Still running lean Reply #30 – January 16, 2009, 12:47:39 PM Quote from: TurboCoupe50;251946Are you sure it's actually in open loop warm??? The EEC will go to closed loop with hot o2 sensors and engine temp over 100*... With the heated 02 sensors that's almost immediately, on a warm restart.. Have you monitored o2 voltages when this happens???I will check this. When warm, if I shut the car off and start it back up, it always takes exactly 90 seconds before it smooths out. If it is in fact supposed to be happening sooner, something else is amiss. I think the DataQ would help a lot with monitoring these oxygen sensor voltages.I will attempt to check the o2 sensors with a multimeter to see if they are correctly plugged in but is there an easier way? Perhaps just unplug one sensor and see what bank the codes say is disconnected? :hick:I think if the above is true, then we may be onto something. I'm not sure it explains the vacuum though. My vacuum reading above is at like 650-700rpm's - it idles incredibly low right now. It gets a little more rough with the IAC disconnected. On cold start, it idles at 1100-1200 rpm's for 10-15 seconds before coming down to ~800, then slowly drops as it warms up. This is only going off stock gauge and going off the speeds the ECU shoots for at idle to figure out how "accurate" the gauge is. Quote Selected
Still running lean Reply #31 – January 16, 2009, 01:51:30 PM The logic to go to closed loop is pretty complicated. It's outlined on page 6-8 to 6-12 of the GUFB document.Without re-taking the time to decipher all of the acronyms, I think it requires...Part throttle"Warm" O2 sensorsThermactor not sending air to exhaust"Warm" O2 sensors requires:A certain number of O2 switches from lean/richTimed delay logic based on time from startup and time above ECT scalar input temperatureYou have cold start, warm start, and hot start, which are all based on ECT temp at startup. You can look at the doc yourself to get the to the nitty gritty. Should be able to find the actual values from bins on eectuning.org. Quote Selected
Still running lean Reply #32 – January 16, 2009, 02:24:22 PM Quote from: Seek;251985I will check this. When warm, if I shut the car off and start it back up, it always takes exactly 90 seconds before it smooths out. If it is in fact supposed to be happening sooner, something else is amiss. I think the DataQ would help a lot with monitoring these oxygen sensor voltages.You can turn on the ign switch for a minute or two prior to starting to see if it makes any difference in the time... This will pre-heat the sensors... Quote Selected
Still running lean Reply #33 – January 16, 2009, 06:44:20 PM Now we're getting somewhere I think - this is all VERY useful information. I will do some of these checks. The performance shop watched the oxygen sensors and said they're switching back and forth around stoich properly but I'm not sure where they measured that from. Either way, I have a few things to check out as it sounds like me driving for an hour on the highway, pulling off, shutting it off, and starting the motor back up should go into closed loop (and in turn run smooth) almost instantly. This isn't the case as I have to wait 90 seconds at which point the rpm's go up momentarily, settle back down, and it runs smooth. Going off the tripminder, this switch from rough to smooth goes from 16mpg up to ~25mpg at the same speed if it switches while I'm driving. Back then I had popping through the intake at that point though - now I just have horrible hesitation where it used to pop. This pop apparently was from a bad seal at the IAC. During this hesitation, it takes a second or two before it stops and starts pulling. Quote Selected
Still running lean Reply #34 – January 16, 2009, 09:25:03 PM OK here's the word straight from the horses mouth(Ronnie, just got off the phone with him)... Since it's been over four years since we worked on his, I was foggy...He said his went through the same lean, rough running 90 sec open loop startup cycle, same as you've described... In the end the EEC did not fix it, BUT changing out the conical air filter for the original air box and filter did put the A/F ratio back near normal(actually a little rich)... Quote Selected
Still running lean Reply #35 – January 16, 2009, 09:55:03 PM I'm using the stock airbox without silencer, with paper filter... *sigh* Quote Selected
Still running lean Reply #36 – January 16, 2009, 10:24:57 PM Check those HEGO wires.... Quote Selected
