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Possible Map sensor problem?


wigenOut-S30

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Long story short, I drove the car a last saturday night about 100 miles each way to the drag strip. on the way home.. I kicked it in third gear and it started leaning out and I got out of it. Wideband went dead lean and I could barely putter a long the interstate. I had a friend drive and I cracked the laptop open and added tons of fuel. This got us home. the next morning I loaded my original map and all seemed fine.. Accept under light load it is lean.. like in the 16s. I have tested the FPR, changed the fuel filter.. the pump is a walbro 255 external about a 3 years old. Injectors are Mk3 supra 440CCs.. My first thought was the pump is dieing? but what about the map sensor acting up? I have got a couple of resets and the dead lean issue happened again right after one of the resets. But I turned the car off.. let it sit for a bit and then cranked it back up.. ran fine again accept for the lean issue under light cruise.

 

I tried to search and the new search function is horrible.. apparently if you search for anything 3 letters or less it will not allow it.

 

"One or all of your search keywords were below 3 characters or you searched for words which are not allowed,"

 

so cannot search if you have GM, or MAP in your fields.

Edited by wigenOut-S30
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Probably best to log it.

If it was the MAP I would think that it would be noticeable with a log. I have unhooked my MAP and made sure it was reading the correct amount for my elevation, not really a great test. So many things it could be, probably logging under cruise may show you something. If you have a vacuum gauge you could also have a friend or yourself write that down and then compare it with what the MAP was reading.

I know resets seem to cause some strange issues with MS. I've read people saying reloading the firmware made a big difference after them. I've noticed this myself or it could of been just coincidence.

Edited by goodoldjam
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Yeah, I have been doing a LOT of reading on the reset problems.. Also found out when you have a reset.. the ECU takes the barometric pressure reading right then and there. SOo if I was in boost when a reset happend.. it would take it that what ever positive boost I was in at the time was 14.7 or atmospheric. and there for lean my whole map out.. I plan on reloading the firmware, do a bit of logging, and eventually I would like to get that 4 bar dual port map sensor. the Mapdaddy..

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Yeah, I have been doing a LOT of reading on the reset problems.. Also found out when you have a reset.. the ECU takes the barometric pressure reading right then and there. SOo if I was in boost when a reset happend.. it would take it that what ever positive boost I was in at the time was 14.7 or atmospheric. and there for lean my whole map out.. I plan on reloading the firmware, do a bit of logging, and eventually I would like to get that 4 bar dual port map sensor. the Mapdaddy..

That's great info, thanks. I didn't know the reasoning behind why it caused issues. This is going to help me down the road. In fact I may do a reload just to make sure also.

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That's great info, thanks. I didn't know the reasoning behind why it caused issues. This is going to help me down the road. In fact I may do a reload just to make sure also.

 

 

Do you possibly have a step by step on how to reload the firmware and software? I have never done this and was like over 3 years ago since I first installed megasquirt.

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Do you possibly have a step by step on how to reload the firmware and software? I have never done this and was like over 3 years ago since I first installed megasquirt.

I always Re-read the steps, so I'll dig up the info. You use a loader program to load the new firmware and if you use the Nissan Coolant sensor you need to use Easytherm before hand I believe. Your running MS1 right?

Edited by goodoldjam
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First off looks like your going to need the software package from DIY. http://www.diyautotune.com/softwarelinks.htm

Ok you want to go to the Megasquirt directory after you install

C:\Program Files\MegaSquirt and go to the MS1 Extra 029y4 folder. There is some update text there you should read first.

Here is a Dated video of a firmware upgrade, you already have the firmware in the package from DIY in the "029y4 folder" and the downloader so the first few minutes are worthless but the install is the same.

When I first did this I was upgrading from a old version of MSnS, so I made a new map by exporting my Spark/Fuel tables from my original and then importing to a new map. Then going through the constants and getting everthing set. So after the update I plugged it in and was ready to go.

I'm assuming your using MS1 so if your not then you need to go to correct folder for your version.

Now if your using the Nissan CHT sensor (MS1) your going to need Easytherm to adjust the resistance values, which is under the DIY package. That was kind of a pain for me to get working but I wasn't paying attention to the instructions.

(Remember after the Upgrade your map is gone)

Edited by goodoldjam
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