I started my 94 C4 on a very cold day and it ran for a few seconds and then died. I was unable to start it again. I put a pressure gauge on fuel line and it showed 45psi. I then thought it could have been the coil/ICM. I was ready to look in this dirrection but thought I should spray starting fluid first and the car started then died. So I then checked each of the fuel injector connections for power and all had power.

I was just informed the computer controls the injectors via the ground, so I have purchased a test kit and will test the connections once again.
If this is not the problem all I can try next is the fuel pressure regulator.

Please let me know if anyone has any other thoughts.

Thanks!

 

The computer is controlling the injectors, so I replaced the fuel pressure regulator and she still will not start.
Not sure what else it could be?
Could it be the security system possibly the chip on the key is bad?
If anyone has any advice I would appreciate it!

 

You need to get a factory service manual and pull codes. What is the status of the security light when trying to crank..on,off, flashing etc? Do you have a working key fob? Do you unlock it by the door key? Have you checked fuel pressure.........

 

I agree with Corvette95. you should get a FSM and pull any codes. You can get a code reader from any auto parts store or use a paper clip in the computer port under the drivers side dash. (Search forum for details). I don't think the car will even turn over if it's the Vats(security system). Just turn key to on (don't start), does your fuel pressure hold at 45 psi for a while. If not you could have leaking injectors or bad fuel pump. Have a helper spray into the engine and start it and monitor what the fuel pressure does until it dies. Pull a couple spark plugs and see if there fouled or wet with gas. If it's wet then you have a leaking injector in that cylinder. If wet also check for gas in your oil. With a plug out check for a good strong spark. You could get a scanner to read whats going on inside your engine. Make sure your battery is good and fully charged. Report back any more info. There's a lot of good help on this forum.

 

Thanks for all your comments!

FYI - I was told if one injector is bad the vette will shut down the entire bank. I will ohm test the injectors soon. I believe all of the testing I have done leaves me with only two remaining possibilities...
1) A bad injector (I need to check on what is the correct ohm reading).
2) A bad computer.

I am leaning towards the injector as the computer has control of the injectors.
To Be Continued....

 

I had issues with starting 1988 Corvette. The car would crank but start randomly - mostly not at all. So I checked the codes and pulled 46 which is a VATS problem. Took the car to a Corvette specialist and he replaced both the key and barrel and the VATS module. The VATS would allow the starter to crank but not activate the injectors. I think the first port of call would be to check the codes - very easy and you can find out what they are from Google if you haven't access to a FSM. Good luck!

 

Hello All,
I checked each injector and all provided a reading of 12.2 ohms.
I also checked the codes and received the following:
Bank#1: C12
Bank#4: - - -
Bank#9: - - -
I also tested my battery it showed 11.99 volts.
From what I was told, it could be the computer.
Does anyone have any other thoughts?
As always I appreciate everyone taking the time to assist me!

 

What is your fuel pressure without engine in run, what is it in run, what is it when trying to start? What are your codes?

 

Hello corvette95
The car does not start however, the fuel presser is about 43-45 after I crank the engine.

FYI - when I changed the fuel regulator there was plenty of gas in the fuel rail.
I checked each injector and all provided a reading of 12.2 ohms.
I also checked the codes and received the following:
Bank#1: C12
Bank#4: - - -
Bank#9: - - -
The car will start if I spray starter fluid, but will dye when I stop spraying the starter fluid.
I also tested my battery it showed 11.99 volts.
From what I was told, it could be the computer.
Does anyone have any other thoughts?

Thank you for your time!

 

There is some info lacking. What does the fuel pressure read after a few minutes of not trying to start...you say 43-45 after crank...wait 5 minutes and what does it read. You say you put a new fuel pressure regulator on it, I understand your thinking but taking a logical approach instead of putting parts on it will save money in the long run. You say codes in terms of bank.......I understand the term "bank" such as in fuel, but there are different modules on the car that have codes, we need not only the PCM codes as well as CCM and or any other codes. These can be pulled manually with a paperclip...search the sticky threads for pulling codes with paperclip or pulling codes manually. I highly doubt it is your computer, that is a "go to" for I don't know what's wrong with it. Let's start with the cars history, when did you get it, hoe many miles on it, when (for certain) did it run correctly last? I suspect but not recommending you replace these yet without the prior information.....pending fuel pressure results as I asked...old fuel in tank- wouldn't run in a brand new engine- thats why I asked how long since it ran correctly FOR SURE the last time, clogged fuel filter- probably needs one but doubt that is your problem, have you pulled a plug and watched the spark (old school) with the plug up against a metal ground? If not, check that, and check the rest of codes.....I asked before about the security light...when you get in is the light flashing, staying on constant while cranking or what? Try locking the car and waiting 15 minutes then unlocking car with door lock key and report back with security light status, could be key pellet issue or vats--has this been worked on before? This is also unlikely, next pending other test, ignition control module, this is about $80, pending that and the codes, opti-spark. Everyone on here wants to help, but there is a procedure to follow, we don't want to have you throwing parts at guessing. You can also take a video of the dash and security light while cranking so we can see and hear what is happening. It could also be a fuel pump that will build pressure but won't maintain. Then there is always the basic like air...where are you spraying the starter fluid? Your air flow sensor needs to be connected and working.

 

Here is everything that was checked...I started my 94 C4 on a very cold day and it ran for a few seconds and then died. I was unable to start it again.

