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Discussion Starter #1 (Edited)
:confused: I am trying to track down issues with my 22RE fuel injection system, so I broke out the ohm meter and took some resistances from the two prongs on the injectors and the two female prongs on the connectors from the harness. Here are my findings.

Injector No / Injector Resistance / Harness Resistance
1 / 2.9 ohm / OPEN/INFINITE
2 / 3.0 ohm / 9.0 ohm
3 / 2.9 ohm / 3.0 ohm
4 / 2.8 ohm / 8.8 ohm
Cold Start / 3.9 ohm / 6.8 ohm

Okay, in addition to that I checked to see if any of these connections were connected to ground. I found that all the harness connectors were connected to ground with a restance of about 70 ohm, EXECPT for the connector for the no1 injector, which had one prong connected to ground and the other is apparently an open (not connected to ground or battery lead positive).

I did all this measuring with the engine off (of course) and the battery disconnected. I had the upper manifold removed and noticed fluid which appeared to be gasoline in the no3 and no4 intake runners.

Additionally here's what my spark plugs looked like after about 6k miles running this way:



The whiteness of the no3 and 4 plugs is very concerning. I have been told this may indicate coolant loss, but I haven't lost a drop of coolant in the last 30k miles since I rebuilt this engine.

Note, I decided to run this test because my engine was intermitantly surging at idle (once every 5 or 10 startups) and once while it was surging I bumped the no3 injector and the surging went away.

Yes the engine was running and drives fine above idle, but gets bad milage and periodically has a very rough or surging idle. This is an '86 22RE.

There is more information in this 4x4wire thread regarding recent valve adjustments and compression checks for the engine, if they help.

Can anyone enlighten me on what, if anything, these measurements can tell me? Are the two prongs on the injector harness connectors supposed to have a finite resistance normally? I thought they would be open/infinite like I found w/ the no1 connector???

Please help! :confused:
 

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the computer controls ground on two injectors at a time. these are called injectoer drivers. what you should do in order to get a correct value is disconnect computer and injectors. then measure you resistance. first each injector circuit then compare.... neg- side gose to computer and pos+ side goes though a resistor that knocks 12 volts down to 3 volts for each injector.....then to pos+ switch source. most of the time its a loose injector connector :D
 

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Discussion Starter #3 (Edited)
I wasn't onto something...

With the engine running I listened very carefully and heard what I thought sounded like a vacuum leak/flowing air. I listened carefully using a metal tube between my ear and different locations around the intake manifold, and found the noise was coming from the no4 injector.

EDIT: Okay I think crash was right. I moved my tube around to other places on the fuel rail and heard similar flow noise indicating this is just the normal sound.
 

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TheBandit said:
With the engine running I listened very carefully and hear what I thought sounded like a vacuum leak/flowing air. I listened carefully using a metal tube between my ear and different locations around the intake manifold, and found the noise was coming from the no4 injector.

So I turned the engine off, left the key in the on position, and jumpered the fuel pump test wire. I found the same leaking/flowing noise was being made with the engine off and fuel pump on, then put my metal tube from ear to the no4 injector and clear as day it sounded like it was flowing.

Next I disconnected the wiring harness from the no4 injector and repeated the test. The flowing noise still came from the no4 injector. It was clearly a flowing noise and I pinpointed it to this injector after checking around the general area with the hose.

Stuck open injector? Please confirm if you agree.

If it is, what do I do next? Does it need to be replaced or cleaned or what? I'm not sure where to get a replacement. Suggestions?
More than likely what you are hearing is the fuel flowing thru the fuel rail. If it was coming from the injector your motor would hydrolock from fuel....
 

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Discussion Starter #5 (Edited)
crash said:
More than likely what you are hearing is the fuel flowing thru the fuel rail. If it was coming from the injector your motor would hydrolock from fuel....
Thanks Crash. I went back and checked and you were right - I found the same noise all along the fuel rail. :shaking:
 

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Discussion Starter #6
Dickdog said:
the computer controls ground on two injectors at a time. these are called injectoer drivers. what you should do in order to get a correct value is disconnect computer and injectors. then measure you resistance. first each injector circuit then compare.... neg- side gose to computer and pos+ side goes though a resistor that knocks 12 volts down to 3 volts for each injector.....then to pos+ switch source. most of the time its a loose injector connector :D
So what do I check? Resistance between the injector connector on the harnes and the connector at the ECU?

The engine is idling really bad, but runs fine on the throttle. TPS is adjusted to spec and doesn't have dead spots. :confused:
 

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I would be shocked if you actually find a shorted/low/high resistance in an injector, they just never have issues with the internal coil failing. One thing that is a very good possablity is a clogged/sticky or bad spray pattern from the injector. You can have a shop do a high pressure clean on the injectors or remove them and send them to an injector specialist to be cleaned and flow checked...
 

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Check your EFI harness for a break in the factory splice on the injector wires. Just start unwrapping the wires and trace it back to where the wires for the injectors meet. From the resistance values you got, I'd say the splice came apart. It probably idles like you dropped a cylinder... start it and pull plug wires carefully one at a time, the dropped cylinder should match the one that you got an open circuit with your ohm meter in your first post.

I had the exact same symptoms on an 86 22re harness, with the same resistance values. Turned out to be what I described to you. The factory splice is crap.
 

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I had the upper manifold removed and noticed fluid which appeared to be gasoline in the no3 and no4 intake runners.
The whiteness of the no3 and 4 plugs is very concerning. I have been told this may indicate coolant loss, but I haven't lost a drop of coolant in the last 30k miles since I rebuilt this engine.
the whiteness also can indicate a lean condition. if fuel is leaking out there then air is probably leaking in. either will cause it to run lean and make the plugs that white.
replace the fuel injector seals, see if that solves the problem.
as far as the open/infinate this would indicate a broken wire/connector in the harness as described above.
 
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