Still running lean Reply #37 – January 16, 2009, 11:07:13 PM Quote from: JeremyB;251991The logic to go to closed loop is pretty complicated. It's outlined on page 6-8 to 6-12 of the GUFB document.Without re-taking the time to decipher all of the acronyms, I think it requires...Part throttle"Warm" O2 sensorsThermactor not sending air to exhaust"Warm" O2 sensors requires:A certain number of O2 switches from lean/richTimed delay logic based on time from startup and time above ECT scalar input temperatureYou have cold start, warm start, and hot start, which are all based on ECT temp at startup. You can look at the doc yourself to get the to the nitty gritty. Should be able to find the actual values from bins on eectuning.org.Jeremy is right here - in fact there is a hot start timer - OPCLT3 it's called, that is set to 60 seconds in A9L. Here is the description:QuoteOPCLT3 - When the ECT at start is greater than the 'Hot Start Min ECT' value this is the minimum time that must pass since exiting crank in order for the WARM_EGO_FLAG to be set.Note: the 'Min HEGO Switches Before Warm' value also needs exceeding.I've never seen my car go closed loop before 90 seconds either, so I wouldn't be too worried about that. I would look into a vacuum leak - you should have closer to 18 in Hg at idle with a stock cam. Have you checked the PCV? I didn't see you mention it above. Do you still have the hose that goes from the TB to the valve cover? Just trying to figure out where you might be drawing unmetered air. Quote Selected
Still running lean Reply #38 – January 16, 2009, 11:21:53 PM Quote from: Cougar5.0;252061Have you checked the PCV? I didn't see you mention it above. Do you still have the hose that goes from the TB to the valve cover? Just trying to figure out where you might be drawing unmetered air.PCV has newish valve, screen, and a custom grommet that grabs it tighter than the stock ones that always get loose after 3 months (in my experience). Hose is new and runs from the valve straight to the single fitting on the back of the intake. The hose is very tight.The line from the filler neck to the throttle body is on there but still the stock line - it seems to fit snug but is easier to pull off than, say, the hose on the PCV(the entire valve comes out when I try disconnecting that thing). I'll try to get a couple pictures of the engine bay tomorrow. I've plugged the charcoal canister, fpr, vacuum tree, other smog(or whatever, goes to passenger side firewall) with no changes. The "MAP" port is capped off. I've disconnected the egr line just to make sure it wasn't opening up when it shouldn't. Quote Selected
Still running lean Reply #39 – January 17, 2009, 12:21:05 AM Quote from: Cougar5.0;252061Just trying to figure out where you might be drawing unmetered air.Someone way back when(old Easyboard), had a cracked intake that was driving them crazy... Quote Selected
Still running lean Reply #40 – January 17, 2009, 01:54:28 AM Quote from: TurboCoupe50;252089Someone way back when(old Easyboard), had a cracked intake that was driving them crazy...How do people manage to crack them? Other than the obvious - a nasty wreck. The intake is the same as in the past motor that ran fine except now it has fresh powerdercoat - 400 degrees cooking for a few minutes to get the moisture out, then more for the powdercoat to melt. Quote Selected
Still running lean Reply #41 – January 17, 2009, 07:51:04 AM Not a clue on how it cracked, but it wasn't obvious...BTW, I've ran my GT40 intake with no upper to lower gasket and honestly couldn't tell much difference... But then my engine only idles 12-13" anyway... Quote Selected
Still running lean Reply #42 – January 17, 2009, 04:47:53 PM I've got a tweecer r/t coming - just need to find the usb/8 port dataq unit that isn't out of stock. Not that I think this will help much, I've been trying to get one for awhile. I was 24 hours away from getting one for $275 on eBay but a day early the Microsoft cashback disappeared from 30% :(I will be out of town next week so I won't be posting in this thread during that time. I will be trying some of these suggestions on the car here in a bit. Quote Selected
Still running lean Reply #43 – January 17, 2009, 05:26:17 PM Are yo sure the lower intake is not leaking? I was trying to follow this for a few days but got side tracked. To me it could be that. Quote Selected
Still running lean Reply #44 – January 17, 2009, 05:44:49 PM Perhaps baking it distorted it since it wasn't constrained as it would be when mounted on the engine. I know I had a stock lower shaved (to match shaved heads) and the machinist was surprised at how much the mating surfaces were distorted. Quote Selected
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