Three out of Eight not good - Understanding results of Injector Test - 94Q

[daegrigg]

My 94Q (72K miles) still has a rough idles after the usual remedies: MAF, Throttle, chemicals. Overall performance is down some but car always starts and has more pep at higher rpm.

Did an injector resistance test using the procedure Wes posted on q45.org (thanks Wes).

Here are the results:

1 (11.9 ohms) 7 (11.8 ohms) 6 (19.2 ohms) 4 (11.9 ohms)

8 (18.0 ohms) 3 (48.8 ohms!) 5 (11.8 ohms) 2(12.0 ohms)

"Normal range" is 10-14 ohms.

6,8 and 3 are out of spec. What does this mean? And is it enough to cause the idle/performance issues I have? Is it conclusive enough to go ahead and replace the injectors?

(Also read that some of the injectors can be replaced without removing the plenum. True? and which ones.

Thanks for your help.

Don

[911/Q45]

1 bad injector will make for a lumpy idle and your worst one requires the plenum be removed. You can try just replacing that one, but the only way to be sure that you won't be in there again is to replace all of them and the hoses, knock sensors and electrical harness that are under there. Injectors 1, 2, 7 and maybe 8 are the ones that can be gotten to without removing the plenum.

[elwesso]

The ones on the passenger side can be gotten to easier because you can easily lift up the plenum (after its unbolted) on the passenger side. Theres only a couple hoses to disconnect and all 4 injectors on that side can be got at. I would surmise that the no 3 and 5 would be the hardest to get at.

For the ones that are kind of iffy like the 18 and 19 ohm ones Id say theyre probably still functioning but could be on their way out. Id just replace one and then keep an eye out (say check them weekly) to monitor any changes. Remember having any acessories on in the car will invalidate your results..

Maybe they have jusdt a little bit of corrosion or something that could cause that extra resistance?