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FERGiEGuRL last won the day on March 5 2013

FERGiEGuRL had the most liked content!

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  • Birthday 09/26/1988

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    89 626 2.2 turbo manual

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    Air/fuel Ratios For F2T Gd

    cheers leev going to do that as well going to install my spare rail with the stock fpr, got a new plenum gasket on order as well, going to wait til that rocks up just in case I break it when I open her back up again lol. But at least I have found how I have found what is actually happening during the bucking it makes it easier to pinpoint errors, I will try and post some videos of the AFR readings, might make more sense lol, the tomei was originally purchased as a part for the commodore for when I do work on it in the future, and with the problems we had with getting the car running in the first place and the original AFPR I bought for the mazda shit itself the tomei went in lol.

    Air/fuel Ratios For F2T Gd

    Thanks DJ, I have actually removed the stock narrowband O2 sensor and have replaced it with the wideband O2 sensor which has a narrowband output that is connected to the computer. the wideband uses a 5.0v range and has the 0.1v-1.0v output separate for stock ECU's etc. The car is behaving exactly the same way with the wideband as it was with the narrowband, so the wideband is not causing my issues. for some reason once the engine is warmed I am losing fuel pressure, then under load fuel pressure drops further, when the fuel pressure regulator is a 1:1 boost referenced, so for every 1PSI of boost the FPR gives an additional 1PSI of fuel, which it does when cold, but not warm I cant remember if I replaced the fuel filter before or after the bucking issue started, done so much now lol. I will install another one just gotta wait deliveries here have slowed down even further with Christmas approaching, and no one near us stocks the correct filter, I am going to rip it off tomorrow after our house inspection and check it out, see what I can find

    Air/fuel Ratios For F2T Gd

    Hi all back again lol. spent the last few weeks testing and datalogging etc. lol. I have now come up with some results. Car cold: Fuel pressure 35PSI at idle and raises to 42PSI at WOT up to approx. 4000rpms (in neutral as I only have a engine bay mounted gauge) AFR is 11.0:1 on startup and raises to 13.5:1 for idle, WOT pulls 10.0:1 on boost and blows some black smoke on boost, still running very rich. Car Warm: Fuel pressure 33PSI at idle and DROPS below 20PSI at WOT up to approx. 4000rpms (in neutral as well) AFR is 13.8:1 at idle, on acceleration pulls 11.8:1, and as turbo kicks in plummets to 17.0:1 and is where bucking starts. So once car is warm I am losing fuel pressure on acceleration thus causing a lean out on fuel. And the lean out will most likely be causing the glowing manifolds. So from testing to date, my bucking is caused by a lean out due to loss of fuel pressure. Now to work out why I am losing fuel pressure when hot. I have a boost referenced AFR, TOMEI. Fuel pressure drops with both vacuum connected and disconnected. and is mounted away from the engine and doesn't get hot. I have 2 brand new fuel pumps and does this on both of them. operation sound doesn't change between before and after engine has warmed up. I am receiving 14v at the pump and have also run a hot wire from the battery straight to the pump bypassing the wiring harnesses and components and still does the same thing, so it is not a voltage issue. I have another fuel filter on order, so I will try a new one again just in case. any extra ideas throw them at us lol, it is an awesome car when it runs well, just need to keep it running well lol

    Air/fuel Ratios For F2T Gd

    yeah I thought that the first time but I have 155-160 psi compression per cylinder. I also plugged every vacuum port and ran the motor and checked for manifold leaks using starter fluid and carb cleaner and couldn't find any faults. it may be the gauge I am using, it only cost me $30, hard to tell unless I buy another one.

    Air/fuel Ratios For F2T Gd

    thanks leev I will keep you updated as I progress. thanks chief tool, I am more then happy to accept every one 2c worth, the more knowledge the better. we have checked and checked for intake leaks and cant find any on that side, we get 18-19 in vacuum at idle. even the throttle body boot has no cracks in it thankfully. is there any diagnostic function on these to tell whether the ecu has successfully entered closed loop operation?? from dead cold it was in the 11.x:1 and slowly rose till it was sitting between 12.9:1 and 13.1:1 and never went any higher at idle. AFR's in the 9.x:1 seemed way to high to me though. that's why I contemplated the VAF adjustment, I have moved it two teeth and idle is sitting in the 14:1 range now and felt a lot better when running, still have to check for cold readings on the next start up. It was running really well when we first got it running and registered and then started with the bucking occasionally to the end when it happened whenever warm, and fuel consumption was great now Really bad. I cant fault it mechanically except that it is dumping in way too much fuel. engine runs smooth and revs up to just under 6000rpm smooth and quickly. That is why we went and got the wideband, to help give a better idea of what is happening as I cant log this ecu. It was running rich when we first got it running you could smell it in the exhaust but it never spat out the exhaust until the bucking started and the smell got stronger. also I had reset the ecu after installing the wideband as well with the -ve off and brake pedal for longer than 30sec. I will keep driving when I can to see if the ECU will learn and run better. thanks again I will keep you all updated

