Help! First Corvette - 1994 Admiral Blue LT1 - Error Code Issue

[SnakeDr]

Two weeks ago I finally purchased my first Corvette, a Admiral Blue 1994 Corvette LT1. I have been a die hard fan since the introduction of the C4 in 1984. After years of looking at Callaway and ZR-1 Corvettes, I decided that I needed to start somewhere. This will not be my last one but its a starting point (I have been a member here since 2009). This car was a South East (in florida and alabama) and has been sitting for a couple of years.

So far I have done the following to it.

• Added sea foam to the crankcase and drained the oil and changed oil filter (Mobile 1 and used A/C Delco filter)
• Installed new air filter (non-a/c delco)
• Installed two new AC delco 02 Sensors.
• Installed a MAP sensor AC Delco
• Throttle position sensor AC Delco.

I'm still getting the following codes:

• DTC 43 - Knock Sensor (KS) Circuit
• DTC 64 - Bank 2 (Right Front) Heated Oxygen Sensor (HO2S) #1 Circuit (Lean Exhaust Indicated)

Has anyone had a error 64 code after changing a 02?

My next thought was to change plugs, wires and knock sensor. I live in NJ and need to get this car to pass inspection.

 

[John Robinson]

In most cases the sensors are good it's the wiring and grounds that have gone bad. Until you eliminated bad grounds and wires as the problem stop throwing parts at it. I am sending copies of the DTC code sheets from 93 FSM. Hope they help you to find the problem. Before you buy any more parts go to ebay and buy a 2 volume FSM set for your car.

 

[SnakeDr]

In most cases the sensors are good it's the wiring and grounds that have gone bad. Until you eliminated bad grounds and wires as the problem stop throwing parts at it. I am sending copies of the DTC code sheets from 93 FSM. Hope they help you to find the problem. Before you buy any more parts go to ebay and buy a 2 volume FSM set for your car.

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Understood. Throwing parts at it ain't going to solve the problem. However at 18 years old it would hurt. I do see one plug on cylinder 8 that needs to be replaced. Looks like the central electrode burned down some and a tiny piece stuck to the ground side.

Thanks for the advice. I'm looking into the manuals. I just got the car so I'm still in the process of getting familiar with it. Droolling over one and owning one is two different issues!!!

 

[boomdriver]

CLUES CLUES ..................... Elementary my dear Watson !

lemme see here..


lean exhaust...

bad o2 signal but the o2 sensor is brand new....

melted electrode on spark plug.. <<---------------------THE BIGGIE (if the titanium or iridium tip on a plug melted away I wonder what the aluminum piston dome is doing?)(begging for mercy):ugh


could it possibly be that there actually IS a lean condition thats maybe caused by antique clogged stale old useless plugged up FUEL INJECTORS ? Car sat for a couple years? Yup... gawd I'm good. :eyerole

Call Jon.
Get your FSM set then call Jon. It'll take him 2-3 days to get your stuff to you and the books can be on the way.

Problem solved.

Admiral Blue...

Congrats on that !

 

[gmjunkie]

CLUES CLUES ..................... Elementary my dear Watson !

lemme see here..


lean exhaust...

bad o2 signal but the o2 sensor is brand new....

melted electrode on spark plug.. <<---------------------THE BIGGIE (if the titanium or iridium tip on a plug melted away I wonder what the aluminum piston dome is doing?)(begging for mercy):ugh


could it possibly be that there actually IS a lean condition thats maybe caused by antique clogged stale old useless plugged up FUEL INJECTORS ? Car sat for a couple years? Yup... gawd I'm good. :eyerole

Call Jon.
Get your FSM set then call Jon. It'll take him 2-3 days to get your stuff to you and the books can be on the way.

Problem solved.

Admiral Blue...

Congrats on that !

Hey Boom,You forgot to leave Jon's #!~!!

