Guest |249| Posted December 25, 2009 Report Share Posted December 25, 2009 hey guys, has anyone had an issue with stalling as you press the accelerator? im not sure if its an ECU issue but i thought i'd give it a try anyway. what happens is the car almost stalls when i hit the accelerator. what happens is it goes lean, hesitates a bit then recovers. if i gradually ease it on it doesnt do it, and if i hit it hard it doesnt do it either which is why im thinking its a fuel map or similar issue. problem is the fuel map isnt showing any obvious problems. i made a video of what happens. link to vid: http://www.youtube.com/watch?v=xPHSLI50Kd4 any help would be appreciated, thanks guys and merry christmas! Quote Link to comment Share on other sites More sharing options...
Guest Dave-Kriedeman Posted December 25, 2009 Report Share Posted December 25, 2009 Have you made any adjustments to the Accelerator Enrichment table. This can be found in the "FUEL" tab. Quote Link to comment Share on other sites More sharing options...
rayhall Posted December 25, 2009 Report Share Posted December 25, 2009 Often flat spots can be a too rich condition not lean. Most cheap (under $1000) wideband will not show the correct AFR when looking for short term AFR changes. Get someone to rev the engine while you look at the exhaust for puffs of black smoke. Ray. Quote Link to comment Share on other sites More sharing options...
Guest |249| Posted December 25, 2009 Report Share Posted December 25, 2009 its a PLX wideband, its not the best out there i guess. i did try changing values on the fuel map but it was still doing it the same way. i haven't touched the accel. enrichment table at all but it does seem as though it is related to it as the help file states: Without acceleration enrichment, when the throttle is abruptly opened the engine will briefly 'lean out'. To achieve good throttle response, acceleration enrichment is required. the upgrades to the car lately have been 740cc injectors, greddy style plenum and a 90mm throttle body but it started doing it around a month after i installed all of these. can anyone get me a screen shot for some typical accel. enrichment table values? im sure that would help. here is what mine looks like: Quote Link to comment Share on other sites More sharing options...
rayhall Posted December 25, 2009 Report Share Posted December 25, 2009 Included with the software are two base maps. V44 Base Map.pcl and V88 Base Map.pcl. Both these have the default settings that work with most engines. Copy all these values into your map. If you did not know you can have two copies of the software running, and copy tables by using Shift+Arrow to select the table values, then Ctrl+C to copy. To paste to the values into the other map press Ctrl+V Ray. Quote Link to comment Share on other sites More sharing options...
Guest |99| Posted December 26, 2009 Report Share Posted December 26, 2009 Hi, Your Accel Load Correction looks a bit light-on. Try using 2.0 @ MAP = 0 and then step down by 0.2 for each 20kPa increase in MAP. Depending on your AFR at the time of Accel then you could also be running too rich. For the above numbers if your AFR before accel is greater than 14.0 then it should get you soewhere close. Quote Link to comment Share on other sites More sharing options...
Guest |249| Posted December 26, 2009 Report Share Posted December 26, 2009 fixed it guys. turned out that the MAP sensor wasnt reading correct values due to a tiny split in a hose. found it and replaced it and its back to normal now. thanks for your help guys. Quote Link to comment Share on other sites More sharing options...
Guest |249| Posted December 27, 2009 Report Share Posted December 27, 2009 it started doing it again. i found another leak in my throttle body, its a tiny leak which is starting to do my head in but i still doubt its causing the problem (but then again, im no expert which is why im here!), but im going to try get a greddy throttle body adapter and check my stock TB to see if that fixes the problem. so far ive played with the injector dead times (made the entire map rich), and accel map which didnt do anything. can a small leak like the one in the TB be causing this? Quote Link to comment Share on other sites More sharing options...
Guest Dave-Kriedeman Posted December 27, 2009 Report Share Posted December 27, 2009 Out of curiosity, what fuel pressure are you running. Do you have the vacuum hose hooked up to the fuel pressure regulator. Can you fit a fuel pressure guage to check your fuel pressure and also make sure that the pressure rises when you crack the throttle open. It is unusual that the problem didnt exist previously, which makes one believe it is an issue else where other than the tune. Unless something was changed in your map to create this problem,previous to it occuring. Quote Link to comment Share on other sites More sharing options...
Guest |249| Posted December 28, 2009 Report Share Posted December 28, 2009 Out of curiosity, what fuel pressure are you running. Do you have the vacuum hose hooked up to the fuel pressure regulator. Can you fit a fuel pressure guage to check your fuel pressure and also make sure that the pressure rises when you crack the throttle open. It is unusual that the problem didnt exist previously, which makes one believe it is an issue else where other than the tune. Unless something was changed in your map to create this problem,previous to it occuring. i've played around with fuel pressure (adjustable) and it hasnt made a difference to it, nothing substantial to the amount of pressure i added. yes there is a vacuum hose on the FPR. there is no air leak other than the small one on the throttle body which i have ordered a new adaptor so i can use the standard one. recently i installed a greddy style plenum and 740cc injectors. it was running great besides a lumpy idle for around 2 or so weeks, afr's were fine and now it is doing this, i then found a leak in one of my hoses which seemed to fix the problem for around an hour and then bam! its back. all i did when swapping over the injectors is change my master from 12ms (380cc standard injectors) to 7ms (740cc deatschwerks injectors) and fixed my afr's, i didnt play with injector dead times or anything but i thought as long as i had my afr's right it wouldnt matter, correct? Quote Link to comment Share on other sites More sharing options...
