datsunan Posted April 30, 2005 Share Posted April 30, 2005 So I put on a new 3" dp and JSK fuel rail, external 40mm wastegate and now I have detonation at about 3500rpm and 10lbs of boost then it goes away for the rest of the pull till 6500 and 14lbs it comes back. Before my mods I was able to boost 16lbs and never heard detonation. I have tried to adjust timing from 20 -23 and no change only better idle at 23, I have raised fp to 40 at idle with vac line disconnected, that made it a little better but my idle suffered. So my thinking is that my fuel map from Jim Wolf does not take into account my engine breathing better with this 3" dp and is not supplying enough fuel at these points.? Any thoughts? I fear for the life of my engine, it is much stronger now and I'm having trouble keeping my foot out of it. If I don't get this fixed soon,,, Booooom! Quote Link to comment Share on other sites More sharing options...
violacleff Posted April 30, 2005 Share Posted April 30, 2005 Sorry I don't have an answer, but since this is my first turbo motor, I was curious, what does detonation sound like? Just so I can be aware Quote Link to comment Share on other sites More sharing options...
tannji Posted April 30, 2005 Share Posted April 30, 2005 if it is a fuel map from JW, wont you have to get a new one now? That is the major gripe I have read about in my recent studies, the need to send ECU's back to JW anytime anything significant is changed in your setup..... Quote Link to comment Share on other sites More sharing options...
Clifton Posted April 30, 2005 Share Posted April 30, 2005 Sorry I don't have an answer, but since this is my first turbo motor, I was curious, what does detonation sound like? Like Satan knocking on your door:icon54:. Actually like a fast metalic knock. Without a wideband there isn't a sure way to know if you are lean but I know I can run down up to 14:1 and not have det and have done it quite a few times messing with the AIC. I am pretty close to my boost limit without knock (within 2 -3 psi). Unless you were on verge of it before I don't think a leaning out is the problem. If they changed the timing maps and it doesn't pull as much timing under load that would for sure do it but you have been running this for a while. Have you got gas recently. Could be lower octane than what should have been in the pump. Could you make 10 psi before at 3500 rpm. Peak torque is were detonation would be most prevalant. Above that you can run more boost with less chance of it at the same psi. Quote Link to comment Share on other sites More sharing options...
datsunan Posted April 30, 2005 Author Share Posted April 30, 2005 If you have ever put cheep gas in a car and floored it going up a hill it makes a metalic tapping or some call it ping, I think that is also detonation, that is what I'm hearing. Clifton thanks for the reply, its hard to tell what boost I'm making at 3500 things are happening to fast to catch it, but what you say about det happening at peak torque makes sense. After a few more pulls today it does seem to happen right when it pulls hardest, for maybe one second then goes away. Its not the gas, same octane I was running. I need to put it on a dyno and see what my A/F ratio is I guess. Tannji There is a guy on this sight Bernardd that has reprogramed the z31 ecu's and I have talked to him about getting the hardware so I can do mine but I think it runs like $500. Once I have it then if I do mods in the future I can make the needed adjustments. I'm hoping Bernardd will respond to this post and give me some more insight. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted April 30, 2005 Share Posted April 30, 2005 Are those 420cc injs aftermarket like RC? Most aftermarket injs should be set to ~43# at idle/line off and if so, that might be the problem. Might want to double check that with the manufacturer. Dont worry about how it idles for now, make sure it pulls under load w/o detonation and when it does, you will need to have it remapped for idle. Quote Link to comment Share on other sites More sharing options...
violacleff Posted April 30, 2005 Share Posted April 30, 2005 Like Satan knocking on your door:icon54:. Actually like a fast metalic knock. Without a wideband there isn't a sure way to know if you are lean but I know I can run down up to 14:1 and not have det and have done it quite a few times messing with the AIC. Not trying to hijack this thread, if this is true, what purpose would an a/f gauge or egt gauge serve? I'm still pretty new to EFI tuning. I was under the impression that a wideband is more accurate for fine tuning, therefore you would not want to tune on the edge with first two. Is this correct or am I way off? Quote Link to comment Share on other sites More sharing options...
