Help! 1982 Fuel System Problem

[MYurchis]

I have a 1982 corvette crossfire injection. ran fine, but has been sitting in a garage for nearly a year. Now the car wont start. If I spray starting fluid into the throttle bodies the car runs until fluid burns off. I have a installed a brand new fuel pump, checked for voltage at the fuel pump (read 12 volts), and replaced the in line fuel filter. If I remove the fuel return line from 2nd carburator on the left side of the engine compartment and crank the engine I see fuel exiting the carburator. Where do I go from here?

 

[wishuwerehere82]

I have a 1982 corvette crossfire injection. ran fine, but has been sitting in a garage for nearly a year. Now the car wont start. If I spray starting fluid into the throttle bodies the car runs until fluid burns off. I have a installed a brand new fuel pump, checked for voltage at the fuel pump (read 12 volts), and replaced the in line fuel filter. If I remove the fuel return line from 2nd carburator on the left side of the engine compartment and crank the engine I see fuel exiting the carburator. Where do I go from here?

I'll give it a try.
1st, when you turn on the key and the fuel pump comes up to pressure, you will hear the pump run for 2-3 seconds, and then a click as the pump comes up to pressure and the relay clicks off. And you will get 2 squirts of fuel out the injectors on both throttle bodies. If not, check your injector fuses on the fuse box.

2nd, if you do get the initial squirts and several as you are cranking the engine, but none after it kicks over, then check your oil pressure switch next to the distributor for loose contacts. That has to be working to keep the fuel pump relay engaged.

3rd, put a guage on the fuel line to the front throttle body (you're going to need to make up some in-line fittings for the guage) and see if your fuel pressure is 12.5 PSI. If not, your fuel pressure regulator in the rear (2nd) throttle body might be stuck open and not allowing the system to pressurise.

4th,The ECM will only fire the injectors as long as it is getting a tach feedback signal from the distributor. Check the wire harness connectors to the distributor to make sure they are clean and making good contact. Especially the white wire that goes to the connection marked "TACH".

 

[MYurchis]

Hi Pete

Thanks for your quick reply! Before seeing this I had already replaced more parts and have made no progress at fixing the problem. So let me state that I never get the 2 squirts out of the either of the injectors into the throttle when starting the car.

Todate, I have replaced the fuel filter, fuel pump/screen, fuel pump relay and ECM. I have checked the 3 amp fuses for each injector, the fuel pump fuse, the ECM fuse and they are all good. I had removed the return fuel line and see fuel coming out of the manifold when I crank the engine. So at this point I am running oput of options. Is there a way a good way to check the fuel pressure regulator? Is that difficult to replace. Do you have better suggestions for next steps?

Thank you,

Monty

 

[wishuwerehere82]

The easiest way to check to see if your fuel pump is coming up to pressure is to listen to it when you turn the key on. It will run for a few seconds and then turn off. If it keeps running, then it's a good bet that your pressure regulator is letting fuel fow through and the pressure in the system is not high enough to spray out the injectors when they fire. Dribble is more like it.

Find out if the pump shuts off before you start tearing into the regulator.

The pressure regulator is the little metal cylinder that is mounted to the underside of the top plate of the injector assembly.
If you look at the fender side top part of the throttle body, you will notice a rectangular hole in the casting between the injector and the rear part of the regulator casting.
If you look in that hole with a flashlight, you will see a little tab extending out with a spring holding it down.
That is the moving part of the regulator. You can insert a small flat blade screwdriver into the hole and lift up on the tab and let it snap back down to reseat the regulator. it might work! If the regulator is the problem.

As far as replacing the regulator, I have never done it.
But it is located on the top half of the drivers side throttle body. You will have to take top plate off the throttle body. You will need a new gasket set, and M10 & M15 torx drivers if you take it apart! There is a round cylinder that houses the regulator. It has a pressed-in cap that must be drilled and pried out to get to the adjusting screw. Like many pressure regulators there is a center part that threads inside against a spring that controls a diaphragm-type pressure regulator. Screwing it in increases the pressure, and loosening it reduces the pressure.

But seriously, check the easy stuff first.

 

[MYurchis]

Hi Pete,

I don't know what to say but I had the car in the far left garage of a three car garage and had to move it. So I had 4 men, and I, push it out this garage to move it to the far right side garage. After pushing the car into the far right side garage I asked for my friend to listen for the fuel pump and to our amazement the car started right up. Go figure! So now after all I have done it who will know what the problem was.

Thanks for your help!!!

Monty

 

[Shaggyvette]

Monty, you may want to check the fuel tank for debris. Sounds like you may have some junk floating around in your tank or something might have been blocking the intake at the fuel pump.

Just my .02 cents....

