MAP sensor problem showing up at 35k miles? Plus some interesting data
Registered User
Joined: Oct 2000
Posts: 4,144
Likes: 0
From: Seattle
I wasn't actually advocating daily whacking; that could lead to sensor failure, or hairy palms.
When stumbling/hesitation symptoms occur, though, a good whack can do the trick. I did have one MAP sensor replaced under warranty.
When stumbling/hesitation symptoms occur, though, a good whack can do the trick. I did have one MAP sensor replaced under warranty.
Thread Starter
Registered User
Joined: Feb 2001
Posts: 2,895
Likes: 1
From: You wish
Pinky, yes, the apocalypse is upon us. Just like relationship advice, its always easier to give engine advice to someone else. :-)
Gernby - IK24's, yes.
Krazik - the breather lead into the manifold doesn't concern me. Its the trail of oil from the breather in front of the TB that has the potential to gum stuff up. The other breather (through the PCV) only opens at high vacuum, which is not a WOT problem.
All - I think I'm going to pick up a new sensor and do a forensics analysis on the old one. Maybe after that I'll look at equivalent replacements. Funny thing is, older Honda MAPs seem to have no issues like this.
UL
Gernby - IK24's, yes.
Krazik - the breather lead into the manifold doesn't concern me. Its the trail of oil from the breather in front of the TB that has the potential to gum stuff up. The other breather (through the PCV) only opens at high vacuum, which is not a WOT problem.
All - I think I'm going to pick up a new sensor and do a forensics analysis on the old one. Maybe after that I'll look at equivalent replacements. Funny thing is, older Honda MAPs seem to have no issues like this.
UL
Registered User
Joined: Apr 2001
Posts: 2,898
Likes: 1
From: Fort Worth
Cleaning the sensor with a solvent or compressed air would likely destroy it. A MAF, yes, a MAP, hell no.
UL, I've seen more than one MAP fail on an OBD2 Honda, so this is no surprise to me. I am surprised you were surprised that the car was peppier with the ECU reset, we've been telling you about that for a few years now.
I don't think the problem is oil buildup. There is no reason for oil to build up there, there is no airflow up into the MAP sensor (not enough, at least). If you remove the TB you will also see that it is a rather convoluted path up to it. The probability is just too low.
I think it is just an issue with Denso's design and nothing more.
An interesting side note, the Field Boxer SFC (or was it AFC?) fuel/VTEC controller used to be flaky and cause the ECU to report a MAP code on a lot of Hondas. People would replace the MAP and reset the ECU (to clear the code) only to find the problem occur again a few months later. Eventually you would find that all you needed to do was clear the code- the problem was the Field unit, not the MAP. Just a spurious error. The Apex'i VAFC doesn't have this problem.
UL, I've seen more than one MAP fail on an OBD2 Honda, so this is no surprise to me. I am surprised you were surprised that the car was peppier with the ECU reset, we've been telling you about that for a few years now.
I don't think the problem is oil buildup. There is no reason for oil to build up there, there is no airflow up into the MAP sensor (not enough, at least). If you remove the TB you will also see that it is a rather convoluted path up to it. The probability is just too low.
I think it is just an issue with Denso's design and nothing more.
An interesting side note, the Field Boxer SFC (or was it AFC?) fuel/VTEC controller used to be flaky and cause the ECU to report a MAP code on a lot of Hondas. People would replace the MAP and reset the ECU (to clear the code) only to find the problem occur again a few months later. Eventually you would find that all you needed to do was clear the code- the problem was the Field unit, not the MAP. Just a spurious error. The Apex'i VAFC doesn't have this problem.
Registered User
Joined: Oct 2000
Posts: 8,821
Likes: 0
From: HouStook TX
I've had those same problems and have gone through 3 map sensors within my first 76k miles. The stumbling through VTEC, rough idle, bogging through stop-n-go traffic(HEAT SOAK), have all been mentioned as MAP sensor related issues on this board. I've done the 'tapping' routine with limited success.
I believe that UL's may have a point about the oil contamination through the breather. At one point, I looked at my TB and noticed the oil buildup on the outside of the butterfly valve and the inside of the intake manifold. I cleaned it and had more buildup after 500 or so miles. Another local S2k showed no signs of oil on the same components. He also doesn't have the oil consumption issues that I do.
Could we really be breathing oil instead of burning it?
My oil trail was pretty thick.
I believe that UL's may have a point about the oil contamination through the breather. At one point, I looked at my TB and noticed the oil buildup on the outside of the butterfly valve and the inside of the intake manifold. I cleaned it and had more buildup after 500 or so miles. Another local S2k showed no signs of oil on the same components. He also doesn't have the oil consumption issues that I do.
Could we really be breathing oil instead of burning it?
My oil trail was pretty thick.
Thread Starter
Registered User
Joined: Feb 2001
Posts: 2,895
Likes: 1
From: You wish
marcucci, I don't think it was the ECU reset that made the car feel better. I've done resets in the past and there just wasn't any noticeable difference (1 hp on the dyno maximum).
joe_s2k, I've got oil trails in my intake tube too. And recently, thanks to some very sticky tires, I experienced my first consistent right hand turn oil smoke phenomena (hard right turn, oil goes through breather and gets burned - very common on those cars that get tracked - not that I'd do that....).
I burn very little oil during extended straight line cruising. I once drove 1000 miles round trip without any noticeable consumption. But one day of hard driving with lots of corners can see the oil level move on the dipstick.
UL
joe_s2k, I've got oil trails in my intake tube too. And recently, thanks to some very sticky tires, I experienced my first consistent right hand turn oil smoke phenomena (hard right turn, oil goes through breather and gets burned - very common on those cars that get tracked - not that I'd do that....).
I burn very little oil during extended straight line cruising. I once drove 1000 miles round trip without any noticeable consumption. But one day of hard driving with lots of corners can see the oil level move on the dipstick.
UL
Registered User
Joined: Apr 2001
Posts: 2,898
Likes: 1
From: Fort Worth
I have an interesting test then. I just drove 1500 miles to Florida on a Tuesday and then back again on a Friday. It was full when I left (fresh change) and I'm about to check it tonite when I get home (has been parked since I returned.
I have experienced NO oil consumption in my S2k with a lot of autocrosses and 3 or 4 track events on it. Street rubber, though.
I have experienced NO oil consumption in my S2k with a lot of autocrosses and 3 or 4 track events on it. Street rubber, though.
Administrator
Joined: Oct 2000
Posts: 17,004
Likes: 7
From: Santa Cruz, CA, US
We don't smoke too much at auto-x in my experience. It takes hard right handers of decent length usually. 180deg high sweepers seem on R compounds are the best at producing it. Usually the car won't start smoking untill about 1/2 thru the corner.
Former Sponsor
Joined: Mar 2002
Posts: 15,526
Likes: 19
[QUOTE]Originally posted by marcucci
[B]I have an interesting test then. I just drove 1500 miles to Florida on a Tuesday and then back again on a Friday. It was full when I left (fresh change) and I'm about to check it tonite when I get home (has been parked since I returned.
[B]I have an interesting test then. I just drove 1500 miles to Florida on a Tuesday and then back again on a Friday. It was full when I left (fresh change) and I'm about to check it tonite when I get home (has been parked since I returned.