    Air/fuel Ratios For F2T Gd

    ok sweet, thanks heaps for that. I went out for some quick runs this morning between rain falls lol. don't want to run in the rain till I get everything sealed up again. Went for a quick run this morning same as the other day 13.0's once warmed, but was surging even when cold. Before I messed with the VAF I did notice something interesting. I drove straight to the petrol station to get fuel first, and was doing the bucking on some pulls and not on others. got fuel, took 38.5 litres and only done 187km. but when I left the petrol station I couldn't replicate the surging. But it was still rich, so I pulled over and started working on the VAF, at idle turned the cog for the spring one tooth, and idle AFR went from 13.0 to 13.4:1, and another tooth leaned it further to 13.8:1. and took it out for quite a nice run for the first time, at WOT on 7.5psi boost the richest it got was 10.37:1. But before I could do any more testing it started raining again. So from my preliminary testing on modifying the VAF and AFR's: Stoich on pump gas (without ethanol): is 14.7:1 Therefore 14.7KG of air for every 1KG of fuel Turning the VAF one tooth adds approx. 0.4KG of air for each 1KG of fuel entering the system at idle At higher RPM this figure may be exaggerated/changed at different rate. On my tests it increased high rpm under boost AFR's by around 0.6KG of air per each 1KG of fuel. I will update when I get some more time without the rain so I can do some more tests.

    Air/fuel Ratios For F2T Gd

    cheers I will give it a go one of the VAF's I found at wreckers already had the mixture screw drilled out, I might use that one to gain access to the gear and with the logging ability of the wideband I can make small adjustments and see exactly what it is doing, at least if I can get that idle closer to 14.7:1 would be a good start then move up from there. thanks heaps again. So when you did your N/A turbo upgrade it did run really rich?? I have always been able to smell ours being rich, knew it would be slightly with the higher compression but did not expect to see 9:1's LOL

    Air/fuel Ratios For F2T Gd

    cheers leev, when I get back I will pull apart one of my VAFs and access that gear and see if I can lean it out a bit, I think it awesome how well you have tuned the 626 by feel and sound, I am more used to cars that you can plug a pc into and monitor all of the critical points and change as needed still getting used to tuning by not being able to have a computer telling what it is doing. does each notch on the gear make a small difference or a large difference in the performance that you felt?? I know I am pig rich to the max lol, I am surprised I don't have fuel just flowing out the rear end lol. I might even do some tables up of air/fuel ratios for each notch that I move it up/down to see how much leaner a notch does make.

    Air/fuel Ratios For F2T Gd

    RORITOR - yeah I agree this project has even taken me a lot further than I wanted lol, but it has been a great learning experience at the same time, and I love a good challenge lol. I am pretty confident that GD computer doesn't have learning capabilities and doesn't actually change the maps, it just has a heap of maps programmed and depending on VAF, TPS, ECT, it determines which map to use and how much fuel to spray into the engine. I did do a reset on the computer before I took it for the test drive with the wideband just in case but it did not change its performance once warm XeNoMoRpH - Thanks for confirming that range of figure for me, I have been on another forum asking around and one guy told me that as low as 9 is completely normal, but I am pretty sure it is too rich, an article on garret turbos states in most cases richer than 11 on pump gas will cause the torque to drop rapidly. All sensors are brand new except for the TPS. I have ohm tested every sensor from its plug to the ECU and no issues there. I have replaced the VAF with 2 others but can only find N/A VAF, I don't whether they are slightly different or not. cant find any markings to differentiate. When I get back home I am going to run logs and play around with a few things and see if I can force it to run leaner and see if it being too rich is contributing to my main problem. You can smell the fuel when it is at idle, it is definitely rich, but I never thought that rich lol
  10. FERGiEGuRL