Dave

 

[wishuwerehere82]

Is that side of the garage built on an old native American burial ground, or something?otfl

 

[MYurchis]

Pete and Dave,

Thanks for your help. I don't know about that side of the garage being spooked by bad spirits but I do know that it was probably not due to debris affecting then intake of the fuel pump since the fuel pump has that large screen banana shaped screened filter to protect it.

Now, the saga isn’t over. I still do have problems starting the car; it starts briefly and then stalls. Again, it seems that it is starving for gas. When it eventually does start the engine runs rough and wants to stall even though I am pumping on the gas pedal to keep it going and the revs high. After going through this 3 or 4 times, the car eventually starts and runs great for the most part. I say for the most part because the engine has stalled when running after letting it idle for a long period (10m minutes or so). Prior to this instance where the engine stalled when driving, the engine displayed a solid Check Light, after the long idle, with an associated Code 44.

I am thinking problem is due to some mechanical sensor that is getting stuck because the car does run for long periods of time just great and even occasionally starts just fine.

PS, when I see fuel drip along with the spray into the throttle body of both TBIs when from look at the fuel being sprayed into the throttle body during an idle.
By the way I have just filled the tank with 18 gallons of fresh gas.

 

[wishuwerehere82]

You might still want to try lifting up on the pressure regulator tab with the engine running. The engine will stall, since the fuel pressure will drop to zero when you do it. But there might be some debris stuck in the regulator that will flush through back to the tank through the return line. Once the debris is cleared from the regulator, it should run at a consistant pressure rate.

The previous code 44 is a lean exhaust condition that would be consistant with the regulator sticking open, or the fuel pump putting out low pressure due to pump failure or the filter clogging. Or your IAC motors could be sticking, which would result in a lean condition too, but only at idle.

The other thing I might suggest is to clean up the contacts on the oil pressure switch that has a brass angle fitting coming off the top of the block, next to the distributor on the driver's side.
The oil pressure switch keeps the fuel pump running after the engine has started. A loose connection there will cause the fuel pump to randomly stop running. If the sensor thinks there is a loss of oil pressure, it will kill the fuel pump to keep the engine from being damaged.
I had a problem with the pressure switch wiring hitting the firewall and pulling the connector loose from the switch after driving it a while. Mostly caused by me after I rebuilt the engine, and had the sensor re-installed at a bad angle that allowed the wire harness to vibrate against the firewall. Once I rotated it back away from the firewall, the problem stopped happening.

The last thing to check is the CTS (coolant temperature sensor) at the front of the intake manifold under the air pump. It has two wires on the connector that have been notorius for breaking. This sensor tells the ECM what temperature the coolant is and the ECM adjusts the mixture accordingly, with other parameters supplied by the O2 sensor, TPS sensor, MAP sensor, Etc.. If the wires are broken or intermittant, or if the sensor is bad, it will throw off the ECM calculations in a major way. The most common symptom is idle surging or stalling at cold start.

 

[MYurchis]

Folks, I may have steered you wrong. It seems that the car starts just fine when the engine is cold. I started it this morning and drove it around nonstop for nearly 2 hours of 120 miles plus of highway and street diving without an issue (8 gallons of gas). It ran great, like a top.

The problem seems to be starting the car when the engine is still warm; it starts briefly and then stalls. It won't maintain an idle. After trying to start the car 3 or 4 times, the car eventually starts but the engine idles rough (surges) and wants to stall. I goose the gas pedal to keep it going and within a few minutes I can eventually the get the idle to stabilize about 1,500 to 2,000 rpm. I can then let off the gas pedal and the idle takes a minute to stabilize at 800 rpm. From then on the car ran fine and held it’s idle.

I am curious about your comments regarding the coolant temperature sensor and was also if the choke might be suspect.

 

[Shaggyvette]

I am curious about your comments regarding the coolant temperature sensor and was also if the choke might be suspect.

My $$ is on the CTS, only because my car did the same thing until I changed it..

ps there is no choke on a throtle body injection engine..

Dave

 

[wishuwerehere82]

CTS Thats what it does when it quits working right.

 

[Shaggyvette]

Right!

 

[MYurchis]

Ok guys, I think you are both right on. Now I found where I believe the sensor to be located which is in a fairly accessible location on the intake manifold top front of the engine block. When looking to order the part, I find that there is, what appear, to be two different configurations of then Coolant Temperature Sensor. The difference between the sensors seems to be the electrical connector on the head of the sensor. In the “AutopartsGiant.com” online parts manual one of the sensors is named “Cool Temperature Guage Sensor”. This sensor has the same electrical connector as the one that I find on my car whereas there is another sensor listed as an Engine Coolant Temperature Sensor which has a different connector. In your experience, do you believe that these are the same just with different electrical connections or do you think they perform two different purposes and that I didn’t look in the right place to find the sensor that I really need to replace. Please note that my car is the collector’s edition and does have a temperature guage.

