Persistent CEL 3 MAP Sensor and Falling Idle
07-20-2007, 07:28 AM
#1
Persistent CEL 3 MAP Sensor and Falling Idle
I have an H22A that was recently installed. It is throwing a CEL 3 for MAP sensor.
When I clear the CEL, and then start the car, the engine fires up, the RPMs fall almost to 0, the CEL comes back and then normal idle speed resumes. There is a little fluctuation to the idle, but not much. I suspect that the stalling idle at startup is because the car is running rich from MAP malfunction.
I have replaced all of the vacuum caps and hoses to the IM.
I have tested for continuity on all 3 map sensor wires back to the ECU. The wiring is good.
I have tried 3 different MAP sensors.
The hose to my MAP was slightly loose so I replaced it with a smaller hose. Same results.
Yes I am resetting the ECU after every step.
Is it worth trying the fluctuating idle fixes, like cleaning out iacv, egr, fitv, and throttle plate? I don't see how this will fix my CEL.
Is my only other option to try to replace the ECU? I find it really hard to believe that everything else on the ECU is good except for the MAP Sensor input pin.
Thanks for any help.
When I clear the CEL, and then start the car, the engine fires up, the RPMs fall almost to 0, the CEL comes back and then normal idle speed resumes. There is a little fluctuation to the idle, but not much. I suspect that the stalling idle at startup is because the car is running rich from MAP malfunction.
I have replaced all of the vacuum caps and hoses to the IM.
I have tested for continuity on all 3 map sensor wires back to the ECU. The wiring is good.
I have tried 3 different MAP sensors.
The hose to my MAP was slightly loose so I replaced it with a smaller hose. Same results.
Yes I am resetting the ECU after every step.
Is it worth trying the fluctuating idle fixes, like cleaning out iacv, egr, fitv, and throttle plate? I don't see how this will fix my CEL.
Is my only other option to try to replace the ECU? I find it really hard to believe that everything else on the ECU is good except for the MAP Sensor input pin.
Thanks for any help.
07-20-2007, 07:45 AM
#2
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Re: Persistent CEL 3 MAP Sensor and Falling Idle (nikolai.)
if you traced all wires back to the ecu and resistance reads less than 1 ohm, and you have tried different maps, and yours possitive you have no vacume leak, then there are only 2 things it could be. bad pin where the connector at the cu touches the pin to the ecu, or a bad ecu. try getting your hands on another ecu to test with,
07-22-2007, 04:00 PM
#4
I'm almost 100% its the ECU. I went through the troubleshooting procedure in the Helm's one more time today. The middle wire is the signal. Apparently when the sensor is removed and the ECU is on, that wire should read 5V coming from the ECU. We'll I'm only getting like 25-30mV. The sensor lead does measure around 3V at idle when everything is connected, which is roughly 20inches of vacuum. I'm going to replace the ECU and see if it fixes the problem.
07-29-2007, 03:03 PM
#5
Replaced the ECU today.
Still getting CEL 3, bouncing idle and running rich. Looking for suggestions. My next step is to go over everything one more time. Then I'm going to light the car on fire.
Still getting CEL 3, bouncing idle and running rich. Looking for suggestions. My next step is to go over everything one more time. Then I'm going to light the car on fire.
07-30-2007, 10:42 AM
#7
check and make sure the pins in the connector at the ecu are not loose, i had one that loosened up on me, and gave me random fuel injector problems because it was loosing contact randomly.
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08-13-2007, 12:55 PM
#9
Eddiebx was right. I just figured it out yesterday. The MAP pin into the ecu was loose. I actually tried extracting it and it was jammed in there for some reason. I'm going to get a new connector from a junkyard and repin it.
I'm 100% thats what the problem has been the whole time though. I removed the top panel from my ecu and checked continuity from the lead inside the ecu case to just on the other side of the connector. All the other leads were fine except for that one.
I'm 100% thats what the problem has been the whole time though. I removed the top panel from my ecu and checked continuity from the lead inside the ecu case to just on the other side of the connector. All the other leads were fine except for that one.
08-15-2007, 12:52 PM
#10
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Re: (nikolai.)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nikolai. »</TD></TR><TR><TD CLASS="quote">Eddiebx was right. I just figured it out yesterday. The MAP pin into the ecu was loose. I actually tried extracting it and it was jammed in there for some reason. I'm going to get a new connector from a junkyard and repin it.
