DuoWing Posted April 9, 2008 Author Share Posted April 9, 2008 I was trying to edit my previous posts, but it looks like I can't? Anyway one thing I came across is, the other day I went out and drove the car around, got it warmed up, then followed the instructions for getting the lights on the ECU to blink simultaneously. Anyway, I finally got them to blink which took a bunch of turning it to the right, which the FSM indicates is adjusting it to be rich? Anyway now my car was running worse, popping, more hesitation, etc. I put it back and now it's better again, so now I'm going to just lean it out maybe a quarter turn at a time to see if I get better results. Oh and I wonder if my alternator which seems to be going bad would have anything to do with running issues? Quote Link to comment Share on other sites More sharing options...
jmmorriso Posted April 10, 2008 Share Posted April 10, 2008 I tuned my MAF with my wideband and the car runs awesome now! No hesitation, easy starts when cold, all that! Putting the MSD 6a box and coil on my car didnt help the stumble, but getting the mixture right sure does. Im going to play with water temp (actual temp not just the sensor reading) to see if some more heat will make more power, or just throw emissions off the charts. Also, by replacing the ECU I have solved my fuel pump control problems. Before when I turned the key to ON the fuel pump would keep running, which is common for this swap even when everything appears to be wired properly. Now the pump only stays on for a few seconds and shuts off. Thought that was interesting. Quote Link to comment Share on other sites More sharing options...
DuoWing Posted April 10, 2008 Author Share Posted April 10, 2008 My fuel pump does exactly the same thing, where it keeps running when the key is turned on. I know I was told that I need to cut the ground wire for my fuel pump and directly ground it to the chassis, and disconnect my fuel pump modulator. I'll have to do that and see if that solves my problem of my fuel pump continuously running. Well I finally went ahead and fixed my ground wiring, and that seems to have cleared up some things. So far I keep turning that screw counter clockwise or lean about 1/4th a turn after every drive, to see if it makes a difference upon the next cold start. Glad to hear that you have finally come to the end. From what I can tell is I'm right about there. I really had pretty much no stumble on my drive home tonight, but now I'm definitely thinking about getting a wideband O2 sensor. Just for future tuning, diagnosing issues, etc. Do you run the wideband O2 sensor in place of the normal O2? Or do you have a separate spot for your wideband? I don't know much about a wideband, but if I could just run a it in place of my existing O2 and make the ECU work with it then I think I'll definitely have to get one. Quote Link to comment Share on other sites More sharing options...
DuoWing Posted April 11, 2008 Author Share Posted April 11, 2008 One other thing I forgot to ask was about your tuning by wideband. Did you just run the car at idle and adjust the MAF until you got the right mixture ratio? One thing I'm wondering is, how much would you say a half turn of that mixture adjustment screw on the MAF cause your mixture ratio to change? If I could get an idea, that might at least help me get closer to getting it right. Anyway my car seems to be running really good. I keep adjusting the mixture screw about a quarter turn after every drive, and it seems like it keeps improving. Although I think I've noticed the lean surging issue that's known with the earlier ECUs. When I'm driving along just for a few moments, mainly at slow speeds or small amounts of throttle, the car feels like it does surge a bit. I don't know if you've encountered this or not, but I don't really have much if any hesitation. If there is during cold then it's very little. I went ahead and ordered a heated 3-wire universal O2 sensor that would fit an 84' 300ZX Turbo. So I'll throw that in and that should make the warm-up period even better as I'll get into closed loop much quicker. Quote Link to comment Share on other sites More sharing options...
jmmorriso Posted April 14, 2008 Share Posted April 14, 2008 I didnt really keep track of how much a 1/2 turn changed the mixture, its possible to turn the pot so much that it stops changing the mixture at all, then you have to go way back It is possible to sub the wideband for a stock O2 and use a 0-1v output on the wideband controller for the ECU's signal, but I have never done it. I just welded another bung in. Quote Link to comment Share on other sites More sharing options...
DuoWing Posted April 16, 2008 Author Share Posted April 16, 2008 Alright, I found out that I was beginning to lean the mixture out too much. I went and actually got my car warmed up for once. I closed the ball valve that I use in place of my air regulator, and the car was idling really badly. So I had to start richening the mixture up, basically go back to the beginning, and then I adjusted it a bit more. The idle smoothed out quite a bit, and my car was starting back up with the air regulator passage closed off without needing throttle and not giving me alot of stumble/hesitation like it used to. So I've wasted alot of time by going way too rich then way too lean. When I could have probably gotten real close to having it adjusted right, by just slowly backing off the richness instead of going back to where I started. Anyway this time I really do seem to be about done with getting it set. Next Up: Nistune and Wideband. Quote Link to comment Share on other sites More sharing options...
DuoWing Posted April 21, 2008 Author Share Posted April 21, 2008 oh, one more thing that I thought. It really stinks having no way to really tell what the mixture is at, but I was curious. If you still check this, do the 2 LEDs on the ECU now blink simultaneously, at least if you do the test? Quote Link to comment Share on other sites More sharing options...
jmmorriso Posted April 23, 2008 Share Posted April 23, 2008 I abandoned the leds and just did it with the wideband, I couldnt get either of them to blink. Quote Link to comment Share on other sites More sharing options...
DuoWing Posted April 23, 2008 Author Share Posted April 23, 2008 That's what I figured. Anyway I'm curious, you're running your car with BCDD plugged off, no EGR, no Air Regulator, etc, right? I think I've now moved it too rich, if I keep the ball valve open during that warm up period the car seems to be really perky and seem to respond quite quickly, but if I run the car during warmup with the ball valve closed then it gets real poppy, stumbling, hesitation, like before. Do you have any issues with after the car's been warmed up, you go somewhere and leave the car for about 10-15 minutes, then when you restart it does it have any problems? It sounded like you had all these problems same as me, but it sounds like after getting the mixture just right it runs just about perfect. Did you set the mixture to 14:1? I may just have to try and find someone who can do an A/F reading or get a wideband, this tuning on the fly sort of works, but still is a pain. Quote Link to comment Share on other sites More sharing options...
naviathan Posted April 23, 2008 Share Posted April 23, 2008 Get a colortune. You can find them on eBay quite a bit and I believe MSA has them, or at least use to. The colortune is handy because not only can you tune your Z, but you can also tune just about anything with a spark plug by just buying the extra adapters. It's much cheaper than a wideband setup and more universal. Quote Link to comment Share on other sites More sharing options...
DuoWing Posted April 23, 2008 Author Share Posted April 23, 2008 I'd assume it's calibrated for 14:1 ratio? Although that's not a bad idea. I may have to look into that. Quote Link to comment Share on other sites More sharing options...
naviathan Posted April 23, 2008 Share Posted April 23, 2008 It's a site glass. Look it up. Basically it allows you to see your burn pattern in the cylinder. Blue is good. Quote Link to comment Share on other sites More sharing options...
jmmorriso Posted April 28, 2008 Share Posted April 28, 2008 I am still running the EGR to keep it legal, but dont have BCDD any more and the air regulator is plugged right now. I think I have a 1980 intake with no BCDD as it was built into the TB and now have the 60mm TB. I will be messing more soon as some other gremlins have reared their ugly heads My alarm is acting up and I have some more interior to finish up. Quote Link to comment Share on other sites More sharing options...
DuoWing Posted April 28, 2008 Author Share Posted April 28, 2008 I went ahead and ordered the colortune as a cheap alternative to getting my mixture correct. So that should be cool to have once I get it. Then I'll hook my air regulator back up, and install my heated 3-wire O2 sensor. Everything by that point should be good. I've been refraining from doing any mods or anything until I've got this running just right. Then I plan to up boost, and add in my mallory ignition. Something interesting I found out, was that using the ball valve in place of the air regulator, the ball valve is capable of passing much more air through it. So even though I kept turning the screw on the MAF more and more rich eventually from a cold start I was running really good, I think at that point I had the mixture correct, but it was matching the amount of air. By Turning the screw lean some, and closing off the ball valve more it would still act the same and run really good. Quote Link to comment Share on other sites More sharing options...
DuoWing Posted May 14, 2008 Author Share Posted May 14, 2008 One thing I was wondering, you said swapping the ECU was what finally corrected the Fuel Pump staying on issue. You mean swapping the ECU so that it was the same year as the MAF? I don't know if having an 86 MAF with an 84T ECU would matter or not. Quote Link to comment Share on other sites More sharing options...
jmmorriso Posted May 16, 2008 Share Posted May 16, 2008 however the ecu controls the fuel pump was a little messed up in the old ECU, the pump would just stay on when the key was on, now it cycles off when the key is on and the engine is off. Quote Link to comment Share on other sites More sharing options...
DuoWing Posted May 19, 2008 Author Share Posted May 19, 2008 I'm wondering if an ECU that keeps the fuel pump running is an indication of a bad ECU? My car runs pretty darn good just about all the time. I still have some hesitation before it warms up. I did some searching and I came up with some solutions, people having the same issues with their 300ZXs. Turns out alot of these had this problem from the factory. So in some case it relies on the mixture, but at the same time the ECU is just messed up. You either need to find an early ECU that doesn't have the issue, or just upgrade to the later ECU. Quote Link to comment Share on other sites More sharing options...
DuoWing Posted June 1, 2008 Author Share Posted June 1, 2008 One last update until I get it finished. Anyway I got ahold of an 86' 300ZXT ECU. I haven't gone for a good test drive or anything, as I need to get a bung/nut welded on so I can use the titania O2 sensor, but I connected the ECU up. Car fired right up and revved well, I also noticed that now my fuel pump works as it should the 2-3 second prime then shuts off instead of staying running. So this should finally correct everything. Quote Link to comment Share on other sites More sharing options...
Guest trey11691 Posted November 19, 2008 Share Posted November 19, 2008 im having the same problems, but its ruff on start up, i have to throttle it then after it warms up it pops and i lose all power and it wont go over 5mph. its an 88 300zx NA. and it doesnt get batter unless i let the car sit for about half an hour Quote Link to comment Share on other sites More sharing options...
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