Idle Surge Die and Pinging!!! (Help?)

[extremetrek]

I tried searching for this but I can't quite find anything that makes sense enough in my head to try.

Over the past few months my car has developed an annoying sense of humor, where it will start and then if the gas pedal is not depressed the idle will surge up to around a grand and then back and then surge and then back and then if you still don't get the clue and hit the gas it will die. On top of this I am experiencing a pinging, which I hope is related.

I noticed the surge and die before the ping, but as soon as I noticed the ping I went from 87 to 89 octane, which seemed to work...at first. Now it pings especially at WOT and the surge and die is getting more and more frequent. The only thing, as far as the ping goes, that is different is perhaps the outside temperature, which led me to believe that the IAT sensor in my intake pipe may be messed up. THe thing is that when I installed my CAI we had to do a number on the IAT to make it go into the predrilled hole. Now this was over 6 mos ago and I don't believe we broke it in that process, but it would be hell to take out. But its possible I guess.

I don't have any fancy gauges/tools but I have the basics and a lot of determination so hit me with your ideas. Any chance of spark plug/wires issues? I bought the car used and I have no idea the last time any of that stuff was changed. The car is a 94 gt convertible with 109k on the clock.

Sorry this was so long and thanks for the help!

 

[extremetrek]

Something else I wanted to add is that fuel milage (15 down from 20) seems really bad and everytime I get in the car, the gas gauge wants to read empty or close to empty (that is the stock gas gauge)...any help?

 

[extremetrek]

More information...

Checked vacuum hoses, nothing that I could see, checked MAF and O2 sensor, also nothing. I did notice that when I turned the car off I could hear something running, like a liquid near the oil pan. I also noticed some "fresh" looking oil as shown in this pic:

That is a sensor just above the oil pan to the side of the oil filter.

I also took a sound clip from under the engine compartment to see if anyone hears anything:

ENGINE SOUND LINK


ANY HELP????

 

[Stanger007]

Is the part you're referring to the oil sending unit?

 

[FastFord]

Well certainly, I would change out the plugs (or at least inspect them), wires, cap, and rotor. And it looks as though you need to retighten the oil sender. At least this would give you a foundation to continue to trouble shoot. ANother consideration is to use seafoam... if you do a search in this forum you'll find alot of comments and testimonials. I know this isn't the answer you would hope for... and maybe someone else will have some good ideas.

 

[extremetrek]

I have confirmed that it is heat related. During the day it was 80 plus and lots of problems. Now that it has cooled off there is absolutely no PING at all

 

[HISSIN50]

Going along the lines of what Jethro said, pinging is more likely to occur with heat. that is what you describe.
I would also (if not mentioned) clean the MAF, ACT and ECT sensors. If you have your timing advanced, back it down some, while keeping the higher octane fuel. I have to run 91 (highest octane here) at sub-stock base timing when it is over 100* outside here.

Cleaning those sensors should take about 5-20 mins.

You might also want to check your fuel pressure when pinging occurs, but i bet it is not the cause of the detonation.

Good luck.

 

[Treachery]

Where are the ACT & ECT sensors located in a '93 GT?

 

[HISSIN50]

Where are the ACT & ECT sensors located in a '93 GT?

Check out this diagram

ECT is #7 and ACT is #44.

Good luck.