Guest |249| Posted December 28, 2009 Report Share Posted December 28, 2009 ive decided not to waste anyones time until i get this throttle body leak sorted. i just think the MAP sensor isnt moving around on the fuel map properly because of the leak. ill report back when ive got it sorted. Quote Link to comment Share on other sites More sharing options...
Guest Dave-Kriedeman Posted December 28, 2009 Report Share Posted December 28, 2009 Injector Dead Times and relavent settings are important. As for the vacuum leak, the hose going to the Map Sensor being split will definately cause you problems. (This you have fixed). A SMALL vacuum leak at the throttle body SHOULDNT NORMALLY give you the symptoms you are explaining. At idle, fair enough you would normally see richer mixtures due to the ECU thinking it has more load via the Map Sensor due to lower vacuum. (rough idle). However from closed throttle (idle) to open throttle (when revving the engine) you wont NORMALLY be effected by this SMALL leak. As the throttle blade opens the manifold vacuum drops away and the ECU will dictate what fuel and timing strategy to take. If however the vacuum leak is bigger than you think this is another kettle of fish. How many Kpa does your engine normally idle at ? How many Kpa does your engine NOW idle at ? If you normally idle at eg: 50 Kpa and now it idles at eg: 80Kpa then you MAY have to much fuel when you rev the engine. You will be entering too deep into the fuel load table too early for the amount of RPM the engine is doing As Ray stated earlier overfueling can cause dead spots,flat spots,bogging what ever you wish to call them. Remember an Air Fuel meter is measuring the amount of oxygen in the exhaust, not fuel. So an overly rich mixture can at times show lean due to the amount of unburnt oxygen in the exhaust. When ever trying to resolve issues with engine tuning, Always deal with the obvious problems first, Correct all injector settings (IMPORTANT) Fix vacuum leak then go from there. Also check your sparkplugs for carbon fouling etc, Weaker than normal spark can cause issues like this. (from previous experience). Quote Link to comment Share on other sites More sharing options...
Guest |249| Posted December 29, 2009 Report Share Posted December 29, 2009 i thought injector dead times were only important if the old map was being used, i.e. not needing a retune. but it was running perfect then it started playing up after a while. im waiting on an adaptor so i can fit the standard throttle body to fix the air leak. we'll see what happens after that. Quote Link to comment Share on other sites More sharing options...
Guest Dave-Kriedeman Posted January 2, 2010 Report Share Posted January 2, 2010 Are your injectors Peak and Hold or Saturated. Quote Link to comment Share on other sites More sharing options...
Guest |249| Posted January 2, 2010 Report Share Posted January 2, 2010 no idea mate, i dont have the injection setup menu on my ECU. Quote Link to comment Share on other sites More sharing options...
Guest |85| Posted January 2, 2010 Report Share Posted January 2, 2010 measure the resistance between the 2 terminals of the injectors. anything above 6 ohms (usually 12 ohms and above) = saturated. 6ohms and below (usually 3-4ohms) = peak and hold. 700cc and above injectors are usually peak and hold. nevertheless still better to verify with a multimeter. Quote Link to comment Share on other sites More sharing options...
Guest |249| Posted January 3, 2010 Report Share Posted January 3, 2010 thanks mate ill check it out. does anyone know what the effects of a bad fuel pump is? does it sound like my issue? Quote Link to comment Share on other sites More sharing options...
Guest Dave-Kriedeman Posted January 3, 2010 Report Share Posted January 3, 2010 You need to fit a fuel pressure guage and check your fuel pressure, also flow rate of the pump. Dirty injectors can cause these issues also. As i posted earlier, you need to see if the fuel pressure rises above your set pressure when you open the throttle. (the pressure should go up when the throttle is opened, due to manifold vacuum dropping). Normally a bad fuel pump will give you lean condiions through out the rev range. However dirty injectors or a leaking pressure regulator can cause the symptoms you are experiencing. What engine do you have and what ECU, PnP,V44,V88. What software and Firmware are you using. Quote Link to comment Share on other sites More sharing options...
Guest |249| Posted January 4, 2010 Report Share Posted January 4, 2010 well i put my standard injectors back in and reverted to the map that was running it... it ended up doing the SAME thing. so ive narrowed it down to the leak in the throttle body or the fuel pump dying. the fuel filter was flowing fine. Quote Link to comment Share on other sites More sharing options...
Guest |249| Posted January 8, 2010 Report Share Posted January 8, 2010 the part came in and i fixed it as far as i can tell. i turned up the master from 12ms to 16ms and it idles much nicer than before. Quote Link to comment Share on other sites More sharing options...
Guest Dave-Kriedeman Posted January 8, 2010 Report Share Posted January 8, 2010 Cool, so did fitting the adaptor fix it, or changing the Fuel Master setting. Quote Link to comment Share on other sites More sharing options...
Guest |249| Posted January 10, 2010 Report Share Posted January 10, 2010 the adapter fixed the idle (it no longer stalled) but adjusting the master fixed the hesitation off acceleration. Quote Link to comment Share on other sites More sharing options...
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