xtremeboost2 Posted July 11, 2005 Report Share Posted July 11, 2005 well when tuning dont us any cheap a** air/fuel gauge. wideband is the best choice aem is what i will be using. also my shop i go to is doing my mpi his name is frank and he runs extreme boost over in orlando he used to live n tampa and he knows alot of stuff on mpi setups give him a call at 407 859 7000 tell him matt told u to call if u run into any problems Link to comment Share on other sites More sharing options...
jr Posted July 14, 2005 Author Report Share Posted July 14, 2005 Thanks, yeah, not to scare anyone, I was planning on having a friend help with tuning. I just wondered if anyone dyno tuned or not. I can change parameters every 250 rpm. It free rev's fairly smooth right now with a slight stumble at about 2500 rpm. Good idea with some interstate runs. What did that wideband run you guys? Thanks for the number onefastconquest. Does he dyno tune cars? 5bat map, eh? That sounds scarey. What kind of head you going to run?? I know when Sakura was running a factory head he was cracking them nearly every run with boost in the 50psi range. Are you looking to be road, or race only? Just curious.... My biggest concern in self tuning is getting the ignition curve to a effective, and safe point, but I must say I'm happy so far... Link to comment Share on other sites More sharing options...
xtremeboost2 Posted July 15, 2005 Report Share Posted July 15, 2005 well trust me my head will be fine i am using something that will work just fine and it's not stock or aluminum- sorry i dont want anyone to know my setup yet. but if u want a good place to bring ur car to be tuned i would go to aerocomp racing over in sanford florida. i live in deltona one town over from them and the are the people u are going to be doing my tuning for my car. number is 407 330 7300 located at 4205 st. johns parkway, sanford florida,32771 www.aerocompracing@mac.com any questions let me know Link to comment Share on other sites More sharing options...
jr Posted August 7, 2005 Author Report Share Posted August 7, 2005 Welp, I've now put about 1 hour of drive time on my 89 MPI!!! It's great feeling. Have the wastegate disconnected, so no boost until I can sort things out better. I'm having some bad stumbling problems when first accelerating from any speed. The engine stumbles, and almost dies, then suddenly recovers and sounds/feels great. jr_ss, or anyone else, any suggestions? I 'think' my problem is mostly ignition, but I'm not certain. I know everyone is using differnt ECU's, but if it's possible, I'd love to see somone elses timing curve. Maybe a screen shot of the table, etc? Thanks in advance for any help. Link to comment Share on other sites More sharing options...
mikec Posted August 8, 2005 Report Share Posted August 8, 2005 If your engine stumbles when you mash the gas but will accelerate if you slowly accelerate then your "accelerator pump" function isn't working right. Any engine needs a shot of extra fuel when the throttle plates suddenly open way up. Throttle position sensors detect this demand for acceleration and cause the ECU to squirt in a bit of extra gas... make sure you've got this programmed in your ECU. Increase the amount of fuel a bit; if the problem gets worse then you've got TOO MUCH gas going in and you're drowning the engine - reduce the accelerator pump fuel value a bit. A throttle position sensor mis-wired will really confuse an ECU: if the TPS voltage drops (instead of increasing) when you mash the gas the ECU thinks you want fuel CUT for deceleration. mike c. Link to comment Share on other sites More sharing options...
jr Posted August 8, 2005 Author Report Share Posted August 8, 2005 Hi Mike, thanks for the reply. I did play with that setting, but it hasn't helped, yet anyway. If I press the pedal really slowly, the motor will actually stall though. I have to punch it to get it past the bad spot, then it revs smoothly. Maybe I have it set too sensitive? If you experienced something like that, maybe I'll try playing with that more. I think the TPS is OK, the ECU status screen actually shows % of throttle, and it seems to corealate correctly to the pedal position... hey, may ask what water temp you / others are targeting? thanks! Link to comment Share on other sites More sharing options...
jr_ss Posted August 8, 2005 Report Share Posted August 8, 2005 You might need to add more fuel in that area to get past the stumble or like Mike said decrease the amount of fuel. It's starving for something, hence the dying out. I'd really go over your maps and curves again and see what's up. Pay close attention to those trouble areas... My car runs at 180F-200F. I have a 180F thermostat and all 3 fans wired in to come on together. It'll go over 200F but that's when I'm digging into boost alot... Link to comment Share on other sites More sharing options...
jr Posted August 12, 2005 Author Report Share Posted August 12, 2005 hmm... Still having some odd 'choking' issues, seemingly no matter what I do with the fuel in that area. I can definitley make it worse if I keep adding more though, lol... I think the default map I'm using may be advancing the timing too quickly. Could some one post a screen shot of their timing map? Also, do ECU's normally map their timing off of the TPS & RPM, or MAP & RPM? Its setting I can change in my ECU, the default is TPS, so that is what I've been doing... thanks again! Jesse Link to comment Share on other sites More sharing options...
Chad Posted August 12, 2005 Report Share Posted August 12, 2005 What system do you have? I have a good program for the SDS to post. Link to comment Share on other sites More sharing options...
jr Posted August 13, 2005 Author Report Share Posted August 13, 2005 I'm using the DTA e48 from http://www.dtafast.co.uk/ , so I appreciate the offer, but it probably wouldn't help. Does the SDS have a PC tunung version where you can 'see' the maps? I'd love to look at shot of someone elses. PErhaps someone running a haltech willing to share? Chad, Just curious, what kind of numbers is your car putting down? Link to comment Share on other sites More sharing options...
jr Posted August 14, 2005 Author Report Share Posted August 14, 2005 Just an update, I greatly reduced the agressivness of my ignition map last night, it stays at 12 deg until 2k rpm, and works its way up to a maximum advance of about 25 deg at 6k rpm. Here's what I not, from idle at a fairly steady 900 rpm, if I press the gas a _slowly_ as I can, the engine will die. If I floor it from idle, it will choke, then rev up pretty cleanly. I've played around with the fuel for a while in the low RPMs, and have now tried the ignition... Any ideas out there? thanks! jesse Link to comment Share on other sites More sharing options...
jr Posted August 14, 2005 Author Report Share Posted August 14, 2005 Ok, I feel, like I'm talking to myself here, but thought I would continue to update. I kept playing with the fuel, and ignition maps, and started playing with the "pressure compensation" maps, and this seems to have been the cause of the motors stumbling. I changed them all to "0" for testing, and It raises from idle without a stumble now, so that is looking better. It has some popping misfires if I accelerate too fast, so I think I will have to go back to the ignition maps again. I've played with them soo much, they probably way off now... more fun to be had... Link to comment Share on other sites More sharing options...
lionbull Posted July 4, 2009 Report Share Posted July 4, 2009 Ok, I feel, like I'm talking to myself here, but thought I would continue to update. I kept playing with the fuel, and ignition maps, and started playing with the "pressure compensation" maps, and this seems to have been the cause of the motors stumbling. I changed them all to "0" for testing, and It raises from idle without a stumble now, so that is looking better. It has some popping misfires if I accelerate too fast, so I think I will have to go back to the ignition maps again. I've played with them soo much, they probably way off now... more fun to be had... update? Link to comment Share on other sites More sharing options...
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