engine while it was running, so it's not that. Anyone have any ideas what could be wrong? We've been troubleshooting for about a month now, and even a trusted Nissan specialist nearby has no idea what's wrong with the engine. Thanks in advance!

*AceInHole* · 05-03-2002, 09:44 PM

hows the dist. cap?? make sure the harness was wired in correctly? are the plug wires on the right plugs???

just a few random thoughts...

mbmbmb23 · 05-03-2002, 10:50 PM

What does it sound like right before it quits??  Did you upgrade the ECU for the motor??  Is there a rev limiter on the engine that didnt get hooked back up?  I'd heard of people loosing 2k revs because they cut a wire.

Hmmm....runs for 3 minutes only??  Every time?  3 minutes sounds like the time it takes for the engine temp to get up to normal level, maybe its related to that.

-M

Alias · 05-04-2002, 04:00 AM

That sucks, so bump for you and maybe someone will see this and help. Did you try freshalloy.com ?

treydeal · 05-05-2002, 04:22 PM

The ignition system, with the exception of new plugs, is the same as what we took off of the car when we pulled the motor, and the plugs wires are on the right plugs.  Right before it quits, it sounds like it has a really harsh race cam, and the car just stumbles and cuts off.  The ecu is still stock, but keep in mind that the turbo is not yet on the car and everything with the exception of intake, exhaust, and pistons/rods is stock.  There really weren't any wires that were cut or spliced so I doubt that's the issue.  I haven't redlined the car b/c I am trying to be gentle until I get some miles on the bottom end, but I assume that the rev limiters are still functioning normally.  If there is a way to "disconnect" them that will cause a problem, please let me know.  I wasn't aware you could disconnect them at all.  The longest the car has run is about 5 or 6 minutes after it sat for about a week and a half, but normally it will run for about 2 to 3 minutes.  Another fact that may help: to get the car to start back up after it cuts off, we have to cycle the switch (ignition on, off, on, off, on, off, then start) about 4 or 5 times.  We know for a fact that all of this has something to do with the timing, as we have hooked up a timing light and watched it retard WAY too much when the car begins to stumble.

cmathews · 05-05-2002, 05:14 PM

I am no expert, but here are my 2 pennies. 3-6 min. is the normal warm up time for the engine, during which the ECU on most cars stays out of our way. It does nothing for our environment and allows the engine to do its thing. After the warm up time, however, the ECU plays God. It has knowledge of everything and makes judgements that affect performance, economy, and emmisions. I hope that someone who has done similar modifications will jump forward and confirm or deny my speculations. My suggestion, but ask and study before doing so, would be to purchase an SDS standalone computer to control fuel and ignition. You will have all of the flexibility you need for the engine to run under any (reasonable) circumstance and will give you considerable flexibility. I am considering going turbo this summer and my first step is going to be the SDS computer. It will eliminate some troublesome parts at the same time (Mechanical Distributor, Mass Airflow Meter, and Stock Computer). Two of the guys at SDS are 240sx owners and each has his own turbo setup. They were a great help when I first started my research.

By the way, I am in no way affiliated with SDS, but am very greatfull of their help and will be purchsing one of their products in the near future.

My $0.02

Chuck Mathews

SDS Homepage

05-03-2002, 09:44 PM	#2
AceInHole Autox Technician Join Date: Dec 2001 Location: New Haven, CT Age: 44 Posts: 3,961 Trader Rating: (0) Rides Gallery: AceInHole Feedback Score: 0 reviews	hows the dist. cap?? make sure the harness was wired in correctly? are the plug wires on the right plugs??? just a few random thoughts... __________________

05-03-2002, 10:50 PM	#3
mbmbmb23 Zilvia Contributor Join Date: Oct 2001 Location: Charlotte, NC. Posts: 1,776 Trader Rating: (1) Rides Gallery: mbmbmb23 Feedback Score: 1 reviews	What does it sound like right before it quits??  Did you upgrade the ECU for the motor??  Is there a rev limiter on the engine that didnt get hooked back up?  I'd heard of people loosing 2k revs because they cut a wire. Hmmm....runs for 3 minutes only??  Every time?  3 minutes sounds like the time it takes for the engine temp to get up to normal level, maybe its related to that. -M __________________ 400x200

