mobythevan Posted April 20, 2004 Share Posted April 20, 2004 I am only running the car in the garage right now so I am only seeing idle to 2500rpm under no load. I have been having problems with my DSM injector install. I think I may be getting an air leak between the injector and the intake manifold. A couple things that came up, how long do I need to run the engine at say 1800rpm no load before I can recheck my spark plugs? I am showing two cylinders running lean so I am trying various experiments to fix this. The second thing is that my volumetric efficiency numbers for this area in my table seem too low. It seems like in order to not run rich on the other four cylinders I need to be around 30% when I think it should be more like 45% or 50%. My engine has unknown miles on it so could that be part of it? I changed my required fuel values for the bigger injectors, but something else seems to be throwing me off. My vacuum is good, would the vacuum always look good if I had air leaks at the injector to intake manifold? I am in the midset that I can only have two possible problems, either bad/dirty injectors or the air leak at the injector. Quote Link to comment Share on other sites More sharing options...
sims76 Posted April 20, 2004 Share Posted April 20, 2004 Moby, This may not be the best way, but this would be my approach. 1. Take note of manifold pressure at a constant idle rpm. 2. Spray some WD-40 where the intake meets the head. 3. If either the MAP or RPM change, there must be a leak. By the way, I ordered a HEI module from Sherco Auto Supply. I'm going to try the MSnS using the HEI as the trigger and a MSD 6A as the output. MSnS will be the middle man contolling the timing. I'll let you know how it turns out so you can update your sticky. -Sims Quote Link to comment Share on other sites More sharing options...
z-ya Posted April 20, 2004 Share Posted April 20, 2004 Like sims76 said, spray some WD40 or carb cleaner around the base of each injector and see if the ide changes. If it does, you have a vacuum leak. You could have an injector that is bad, or clogged. I assume that they are used? I think it's worth spending an extra $100 to have them cleaned and checked. If just a couple of cylinders are running lean, I would point the finger at the injectors. Another thing to keep in mind is that a turbo L6 doesn't require much fuel to idle, so if you put much bigger than stock injectors in, you will have to do quite a bit of fine tuning to get it to idle smooth. The problem is that the injector opening time may be too small for the injector to respond. I'm assuming that they are high Z injectors, correct? Hope some of this helps, Pete Quote Link to comment Share on other sites More sharing options...
mobythevan Posted April 20, 2004 Author Share Posted April 20, 2004 They are used injectors and they are low impedance. I think you are right, I need to send them in to be tested and cleaned. Take one more variable out of the equation. I tried the carb cleaner trick already but I'll try again because I had a couple other issues crop up, like fouled spark plugs. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted April 21, 2004 Author Share Posted April 21, 2004 OK, I played with it some more tonight and this is what I found. If I up my number of injections per cycle it idles much smoother, but this is backwards to the manual. Because this is taking me farther away from ideal settings for idle pulse width and required fuel settings. Seems to run much smoother all the way around. From the manual's stanpoint I should be set at 1 injection per cycle, this gives me the best required fuel and best idle pulse width for the injector size. The engine runs the worst at that setting. Runs much better at 2 injections per cycle and even better at 3. So I'll stay at 3 until something else doesn't look right. I checked for air leaks and I don't have any. Let idle for 20minutes and checked plugs, they all look the same now, all way too rich, wet. Since they all look the same and the engine sounds good now I am going to start in with the wideband tuning and if I can't get the mixture leaned out at idle I'll go back to less injections per cycle. Atleast it is running smooth again like it did with the stock injectors, although I can't see how with the plugs being wet at idle? I never said I knew what I was doing, but I'm learning. The more injections per cycle the tougher it should be to get idle working with a big injector?? Quote Link to comment Share on other sites More sharing options...
z-ya Posted April 21, 2004 Share Posted April 21, 2004 In the 10:1 L28 power 240Z track car I have a MS in, I too had to set the number of squirts higher than one. I think I have it set to 2. I'm running stock 19lb injectors too. It runs much smoother. Check that your TPS is still OK. Use the calibration tool in Megatune. I had a problem with it being way too rich, because my TPS failed. What would happen is the voltage on the TPS input would slowly creap up, confusing the MS into thinking that the throttle was open. Two sets of plus later, and a lot of black stains on the floor behind the car, I finall fixed it. Runs awesome now. I assume you are running simultaneous injection? I am. Pete Quote Link to comment Share on other sites More sharing options...