    Air/fuel Ratios For F2T Gd

    Hey dj. I don't think these tables are in the WSM I have had a look but as these figures are set in the factory and not adjustable I don't think they are shown. And LEEV yeah still running the AFPR at 32psi at idle with vacuum applied, 41psi without vacuum.
  11. Hi all, was wondering if anyone has air/fuel ratio maps for the standard F2T computer? or does anyone have a wideband hooked up to theirs that can give me some of their readings? I have been struggling getting the mazda running well now, there is thread on here about the bucking and surging it does under load. I am thinking down the path now of aftermarket ECU (possibly megasuirt) so I can see whether the computer is giving me issues or at least be able to log and read realtime stats of when the bucking happens to help locate our issue. I installed a new fuel pump to fix a small fuel pressure issue but the surging remains so I installed a wideband to see what is going on. I only had a little time before coming to work to do some tests and will do more when I get back from work and holidays, the family is still in Brisbane atm lol. But here is a quick rundown of what I have tested so far: on cold start up once engine is fired AFR is at 11.2:1 I let it idle from cold to running temp and AFR slowly rose to 13.0:1 Both these readings only fluctuate 0.1:1 at idle and hold fairly steady. I went for a quick drive before I ran out of time and got under moderate acceleration it drove quite well and got down to 10.1:1 On hard acceleration with boost it would drop down to 9.3:1 and this is when the bucking would start occurring. on deceleration lifting foot off pedal AFR would lean out past what the wideband is capable of reading >22.4:1 and once back at idling it would be back at 13.0:1. To me this seems like it is running extremely rich and may be one of the issues causing our problems. I am looking for the maps or if any one could be kind enough to give me a couple of their read outs of AFR so I can compare with what our car is experiencing, from what I have read and what I understand richer than 11:1 AFR on pump petrol you start losing torque at an exponential rate. Any ideas or map or figure locations would be greatly appreciated, I have spent hours searching online now and cant find anyting in WSM that helps yet. Thanks again everyonw
  12. FERGiEGuRL

    Fuel Cut!!!

    On the GD models the fuel cut is governed by the VAF meter, when it registers that the turbo is pulling too much air through it it shuts off the injectors, need a fuel defender system or chip, or go aftermarket ecu, or you can modify the VAF to not open as much therefore more boost before fuel cut, but that will probably cause other issues like incorrect fuel/air ratios etc. correct me if I am wrong but that is how I interpreted its system lol. I wish I could pull a vacuum hose like the GC's to remove it lol.
  13. FERGiEGuRL

    1991 Manual Transmission

    there are 2 manual transmissions for the GD as far as I know there was the G5M-R for the non turbo and the H5M-R for the Turbos.
  14. FERGiEGuRL

    Random Engine Surging Under Load

    lol I keep forgetting you guys are on a different time to us lol. We don't have emission testing where we are but the car must have all emission controls connected on the car including the CAT. I might drop the cat in the morning and inspect it (if the bolts aren't seized) might have some melted cores in it restricting flow. I would love to just remove it, but don't wanna get defected for not having it. Worse comes to worse I could break out the centre if it is melted, at least so I could do tests and drive it to a muffler shop to get a new one fitted lol.
  15. FERGiEGuRL

    Random Engine Surging Under Load

    So I have checked the turbo and cant fault it, still on the car but the shaft has no deflection or play, isn't rubbing, no bent or damaged fins and spins freely and smoothly. I will grab another anyway just to be sure though. Can anyone tell me if the standard Cat Converter in these is a honeycomb or ceramic ball type? There is no rattling when hitting the Cat but I have read that a bad Cat could cause similar problems to some of what I have. I noticed today that my exhaust manifold had two loose nut and was leaking, I could feel the exhaust leaking, tightened it back up and now it idles a little rough, if I loosen the two nuts and let it leak it seems to idle a lot smoother, I could be clutching at straws here, but I do want to repair any problems as I find them. Could it be possible that the Cat is backing up exhaust gas causing extreme manifold temps? my IR heat probe only goes to 250C so cant really get any reliable measurements. When I check it just tells me 'HOT' LOL. The Cat is the one that I got with the car and the car had beensitting in the PO's backyard for nearly 10 years. and never got started. Also haven't drove the car since the glowing exhust only let it idle to do tests, don't want to drive it and risk cooking the head or worse. Engine temp runs good but exhaust temp is extreme.