Hey guys, I have93' 40th ann. ed. andI need some help or a few suggestions... Long story short my Service Engine Soon (SES) light came on about 3 weeks ago,I haven't had the money to get my car diagnosed because everywhereI go its $120 plus. I'm a college student who has very little money at the moment. Anyways,I bought my corvette 4 months ago from a guy pretty much in mint condition, the car has 83,000 miles with new tires, brakes, oil change etc... So this weekendI decided to drive it home to LA from SF. I've made the drive before with NO hassle... But this time wasn't so smooth. About an hour and half (145mi) into my trip my car started to stall, the car was still on but when i gave it gas it wouldn't accelerate. The rpm's stayed at about 1000. Itowed my car back home from whereI stalled. My main concern was it could've been the fuel pump becuase it hasn't been changed since the car came out.I been reading that the fuel pumps go out intermittenly. My mechanici, who was going to originally diagnose the probelm back home for me, told me that the fuel pump could be going out or it might be a very dirty air filter. Then i looked back to the fuel that was put into the car,I did (by accident!) put 87 grade fuel in my car.I have never put that in the vette and to my understanding the engine flutters with anything less then 91 octane.I just replaced the fuel pump today -tomorrow ill replace the fuel filter- and my car is running great but the SES light is still on and I am concerned that it might give out on me again if I drive it longer than an hour or so.... If anyone could help me on any suggestion that would be awesome!!!

 

Need trouble codes from CE light, then I might be able to help you.

 

$120??? For a PAPER CLIP???



Code Recovery: 1984 through 1993:

To recover ECM codes from the 1984 through 1993 Corvette, place a short as shown below between pins "A" and "B" on the ALDL (Assembly Line Diagnostic Link) connector. This connector is located under the dash just to the right of the steering column and has space for 12 pins although not all of the cavities will be populated.

From here:
http://www.corvettebuyers.com/c4vettes/codes.htm

 

my uncles mechanic got the code for me, its "43"...

 

Get ALLDATA, or Mitchell's online, and do the diagnostic. EVERY step.

A cut wire (among MANY other things) can cause a faulty signal. A new part will NEVER fix a cut wire.

 

MAF, either sensor is bad or you don't have 12v to it. Test to do, tap on MAF, if car stumbles, sensor is bad.

 

I had my car diagnosed again by a certified mechanic my friend knew for free, which was a great benefit for me, the ECM relayed the same code from before..43. I looked it up in the Haynes Corvette Repair Mauaul for C4's and code 43 is for the Electronic Spark Control (ESC).. both knock sensors are faulty and it is not going to be much to replace them from what I was told...

 

Knock sensor will not make the car die, it only reports to the ESC module which retards ignition timing 3 degrees when the sensor detects detonation. I suspect you probably have other problems in the spark control end of the spectrum.

 

Why you gonna' replace 'em?

Remember;

But, if you're determined to replace them, and not test to see if there's 12 V in the circuit (or a faulty ground), help yourself.

If you're wealthy, and got tons of $$$, feel free to wing some my way?

 

Ill have a professional check out the voltages and the wires... technically my car didn't die because it was on, the engine was just shuttering whileI was on the freeway which caused me to pull over on the side of the highway. So thenI turned the car off then turned it back onandI got spark, then whenI gave it gas it was shuttering again so I decided not to drive it any further and towed the car back home. Another question I have is about the octane levels in the car causing a malfunction, the repair manual says, "Irregular octane levels in modern gasoline can cause detonation in a high performance engine. Detonation is sometimes referred to as "spark knock." This condition causes the pistons and rings to vibrate and rattle... Loss of the ESC signal to the ECM will cause the ECM to constantly retard EST. This will result in sluggish performance..."From what the books saysthis sounds verysimilar, if not exact, to what my car did. SinceI ACCIDENTLY put 87 octane in my car, whichI have never done (only 91 octane), im assuming that this caused irregular octane levels, along with whatever is wrong with the sensors???

ps. if I had "bank", this problem would've never happened! lol