BC

This is great Tony. Maybe Cruisin Peformance or even rc engineering would be a good place to get the injector.

Do you have any pics of the injectors - Ithought since you were snapping shots, - do you have any of the tips?

heinrich

... NICE!

bd0nalds0n

IIRC, Tony was replacing his 30# with 24# injectors; I don't know that the 24# ones had ever been in his car before. If they were used, then they were bad from the get go.

Jim_H

Bill Ball

Tony:

Just for the record, were these #24 injectors new, old ones you had sitting on the shelf, pulled from a junker, sold to you as good, found by the side of the road? What's the story? Four bad ones is quite a terrible coincidence.

Tony

yeah, it was just a swap. they had never seen my car prior. They had been in another car where they apparently ran fine?
They all tested at 14.4 ohms as well?

This leads me to a question.
How do they fail?
And how is it detectable besides the process i just went through??
John Speakes little tester was just the gizmo to find out

Im thinking at somepoint, something may of happend to damage one entire bank under previous use.?? Then i happend to install them in the sequence i did, with 3 on one bank and the single bad one on another......This is what lead to some real head scratching!
I was thinking maybe it was my car that was the problem, but how would i kill 4 injectors..3 on one side...1 on another...on 2 seperate circuits with the turn of a key? My car never started...turning the key was as close as it got to turning over.

Anyway, looks like im on my way to getting things solved. Pretty good mystery i tell ya! In the meantime ive had the opportunity to really give my car a good "electrical" going through and fix MANY other electrical things along the way

Im still going to try a local place to have the 24#'s tested.

SharkSkin

Maybe they are just gummed up, and could be cleaned...

dr bob

One thing to remember when "testing" injectors-- the actual firing voltage is a little less than 12. Depending on the total impedence of the injectors and wiring plus the RDSon spec from the FET that fires them, you might find that the voltage across the injector when it fires is in the 9 or 10 range. Putting full battery voltage 12+ across an injector will kill it in seconds! One might inadvertently 'kill' a nozzle or four by grounding the low-side injector return wiring to the LH controller while the key is on. For instance...

When you measure the voltage in the injector circuit, it's tempting to read from the "hot" side of the harness to ground using a meter. From there you'll see battery voltage (12V+) and might think that that's what the injector sees. In reality, the FET switches in the LH brain only pull the low side down to a volt or three --above-- ground potential, hence the 9 to 10 volts that the injector coil actually sees. The 'scope is the tool of choice for measuring that value, since it only happens that there's any potential across the injector at all when it fires.

So to Tony's question about how to check an injector without John's WonderTool, the poor man's solution is a 9V transistor radio battery. An old fuel pump, some plumbing, and a can of B-12 to pump through the 'system' may be all that a poor man needs to restore a partially varnished injector in a pinch, triggering the injector with the little 9V battery.


I want a ride in it after the injection saga is behind you, Tony. Is it better than a full-power roll-on in an empty 757? Is there a V1 uh-oh point in the pressurized 928?





Edit/Added: On the later S4 cars, to make the "shuts one bank down on detected ignition failure" scheme , the nozzle wiring would have to be grouped to the same cylinders that an individual distributor is wired to. Lose fire in one coil, the system drops to four-cylinder mode by stopping fuel to the cylinders that aren't firing. So expecting a common-to-one-side-of-the-engine failure may not be realistic. Is the early S4 injector wiring paired up like the later ('89+) cars with the exhaust temp monitoring [should be]?

Tony

Well,the lone 30# is no clicky. So im not sure if that is a cleaning issue?

Good stuff there Dr Bob! Im not sure what the problem is but getting new injectors is a PITA!
Fords sells them in a group of 8 or 4. As does Summit but for a $$$$$ less.
4 are $175 to the door...8 , $240 to the door...may as well order 8!
What a F'ng crock!

but i have a plan..."Gee, these "8" really arent going to work for me, sorry, heres my 90 day return"

now...i wonder how clean my bad one is

Anyone knnow where i can find a single FMS-9593-B302 injector?
Be sure to get Shartoberfest off this year! It sets you back in your seat but not THAT good
You know when those traffic lights turn "orange"...you look down at your speed...you look in the rear mirror...you look around...loo at the speed again..make the decsion. Thats a somewhat close analogy but in the airplane it is done at a much higher speed with much more on the line

bd0nalds0n

On a running car, should one be able to feel the clicking of the injectors firing, such that he could rest a hand/finger on the injector and feel it fire? Or is it better to unplug individual injectors and be able to detect rougher running? I gather that you didn't notice running on 7 cylinders, other than the variable idle? Wouldn't that cause a lean condition on the o2 sensor? You're getting all the air from 8 cylinders, but only burned fuel from 7. Seems like the ratio of oxygen/unburned hydrocarbons would have to be leaner if one injector/cylinder wasn't firing.

Tony

True.
I just know one isnt working now. Im going to go out and clean it in a few. Ebay has a bunch for sale also...various flow rates BTW

Bill Ball

Tony:

This isn't all just a bad story. Your FI harness was marginal at best (I wonder if it killed the injectors?). So, now you have that all fixed up. Needed to be done. S*^t happens for a reason.

Chris

Nice fixing, now to burn some rubber !

Chris

Tony

Now the plot thickens!

Ok. The odd 30# injector NOW WORKS. I shot some carb cleaner down the top of it then a blast from the air hose...fired up Johns tester, hooked up the injectors and it works (all 8 30# do now)


Hmmmm...me say try this with the 24#s that dont work.

Sure is nice to be able to fire these injectors with out turnign the motor over! I should be able to spray the cleaner in while they are still in the manifold, blast some air at them and then try the tester again.

More later......

bd0nalds0n

Tony did you buy the Speake tester or is it on loan from somewhere? I'd like to plug one in at some point to confirm that my knock sensors are working properly and that I'm not running retarded...