 

[Shaggyvette]

Let's make this real simple, look at the front of your engine, up by the upper radiator hose where it goes to the goose neck (into the engine) there is a brass colored sensor with two wires coming out of it ( one black and one yellow). Go to your local NAPA, Autozone,Advance Auto Parts, or wherever you buy parts and purchase a new one. The cost is less than $20 and real easy to install. Good luck and let us know how you made out.

Dave

 

[MYurchis]

Hi Guys,

There is no way I can express my THANKS for all your advice! I did replace the CTS and I car does start more consistently now. I still do sometimes experience an idle that oscillates from a near stall to a surge and the car bucks, at first when driving, after starting the a warm engine. The idle and the car does finally settle and runs fine thereafter after a few minutes of driving.

Here is something interesting, I had to replace the intake manifold CTS for my 1982 corvette with an engine block CTS from a 1984 corvette because that was the part that was installed in my car. My car has wiring with an electrical connector that matches the connector on the head of the engine block CTS for the latter model corvettes. This is why I asked so many questions regarding the CTS. I ordered three of them and three all were different than what I had installed (The electrical connector on the ead of the CTS was different).

I found the right part after visiting the local GM dealership parts department. When I showed the parts man my old part he said that that was the engine block CTS and not the intake manifold CTS. There were two of them on later model corvettes, one in the engine block and the other on the intake manifold. I don’t know what difference it makes to have a 1984 engine block CTS installed versus the 1982 intake manifold CTS. Someone must have spliced new wiring with the new electrical connector into my wiring harness at some point to allow for this 1984 engine CTS installation. I gather that the CTS in a dynamically variable resistor whose impedance changes with the temperature of the coolant and that they all must be around the same specifications. Do you have any thoughts on this or know more about the differences between these CTSs?

 

[jdp6000]

Hi Guys,

There is no way I can express my THANKS for all your advice! I did replace the CTS and I car does start more consistently now. I still do sometimes experience an idle that oscillates from a near stall to a surge and the car bucks, at first when driving, after starting the a warm engine. The idle and the car does finally settle and runs fine thereafter after a few minutes of driving.

Here is something interesting, I had to replace the intake manifold CTS for my 1982 corvette with an engine block CTS from a 1984 corvette because that was the part that was installed in my car. My car has wiring with an electrical connector that matches the connector on the head of the engine block CTS for the latter model corvettes. This is why I asked so many questions regarding the CTS. I ordered three of them and three all were different than what I had installed (The electrical connector on the ead of the CTS was different).

I found the right part after visiting the local GM dealership parts department. When I showed the parts man my old part he said that that was the engine block CTS and not the intake manifold CTS. There were two of them on later model corvettes, one in the engine block and the other on the intake manifold. I don’t know what difference it makes to have a 1984 engine block CTS installed versus the 1982 intake manifold CTS. Someone must have spliced new wiring with the new electrical connector into my wiring harness at some point to allow for this 1984 engine CTS installation. I gather that the CTS in a dynamically variable resistor whose impedance changes with the temperature of the coolant and that they all must be around the same specifications. Do you have any thoughts on this or know more about the differences between these CTSs?

The replacement CTS is different from the original. It comes with a new connector. They don't make the original design anymore.

Jim

 

[MYurchis]

I ordered three 1982 Intake Manifold Coolant Temperature Sensors from three different vendors and they all came looking alike with a white plastic round connector with a pin in the center. It kinda looks like a coax connector. Whereas the connector that is needed for my car is oval with a rectaglar plug in the center that has holes for two pins.

The only sensor that I found for my connector is for an engine block Coolant Temperature Sensor. I can't find a vendor with the intake manifold Coolant Temperature Sensor that has my connector. I am tired of having them shipped to me for me only to have to return. Actually, the GM parts man showed me an Intake Manifold Sensor for later model corvette and it had the same connector as those three that were shipped that I had to return. The GM parts man then showed me the engine block Coolant Temperature Sensor for a later model corvette and it had the connector that I needed.

Geez, such as easy simple part but whatever happened here on my car is confusing.

 

[jdp6000]

It sounds like you have the new style with the new style connector. I was never able to find that one that looks like a coax cable connection (its what i originall had). I had to cut the wires and splice in the new connector. I also bought mine from a GM dealer.

If it works I wouldn't worry about it.

The sensor you are talking about is located in the front of the intake below the thermostat housing. The way it works is that sensor takes a reading of the coolant temp. Once the stat opens cooalnt rushes through and it takes a reading which it sends to the ECM.

Jim

 

[MYurchis]

:L How should I get so lucky that I should only find the old style CTS with the connector that looks like a coax connector at three different vendors and not find the new style referenced.