Bernardd Posted May 1, 2005 Share Posted May 1, 2005 So I put on a new 3" dp and JSK fuel rail, external 40mm wastegate and now I have detonation at about 3500rpm and 10lbs of boost then it goes away for the rest of the pull till 6500 and 14lbs it comes back. Before my mods I was able to boost 16lbs and never heard detonation. I have tried to adjust timing from 20 -23 and no change only better idle at 23, I have raised fp to 40 at idle with vac line disconnected, that made it a little better but my idle suffered. So my thinking is that my fuel map from Jim Wolf does not take into account my engine breathing better with this 3" dp and is not supplying enough fuel at these points.? Any thoughts? I fear for the life of my engine, it is much stronger now and I'm having trouble keeping my foot out of it. If I don't get this fixed soon,,, Booooom! Could be a # of things. I wouldn't think it's the tune. JWT maps a 10:1 ish afr in higher boost areas with high teen's for timing. How are the plugs? Is one of them lighter meaning leaner? If you call JWT give them the maf voltage where this occurs, rpm and boost. Do a couple of tests with reduced base timing to find out how much you've had to reduce it to get rid of the detonation, and or increase the fp clear it up. If you want to tune it yourself, go to http://www.batronix.com. Buy a programmer for under 100.00 and get the new wideband from innovate for 200.00. I'll help you out with the tuning. Quote Link to comment Share on other sites More sharing options...
monster626 Posted May 2, 2005 Share Posted May 2, 2005 it would be smart to lower your timing to about 15* btdc as a base and up the fuel at least this will save your engine for the time being. Quote Link to comment Share on other sites More sharing options...
datsunan Posted May 2, 2005 Author Share Posted May 2, 2005 Thanks for the reply guys. My plugs look good #1 is light but it may be from before, when I pulled my stock fuel rail off I found a small peace of rubber in the injector neck. The plugs are new and are gapped to .035 with Msd 6 running them. Bernardd, How does my JWT ecu know what boost I'm at and where timing should be. Would it help me any to add a boost retard? I will try to reduce timing and see if that helps tonight. Hopefully I can get this fixed so as I can not go boosting all over town much more. I got a ticket for 92 in a 65 last night, ouch! Quote Link to comment Share on other sites More sharing options...
Bernardd Posted May 3, 2005 Share Posted May 3, 2005 Thanks for the reply guys. My plugs look good #1 is light but it may be from before, when I pulled my stock fuel rail off I found a small peace of rubber in the injector neck. The plugs are new and are gapped to .035 with Msd 6 running them. Bernardd, How does my JWT ecu know what boost I'm at and where timing should be. Would it help me any to add a boost retard? I will try to reduce timing and see if that helps tonight. Hopefully I can get this fixed so as I can not go boosting all over town much more. I got a ticket for 92 in a 65 last night, ouch! JWT knows the formula the ecu uses to calculate load. From maf voltage and rpm they can figure out where you are in the load table. Reduce the timing as much as necessary for it not to detonate. Make sure that the tps is closed and you're fully warmed when adjusting the timing. I still think that unless you're way over 450hp at the crank, you should be ok. BTW what kind of plugs are you using? Quote Link to comment Share on other sites More sharing options...
datsunan Posted May 3, 2005 Author Share Posted May 3, 2005 My plugs are NGK BPR8es. Bernardd let me run this by you, when I installed the msd ignition my apexi boost controller lost the tach signal. It was hooked to the tach signal for the ecu. I hooked the Apexi boost controller to the tack output lead from the MSD and it worked fine but if I try to hook the ecu to that lead the car dies. Maybe my ecu is not seeing the rpm anymore? If I rev the engine with my timing light hooked up I see it advance, does that mean it is seeing the rpm or does it advance off something else? the MSD was installed before my last round of mods listed above and had no problem, but then again I had a hard time remembering how the coil and msd were wired when I put it back together, maybe I should check my coil wiring. I know if it is wired +/- reversed that it will run but not as well. Thanks for your help, Paul. Quote Link to comment Share on other sites More sharing options...
