86 DME injector xperts!

[cgarr]

I have been chasing down a lean condition on the left side. I checked the injectors using the test method by touching pin 14 to ground on the DME, this is for 1,2 and 3 but I get all 6 injectors clicking. I checked the right side grouning pin 15 for 4,5 and 6 and all 6 still click. Should this happen? I assume only the side pin 14 controls should be firing?

Thanks

Craig

[ischmitz]

In the harness all six injectors are wired together. There are two pins on the DME to distribute the power and to reduce losses. So unless you unplug one side (at the injectors) all of them will open.

BTW, I personally don't like the method of applyiing full 12V power to the injectors. These are low-impedance and they will draw quite a bit of power. A 9V block battery will do. Else if you really think the injectors are the root cause have them professionally checked/cleaned. Or swap them over from one bank to the other to see if the lean condition moves along.

ingo

[cgarr]

I had the injectors serviced. What I was trying to figure out is when I put the engine back together maybe I had switch left side with right side injector wiring?

[E Sully]

I can't see it being a fuel supply or injector wiring problem. I would think the chances are more likely an air leak in the intake manifold , or possibly an injector not flowing properly. Pull the spark plugs and see what the tips look like. This will give you an idea of what is going on in each cylinder.
First thing I would do is check for a vacuum leak.
If you find a plug that doesn't look right, you could move the injector to the other bank and see if the lean condition follows the injector.

[cgarr]

This wiring helps a lot, Thanks! I can at least tell if they are on the correct side, don't know if it makes a difference but now I can check them. The injectors were all rebuilt/tested etc. I replaced all intake gaskets/rubber seals on the intake. Pinched off all possible vac lines/brake booster etc and nothing changed the left side running lean but only at idle. All the left side plugs are the same rather white or lean looking, right side darker brown.

[techman1]

Since it is all 3 on the left, what do they have in common? Fuel supply line for that side? Ground for that side? And last, but not least, air on that side.
How are the injectors grounded, through the DME or a ground in the engine bay?

Is there a fuel delivery test that can be done to measure injector delivery, like I have heard done on CIS?

[rusnak]

I would focus on either vacuum leaks (I know Craig said he already checked in the other thread), or injector timing, or a stuck injector.

I agree with Sully's recommendation to check the plugs. In fact, maybe install new plugs and then check them after a highway run.

[86 911 Targa]

Here is a vaccum line layout.

Verify that the vaccum line connections on the back of the throttle assy are connected the correct ports.

[E Sully]

All the grounds are on the intake manifold. The fuel pressure has to be the same throughout the system due to the design. The area circled and, where the manifold meets the head are the only areas I would think an air leak could cause the left bank to be leaner than the right. On my 3.2 the short rubber hose in the middle of the circle was cracked and needed repair when I rebuilt the engine.

[cgarr]

Ed, Thats the last area I really have to check. I did spray some carb cleaner in that area and did get a change in my AFR's but it was not a quick change, maybe it was just the spray mist making its way into the air filter intake?

The only other thing, I am running an Andial splitter for twin spark but that should not really have anything to do with it unless some plugs were not firing but I also ran the engine on just the upper and then lower plugs and it was the same for both.