240hoke Posted April 22, 2003 Share Posted April 22, 2003 Im having alot of problems getting my SDS working right. THe car stumbles and wont rev past around 4500 rpms. At this time the tach also goes crazy flipping from redline to idle. Ive been talking with the sds guys, and were both out of ideas. I have double checked and replaced the magnets, everything seems to be fine. All wiring has been rerouted to the coils, and several types of spark plug wires have been used. Nothing has worked. Im convinced it is an ingnition problem beacuse of the tach and how it reacted on the dyno. Hoping it might be something simple though. Any ideas? Thanks in advance -Austin Quote Link to comment Share on other sites More sharing options...
240hoke Posted April 22, 2003 Author Share Posted April 22, 2003 It runs great all the way up to 4500. Very smooth in the lower rpms. Quote Link to comment Share on other sites More sharing options...
Nigel Posted April 22, 2003 Share Posted April 22, 2003 No RPM Error on the display? Nigel '73 240ZT (SDS EM3-6F) Quote Link to comment Share on other sites More sharing options...
240hoke Posted April 22, 2003 Author Share Posted April 22, 2003 Yeah thats the odd thing about it, no rpm error. Right now since ive already gone through all the ignition stuff, thinking it might be fuel issues. Im not running high boost or anything though, right now its retty much stock. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted April 23, 2003 Share Posted April 23, 2003 Do you have a 240Z? If so, the tach itself could be your problem. My stock tach did that when I converted to standard turbo electronics. Maybe you should try an aftermarket tach and disconnect the stock on just to see. Know anyone you can borrow one from? Quote Link to comment Share on other sites More sharing options...
Nigel Posted April 23, 2003 Share Posted April 23, 2003 Can you rev it past 4500 in neutral? I have a stumble past 5000 rpm, but only at full throttle in 3rd gear. I'm pretty sure its fuel related. However, for some silly reason, I never bothered to check the duty cycle before I put the car away for the winter (only had the car on the road for 2 months last year, after 8 year restoration!). I guess I asumed that I couldn't be having fuel problems since I was running stock boost (stock injectors). But the head has been ported and I've got a hybrid turbo, low restriction exhaust, etc. So, I think it's quite possible I was maxing out the stock injectors. Over the winter, I replaced the injectors with 440 cc RX-7 injectors and I just bought a 255 lph high pressure pump, so that should more than take care of my fuel needs. With any luck, that will be the end of my stumbling problem, but it's going to be a few more weeks until I get the car on the road again to find out. Could be the same issue for you. Wierd about the tach though, but it could just be an odd side effect of the stumble... Nigel '73 240ZT Quote Link to comment Share on other sites More sharing options...
Guest Zcarsmakemyheadhurt Posted April 23, 2003 Share Posted April 23, 2003 Ya does the car rev past 4k in nutural? Your car has a hi pressure fuel pump right? I had a problem with the magnets once and found out by holding the sensor while reving the car. As long as I held it to keep it from vibration it would rev. If you have a factory pump on the car dump it. Good luck let us know. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted April 23, 2003 Share Posted April 23, 2003 Good advice so far. If the engines revs past 4500 in N, then you need to check the DC% when it starts going flaky and if it shoots up to a very high %, then the problem is fuel delivery. Check the following: - Stock pump will not cut it! - Kinded fuel line - If you are using the stock fuel tank with a front pickup, you might be getting cavitation with the fuel flowing away from the pickup under acceleration - Clogged fuel filter or internal screen/filter in the pump if it has one - If you are using the factory wiring, check for a bad conection or corrosion, then completely rewire the pump with 10-gauge through a relay and using the factory wiring to trigger the relay Quote Link to comment Share on other sites More sharing options...