1) I put a pressure gauge on fuel rail and it showed 45psi.

2) I then thought it could be the coil or the ICM, so I put an inline tester on the coil and a few spark plugs and they all had spark.

3) I tried starting fluid and the car started then died.

4) I then checked each of the fuel injector connections for power and all had power.

5) I was informed the computer controls the injectors via the ground, so I purchased a test kit and tested the connections once again and found the computer is controlling the injectors (the light blinks when trying to start the engine).

6) I then replaced the fuel pressure regulator and she still will not start.

7) I was then told if one injector is bad the vette will shut down the entire bank to protect the engine, so I performed an ohm test on all of the injectors and the reading was 12.2 for each. I am not sure what the proper reading should be for the injectors, but have heard if it you get less than 10 ohms the injector is bad.

8) I also checked the codes and received the following:

Bank#1: C12 (On-board diagnostics no codes)

Bank#4: - - -

Bank#9: - - -

9) I also tested my battery it showed 11.99 volts. Just be see if it is the battery, I have charged it and used the charger in assist start mode and she still will not start.

10) I then thought if it could be the VAT system/security system. However, everything I have read states the engine would not crank if this was the problem and she does crank, so I have eliminated this possibility.

I was told by another vette owner that it could be the computer. However, the computer appears to have control of the injectors when I tested each of them.

I am not sure what else it could be?

 

With fuel pressure gauge on the rail , it reads 45, them the cars tries to start...so after you stop trying to crank it, how long does the fuel pressure hold and what pressure for how long? I don’t think it is the ecm or a single injector . Have you tried pulling code manually with counting of the check engine light flashes? When was the last time it ran well... that information is needed.

 

Hello corvette95,

I will need to get back to you regarding how long the pressure holds after trying to start the car as I have not timed it. I assume 30 minutes would be enough of a test?
With regards to pulling the codes manually, I will need to try that and get back to you as well (how do I perform this?).
The car has always run well until this issue.
I have a 94 6 speed base model.

Thanks!

 

http://forums.corvetteforum.com/show...read+obd+codes

 

Does it crank? Is the security light on? You have fuel in the rail, so either the injectors aren't firing due to vats, or you don't have spark. Check a spark plug for spark, then you'll know which way to go.

 

Hello All,
I finally figured out what was wrong with the car.
I have water in my gas tank. I assume it got into the tank after a heavy rain. The gas cap was loose and the drain was clogged. I believe there was a water buildup which found its way into the gas take.

So far I have pumped all of the fuel out of the tank and let the cap off to possibly allow what is left to evaporate.

Does anyone have any suggestions as to how I should continue and what kind of damage I may have with regards to the fuel system due to the water?

Thanks!

 

That’s why I was asking about it sitting and how long since it ran right. Pull the fuel pump and sender, pump the tank empty , dry up all remaining moisture and fluid from tank (diapers work well for this) if your pump and sending unit is rusted , let it sit in Evaporust overnight. Replace fuel pump if needed (likely ok) replace fuel filter, replace pump and sender (maybe gasket) put fuel in tank, cycle ignition on and off, recommend purging fuel lines at shrader valve....go from there . That’s your start.

 

Oh my, have I got a "water in the gas tank" story! But short answer, the engine fired up and ran for maybe 10 sec and then died. Wouldn't restart. The fuel pump fuse had blown. That's a 10A fuse and the nominal current draw is around 6-7A with the engine running - but more about that later.
My '96 LT4 was sitting outside, under trees (such DIRTY trees!), uncovered for over one year. The fuel hatch compartment was full of tree stuff and the drain couldn't let the water out. Sound familiar? Over months of rain and temperature and atmospheric pressure changes the gas tank sucked in over TWO GALLONS of water! I have photos to prove it. The fuel pump was not too happy pumping that water and probably partially seized in the process blowing the fuse.

I ended up siphoning all the residual water out of the bottom of the tank along with around 15 gal of old gas and into multiple buckets and clear containers. Adding some denatured alcohol to the gas forced the water to separate out much easier than I thought and also allowed me to return ethanol-free (but old) gas back into the tank. My siphon consisted of several sections of tubing, the first was a plastic plumbing pipe used to connect sink faucets to the water supply shutoff valve. This was an important tube because it was straight and easy to place exactly where I wanted it to be on the tank floor. Flexible hose isn't easy to control and difficult to make sure it's touching the areas you want. Connected to that pipe was maybe 5 feet of 3/8" black, rubber fuel line. To start the siphon I connected a Harbor Freight siphon pump then pulled it out of the way when the fuel started flowing. Yeah, this is a pretty dangerous operation so I don't recommend it unless you can watch all your operations carefully and keep a gasoline-rated fire extinguisher at hand.

Done, and after adding the clean gas back in the tank, I immediately fired up the engine and let it run for a while to help purge any last traces of water from the fuel injectors and fuel rail. Rust forms very quickly in a fuel injection system and I wasn't going to let even one day go by knowing what was possibly still in the lines. Eventually I replaced the fuel pump, finger strainer and main fuel filter. Don't wait long to replace those parts. There's a towing bill just waiting to happen if you leave the old parts there.

Good luck!

 

Just went through same problem with my 1988 c4, replaced long list of items. Found out by tearing dash apart, the VATS system had a loose prong. Replaced prong and zip tied connector. It is working great now! Good luck!