Pinging is gone right after I start the car, regardless of temp ??

[jb89coupe]

So I got a new computer for my car. That solved all the sensor error and ground resistance problems I was having, and I was hoping it would get rid of my pinging too - no luck. Up until today I thought it was heat related (when my engine warmed up it would ping), so I figured it was carbon buildup.

Today after driving for an hour or so, I shut off the car for about 5 minutes, started it up and got right on it - no pinging. After a minute or so it would ping again under load. I tried it at a stop sign and same thing - I can put all my weight in the pedal and I can't get a ping out of it right after I start it up.

I'm guessing it's sensor related (??)... It also idles high for the first minute or so, so I have to assume the computer's in a different "mode". So my question is, what sensors does the computer ignore/bypass when you first start it up? Anything else this could be? When it's cold in the morning I can get 10 minutes or so where I can get on it and no pinging, after it's hot I get about 1 minute after I start it.

 

[Daggar]

Looking at your sig and your description, I can think of a couple of things you could try. The first would be to look at your timing and see where it's at. More than 14* and I'd think about bringing it down some. What octane gas you running? What's a "densecharger"? If timing isn't your issue then look at your T-stat. Try a 180* and see if that had any effect. You can also try putting your STOCK waterpump pulley back on and see if that makes any difference. As far as sensors go, you could check and see if your intake temp sensor is out of range. If it's within range that still doesn't mean it's good. It may be so gunked up that it's reporting garbage back to the computer. Your throttle body and MAF sensor strikes me as being a little large for your setup but I don't know if that would have anything to do with your problem (perhaps someone else might know). The last thing I can think of is the coolant temp sensor (your intake temp sensor has more to do with your air fuel ratio after it's warmed up though).

You can also check for vacuum problems. Even a minor one in the right location can screw things up enough to cause a lean condition and thus....'pinging'.

Have I left anything out?

 

[jerry beach]

Good reply Daggar.

I would pull a plug or two, and expect to see white. Pay attention to what kind and heat range they are too.

What do you have for a temp guage, it may be overheating and you dont know it.

If it is carbon build up, I have used the Seafoam from Napa with some success. Its a little pricey, but it does work. Small amounts of water will do the same, but the steam may break off big chuncks I have heard. I slowly added about 1/4 can of it to an old motor and lots of smelly black junk came out of the pipes. It stopped pinging on 87 octane too. This car has been driven by an old man for the last 23 yrs.

 

[jb89coupe]

Daggar:
I backed my timing down to 10* after the pinging started - still pings using 93 octane. I've tried to go even lower with no change. When I got the car it ran fine at 16* and then just started pinging like crazy one day (this was long before the intake/tb/maf or even the pulleys). To make a long story short the computer "went" a while ago (I got codes for every sensor on pin 46 - ect,tps,act,bap,evp,maf,nds) and replaced/tested most of them with no change. I was getting bad ground resistance on those sensors too. I finally just popped a new computer in last weekend and that took care of that. A densecharger is a cold air kit (www.densecharger.com). Is the intake air sensor you're talking about the same as the air charge temp sensor? I'll grab a new one just to see. The ECT sensor has been replaced recently. BTW I know the maf/tb are a little big but I got a killer deal on the tb and I'm planning on a rebuild + H/C this winter so I should grow into it.

Jerry:
I just did the plugs/wires/rotor/cap a couple weeks ago. They were a little white but nothing too bad. I put Autolite ar25's in (I know I could go to 24's but that would just be sidestepping the problem). I have an autometer water gauge, my cars runs 180-200f with the stock thermo. I plan on throwing a 180 in there anyway.

I don't think it's carbon buildup or even a heat issue at all anymore. Even when it's at 200*, if you shut it off for a second and restart it you can plant your foot in the throttle through all the gears and no pinging at all. Then it starts again after a minute or so.

 

[Daggar]

Yeah... intake air sensor = air charge temp sensor. It has a large part in telling the computer how much to lean out or richen your fuel mixture based on how cold it thinks the air is going into the motor. If replacing it doesn't have any effect you can try relocating it to the section of your cold air kit upstream of your MAF. That should richen up your mixture accross the powerband though I'm not sure if it has any effect at WOT on mass air cars.

If all else fails you could isntall a wideband 02 sensor and reader. At least then you would definitely know if it's a lean condition.

Edit: BTW... nice cold air kit. That may be just what I've been looking for to run air into my Kenne Bell. I've got the march ram air kit on there now and it works well but I've never been a fan of the dryer hose that runs from the scoop to the airbox.

 

[dvs bullet]

You could have a coil breaking down, I'm running the same prob. and that is the only thing that I haven't replaced.

 

[jb89coupe]

I'm not sure I understand how a coil could cause these symptoms, but if it does the trick for you let me know.