Bernardd Posted May 3, 2005 Share Posted May 3, 2005 What do you mean by the ecu tach signal? At the ecu, what pin are you referring to? The ecu uses the CAS signal for rpm. Pin 8 or 17 I think. Perhaps you mean the coil signals? Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted May 4, 2005 Share Posted May 4, 2005 Did not see a response to my question about the injs. Quote Link to comment Share on other sites More sharing options...
jeffp Posted May 4, 2005 Share Posted May 4, 2005 I am assuming you bought the injectors from JWT. That being the case the injectors are run at bar static for the sport 400 package, and at 4 bar for the sport 450 package. I would recommend you reducing the gap atthe pluge to .025 and see how that works. The MSD is a good system, but it does tend to misfire under good boost loads. A wide band will not do you to much good, though, it will work, but undr boost it will give you readings that may or may not be accurate. Boost has a way of messing up the sensor readings. Still get some readings and go from there. I would try the point gap first. My car had a problem trying to go lean at the 5K range so it may also be the fuel map as well. Get as much information as you can to try to determine the problem, then give Clark a call about it. hope that helps. Quote Link to comment Share on other sites More sharing options...
jeffp Posted May 4, 2005 Share Posted May 4, 2005 Thats 3 bar static for the sport 400 and 4 bar for the sport 450 package. Quote Link to comment Share on other sites More sharing options...
datsunan Posted May 4, 2005 Author Share Posted May 4, 2005 Sorry Scotti GNZ, yes they are aftermarket Bosch but they were in before this round of mods and worked fine at 37psi like JWT recomended. I have not yet tried 43psi yet I have not had much time to mess with the car, maybe I'll try that tomorrow. Thanks for the suggestion. Bernardd, its a yellow/white wire #5 that goes to the transistor thingy at the coil, I had my Apexi hooked to that for tach signal then it went away when I hooked up my MSD. What is the CAS? is that the disc in the dist with all the slots in it? While driving the car tonight if I hit 14psi at low revs like under 3500 it does not det but as the revs pass 4500 it dets for 1/2-1 sec then goes away, don't know if that helps. I wish I could get it on a dyno and see my afr and timing are doing but I don't have the cash for that right now. Can someone lay on my fender and shoot the timing light while I do a 3rd gear pull? Quote Link to comment Share on other sites More sharing options...
datsunan Posted May 4, 2005 Author Share Posted May 4, 2005 So jeff your saying I should set my inj to 44psi for the 400hp? I wonder why Ben at Jwt did not tell me that, he told me 37. I'm going to try that right now I'll be back in a few. Quote Link to comment Share on other sites More sharing options...
datsunan Posted May 4, 2005 Author Share Posted May 4, 2005 Well that was better but I still heard some, faint and short but better. 44psi timing at 20deg, idle sucks and the exhaust burns my eyes. I got bad gas milage before I can only imagine what it will cost me to get to Vagas this weekend, but hopefully I will make it now. I'll have to see how it is when its warmer out tomorrow. Maybe I should try to regap my plugs? Is .25 what I should be going for? I have heard conficting ideas on this. Quote Link to comment Share on other sites More sharing options...
jeffp Posted May 4, 2005 Share Posted May 4, 2005 Give the .025 plug gap a try. As I said I had to do that with my setup because what was happening was a misfire, and it sounds like pinging when that happens. The AFR goes to heck and it sounds like pinging. Another thing to check just to make sure is the O2 sensor, make sure it is operating and not broken and not working. Your 3500 rpm level is right where the ecu goes from open loop to closed loop and vice versa so check that out. To bad you cant get a BIN file of the program we could get a look at. hope that helps you out. Quote Link to comment Share on other sites More sharing options...
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