map sensor question
Outstanding HDF Member
Joined: Jul 2007
Posts: 2,609
Likes: 1
From: Indy area
RE: map sensor question
If it moves both up and down, check your fuel pressure. Check your fuel pressure. Did I suggest you check your fuel pressure? Check it. Do the simple things first and check your fuel pressure.
Road Warrior
Joined: Mar 2008
Posts: 1,691
Likes: 3
RE: map sensor question
That is normal. It should close and reopen when you turn off the power. It leaves it at the position it should be to start the bike so it does not need to move when you power it on. If you start the bike it should go from about half open to an eighth open over about ten seconds. There is not much differance in temp over a half minute. So it seems unlikely it is the IAC but you might as well check it is working the same when you have trouble starting it.
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Road Captain
Joined: Jun 2007
Posts: 676
Likes: 0
From: harrodsburg
RE: map sensor question
ORIGINAL: glens
If it moves both up and down, check your fuel pressure. Check your fuel pressure. Did I suggest you check your fuel pressure? Check it. Do the simple things first and check your fuel pressure.
If it moves both up and down, check your fuel pressure. Check your fuel pressure. Did I suggest you check your fuel pressure? Check it. Do the simple things first and check your fuel pressure.
Road Warrior
Joined: Mar 2008
Posts: 1,691
Likes: 3
RE: map sensor question
There is a pressure regulator that maintains a consistant pressure relative to the map pressure. It maintains pressure be bleeding off excess fuel back into the gas tank. It does not boost pressure so the fuel pump has to put out enough pressure to start with.
Outstanding HDF Member
Joined: Jul 2007
Posts: 2,609
Likes: 1
From: Indy area
RE: map sensor question
I have seen fuel pressure regulators fail. There are two ways they can do so. One is to bleed off too much, causing a lower fuel pressure. The other is to not bleed off enough, causing a higher fuel pressure. When they do not bleed off enough pressure you will have exactly the situation described in this thread. I am not saying for sure that is his problem, but the description matches and it is a very likely candidate.
Once running, the closed-loop mechanism, if it were being used, unlike in this case, would fire the injectors a shorter time to compensate and might be able to reign the situation in.
Like I said earlier, the operation really does not require turning any screws, nuts, or bolts and an offer of a six-pack or something to a tech with the adapted gauge may just get the pressure checked while he is on lunch, or maybe even any time of the day. Apart from getting to a place with the gauge, this is the easiest test to do.
If the regulator is malfunctioning it will require popping off the dash and opening up the tank. Not difficult work at all compared to some of the other possibilities.
Once running, the closed-loop mechanism, if it were being used, unlike in this case, would fire the injectors a shorter time to compensate and might be able to reign the situation in.
Like I said earlier, the operation really does not require turning any screws, nuts, or bolts and an offer of a six-pack or something to a tech with the adapted gauge may just get the pressure checked while he is on lunch, or maybe even any time of the day. Apart from getting to a place with the gauge, this is the easiest test to do.
If the regulator is malfunctioning it will require popping off the dash and opening up the tank. Not difficult work at all compared to some of the other possibilities.
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Road Captain
Joined: Jun 2007
Posts: 676
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From: harrodsburg
RE: map sensor question
i talked to a tech today to see about getting the bike in and he told me it would be a while before i could get it in cuz they were busy but he told me how i can check it myself without the speial gauge the book says use. he told me to release the quick disconnect from the tank and remove the clamp that holds the disconnect fitting. then he said to remove the fitting from the 5/16 hose and then get me a tee and hook it to the gas line and then hook another hose to the other end , the hook the fitting back to it and plug the fitting back on the tank and on the tee just hook a reguler fuel pressure gauge to it and turn bike power on then hit the run button and see what the pressure is..now is he telling me right..i did look at the quick disconnect on the tank and it looks like a 5/16 hose with the disconnect pushed in the line and clamped on..
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Road Captain
Joined: Jun 2007
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From: harrodsburg
RE: map sensor question
ORIGINAL: LilBudyWizer
When it comes to simple things seems cleaning the air filter element would not hurt just to be sure.
When it comes to simple things seems cleaning the air filter element would not hurt just to be sure.
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Road Captain
Joined: Jun 2007
Posts: 676
Likes: 0
From: harrodsburg
RE: map sensor question
what would cause it to cough out of the breather..if i were to unplug the ecm and remove the pc111usb would that reset the ecm and clear the pc3.. also would the timing need to be set up on the pc3 or maybe a upgraded ignition coil , im going to get a fuel presure gauge in the morning and try to see what the fuel pressure. i did go through a few maps today to see if there were any changes to the way the bike starts and runs but nothing seems to help it..it just seems that what ever the problem is with the cold starting is also effecting the mpg and power...bike just seems weak..
Road Warrior
Joined: Mar 2008
Posts: 1,691
Likes: 3
RE: map sensor question
I assume backfires through the intake are basically due to the fuel not vaporizing. Liquid gas does not burn very well but gas vapors burn real good. So the gas vapors burn during the power stroke vaporizing some of the liquid gas. That gas continues to burn through the exhaust stroke. When the intake valves open there is still flame in the cylinder which ignites the vapors in the intake.