sims76 Posted April 21, 2004 Share Posted April 21, 2004 Moby, See my other post with the new fuel map. This map is for 19lb/hr injectors. You can scale the table for your larger injectors. I'm using 2 squirts alternating. http://hybridz.org/nuke/index.php?name=PNphpBB2&file=viewtopic&t=33313&highlight= Quote Link to comment Share on other sites More sharing options...
mobythevan Posted April 21, 2004 Author Share Posted April 21, 2004 I was using 2 squirts alternating, but it seems much better at 3 squirts alternating. I'll check out your table. I think I am getting closer. Thanks Quote Link to comment Share on other sites More sharing options...
mobythevan Posted April 21, 2004 Author Share Posted April 21, 2004 BTW, if everything was perfect then in theory wouldn't the VE table be the same no matter what injectors you swap in? Only the required fuel value would change. I just want to make sure I understand that part. I know that other things happen like the minimum pulse width of a big injector causes issues at idle on a small engine. Quote Link to comment Share on other sites More sharing options...
sims76 Posted April 21, 2004 Share Posted April 21, 2004 I should have been more specific. You can leave the Req_Fuel alone and scale the table. Or, change the Req_Fuel and leave the table alone. I would leave the Req_Fuel that you have and use the "Scale VE" button. Use the following logic: Old Req_Fuel = 12.8 (the value that I'm using) New Req_Fuel = 12.8 * (19lb/hr) / (your injectors in lb/hr) Example: Let's say you have 42lb/hr injectors. Old_Req_Fuel = 12.8 (my value) New Req_Fuel = 12.8 * (19/42) = 5.79 5.79 is 45.2% of 12.8. The program will multiply all of the values in my table by 45.2%. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted April 21, 2004 Author Share Posted April 21, 2004 That is what I thought, but wanted to make sure. Either scale the required fuel value or the table. Quote Link to comment Share on other sites More sharing options...
Tony D Posted April 21, 2004 Share Posted April 21, 2004 I tried simultaneous 1, alternating two, simultaneous two, and really didn't notice much difference between all three settings other than the pulsewidth changed a bit. With 2 Alternating and 1 simultaneous it seemed to run the best, so I went with 1 simultaneous to keep injector clicking noise down (odd reason, eh?) For the life of me I can't remember the pulsewidth it shows, but it's around the 730 position on the megatune dial---maybe 2.3ms? My req fuel was around 11.8 initially I believe. I am using the stock turbo injectors, fpr, etc. I have over five hours of smooth idle time now. I actually moved the car fifty feet forward and back last night to check my clutch install! Woo Hoo! Still have the interference problems, but it's not affecting me at idle that much. My idle vacuum is around 22"Hg at 800rpm, and snap-throttle spike is upwards of 29"! Warmed up, of course. My compression (though not checked) seems good as the pulses out the exhaust are even and strong. You may want to check your compression and make sure your cylinders are all up to snuff before going to much further. I had an idle air leak around my idle bypass screw, plugged it and vacuum went from 20 to 22" and idle dropped from 950 to 800 even. Little leaks all over make a difference. I had my 1/4" sensing line off altogether and it ran...rich as heck, but it ran! Remember that lower vacuum means it will go rich. I agree with the TPS Cal comment, it made a lot of a difference on my engine (got it to run!). The Oh-Silly-Scope is on my dining room table now (Beckman 1509---thanks JeffP!) now to figure out how to set it all up and go after the spikes! Good Luck Moby. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted April 21, 2004 Author Share Posted April 21, 2004 I just realized from reading in the MS group archives that increasing the number of squirts will decrease the amount of fuel delivered because of having to suffer the open/close time of the injector during each squirt. So it looks like I am just leaning out the idle mixture by upping the number of squirts and that is why it is idling better. Well, I will put the wideband on tonight and see what else I can learn. Quote Link to comment Share on other sites More sharing options...
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