Hi-Can fuel delivery problem be caused by a faulty MAP sensor? I have a misfire and hesitation while accelerating...

Originally thought misfire and hesitation was caused by coils. Engine diagnosis says there is no problem with the coils

Any advise greatly appreciated...

Dan

 

Dan,

If a MAP sensor is not sending the correct signals to the engine computer, an imbalance of pressure may result in rough engine performance. This will be most noticeable during acceleration or slowing down, as these are the times when there is the greatest difference between atmospheric pressure and the pressure within the manifold. A rough idle is a common manifestation of faulty MAP readings.

A faulty MAP sensor may result in poor synchronization between the air intake and the release of gasoline from the fuel injectors. Delayed acceleration followed by a sudden surge is a common sign of this type of problem.

A faulty MAP sensor may trigger the 'check engine' light to come one. Is your 'check engine' light on? I would check that the engine code would indicate that there's a problem with the MAP sensor..

However, sometimes an engine code will incorrectly indicate a faulty MAP sensor. This is commonly caused by a leak in a vacuum hose or port attached to the intake manifold. Prior to replacing a MAP sensor, inspect the vacuum lines and repair them as necessary. This alone may solve the MAP sensor problems.

I would ultimately advise cleaning the MAP sensor to see if this alleviates the issue. Follow these steps to clean your Fit MAP sensor:

1) Open the hood and locate the MAP sensor. The sensor itself is a small black box. The exact location is depicted as Ref # 17 in this Fit intake manifold diagram.

2) Remove the electrical plug running to the MAP sensor. Squeeze the release tab on the top of the plug and pull the connector off.

3) Remove the screws holding the MAP sensor in place and remove the sensor.

4) Turn the sensor upside down on a flat surface so that the sensor end of the MAP sensor is exposed.

5) Spray the sensor liberally with electronic parts cleaner. Remove any visible signs of dust or other contaminates. The electronic parts cleaner will evaporate, so there is no need to wipe it down.

Re-install the MAP sensor. Installation is the reverse of removal. Hopefully this will clear up the misfiring issue that you are having. If not, then perhaps the problem lay in the fuel system..

 

Thanks-will give this a try. Although my mechanic thinks the problem may lie with an ignition fault which came up during a diagnosis check. Looks like i might have to find a supplier of coils and starter plugs in the uk....

Once again, many thanks

Danny

 

Did you ever figure out if it was your Map sensor or not?

 

Has anyone replaced/cleaned their MAP sensor and solved their hesitation/misfire problem?

 

[QUOTE=damoaten;1017429]Hi-Can fuel delivery problem be caused by a faulty MAP sensor? I have a misfire and hesitation while accelerating...

Originally thought misfire and hesitation was caused by coils. Engine diagnosis says there is no problem with the coils.....

My experience has been that you can feel the jerk and hesitation for quite a while before the cars computer will notice this as a problem worthy of giving you the "check engine" light. So far for me, the jerk and hesitation has always ended up being a faulty ignition coil. Please check out my post "bad ignition coils" .

 

I have done this on other vehicles but never on a FIT. I have never has a had a bad MAP throw a code, but I have had them cause starting issues and poor acceleration and starting issues. When I suspect one of these problems problems I just go buy the part and try it. If that does not help I simply return the one I bought.

 

Most stores won't let you return electical/electronic parts.

 

Go to AutoZone. I've never had a problem returning one.

 

Have you checked your spark plugs? And did you check OBDII ?

 

I have a problem with my 04 jdm fit sport 7speed where it stops hard and the engine feels like its being thrown ( no bad mount) and moving office rough but the problem is sporadic. Since recently it has gotten much worse and I'm wondering if the coils can cause that.

 

Can someone put up another engine diagram? Preferably in manual, 2008? I can't seem to find any