Welcome to FuelInjectorConnection.com

 

[John Robinson]

Boom I like your answer. But as you have said many times the wiring on these cars is always suspect and since I did not have the information on the melted plug I felt the problem was a poor signal to the ecm. I think that the fact this car sat for 2 years and is 18 years old I would still clean all the ground points and check the ground bundle for the tps, knock sensor,etc.

Maybe you could provide the OP with the procedure to check the injectors so he can verify they are bad before buying new ones.

I just thought about the possibility that the car when it was restarted pumped a lot of crude into the fuel filter and that is why it is running lean. Something else for the op to check.
Carrying that thought a little further is it possible that it did pump the crude from the tank and it through the filter and lodged in the first injectors it came to and that is why it is lean. That would explain a bad injector and a lean cylinder. It would be interesting to know which cylinder had the bad plug. If it was on the right bank which is the closest to the fuel tank would be interesting to know because we have a lot C4 lately that have been stored for a while having trouble with injectors that have relatively few miles on them.

If the op would provide that information maybe this cold develop into a what to expect article for future long term storage cars.

 

[SnakeDr]

Hey Boom,You forgot to leave Jon's #!~!!

Welcome to FuelInjectorConnection.com

Took it for a spin out of curiosity after cleaning the passenger side plugs and now the pinging\stumbling is more obvious. Plug was not necessarily melted but was definitely worn out.

It actually ran a little better before cleaning.

 

[SnakeDr]

Boom I like your answer. But as you have said many times the wiring on these cars is always suspect and since I did not have the information on the melted plug I felt the problem was a poor signal to the ecm. I think that the fact this car sat for 2 years and is 18 years old I would still clean all the ground points and check the ground bundle for the tps, knock sensor,etc.

Maybe you could provide the OP with the procedure to check the injectors so he can verify they are bad before buying new ones.

I just thought about the possibility that the car when it was restarted pumped a lot of crude into the fuel filter and that is why it is running lean. Something else for the op to check.
Carrying that thought a little further is it possible that it did pump the crude from the tank and it through the filter and lodged in the first injectors it came to and that is why it is lean. That would explain a bad injector and a lean cylinder. It would be interesting to know which cylinder had the bad plug. If it was on the right bank which is the closest to the fuel tank would be interesting to know because we have a lot C4 lately that have been stored for a while having trouble with injectors that have relatively few miles on them.

If the op would provide that information maybe this cold develop into a what to expect article for future long term storage cars.

After I made my initial post I started putzing around in the garage. It looks like cylinder 8 or the last/closest plug to the cowl was bad. I did put a couple of pints of Sea Foam in the tank. I buy the cleaner by the gallons.

Sea Foam | Products

 

[SnakeDr]

Boom I like your answer. But as you have said many times the wiring on these cars is always suspect and since I did not have the information on the melted plug I felt the problem was a poor signal to the ecm. I think that the fact this car sat for 2 years and is 18 years old I would still clean all the ground points and check the ground bundle for the tps, knock sensor,etc.

Maybe you could provide the OP with the procedure to check the injectors so he can verify they are bad before buying new ones.

I just thought about the possibility that the car when it was restarted pumped a lot of crude into the fuel filter and that is why it is running lean. Something else for the op to check.
Carrying that thought a little further is it possible that it did pump the crude from the tank and it through the filter and lodged in the first injectors it came to and that is why it is lean. That would explain a bad injector and a lean cylinder. It would be interesting to know which cylinder had the bad plug. If it was on the right bank which is the closest to the fuel tank would be interesting to know because we have a lot C4 lately that have been stored for a while having trouble with injectors that have relatively few miles on them.

If the op would provide that information maybe this cold develop into a what to expect article for future long term storage cars.

s

I would like to test each injector before installing a new set. I didn't mention this Corvette has 120k on it. After doing various reading around the net not to mention the symptons its pointing a fuel injector problem.

 

[SnakeDr]

s

I would like to test each injector before installing a new set. I didn't mention this Corvette has 120k on it. After doing various reading around the net not to mention the symptons its pointing a fuel injector problem.

