Drax240z Posted April 28, 2001 Share Posted April 28, 2001 Its somtimes amazing how much you can learn about something just trying to track down 1 little problem, isn't it? Sounds like you are on the warpath scottie. Good luck to you. Let us know how you're intake temps differ across the NPR and the air-water when you get it setup. I'm interested in knowing. Quote Link to comment Share on other sites More sharing options...
TimZ Posted April 28, 2001 Share Posted April 28, 2001 Scottie - I certainly don't want to be held responsible for blowing your motor up (i.e., try this at your own risk ), but you could try just disconnecting the knock sensor for a run and see if your problem goes away. As long as you have confidence in your base calibration, and are certain that the timing didn't _need_ to be pulled for some reason, and you are running enough octane, this shouldn't be a problem. I'm pretty sure that the sensor failure detection for the knock sensor is almost non-existant, so the controller should think everything is fine. (Oops - just noticed that Blkmgk already suggested this - I still think it's a good idea, though...) [ April 27, 2001: Message edited by: TimZ ] Quote Link to comment Share on other sites More sharing options...
clint78z Posted April 30, 2001 Share Posted April 30, 2001 You mentioned you might be loosing boost, hmm I have a thought for testing that. To actually test a turbo system for leaks is usually hard. I plan to get an adapter and use the air compressor to pressurize the entire intake system to about 20 psi. I will then use soapy water to detect leaks. Just a thought I had, our company air tests alot of pressure vessels this way. Quote Link to comment Share on other sites More sharing options...
clint78z Posted May 1, 2001 Share Posted May 1, 2001 Stick a potatoe up the tailpipe, serouisly a you could temporarly seal the exhaust pipe, voila !! Small leaks usually occur at a low pressure, and bubbles from soap show up easily. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted May 1, 2001 Share Posted May 1, 2001 Hmm, good point! Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 1, 2001 Share Posted May 1, 2001 And rev it up a few times and have the biggest spud gun you've ever seen! "News today. A neighbor was killed today by a spud projectile shot from a Datsun Z.. News at 11:00." Lone Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted May 1, 2001 Author Share Posted May 1, 2001 I have to put any serious testing on hold for a short while as my BFG DRs have struck a chord with me, err, have the CORDS showing . I might try some 3rd gear acceleration testing but I will have to ease into the boost. All I have laying around are some 215/60HR15s and they are only good for holding the car up or cruising down the hi-way. Tim, I was tempted to disconnect the knock sensor Wed night but I did not have the b*lls and luckily I stopped as the tires were shot anyway. I sprung for a new sensor and if it continues, I can program the chip to ignore any knock to a certain MPH and 65mph will get me through the 2-3 shift. Clint, the soapy water is a good idea but my problem occurs in the upper RPM and boost range although I suppose a minor leak could manifest itself. What I have found in the past is that if I have a minor leak at a hose connection, that puppy comes flying off at 20# boost. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted May 1, 2001 Share Posted May 1, 2001 Clint I had the same thought a while ago, but it really won't work very well. It would be difficult to find and engine that at any point in its rotation has one valve in each cylinder closed. If any 1 cylinder has both valves open you are going to have a tough time holding pressure. Maybe if you had enough airflow you could do it... But I'm guessing that amount is going to be pretty high. Quote Link to comment Share on other sites More sharing options...
clint78z Posted May 1, 2001 Share Posted May 1, 2001 Funny story, my brother wanted to quiet down his 3" for a trip. He got a can and drilled a whole bunch of holes in it. He reved it up and the can shot out. Our puppy snagged it and ran like hell. So he find a piston out of a rototiller and clamps that in. I told him that the pistons have to be in the engine to make more power, he flipped me the bird Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 1, 2001 Share Posted May 1, 2001 Given the way the knock sensor (piezo-electric transducer) works, it would be my guess that the normal failure mode is not one that indicates excessive detonation. In other words, to output the voltage signal, the piezo-electric crystal has to be deformed / distorted. This happens when shock waves from the detonation vibrate the block. The piezo-electric crystal isn't going to just sit there and create voltage spikes on its own. Given that the same sensor has been used for years on GM engines, I would bet it is pretty reliable. Probably the most common "failure" mode of this sensor is mis-diagnosis! One further note to BLKMKG, is that yes this same sensor is used in many aftermarket systems (another testimony to its reliability), but the filtering / analyzing of the data it outputs is VASTLY different among OEMs, model year, and aftermarket. later, Steve Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted May 3, 2001 Share Posted May 3, 2001 Yes, the filtering etc. is different - an din this case that may very well be wahts' wrong. Heck, ignition energy could be leaking into the sensor lead and causing false readings. It could also be some sort of weird valvetrain bit - who knows? I'll be real interested to see where this winds up and how it gets fixed... P.S. Scottie, I've got th epics that I took of your car in Florida out of the camera on disk - you want I should put them up? [ May 02, 2001: Message edited by: BLKMGK ] Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted May 3, 2001 Author Share Posted May 3, 2001 Not unless they are going to embarrass me . Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted May 5, 2001 Share Posted May 5, 2001 Here ya' go! Only three pics, shoulda' taken many more but the camera has very limited space (sigh). http://216.254.117.47/others.nsf/bf1cfce3711ab30d852569f90083bfc3/4c36a53d3289a83185256a4300053f1a?OpenDocument Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted May 5, 2001 Author Share Posted May 5, 2001 Hey, nice engine . What a difference mandrel-bent piping makes in appearance. Quote Link to comment Share on other sites More sharing options...
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