05-05-2002, 05:14 PM	#6
cmathews Leaky Injector Join Date: Feb 2002 Posts: 61 Trader Rating: (0) Feedback Score: 0 reviews	I am no expert, but here are my 2 pennies. 3-6 min. is the normal warm up time for the engine, during which the ECU on most cars stays out of our way. It does nothing for our environment and allows the engine to do its thing. After the warm up time, however, the ECU plays God. It has knowledge of everything and makes judgements that affect performance, economy, and emmisions. I hope that someone who has done similar modifications will jump forward and confirm or deny my speculations. My suggestion, but ask and study before doing so, would be to purchase an SDS standalone computer to control fuel and ignition. You will have all of the flexibility you need for the engine to run under any (reasonable) circumstance and will give you considerable flexibility. I am considering going turbo this summer and my first step is going to be the SDS computer. It will eliminate some troublesome parts at the same time (Mechanical Distributor, Mass Airflow Meter, and Stock Computer). Two of the guys at SDS are 240sx owners and each has his own turbo setup. They were a great help when I first started my research. By the way, I am in no way affiliated with SDS, but am very greatfull of their help and will be purchsing one of their products in the near future. My $0.02 Chuck Mathews SDS Homepage __________________ "It's not how you stand by your car, it's how you drive your car. You better learn that." Winning comes only after preparation. If you don't prepare so you can win then you are inadvertantly preparing to lose. Drive it like you stole it!

05-03-2002, 08:13 PM	#1
treydeal Join Date: May 2002 Posts: 2 Trader Rating: (0) Feedback Score: 0 reviews	I have a 95 240SX SE that had around 120k on it, and I decided I wanted some more power. Turbo seemed like the way to go, so I built the engine low compression using the shortened Arias piston/lengthened Carrillo rod combination. The block was bored .020 over and cleaned up, and all parts that are normally replaced during an engine rebuild (bearings, seals, gaskets, timing equipment) was replaced with brand new parts. Also a full 3-angle valve job was done on the head. The engine cranked right up and runs great, but only for about 3 minutes or so. We hooked up a timing light and the timing retards to the point of the car just cutting off, regardless of throttle position. Even at WOT, the best we could do is keep the car at 2,000rpm. By the way, we also took the knock sensor off of the side of the block and held it away from the engine while it was running, so it's not that. Anyone have any ideas what could be wrong? We've been troubleshooting for about a month now, and even a trusted Nissan specialist nearby has no idea what's wrong with the engine. Thanks in advance!

05-04-2002, 04:00 AM	#4
Alias Zilvia Member Join Date: Mar 2002 Location: Piqua,OH Posts: 229 Trader Rating: (0) Feedback Score: 0 reviews	That sucks, so bump for you and maybe someone will see this and help. Did you try freshalloy.com ?

05-05-2002, 04:22 PM	#5
treydeal Join Date: May 2002 Posts: 2 Trader Rating: (0) Feedback Score: 0 reviews	The ignition system, with the exception of new plugs, is the same as what we took off of the car when we pulled the motor, and the plugs wires are on the right plugs.  Right before it quits, it sounds like it has a really harsh race cam, and the car just stumbles and cuts off.  The ecu is still stock, but keep in mind that the turbo is not yet on the car and everything with the exception of intake, exhaust, and pistons/rods is stock.  There really weren't any wires that were cut or spliced so I doubt that's the issue.  I haven't redlined the car b/c I am trying to be gentle until I get some miles on the bottom end, but I assume that the rev limiters are still functioning normally.  If there is a way to "disconnect" them that will cause a problem, please let me know.  I wasn't aware you could disconnect them at all.  The longest the car has run is about 5 or 6 minutes after it sat for about a week and a half, but normally it will run for about 2 to 3 minutes.  Another fact that may help: to get the car to start back up after it cuts off, we have to cycle the switch (ignition on, off, on, off, on, off, then start) about 4 or 5 times.  We know for a fact that all of this has something to do with the timing, as we have hooked up a timing light and watched it retard WAY too much when the car begins to stumble.