240hoke Posted April 23, 2003 Author Share Posted April 23, 2003 Hello, thanks for all the replies. The car is a 260z. Im using an MSD EFI pump, all new wiring, new fuel filter. Stock tank, with a surge tank in the engine compartment and a low pressure generic feeding that. The car behaves the exact same way in nuetral, if not worse. I will try holding the sensor to see if it is the vibrations. Using the stock injectors for now, but im only running 8 psi. Once i get this cleared up i plan on upgrading. Could bad injectors cause a problem like this/ i have no idea the condition of these. By the way i have a video of the sds programmer and the tach at 4500 if it might could tell you something i can email it to you. ALso can send pics of wiring etc. I really want to get this thing figured out. Thanks again -Austin Quote Link to comment Share on other sites More sharing options...
z-ya Posted April 23, 2003 Share Posted April 23, 2003 Yes, bad or dirty injectors can cause this. I would send yours out to be cleaned and tested. Otherwise you have no Idea what you are dealing with. You can get this done for less than $100 for all six. Pete Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted April 23, 2003 Share Posted April 23, 2003 Austin, does the video show Gauge 2 mode? If it is not terribly large, go ahead and send it to me but no promises on what I will see. Hopefully bad injs will show flaky DC behavior but there is certainly a difference in the load when in N. Strange. Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted April 25, 2003 Share Posted April 25, 2003 If you have knock sensing - set the retard value to 0 and then try it. My em3-6 was doing this when I first got it together. The knock sensor was picking up some vibration and backing down the timing at high rpm. Just remember that you have no knock sense when you run it! Cheers - Doug Quote Link to comment Share on other sites More sharing options...
240hoke Posted April 25, 2003 Author Share Posted April 25, 2003 Hello, I have tried holding the hall sensor and i have turned the knock sensor off. Nothing has changed. Ive have given the ignition a good chck over and havent found any problems, so right now im turning toward the fuel system. Yes, bad or dirty injectors can cause this. I would send yours out to be cleaned and tested. Otherwise you have no Idea what you are dealing with. You can get this done for less than $100 for all six. Pete Where can i get this done, should a local place be able to do it or is there a good place i can send them? Thanks again Austin Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted April 27, 2003 Share Posted April 27, 2003 Any luck? The problem could be anything but more than likely it will show up as an oddity in either IGN or DC in Gauge 2 mode. you just have to know how to interpret it. E.g., if you look at your IGN and IGN RET maps, you would know exactly what the timing should be for 4500 RPMS & 8psi boost. Lets say it is 25*, derived from 33* advance @ 4500 minus 8* retard @ 8psi boost. If IGN in Gauge 2 is reading 8* under those conditions, then it is probably the result of the knock sensor as suggested. Either real knock or the knock sensitivity needs to be adjusted. Make sure you have good IGN & IGN RET maps so the timing is accurate. I would not waste money cleaning stock turbo injs. Get a set of used SVO 30# injs and have those cleaned then reprogram the SDS. Here is where you see one of the benefitsof a programmable system. No worries about the bigger inj making the engine run rich at idle or off-idle. Quote Link to comment Share on other sites More sharing options...
240hoke Posted April 27, 2003 Author Share Posted April 27, 2003 No luck yet. I'll give my values another good look over and Im going to make a spreadsheet of my values and let you guys take a look maybe there sumthing i'm not seeing. Are the SVO injectors o-ring or barb? I'm thinking about going ahead and swapping the injectors even if they arn't the problem becuase i know that i will want to in the future, plus this will be one more thing i know isnt causing the problem. Right now i have the knock sensor at the lowest sinsitivity and it is only active below 2500 i believe, so it is as good a off. Thanks for the help -Austin Quote Link to comment Share on other sites More sharing options...
Mudge Posted April 27, 2003 Share Posted April 27, 2003 SVO are O ring, anything modern is O ring on an American car (generally speaking). Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted April 27, 2003 Share Posted April 27, 2003 I did a little write on how to mod the SVOs to fit the L28ET. It is in my old L28ET webpage which was hosted on zdriver.com. I left it there in case anyone could find it beneficial but now it is not accessible. I have no urge to fix it or rehost it so if anyone still wants it up, contact zdriver.com and see if they will fix it. Quote Link to comment Share on other sites More sharing options...
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