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How goes it? I was just wondering if a few people could post what their trucks idle at when at running temp. I have a 3.4 V6 and it seems to go from about 750 - 1250 or so. Which brings me to my next question. do those of you who have the v-6 notice that your trucks (when at idle) go up and down in RPMs about evere 35 - 60 seconds? sorry i now this may be kind a wierd set of questions but im trying to trace down some very bad gas mileage issues... Thanks in advance................................................ :confused: DAN
 

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dagrace21 said:
How goes it? I was just wondering if a few people could post what their trucks idle at when at running temp. I have a 3.4 V6 and it seems to go from about 750 - 1250 or so. Which brings me to my next question. do those of you who have the v-6 notice that your trucks (when at idle) go up and down in RPMs about evere 35 - 60 seconds? sorry i now this may be kind a wierd set of questions but im trying to trace down some very bad gas mileage issues... Thanks in advance................................................ :confused: DAN
Mine holds around 750 pretty steady. If I recall someone had your problem before and it was a vacuum leak which would also explain crappy mileage. Hope it helps. Matt
 

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About 600 steady. Kinda low compared to 750. I think my problem is a bad TPS.
 

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wisctaco04 said:
Mine holds around 750 pretty steady. If I recall someone had your problem before and it was a vacuum leak which would also explain crappy mileage. Hope it helps. Matt
Hey Matt for hot starts do you ever idle at around 500 rpm? My does that once in a way. It might be the FTC sharing cells. Probably the cause of my hard cranking. BTW. I upgraded the wiring harness based on teh TSB. It didnt really help. I think its the FTC.
 

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Super Doody said:
Hey Matt for hot starts do you ever idle at around 500 rpm? My does that once in a way. It might be the FTC sharing cells. Probably the cause of my hard cranking. BTW. I upgraded the wiring harness based on teh TSB. It didnt really help. I think its the FTC.
Are any of your values at or below 9.4 in the srating rpm/vac area? I was just fine tuning yesterday and realized if it at or below there are starting issues. Rob(red dub cab) from Texas had a good reply on this on the old board that I had forgotten. The values at start up are at a point shared since the engine is cranking but not much vacuum. The other interesting thing to watch is what cells are involved at starting. After tuning it yesterday it fires up quicker now that the starting values are at 9.5/9.6. When it's warm already it fires right away and does idle a hair lower and goes to closed loop immediately. That sucks on the TSB. Time to get the laptop out.
 

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wisctaco04 said:
Are any of your values at or below 9.4 in the srating rpm/vac area? I was just fine tuning yesterday and realized if it at or below there are starting issues. Rob(red dub cab) from Texas had a good reply on this on the old board that I had forgotten. The values at start up are at a point shared since the engine is cranking but not much vacuum. The other interesting thing to watch is what cells are involved at starting. After tuning it yesterday it fires up quicker now that the starting values are at 9.5/9.6. When it's warm already it fires right away and does idle a hair lower and goes to closed loop immediately. That sucks on the TSB. Time to get the laptop out.
Matt,

Thanks for your reply. I have the old post by Robert..

"Well I spent a good part of my weekend tuning the closed loop segment of my URD kit and here are my observations. I'm still learning myself so bare with me.
I'm running the 305cc injectors (p/n 23209-46031) and now have my Long Term Fuel Trims at "-.8" to "0". The Short Term Fuel Trims are fluctuating close to zero but vary back and for from positive to negative depending on what the throttle position is for a specific FTC cell.
When I first started the truck I set all of the cells on the FTC to 9.6 and this was a good start point. The truck started so I could begin data logging with the OBD/II unit. Once started I was reading positive (+5 to +15) on both ST and LT trims (lean) so I began increasing the cell values by .1 until the trims started dropping. This has to be done throughout the RPM band and Pressure range.
One helpful tip is to monitor what the FTC is doing in real-time. For this you want to connect the FTC via a 9-pin serial cable to a laptop PC. Then you can pull up the Fuel Map A and watch the cursor moving around through the RPM and Pressure cells.
* Note: make sure that the FTC is configured correctly under the "Options" menu as a "Programmable Signal Calibrator" for the application and is reading "Vacuum/Pressure" for the display mode.
The idle was a little tricky because the fuel trims wanted more fuel while in park and in gear. I increased the cell value accordingly and everything was fine until I tried to start the truck again. The idle was horrible and the truck was shaking bad.
Well guess what? There are a few FTC cells that are shared in both open-loop and in closed loop mode. When you first start the truck it goes into open-loop until your oxygen sensors heat up and then the truck goes back into closed loop. During the open-loop portion the truck is being flooded with fuel and can't stay on. I had to cut the fuel back so it was reading positive for the trims with the data logger. The truck idles now but isn’t as smooth like before the fuel kit and while in park I can detect a slight misfire."



Rob is talking about too much fuel in the vaccum areas mentioned but for me I blieve I don't have enough fuel. I been playing with idle for quite some time now.
The cell responsible for starting is near or at 0 psi. (turn off your engine with the FTC connected. The blue highlighted cell is your starting cell)...This is what Gadget told me. Since your ODBII only gives your fuel trim after the truck has started, there is no real way to tell if you need to decrease or increase fuel for start up. You just have to experiment.

My cold start ups are great but once in a while hot starts are problem about >1% of the time.
 

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Jim
That's the thread from the old board I remember. I have the manual tranny so my idle and gear cells are not affected as his were. Can you send me a copy of your current fuel map? I am curious what the difference in those values are now. Matt
 

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wisctaco04 said:
Jim
That's the thread from the old board I remember. I have the manual tranny so my idle and gear cells are not affected as his were. Can you send me a copy of your current fuel map? I am curious what the difference in those values are now. Matt

I have also have manual transmission. map coming your way
 
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