240hoke Posted August 12, 2003 Share Posted August 12, 2003 I've had the same problem with my engine from the first day i cranked it, and i have been trying to figure it out since then. I have posted threads about it before and got lots of advice but nothing has worked or changed it in the least bit. It's been 9 months and i'm ready to figure it out! So.. Quick info aout my car before i start ranting on my issues. 74 260z l28et sds em4-6f npr i/c t3 3" exhaust 370cc injectors ZCC fuel rail n42 intake 240sx tb Basically I cant rev over 4500/5000 rpms. This is both while underload or just reving the engine. Several things happen whenever i reach this point, the engine makes "sputtering/strange" noises and refuses to rev any farther, and at the same instant the tach needle goes off the wall, fliping back and forth until I let off the gas. Things I have already done: - Checked all my maps/values and made improvements via scottieGNZ's suggestions - Checked my coilpacks for spark via SDS maual - Checked Spark Plug wires and tried differnt types, along with spark plugs -Checked plug gap and narrowed it to .035 - Checked Fuel Pump, fuel reg, injectors, and fuel pressure (28 at idle) - Checked all grounds - Checked magnets and hall sensor alignment, i have tried moveing the hall sensor closer and farther away - Checked knock sensor/turned knock sense and knock retard off in the computer I found very little that was wrong and what was off i fixed, nothing however changed "the problem" (as i refer to it). I really want ot get this problem fixed so any help is greatly appriciated! Thanks, -Austin hoke Quote Link to comment Share on other sites More sharing options...
Guest szlash280z Posted August 12, 2003 Share Posted August 12, 2003 maybe try a valve adjustment? Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted August 12, 2003 Share Posted August 12, 2003 Is that fuel pressure with the vacuum closed to the regulator? I believe fuel pressure for stock type injectors is ~36 and I know my 440's have a base of 43... Quote Link to comment Share on other sites More sharing options...
TimZ Posted August 12, 2003 Share Posted August 12, 2003 Are you sure it's a hall effect pickup? The TEC-II uses an inductive style pickup (variable reluctance), and it will act pretty much exactly as you describe if you have the pickup wired backwards. Polarity does matter. The tach going crazy is a very strong sign that your timing signal is getting scattered for whatever reason. How exactly is the pickup wired (+, -, shield)? Do you have any rotating magnetic fields (a/c clutch, alternator, electric fans) nearby? Quote Link to comment Share on other sites More sharing options...
240hoke Posted August 12, 2003 Author Share Posted August 12, 2003 I have adjusted a readjusted the valves to make sure they are correct. As far as the hall sensor is concerned, it is triggered by magnets in the pulley. Im not to hot on electronics, but SDS calls it a hall sensor. i have checked all my magnets about 5 times, i even replaced all the magnets so there would be no doubt, then as mentioned before i tried adjusting the sensor clearence. Im not sure as far as how the sensor is wired, please lemme know how i can check and i will do so. There is only on way to plug it into the ecu and all the wiring was done by racetech (sds) but i guees there could be a possiblity of them wiring it backwards. There are two electric fans mounted on the radiator, the problem exists wheather they are on or off. The hall sensor is located on the opposite side of the engine and the signal wires run around the other side of the engine, they come closest to any alternator wiring where they enter the firewall on the passenger's side where the a/c line used to exist. i have no a/c. So the only place i figure any interference could come from is the alternator/charging system. I have tried to keep my wires as far away for them as possible. oh on the fuel pressure that is with the vac hooked up. i believe it reads 35 with the vac line unhooked. I am useing a stock turbo FPR. I had the same problem when i was using the stock turbo injectors. But in an effort to make sure the fuel system was working properly i went ahead and replaced the injectors. -Austin Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted August 12, 2003 Share Posted August 12, 2003 Since you changed injectors, have you remapped the ecu? If not, I would think you need to do that. What happens exactly when you get the sputtering? What comes out the tail pipe? Have you tried wiring up an aftermarket tach, and seeing what happens? What about a rev limiting feature, does the SDS have that? Have you checked it? That is my suggestions. I would be surprised if you had interfereance from the wiring of the alternator, but I guess anything is possible. Good luck. Quote Link to comment Share on other sites More sharing options...
240hoke Posted August 12, 2003 Author Share Posted August 12, 2003 yes i have redone the fuel/rpm map to reflect the larger injector size. I have noticed that sometimes when reving it in neutral a puff of whitish smoke will come out at this spot. I have not tried an aftermarket tach mainly becuase i dont have acces to one, id have to buy one. but it is sumthin i would like to try SDS does have a rev limiting feature, i have it set to "no limit". A far as the interference thing goes, It is what it sounds likes to me too. however I just cant find where it's coming from and in addition The gauge mode displaying ign. is supposed to read "err" if there is ever interference and it wont disappear untill the ecu is turned off. Could there be any mechanical reason for the engine to do this? Thanks for the help so far guys -Austin Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted August 12, 2003 Share Posted August 12, 2003 Hoke, my brain is a little fuzzy on the details, but here is one more suggestion. Z-Gad's comment on the FP got me thinking. I suggest you buy a FP gauge, connect it into the system before the FPR with a long hose that will allow you to tape it the windshield while driving. The test is to see what the FP is at 4500. It should = base (line off) + the amount of boost you have. I thoroughly dislike the stock FPR and worse when you have an upgraded combo. It is possible you do not have enough fuel pressure at that RPM/boost. For safety sake, have a buddy in the car wattching the boost gauge and calling out the boost while you focus on the road and gauge in front of you. FYI, I have a FP gauge on a long hose permanently installed on my engine, with the extra hose rolled up and the gauge resting under the brake booster. When in doubt, I tape the gauge to the wiper to check FP at boost. As a practice, always check FP at idle with the line off, capping the open line so the engine continues to idle OK. Quote Link to comment Share on other sites More sharing options...
