Engine Cuts Out At Stoplight

[2ndGenPreludeSi]

My car is fuell injected and has almost 220,000 miles, everytime I start it up it idles at around rpms 1000 for a short time. By the time I get to the stoplight around the corner from my house it will start to idle lower around 750. Then all of a sudden it will drop and bounce around at 400-500. At this point you can't do anything, it won't go anywhere, and the gas pedal doesn't do anything, like it's not connected. it has never completely stalled, and it recovers if you give it time. It will just all of a sudden kick in to gear and take off. It has thrown a code for oxygen content once or twice while it's doing this. sorry for the long post. Any advice would be appreciated!

[Dr_Snooz]

What code is it giving you?

[2ndGenPreludeSi]

It has givin me code 2 a couple times, but it weirds out like this everyday, and usually the engine light won't come on. someone told me that it might throw this code because of a misfire, is this true? Also it used to throw a code 12 [egr I think] when you drove it hard, but it stopped doing that, i don't know why because i didn't do anything if that matters.

[Dr_Snooz]

Code 2 is for O2 sensors, which can cause rough idle and poor performance. Check your fuel pressure, condition of the O2 sensor wires and replace the sensors as a last resort.

The EGR can also cause a rough idle and it would be worth investigating to make sure that system is functioning optimally. For that, however, you'll need to dig up a shop manual. I'm not sure if any are available for download, but you can buy the printed edition at www.helminc.com. It's well worth the investment.

Let us know how it turns out.

[2ndGenPreludeSi]

I downloaded a helms, which is awesome. I was checkin out the oxygen sensor and all looks fine, I don't think they're that expensive though. It might be worth a try. Is it possible to clean out the egr or do they fail beyond repair?

[ecogabriel]

The car does not use O2 sensor input when engine is cold -ECU uses default values. Once it is warmed up it enters closed loop using sensor inputs to calculate fuel. If the O2 sensor is screwed up that is where I would expect problems to show up.

A visual inspection would not reveal anything; only observing its switching from lean to rich with an oscilloscope would. Anyway, they are cheap so it is not worth the trouble. An universal-type sensor costs about $20 ; they come without the connector so you need the old sensor to get the plug from it.

You'll also need a sensor socket to remove it, and anti-seize paste to install the new one (if it does not come with it); it makes future removal easier.

[ecogabriel]

EGR valve cleaning is possible but I am not sure that the problem is there. If the valve is stuck open even partially your idle would be rough. Moreover, once the engine is warmed up the ECU would pick up if the EGR sensor (at top of valve) is not seating where it expects it to be.

EGR code when driving would be due to a "lazy" vacuum system. In the 86-87 accords there is a hose (#17) that should be attached to the pipe from the air filter box to the throttle body. If it is unattached, dust will be sucked in all the time and it will eventually start clogging the vacuum system. It happened to my car, and the only solution was getting that loose hose connected back where it should be, and cleaning a small yellowish canister inside the black box.

88-89 Accords have a slightly modified system so they may not have that problem.

[2ndGenPreludeSi]

All right, thanks for the info, it helps out a lot. I pulled the vacuum hose off the fuel pressure regulator and it stinks bad like gas, it is dry and no gas came out when i started it up, but does this mean I have a faulty regulator? Would this even cause the problem that I'm having?

[2ndGenPreludeSi]

Hey if anyone wants to know, it was my fuel pressure regulator. I actually replaced it with one from an accord from the junkyard. They weren't exactly the same, but after I put it on, the car stopped doing the wierd stuff at the stoplight, and most of you were helping me out with my hot start problem, which stopped as well. pretty awesome for just five bucks!

[Dr_Snooz]

Nice! Thanks for posting back with the solution.

[slowA20tog22]

this sounds like the issuse i have been having with my car.... i just replaced my fuel filter although im confused i forgot were the hoses go...

[kentwat]

Great info. I haven't been driving my 3g due to my son getting license and he has been driving it. I wish I could get him to appreciate it as much as I do. But oh well maybe in time. He's been complaining about jerking and hesitating while driving. I took it for a drive and it seemed ok. This was when it was cold. I later used it the next day and after warm up stuttering and general poor performance. Giving full throttle was like a carb bogging. I then checked codes and code 1 for primary o2 sensor. Then I searched and found this info thanks. Sorry for long winded. I need to check my manual and see about wire colors and location for primary on an 86 lxi.


A side note the manual shows a 6mm bolt to check fuel pressure on fuel filter but mine doesn't have an extra bolt?? Another thing is there actually another fuel filter back by the tank on an 86? thanks it now has 310k on it.