Ive got a white 87 auto that I picked up about a year ago. Anyways I've been having a rough idle for about a month now till until the car warms up. About a week ago the car stalled when I placed it in reverse to back out of the garage. Did this about three times then I let it warm up and it was fine. Done this on another occasion since. Its got an open exhaust that I worked on about two weeks ago to get the main cat gutted(pre-cats taken out about a year ago when I initially did the exhaust). A local shop guy said a heated O2 sensor will help the idle stablelize during initial run time. Is this correct? It's been running a bit sluggish at WOT as well. It usually pulls real hard. The sluggishness goes away for a couple of months after I change spark plugs, but I shouldn't have to change them out so quickly. My ignition system is stock except for bosch platnums, 8.5mm MSD, and borg warner cap and rotor. What kind of spark plugs should I be using? What kind of problems do I seem to have and how do I fix it? Car is due for an upgrade but what exactly do I do???? :confused: :confused: Thanks in advance guys!!

 

Take a look here:
http://forums.corvetteforum.com/zerothread?id=452865

Sounds like it might be a similar problem :blueangel:

 

Got to check that as well. Any thoughts on the ignition problem??? :smash:

 

Well the first thing you can do is ditch those Bosch plugs. You are not the first person who has had trouble with +4's, myself included. I tried a set of those plugs in my old car and they made the car run so bad that they were in and out in less than 4 hours. Even if they are not directly causing your problem they certainly aren't helping anything but lightening your wallet. $60 for spark plugs is insane, these things are just a gimmick, always have been and always will be.

A good standard plug like an Autolite, NGK, or AC Delco will be just fine. Platinums are supposed to wear longer but I've heard more than once that they foul easier. I'm not sure if that's true, but from a money standpoint alone it will be worth it to try something else. Throw in the original AC Delco's that are supposed to be in your car and see if that makes a difference.

As for the heated O2 sensors, maybe. You say it has a rough idle until the car warms up, how warm? You see when your car first starts up you'll be in open loop mode and the O2 sensor will be ignored by the computer for A/F adjustment. You will be running off of set values until a certain amount of conditions are met. Once these conditions are met it will go into closed loop and begin to rely on the O2 sensors for info. Then and only then would a heated O2 sensor help. I know this because I've just gone through a similar thing. Here's the deal, see if it sounds familiar.

I have a 92 which I have installed long tube headers on. This means that the cats are gone, so the O2 sensor location has changed and backpressure has changed a lot. I drove it for almost a year like this and it was OK. I had a few little driveability things but I figured it was just in the tuning. After I installed my cylinder heads I had the same few driveability quirks but for the most part everything was fine. Then it started getting cold. As the weather got colder, down around 30 degrees or less I noticed some bizarre trouble. The car would start and run perfectly for a minute or two until it warmed up a little then it would start acting very strange. The idle went to crap, it would feel like it was hunting for idle. It be VERY sluggish at part throttle, almost as if it was only firing on every other cylinder. Now if I gave it enough gas it would go like a bat out of hell, but it was a very fine line, there was no middle area. It was either stumbling like mad or going very fast. And to make it worse, it only happened when I left work, it never did this on my way in to work.

The solution was heated O2's and here's why. When I go to work in the morning it's at least 2 miles before I'll get to any amount of traffic. That means I can leave the house and drive at a good constant RPM for a few minutes. This was enough to warm up the O2's so that they would read OK when I did get into traffic. Essentially I would start it up, it would be in open loop until I got up to my speed, by the time it switched to closed loop I was running at a good RPM and was keeping the sensors warm. However, when I would leave work it was a different story. It was typically colder because the car has been outside rather than a heated garage, AND I go immediately into stop and go traffic. I could start the car up and move, but I could only go an 1/8th of a mile or so and I'm in stop and go. Since I then spend most of my time idling the sensors never get warm enough. The sensors therefore always show lean, making the car richen it up. The sensor still shows lean so it tries to richen it up more, etc. This goes on until it's on the verge of not running at all. The car is running so rich that you can smell it and it burns your eyes, yet my A/F gauge is off the scale lean. As I limp through stop and go the problem doesn't get any better. As traffic finally thins out and I can make a decent speed the problem all the sudden goes away. The car drives perfectly again and everything is cool until I leave work again.

So the key points here are that it ran great when you first fire it up, open loop mode. It ran fine when it was plenty warm. The only real problem was when it was still fairly cold, yet in closed loop mode. If this sounds like you, then it's probably your trouble. The key though would be if it runs good during open loop. Cold startup and WOT should be open loop and will ignore the O2 completely. Theoretically these could be affected if you're fouling your plugs out from running rich. Perhaps why it gets better for a little while after changing the plugs.

In short I guess it's worth a shot. You've only got one sensor to change so you can do it for about $60 and some time. It certainly won't hurt anything. :cheers:


[Modified by Nathan Plemons, 6:03 AM 12/16/2002]

 

Well Nathan thanks for the great advice. As far as the car getting warmed up I wait till the coolant temp. is at about 150 and/or the car has been sitiing for 5 minutes. The stalling is what concerns me though. Did it again yesterday when I was pulling out of the driveway. The cars RPM's will drop really bad and then the car will stall. I probably will go with the AC Delco's or the NGK. The plugs I've got in there are probably fouled. I hope this will solve the sluggishness issue. Before all this began to happen when I was at WOT the cars RPM's would instantly jump the the car would fly...now at WOT the RPM's climb slowly. A heated O2 sensor seems like a good idea as well. I'm in Washington State and the weather here is kind bad during the winter months. As far as ignition upgrade systems :D What options do I have?? Who is the best or what do you guys recommend??? I'm confused as what to get (MSD, DUI, Flamethrower, etc.) :smash: :smash: :smash: