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Discussion Starter · #1 ·
Hi, Newbie to the group here. Any help will be appreciated . I have an 85 vette 4+3. Symptoms are as follows:Car starts & barely runs. Super rich black smoke shaking and missing. At High rpm's will smooth out a bit and stop the smoking, but as you get down under 3500 rpm, it runs more and more like crap. This is what I have done so far. I replaced the Maf sensor, the CTS, the intake manifold temp sensor and the 9th injector sensor. Also installed a adjustable fuel regulator and plugs/ wires. Not with new, but known working units except for plugs and wires. Runs exactly the same, like crap. Obviously all I replaced was fine.:WTF Had injectors out and checked for leaks. Ohmed out injectors all 8 at about 16 ohms. Checked for vacuum leaks, do not appear to have any. Started engine. Same problem persists Coolant temp gauge shows 299 degrees and later goes to low. Car is not overheating. Jumped connector and pulled the following codes. 12.. 22 replaced Tps and set voltage to 5.3..,, 33 Maf high ( have 2 know for sure one is good).., 43 Electronic spark control ( what can be done?).., and 45 rich exhaust.. like I didn't know that.. I am out of clues. Any help as I said before would be appreciated.
 

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Discussion Starter · #2 ·
A liitle more info about the problem.

Disconnected the battery and reset the codes. Before starting there were no codes only the 12. After starting I disconnected the MAF and the engine ran better, much less smoke smoother idle. Then I disconnected the TPS and it ran about the same but idle was higher. Reconnecting maf made no difference while running except after shut off, On start up ran super rich again. Tried other MAF: same result. Knock sensor is disconnected and plug is burnt/ melted. Lots of gas in the oil, but dont want to change until issue is rectified. New codes are only 22 and 33. Also is the cooling fan supposed to kick on when shorting A/B to get codes. Mine does.
 

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Knock sensor is disconnected and plug is burnt/ melted.
Fix knock sensor.
If ECM does not see knock sensor it affects timing. Will not let timing advance over a certain amount

DTC 43
Trouble Code 43 indicates that there may be a malfunction in the Electronic Spark Control (ESC) circuit.

ESC is used to sense spark knock (pinging) and retard the timing to eliminate it. Knock sensor sends signals to an ESC module which then signals the ECM that knocking is being detected. The ECM will retard the timing by as much as 20 degrees in 1 degree increments.

Loss of the ESC signal to the ECM will cause the ECM to constantly retard the timing to its maximum. This results in sluggish performance and a Code 43.

The conditions for setting this code are:

* Engine is running
* ESC input signal has been low more than 2.23 seconds


Typical causes for this code include:

1) Open or shorted knock sensor
2) Loose knock sensor
3) Excessive mechanical noise within engine
4) Improper or incorrectly installed PROM or CALPACK in the ECM or defective ECM
5) Intermittent open in the EST line to the ignition module


Also is the cooling fan supposed to kick on when shorting A/B to get codes. Mine does.
When computer in diagnostic mode fans run
 

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Had injectors out and checked for leaks. Ohmed out injectors all 8 at about 16 ohms.
That isn't meaningful. That test is only to see if the solenoid is good or not. If it is spraying like mad but it is in a stream instead of a cloud, you won't get much combustion.

Have those checked properly. That and the 9th injector.
 

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Do you have a scanner? That way you can see what the ECM is reacting to and go from there. Are BOTH banks firing and getting fuel? Did you run a noid light to each injector?
 

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Lots of gas in the oil, but dont want to change until issue is rectified.
This is not good! I would not run the engine this way as it will shorten the life of the bearings dramatically, not to mention what it might due to your valve train. I would check the fuel pressure after shut down, It should hold pressure for at least 15 minutes. If it falls off right away than it may be a leaking injector(s), which would explain the gas in the oil. This could also explain it cleaning up at high rpm.
 

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This is not good! I would not run the engine this way as it will shorten the life of the bearings dramatically, not to mention what it might due to your valve train.

I would check the fuel pressure after shut down, It should hold pressure for at least 15 minutes. If it falls off right away than it may be a leaking injector(s), which would explain the gas in the oil. This could also explain it cleaning up at high rpm.
I would dump the oil and use cheap oil. Cheap oil with no gas in it is better for lubrication than great oil with gas in it.

Thinking aloud here but IF the FPR is weak, won't it lower pressure and let less gas into the system? Also, I would say that if you clamp off the return line and the fuel pressure still drops, the injectors are leaky. If it holds when the clamp is present but falls off quickly without the clamp, the FPR is weak.
 
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