Ran a test on each injector

Driver side front to back (left to right)
(12.6 ohm/10.64v 12.5 ohm/10.62v) (12.4 ohm/10.83v 12.6 ohm/10.6v)

Passenger rear to back (left to right)
(10.7v/12.6 ohm 10.7v/12.6 ohm) (10.7v/12.6 ohm 10.7/12.8 ohm) Bold face is the one with worn electrode.

 

[JJS]

Congrats!

Congrats on your 1st Corvette Man - Admiral Blue is a great color.
Best of luck and welcome!

-JS

 

[LT4man]

Just because the ohm readings are within specs, does not mean the fuel injectors are working properly. Electrically they might be fine. Mechanically is another story.

If the injectors are original, chances are they are all suspect.

Jon, at Fuel Injector Connection, can give you the complete scoop.

In the meantime, you can read about my experience with Jon: http://www.corvetteactioncenter.com...injectors-work-awesome-caution-long-read.html

After replacing your fuel injectors, please be sure to SAVE the WAVE!

 

[SnakeDr]

Just because the ohm readings are within specs, does not mean the fuel injectors are working properly. Electrically they might be fine. Mechanically is another story.

If the injectors are original, chances are they are all suspect.

Jon, at Fuel Injector Connection, can give you the complete scoop.

In the meantime, you can read about my experience with Jon: http://www.corvetteactioncenter.com...injectors-work-awesome-caution-long-read.html

After replacing your fuel injectors, please be sure to SAVE the WAVE!

Ha! Thanks LT4man. I spoke to Jon yesterday. According to Jon, since all or most gasoline is blended on ethanol, the injectors should be replaced on general principle. He said something about the ethanol degrades the wiring in injectors. I had a 1969 442 and had a similar issue with a rebuilt motor. It was detonating and/or pinging due to the unleaded gas. I had to put lead additive in the tank (this was the early 1990's and in the early years of Year One) which was nasty stuff to handle. Today they replace the valve\valve seats\guides with better materials so it can handle the unleaded.

And yes I know it can spec out electronically but fail mechanically. I also discussed it running lean and Jon did recommend changing the injectors. This problem is pointing to suspect injectors.

 

[toptechx6]

This could certainly be an injector problem, but with 120K on the clock and unknown maintenance history it might be a good idea to check the fuel pressure first, could be as simple as a restricted fuel filter.

 

[SnakeDr]

This could certainly be an injector problem, but with 120K on the clock and unknown maintenance history it might be a good idea to check the fuel pressure first, could be as simple as a restricted fuel filter.

I was thinking the same thing. I will test and change it tonight and see what happens.

 

[SnakeDr]

Just because the ohm readings are within specs, does not mean the fuel injectors are working properly. Electrically they might be fine. Mechanically is another story.

If the injectors are original, chances are they are all suspect.

Jon, at Fuel Injector Connection, can give you the complete scoop.

In the meantime, you can read about my experience with Jon: http://www.corvetteactioncenter.com...injectors-work-awesome-caution-long-read.html

After replacing your fuel injectors, please be sure to SAVE the WAVE!

This was a good read. No matter what the maintenance history is the injectors appear to degrade over time. I want the car to feel like the first time I ever driven a C4 Corvette which would be 1986 or 87.

 

[SnakeDr]

I bought a set of rebuilt injectors from FIC. It should be here in a few days.

 

[SnakeDr]

Hey Boom,You forgot to leave Jon's #!~!!

Welcome to FuelInjectorConnection.com

My rebuilt injectors from FIC and A/C Delco plugs came in the mail today. Waiting for the fuel filter. It should be here tomorrow (Friday). I hope.

 

[Toms007]

Have you researched how to replace the fuel filter. There is an easy way and there is a hard way to do it. I've done it both ways, and the hard way will nearly make you want to sell the car. The easy way is the way to go.

 

[Toms007]

Un screw the bottom side. Take off the clamp that holds the lines to the frame and pull it up and out from the top. Then you can unscrew the other fitting.....then reverse to put it back in.