86 Accord Idle PGM-FI Light

Hi,

Tuesday Morning - Started car with remote start, let it warm up 6-7 minutes like usual. Everything was running and idleing fine until I drove about a half a block. At the first stop sign the idle would not hold. It went up and down several times and then the car died. I started it back up just fine, turned around and went back home. As long as my foot was on the gas the car would stay running. During this time my PGM-FI light came on. Temperature was about 8 degrees farenheit (Coldest morning yet this year)

Tuesday Evening - Got off work, started the accord up when I got home. Car idle'd just fine, I let it warm up for about 10 mins, got in and had no problems this night. Temperature was about 30 degrees farenheight. PGM-FI Light was off.

I put my key in and looked at the ECU?/ECM? light through the little window to see if the red light would flash. The light flashes 12 times, pauses, flashes 12 times, pauses ect... Just keeps doing that. (this is with the PGM-FI Light off.

I looked up that error code and that says Check the EGR Valve.

Anyhow since things were running good Tuesday Evening, I tried to use the Honda to go to work again on Wednesday. Same exact thing as tuesday morning.. The car started and ran fine until I went about half a block, then idle drops at stop signs or when I let off the gas. The PGM-FI light DID NOT come back on though. Temperature was about 18 degrees farenheight.

Wednesday Evening - Temperature is back up to 30 degrees when I get off work, I start up the honda and it's working fine again.

I took off the EGR valve tonight and visually inspected it and cleaned some of the carbon off with brake cleaner. The plunger was not restricted before, and is not restricted now. I did notice that if I pushed up on the plunger and held my finger over the vacuum port, the diaphramgh slowly let the air back in. Could this be a vacuum leak or is it supposed to do this?

Does the problems described above sound like an EGR Valve problem, or what does it sound like? Is there a possibility there are more error codes that I can't view? Does it only show the last error?

I have never had any problems with this car until now... Except every once in awhile, on a cold day when first starting the car.... Every once in awhile as it warms up, it will drop from 1500 rpm's (normally what it idles at when first started on cold day) down to 1000 rpm's and then jump back up to 1500. It will do this little routine for a couple of minutes until it is warm enough to sustain a 750 rpm idle (normally what it idles at when warm)

Thanks for any help.

Vince Wiley

The approved test for an EGR valve is to pull a 8 in/hg vacuum and see it it will hold at the 8 in/hg. If it won't you have a leakee diaphram. Generallly, the ECU tells the EGR to open and the sensing module on top of the EGR registers to the ECU that it has opened. If it doesn't get the proper signal from the EGR, the EGR fault code comes up. Also if it gets a signal from the EGR that it is opened and the command to open was not sent from the ECU, you will get a fault. The engine will stall if the valve is open and the idle is below 1500 rpm. So the EGRvalve is probably bad. You can reset the stored ECU codes by disconnecting the neg. battery terminal for ten seconds then reconnecting.

Very Helpful, Thanks for that information.

2 new questions now. How do I get an 8 in/hg vacuum so I can test. Also, is it possible that the EGR just doesn't open when it's really cold, that is the only time I seem to have the problem. The thing I find weirdest is that it idle's fine (even when warmed up) as long as I don't put it in Drive and start going.

Anything else it could possibly be besides the EGR?

I use a small vacuum pump and engine guage. When I reach the desired vacuum I pinch the hose with the guage on the EGR side. Then watch the guage to see if the vacuum holds.

It could be sticking open which would explain the problem with idling.