</TD></TR></TABLE>
i said this would be one of 2 things, bad pin or bad ecu. I typed to fast and meant to tell you to check for a bad connection or loose pin, for some reason i meant to say connector in my fisrt post and it came out at cu?
glad you found the problem
</TD></TR></TABLE>
i said this would be one of 2 things, bad pin or bad ecu. I typed to fast and meant to tell you to check for a bad connection or loose pin, for some reason i meant to say connector in my fisrt post and it came out at cu?
glad you found the problem
08-20-2007, 06:11 AM
#16
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Re: (nikolai.)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nikolai. »</TD></TR><TR><TD CLASS="quote">I ogt a new connector and changed that one pin and the code went away. I still have an eratic idle, despite everything else that was done. </TD></TR></TABLE>
check your EGR...and TPS
check your EGR...and TPS
08-20-2007, 06:50 PM
#17
cleaned out the egr already when i cleaned out my iacv and fitv. i also have the egr vac port capped off. when i connected it to the IM the car ran like crap.
i actually am thinking about the tps now. i sprayed all my vacuum caps, hoses and my IM gasket with carb cleaner to check for leaks and notices that there is some air getting sucked in around my TPS.
I also tried unplugging my iacv. The idle dropped to normal but was still bouncing.
i actually am thinking about the tps now. i sprayed all my vacuum caps, hoses and my IM gasket with carb cleaner to check for leaks and notices that there is some air getting sucked in around my TPS.
I also tried unplugging my iacv. The idle dropped to normal but was still bouncing.
08-23-2007, 11:48 AM
#20
Re: (nikolai.)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nikolai. »</TD></TR><TR><TD CLASS="quote">
i actually am thinking about the tps now. i sprayed all my vacuum caps, hoses and my IM gasket with carb cleaner to check for leaks and notices that there is some air getting sucked in around my TPS. </TD></TR></TABLE>
Wasn't the TPS leak. Sealed it up well with some Hondabond. Tried screwing my FITV in some more (it was all the way out). Same results. All I can think is that there is a vacuum leak somewhere that I cant find. It may be leaking from the IAB vacuum switch/tank thats under the IM. I am basically going to read the entire section on the Idle Air Control system in my Helms and see if I've missed anything, unless anyone can give anymore help.
Key point here: It doesn't act like your usual FITV issue because the idle still bounces when the car is warmed up. Though the bouncing is not as bad when warm.
i actually am thinking about the tps now. i sprayed all my vacuum caps, hoses and my IM gasket with carb cleaner to check for leaks and notices that there is some air getting sucked in around my TPS. </TD></TR></TABLE>
Wasn't the TPS leak. Sealed it up well with some Hondabond. Tried screwing my FITV in some more (it was all the way out). Same results. All I can think is that there is a vacuum leak somewhere that I cant find. It may be leaking from the IAB vacuum switch/tank thats under the IM. I am basically going to read the entire section on the Idle Air Control system in my Helms and see if I've missed anything, unless anyone can give anymore help.
Key point here: It doesn't act like your usual FITV issue because the idle still bounces when the car is warmed up. Though the bouncing is not as bad when warm.
08-24-2007, 03:48 AM
#22
yes. if you aren't getting a map signal (or the wrong signal for that matter) you ecu will run very rich off its fuel tables, which are usually adjusted based on map readings.
08-24-2007, 05:25 PM
#25
fixed everything this evening. Removed the FITV again and screwed it all the way in. Set the idle adjustment screw according to the steps in Helms. Idle was still bouncing between 600-700 at idle warmed up. Bleed the coolant for what must have been 45minutes to an hour. Decided to changed the plugs. They were completely fouled from running with no MAP (duh..). Changing the plugs took care of the remaining bouncing idle. I think it was a culmination of several issues.
The one thing that I still don't understand is that I still have a vacuum on my FITV port in the throttle body even when the car is completely warmed up. I can only assume that I still have air in the system that need to be bled out OR the FITV is indeed bad.
The one thing that I still don't understand is that I still have a vacuum on my FITV port in the throttle body even when the car is completely warmed up. I can only assume that I still have air in the system that need to be bled out OR the FITV is indeed bad.