loose Distributor CAP = Perfect idle

[Zed Head]

The light test is one way to see if the electrical connection is working.  Many ways.  Screwdriver on ear and injector, stethoscope, colortune, ...

[ira]

43 minutes ago, Zed Head said:

The light test is one way to see if the electrical connection is working.  Many ways.  Screwdriver on ear and injector, stethoscope, colortune, ...

stethoscope is what i used to figure out injector #6.  then i did the harness swap to rule out the connectors/harness.  injector 5 remained working.  inject 6 remained not working.  

i cant imagine the new injector is DOA.

[Dave WM]

if its 16 ohms it may just be the high impedance coil on the injector, not designed to use the dropping resistor. The main problem I have is how that is fixed by the propped up cap, that observation points to a ign issue. IF you hear it clacking away that would tend to mean the coil is sufficiently energized, but that does not mean its flowing fuel. If its flowing fuel you should be able to see a wet plug. I really wish the lifting of the cap did not fix it, that really throws a metaphorical wrench in the works.

[dutchzcarguy]

11 hours ago, ira said:

i cant imagine the new injector is DOA.

It would not be the first time..   check,check double check..

As sayd.. do a compressiontest. Also i would look for a airleak.. that can do strange things to a engine.

Did you know that these injectors  all 6.. fire at the same time each time? Long ago i thought they fire just before the intake opens but that seems not the case..  I hope i'm right if not please chip in!!

Edited November 4, 2020 by dutchzcarguy

[ira]

10 hours ago, Dave WM said:

if its 16 ohms it may just be the high impedance coil on the injector, not designed to use the dropping resistor. The main problem I have is how that is fixed by the propped up cap, that observation points to a ign issue. IF you hear it clacking away that would tend to mean the coil is sufficiently energized, but that does not mean its flowing fuel. If its flowing fuel you should be able to see a wet plug. I really wish the lifting of the cap did not fix it, that really throws a metaphorical wrench in the works.

Yeah, and what makes it more strange is that i checked for spark plugs Spark from the get go.  i put the In-Line Ignition Tester on each one of them and watched.

[ira]

6 minutes ago, dutchzcarguy said:

It would not be the first time..   check,check double check..

As sayd.. do a compressiontest. Also i would look for a airleak.. that can to strange things to a engine.

Do you know that these injectors fire at the same time each time? Long ago i thought they fire just before the intake opens but that seems not the case..  I hope i'm right if not please chip in!!

Hey Dutch,

i believe they are suppose to fire at diff times.  at least that's what i saw when i had the rail partially out.  im gonna try to loosen the screw at the tip near the belts and move the fuel rail far enough to put a paper and watch them spray. 

i did the obvious air leak check but any hints on deeper diags of airleak chk would be appreciated.

im gonna look in to the compression test, but my understating is that comes in to identify lack of power.  right now i cant figure out why spark plug 6 looks diff from others

logically when i used harness# 6 on injector 5, the injector continued to operate.  and when i used harness #5 on injector 6, it remained not working.  this should rule out that harness is good and injector needs to be replaced.

the new replacement appears to act the same.

[ira]

10 hours ago, Dave WM said:

if its 16 ohms it may just be the high impedance coil on the injector, not designed to use the dropping resistor. The main problem I have is how that is fixed by the propped up cap, that observation points to a ign issue. IF you hear it clacking away that would tend to mean the coil is sufficiently energized, but that does not mean its flowing fuel. If its flowing fuel you should be able to see a wet plug. I really wish the lifting of the cap did not fix it, that really throws a metaphorical wrench in the works.

Dave, 

i forgot to mention that when i listened to the new injector #6 via stethoscope, it sounded exactly the same as the original injector#6.  unlike the other five, it sounded very low, dim,  the knocking was not as near as loud or as obvious as are the others were

 

 

   

[dutchzcarguy]

12 minutes ago, ira said:

the new replacement appears to act the same.

So the new one is also a defect one?    change pos 5 and 6 injectors, now the problem is inj cil.5?  you have a new dead injector..

I took a good look in my electr. inj. book i got for the L28 and the injectors have 6 different lines from the controlunit, so it appears to have different timing on them when to inject.. on the other hand.. how does the electronic controlunit KNOW when to inject?

Answer..   (out of my serv.man. EFI)  The injectors are fired twice during a complete cycle of the 4 cycle engine!   It does not know where exact and it does not need to know.. every cylinder sucks it's part in when it needs fuel/air mixture.  So EFI does fire the injectors at the same time and in 2 steps..  There is an air/fuel mist all the time in the intakemanifold.. 

[Zed Head]

Lots of good stuff in the FSM.  Like the injector coil resistance, 2-3 ohms, and the injector opening description.

[Zed Head]

If you have the old injector and a 9 volt battery you can jump the terminals and it will click if the solenoid and spring are working.   You can use a 12 volt battery also but it makes some people nervous.  Just tap the terminals, don't leave it connected.

[ira]

48 minutes ago, Zed Head said:

If you have the old injector and a 9 volt battery you can jump the terminals and it will click if the solenoid and spring are working.   You can use a 12 volt battery also but it makes some people nervous.  Just tap the terminals, don't leave it connected.

So i managed to take it for a spin while Dist Cap elevated.  car ran extremely well compared to having a tight CAP.  i was never able to engage turbo, and could not get above 30mph.    i was able to boost, i see the turbo happy and i was able to hit 70 miles pretty quick.

knowing my Z, id say im about %80 of it overall performance.

running out to pick up a 9v Bat & Compression test tool

 

[Zed Head]

Does injector #6 work with the cap up?  Can't tell if you're saying that you got boost and up to 70 on 5 cylinders or something else.  How does spark plug #6 look after boosting to 70 mph?