Well, I don't know if there was a recall or not, there are Technical Service Bulletins on using the correct solvents for cleaning the poppets and a revised injector balance test procedure. But they wouldn't honor any recalls from 1996. With a capable scan tool, you can do a fuel injector balance test which is what we do now for any suspected injector issues, it consists of monitoring the fuel pressure while pulsing each injector a certain amount of time, one at a time. And if there is a fuel injector that drops more or less fuel pressure than the others then you know that injector has a flow rate issue. This being a 1996, that was the first year for OBD2 switch over. I have seen the injector balance test done on these with one of the Launch scan tools I believe it was. I can check on that for you.
Below is a picture of the injection system you have now, you can see there are no solenoids at the end of the tubes like on the updated unit. This has just the poppets at the end of each tube which opens when the correct fuel pressure is reached. The solenoids are all in the upper electrical unit.
You can remove the entire unit and try to clean out each of the poppet nozzles. But as for testing, you can swap the number 2 spark plug and wire to a different cylinder and see if the code follows. If it doesn't, you can do a compression test on that cylinder or a leak down test and see if the cylinder is sealing well. Besides that, it comes down to fuel injection to that cylinder. I will dig up some info on pulling out the fuel metering unit if you want to try to clean it. For the updated unit, you can google it, it will come right up. Just put in 1996 gm updated spider injection unit. I see some from about 160 to 400 dollars. The OEM from GM would be the best, depending on how long you are planning on keeping the truck. But I will post some more info on cleaning the unit you have now shortly.
Diagrams 2,3 are for relieving the fuel pressure by pulling the Fuel pump relay and cranking the truck over, it will run for a second and then stall out. Now the fuel metering unit is under the upper intake manifold. I have never attempted to clean these units out, so I'm not sure how difficult it will be. There are probably videos on doing it but try the other testing first with swapping some ignition components to other cylinders and see if the code follows, if you do a compression test, do one cranking and then one running and compare it to another cylinder. If you have a scan tool that can read live data, you can look at the Long and Short Term Fuel trims to see if the ECM is taking away or adding fuel due to an issue. If you have an injector that is not flowing well, you will have positive fuel trim numbers, and the opposite if an injector is flowing too much fuel.
I will try to see what scan tool it was that can do a fuel injector balance test on these.
Here is a great video on the whole spider injection system, he also installs the updated unit and shows the injector balance test:
https://www.youtube.com/watch?v=ExdDt0RnCH8
https://www.2carpros.com/articles/how-to-test-engine-compression
https://www.2carpros.com/articles/how-to-test-a-fuel-injector
https://www.2carpros.com/articles/how-to-check-for-ignition-spark
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Thursday, June 15th, 2023 AT 10:55 AM