VAN DOWN! Running on 3 cylinders.. injectors?

[85CargoSpace]

Hey guys, anyone know if the injectors from a 4Y engine are interchangeable to a 3Y Engine? My van recently stopped firing in cylinder 3, I have spark and compression but no go. Any Knowledge would be appreciated!! thanks

[timsrv]

Here's a quote from another thread to help determine which cylinder is giving you issue:

................. Running rough can be any number of things. How long has it been since the last tune-up? If it's overdue then do that 1st. Check your throttle body intake tube for cracks and make sure all the vacuum hoses are in good shape/hooked up. Check the injector connectors (the ones you can get to) to verify they are hooked up and the wires are secure. If it still runs rough pull a spark plug wire with the engine running to determine if that cylinder is firing. When you pull a wire the engine should stumble and run worse. If it does, then that cylinder is firing. Try that with all 4 wires (one at a time). If you find one that doesn't effect how it runs, then that cylinder isn't firing. If you find a faulty cylinder, check to make sure there's spark at that plug. You can do that by pulling the plug, grounding the metal case while it's hooked up to it's plug wire. Crank the engine and watch to see if it sparks. If it doesn't then it's likely a bad plug, plug wire, or distributor cap. If it sparks then you likely have an issue with that cylinder's injector or it's injector connector/wiring.

One other thing worth noting is compression. If you have a dead cylinder that's got fuel & spark, then there's likely a compression issue. If you know what to listen for you can hear a bad cylinder just by disabling the ignition and cranking the starter. Tim

With few exceptions, injectors are the same from 84 - 87. 88 - 89 injectors will physically fit the manifold, but the connectors (for the wires) are different. If you go to all the trouble of removing the upper intake for access, I would recommend taking them all in for cleaning & testing. Be sure to check your injector connectors as the van is hard on these (trapped heat takes a toll). It's not unusual to see a damaged wire or one pushed out of a plug.

Last time I had a problem with an injector I was lucky enough for it to be #2 (easy access). I was able to pull the connector and apply voltage directly to the injector (to verify it was drawing current.........it was). Next I rotated the engine so #2 intake valve was open & removed #2 spark plug. Next I put an inspection camera down the spark plug hole & activated my fuel pump. With fuel system active I put power to the injector and verified with my camera that there was no spray.

I'm not sure if you have the ability to test like this, but I feel a lot better pulling things apart when I know for sure it's necessary. In my case it was already a new injector (had never been fired). It was probably stuck from sitting on the shelf. I tapped on it while applying/removing power & it finally started working (thank God). Having an inspection camera isn't necessary, but it's nice being able to verify fuel spray entering the cylinder. Before I had my camera I used Engine Ears and could hear injector spray entering the cylinder. Anyhow, in my case, after that injector started firing my van has been running awesome & hasn't missed a beat since (I've put 3k miles on it now). Tim

PS: You can also test injectors 3 & 4 like this, but it requires you to gain access (electrically) by opening the wire harness.

[ninz30]

Tim what is the voltage that needs to be applied to activate a fuel injector?

[djshimon]

I used 9 volts to clean my injectors. Short spurts.
I heard(internet) that you shouldn't use 12v.

[timsrv]

I've always used 12vdc, but only in short spurts (like 2 or 3 seconds). It wouldn't surprise me to find out you're not supposed to do that, but I do a lot of things I'm not supposed to . Tim

[ninz30]

If you look over the schematic there is a set of resistors before the injectors... So I would assume 12vdc isn't the right amount... But I'm still not sure what is, and in short burst they can't do much harm.

[timsrv]

In my case, perhaps it was the shock of 12VDC that jolted my lazy injector back into action .

[ninz30]

In my case, perhaps it was the shock of 12VDC that jolted my lazy injector back into action .

Lol .... Perhaps