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5th Gen 2 Blinks "MAP Sensor issue


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Please help me viffers, I have a 2000 honda vfr 800 f.i giving me 2 blinks I replaced the MAP sensor from a running parted bike off ebay still same issue persist, as soon as I start her up she's revving very high I'm talkin 7 to 9k rpms very loud and annoying, I even tried to unplug the MAP sensor connector to see if it'll make any differences, none at all still stayed reving high so I hit the kill switch to cut the bike off. Bike was running fine last season after I woke it from it's coma stage replacing main & sub wire harness, TB & gas tank along with fuel pump/ filter

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MAP sensor should not cause that high rpms I wouldn't think... should only make minor adjustments to the fuel map via ECU.....  there's likely another issue??  Throttle cables clear and working properly?  Wax motor or something physical holding the throttle plates open slightly?  Check all vac hoses still connected?

There is a second MAP sensor behind rear cowl right side, vented to atmosphere (no hose).

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Throttle cables were fine, I re-lubed them just because I had already takin them out of the throttle control to make sure it wasn't wrapped inside, I am gettin a flash code for 2 blinks however leading me to this topic. I pushed on the wax idle unit while on throttle body area seemed like it was moving free wasn't ceased or anything I did hit it with some PB blaster, I'm about to try some electrical spray to see if that helps out with the connection, however, I did not know they're were 2 MAP sensors on this motorcycle. I am aware of the 1 that sits by the #3 hose on the bottom of the air box

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MAP on the air box is Manifold Air Pressure, one out back is atmospheric air pressure (I assume for riding at various altitudes).

I had a blinky as well, replaced the air box MAP with a used one, it cleared fine.  No symptoms like yours, in fact none, bike ran fine.

For very high rpm issue 7-9k, I would think physical cause holding throttle open slightly... just my guess.  Throttle freeplay should be very small but not zero.  Wax motor should not hold throttle open when warmed up.  I'd try to judge how much throttle held open (by wax motor) when cold, perhaps judge gap at idle adjust screw?

I know the manual says don't adjust wax motor, but I would if I needed to.

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So after replacing the 1 under the air box back to the original I had and the 1 purchased off ebay to the back cowl area with some electrical spray I'm back on the road, as I took it around the block my left side rear cowl snapped as I forgot to screw bolts back in now to replace the rear cowl😑, thanks a million man seriously if it wasn't for you to tell me about the second map sensor I'd still be stuck going on a lil over a month cuz even my clymers manual only shows/ explain of the 1 under the air box "TAKE NOTE VIFFERS 2 MAP Sensors"

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I had the same double blink not long ago but it was a self induced situation. I’d had the air box off while chasing a lose hose clamp / coolant leak in the valley under the throttle bodies. When putting things back together the first time I must have left one of the connectors lose. Cogs well and Grum were quick to guide me in the right direction and which plug was most likely the problem maker. 

 

The direction I was pointed in:
 

“An easily missed electrical connection to the airbox is the plug to the inlet air temp sensor.  It's located on the bottom of the box and is white.  After getting the air horns unscrewed, just lift the box slighly from the clutch side and see if it's plugged in.”

 

“Two blinks indicates a MAP sensor issue. Check for a "loose or poor connection of the MAP sensor vacuum hose".

Also check you haven't electrically unplugged it.”

 

 

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Something very strange here. A Baro or Map sensor gone faulty should not cause idle rpm to reach 7000 to 9000.!!

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1 hour ago, slowbird said:

Anyone have a picture of the location of that 2nd MAP sensor located in the rear of the bike?

For future users. 

Service Manual page 5-69 shows the Baro sensor. 

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On 4/4/2021 at 4:48 AM, 5THGENVFR800MADNESS91 said:

So after replacing the 1 under the air box back to the original I had and the 1 purchased off ebay to the back cowl area with some electrical spray I'm back on the road, as I took it around the block my left side rear cowl snapped as I forgot to screw bolts back in now to replace the rear cowl😑, thanks a million man seriously if it wasn't for you to tell me about the second map sensor I'd still be stuck going on a lil over a month cuz even my clymers manual only shows/ explain of the 1 under the air box "TAKE NOTE VIFFERS 2 MAP Sensors"

 

I sure hope you've got your bike properly sorted, otherwise you could be riding a death trap!!!!

 

That Baro sensor (that you replaced) will not cause rpm to go to 9000rpm. There's no way Honda would allow that to happen given a faulty sensor, nor can it physically do this.

 

So, you said you replaced the Throttle Bodies!..........

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18 minutes ago, Grum said:

I sure hope you've got your bike properly sorted, otherwise you could be riding a death trap!!!!

That Baro sensor will not cause rpm to go to 9000rpm. There's no way Honda would allow that to happen given a faulty sensor.

So you said you replaced the Throttle Bodies!..........

yup, only way engine can rev to 9000rpms is that it's sucking in sufficient air to rev to 9000rpms. Where is all this extra air coming from???

 

Note that MAP-sensor only measures intake air and reports it to ECU. It responds to effects after the fact but cannot cause changes in airflow.

 

For example, to idle at 1200rpms, engine needs to be sucking in about 15-CFM of air. In order for it to rev to 9000rpms, about 93-CFM of airflow is needed. MAP-sensor certainly doesn't control air-flow, it doesn't have any large airflow passages and certainly not any kind of valving to open up extra airflow. Where is this extra 78-CFM of air coming from to enable engine to rev to 9000rpms?? 

 

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Thank you all for your input/ replies, I highly appreciate it🤝, so I don't know if the hose that plugs into the map under the air box would make a difference but I did hook it up after seeing it was not, not to mention the bike sat outside uncovered for the last 9 months after I restored it from it's coma stage, and I replaced the TB because the TPS sensor was faulty shooting me the code and I didn't want to risk tweaking 1 to spec so I just order a new TB, these 5th gen vfr 800s will turn you into a mechanic for sure I'll tell ya, I also used a jumper wire to reset the computer after replacing the sensor so it can reset the blink and hasn't came back on since. However, now the bike fan seems to come on late causing overheating issues and a steady FI light on as I noticed riding yesterday evening it kinda stutters as if it wants to shut off hitten 230° to 244°. Man these bikes seem to be for a person with patience, time & money because the parts for it do not come cheap either my boyz...

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