hi good afternoon, i need to test the injectors, does anyone have a way? As the car has not been used for eight years it seems that they are clogged because I start it and it does not inject gasoline, the spark plugs come out dry so I do not know if the injectors are clogged or do not give them energy. Or could it be the ECM? the fuses are ok

 

plenty of videos out there. try youtube. I've done some (basic) cleaning and testing of various injectors, cant say for sure if things were spot on or not, but never any significant issues. on my 85, vast improvement by swapping out the original bosch injectors with a set of "threes" from FIC. really not worth the effort for a DIY on originals when a matched, upgrade set won't set you back much money. IMO, FIC is the only way to go, and 99 out of 100 folks here probably agree. (my 2-cents FWIW)


BTW, 5X repeat FIC customer. two thumbs up Jon!

 

do you have the link to purchase?

 

Verify that there is ample fuel pressure at the Schrader valve both at key On and holds during cranking, and that the ECM is firing the injectors.

 

the fuel pressure is 40 +/-? and how do I check if the ecm fires them?

 

https://fuelinjectorconnection.com/c...uilt-injectors

 

I don't think you are ready to start throwing expensive parts at the Corvette yet. It is highly unlikely that your ECM is causing the issues at hand. Please don't start throwing new parts at the Corvette or it will get really expensive.
The reasons for the injectors not firing and the your spark plugs are dry has more to do with fuel pressure than injectors operating. If there is no fuel being sent in the injectors will not be able to work. Be careful with your power going to your injectors as they have 12 volts sent to them when the engine is in the "Run" position. The injectors only inject gasoline when the ECM sends a ground signal to the injector, it sends a ground signal which completes the circuit and the injector injects. Some people really freak out when they find 12 volts at the injectors all the time.

You that HAVE to verify your fuel system is pressurizing and supplying fuel and the only way I know of doing that is to put a Fuel pressure Gauge on the schrader valve on the fuel rail near the rear end of the passengers side fuel rail.

I had a fuel supply line rust shut internally due to the ethanol in the gasoline today and that would not allow the engine to run due to insufficient fuel VOLUME.

Do you hear the fuel system pressurize when the key is moved to the run position? It should last only a couple seconds and sounds like a hum. This should happen every time the Corvette is started up.

Another issue I experienced was when the car sat for a while the voltage of the accessories dropped almost 2 volts inside the Corvette. I measured the battery voltage and then I measured the voltage at the fuse panel and they were different by almost 2 volts. I removed the connectors on the post and cleaned each of the seven ring terminals that connect to the battery positive at this post. This is where the fusible links get their power from. The fusible links are the last line of defense of your Corvettes Electrical system. This voltage drop kept my fuel pump from running at all. After removing the cover over the gas tank filler I was able to supply a solid 12 volts to the fuel pump and it worked just fine.

Fuel injectors after sitting with oxygenated gasoline will corrode shut as well. You will likely have to replace the injectors but that is not the first thing I would do. FIC does have a good reputation as does South Bay Injector who has great prices and awesome service who is closer to home for me. I would check around but buying injectors on Ebay might be more dangerous move and I suggest you not do that. The best way to "Check your injectors" is to remove them and send them to a shop who can test them and then rebuild them if needed. FIC and South bay will both offer these services testing the injectors.

You need to get a set of the Factory Service Manuals and do your troubleshooting the way GM intended you to. Another item you will have to replace is the Oxygen sensor as they are only good for 24 months of service or 50k miles.

Try and get hold of some NOID lights to verify that your injectors are getting a signal. You will also want to check your Fuel Pressure Regulator as this item is exposed to gasoline and the ethanol destroys it. It is very common to have to replace the FPR Diaphragm. It is under the intake plenum and is a bit challenging to work on. Your throttle body might need some cleaning but be careful not to use strong cleaners that might remove the coating applied at the factory. The Throttle Position sensor and the Idle Air Control will need to be replaced or adjusted to get the engine to runs smoothly.

After 8 years it is likely your Corvette will need new brake fluid as well. The brake fluid absorbs moisture and will rust shut internally. I have had a line blow out due to rust on the steel. Not fun to replace the brake fluid lines on the C4's. Be sure to drain out the old gasoline before you try to run the Corvette. Nothing worse than pressurizing the system with gunk from bad gas.

I guess my point here is to stop and take a breath before buying parts needlessly. Start at the battery and work your way through each issue you have. If you start at the ECM it will be expensive so try looking at your problem from the simple things. The troubleshooting guides in the FSM are the very best to help solve your problems.

Don't worry about getting in over your head, there is a lot of 1985 Corvette experience on this Forum!

 

THIS will check for injector pulse. Disconnect an injector and stick it into the plug and crank. If it lights up, you have pulse. Get a fuel pressure gauge. When you turn the key to "run" for the first time in a while, it will prime the system. The pressure should hold for a while. If it doesn't, you have issues that need to be resolved.

 

I check the injectors and I have these measurements,
1 16.8
2 16.5
3 16.6
4 16.6
5 16.4
6 16.4
7 16.2
8 16.6
but the wire going to the injectors shows 6.0 ohms, I turn it on and it continues at 6.0 ohms, the fuse is ok, is it the ECM?

 

Don't care. I don't use the ohm test for much. It's cheap and easy and could be misleading. I can cut the bottom off the injectors and they will still ohm good. Your basket filter can be clogged and it will still ohm good. All that does it check the coil which is half of the equation. If it tests good, you might just cross the injectors off the list and that might not be good. First of all, what do you have for injectors?

 

I have Bosch, Today I tried to give it 12v with the battery and you feel the noise inside, I think they work, the connector of the injectors gets 6.0 volts while the ECM gets 11.59 and with the key in ignition they get 11.29

 

These injectors pass your ohm test and your feel test. If you suspect injectors, you need to send it for bench testing to be sure that the spray pattern and volume is right. If your basket filter is clogged, everything will be right according to the "tests" you used.

You asked if there was a way to test it. You got the way now. THIS is the site. From what I can see, there is a test, which involves a bench and there is a guess which involves what you mentioned doing.

 

I have those 11 cables cut, is that why it did not start? I have to put them together and test.

 

Is this chip the original?

 

IDK. The ECM is reman since the label says so. The EPROM, makes me think it is aftermarket or has been molested somehow. Others will chime in,.