240hoke Posted August 12, 2003 Author Share Posted August 12, 2003 please lemme know what info i can supply, i'll do my best to fill in the details. i already have an FP gauge mounted in the car with a sender unit in the engine compartment. it rises a steady 1:1 under boost and doesnt change at 4500 rpms's. im going out for a ride right now to help a buddy on his z, ill get a maximun FP reading when im out. -Austin Quote Link to comment Share on other sites More sharing options...
240hoke Posted August 13, 2003 Author Share Posted August 13, 2003 ok - - 36 psi base 50 psi @ 14 psi boost I know this is a bit low for the 370cc injectors, but it is dead on for the stock FPR. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted August 13, 2003 Share Posted August 13, 2003 Tim the SDS uses a hall sensor for sure. Completely different than the EM unit. How is your fuel pump wired 240hoke? Are you using a relay? What gauge wire to the pump? What pump are you using? Quote Link to comment Share on other sites More sharing options...
Guest szlash280z Posted August 13, 2003 Share Posted August 13, 2003 could 50PSI be too much for those injectors at the boost you are running? Quote Link to comment Share on other sites More sharing options...
240hoke Posted August 13, 2003 Author Share Posted August 13, 2003 Right now i have my pump wired directly to the battery through a toggle switch. Im using 12 gauge i believe. i just did this temporaily to be sure it was getting full juice. I can also hook it up into the fuse block i made which is on a relay. The pump is an MSD unit, Pn2225. I called MSD and talked with them about the pump, they told me that it was more than enough for my app and it was anything but the pump. But who knows... here's a link to it: http://www.msdignition.com/fuel_8.htm "High Pressure Electric Fuel Pump Multiport EFI systems require a stable fuel supply to maintain best performance throughout the engine’s rpm range. This high pressure and high flow Fuel Pump features a roller vane pump mechanism which is extremely resistant to clogging and jamming. The pump mounts in-line (out of the fuel tank) with two supplied cushioned clamps for a quick and sturdy installation. The nipple inlet is 3/8†with a 5/16†outlet. The wire terminals feature brass studs for secure connections. Made in the USA, the pump is ideal for use as a “booster†for nitrous oxide applications, or as a stand alone pump for multiport EFI systems on engines up to approximately 500 HP. Capable of 43 gph at 40 psi/162l/h. High Pressure Electric Fuel Pump PN 2225" -Austin Quote Link to comment Share on other sites More sharing options...
240hoke Posted August 14, 2003 Author Share Posted August 14, 2003 anybody got some more ideas? Quote Link to comment Share on other sites More sharing options...
Drax240z Posted August 14, 2003 Share Posted August 14, 2003 How about a rag in the intake? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 14, 2003 Share Posted August 14, 2003 How is the crank angle sensor mounted? I've seen two mounted in flimsy aluminum mounts that vibrated at high rpm. When the sensor vibrates the timing scatters. I've seen this on 2 TEC-II equipped motors. One completely stopped on the track mid race when the pickup came in contact with the trigger wheel. The other was in the pits for a loooong time. Never saw that car run, probably had to trailer it home. I assume that the sensor hit the wheel on that one too. Jon Quote Link to comment Share on other sites More sharing options...
240hoke Posted August 14, 2003 Author Share Posted August 14, 2003 My hall sensor braket is 1/4 steel, mounted to the timing cover, cant budge it at all even with a hammer. i even sent pics of it to SDS for their approval. Im going to post some pics of my setup and wiring on my webpage, i'll have a link: PICS the rag is one thing i havent check for, lol but seriously this thing is really buggin me and it's exhausted my limited automotive knowledge so im hoping you guys can help me. -Austin Hoke http://www.geocities.com/datsun260zt Quote Link to comment Share on other sites More sharing options...
Drax240z Posted August 14, 2003 Share Posted August 14, 2003 I'm semi-serious about the rag, I've seen it before... By a bunch of people that knew very well what they were doing in and around an engine. These things happen sometimes. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted August 14, 2003 Share Posted August 14, 2003 could 50PSI be too much for those injectors at the boost you are running? It's not the injectors that are seeing 50 psi. The injectors are seeing the FPR pressure of 36 psi because they are spraying into the intake pressurized to 14 psi. But even 50 psi is not often a problem for EFI injectors, some Honda setups with RRFPRs hit 100 psi fuel pressure (not that the injectors run well though.) Quote Link to comment Share on other sites More sharing options...
240hoke Posted August 14, 2003 Author Share Posted August 14, 2003 Ok Drax, i checked the intake manifold just for kicks. no rags to be found. However i did find another problem, my TB wasnt opening all the way , adjusted the throttle pushrod and it was good to go. This should make some differnce as far as a WOT, but it didnt change "the problem" I tried running the car with everything turned off but the EMS. only the fuel pumps and the engine managment system had power. Nothing changed, so i think we can rule out interference. I was listening to the engine while reving it this afternoon and noticed the valvetrain makes a distinctly different noise right around 4500-5000 rpms. A kind of static like noise. Could it be possily my cam or something in the valvetrain could be causing this. -Austin Quote Link to comment Share on other sites More sharing options...
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