injector failure?
 

For those w/long memories I posted about a severe under load vibration at 3k rpm a '87 S4 has after an extensive intake R&R.

I managed to get to the car this aft/evening and pulled the fuel rails to have one fuel injector pintle caps fall off into the intake/head!!!
It was on the FI as it was gently pulled but dropped off without excess pressure which begs the question could this contribute to a misfire to cause the bad vibes?

The other FIs came out intact but there operation is unknown under load. The FIs are refurbed Ford 4 hole units.

Nope, won't be the issue. I've pulled a quite a few injectors w/o pintle caps. They just end up in the combustion chamber and melt away.

You've got something else going on. This sounds more like a ignition issue.

thx Sean.........an ignition issue was suggested in the previous 'bad vibes' thread but changing the disti caps and rotors, new Beru wires and new spark plugs didnt change the issue

Seriously, the fallen pintle wont be an issue?

Hey Malcolm,
 

Agree with Sean that it's extremely improbable that the wee bit of plastic would cause issues in the combustion chamber environment.

Had the same problem, and after hours of fishing we got the little B!@#$!$#ard out from the chamber, but after reading here and thinking about it, not much chance for any long term issues. My one bad injector caused the "safe" mode to trip, with one bank running cooler.

can you get it out try using wire with some grease on the end
or you could pull the intake off and reach it, this is easier.

Also make sure to close the intake valves for that cylinder.
NOTE on the end of the injector is a pintle cap a rubber O ring and plastic washer also verify that 4 hole diverter plate is still on the bottom of the injector.

I wouldnt leave it in there if it should get stuck tween the valve and seat you may bend a valve

Seriously
 

Apparently it's not unusual at all to find them missing in action.

And, when you think about it, the temperatures and pressures in the immediate area, combined with the mechanical valve action....plastic wouldn't last long enough to make any real impact.

Correction
 

Previous should have read
"after hours of fishing we got the little B!@#$!$#ard out from the head".

Stan may have a point that in a worst-case scenario, there might be an issue with the valve seat.

I got the Oring and washer.....ONLY the pintle fell. Its not my car so not my decision as to what should be done next.....I did idscuss pulling the intake, again :(

Malcolm suck it out with a shop vac

Did you get it out of there?

Malcolm,

f this is an automatic and you have access to a lift, take a close look at the flexplate connection area. Presumably you have checked for flexplate migration. When I had this problem 12 years ago I felt a noticeable vibration at 3k rpm [3050 to be precise].

If you do go in there suggest you also take a careful look at the area at the base of the driveshaft taper [small end] to see if there are any signs of axial cracking/delamination occurring in that area between the splines/taper . Hopefully not the prolbem.

Just a shot to nothing here to eliminate a failing drive shaft from the range possibilities.

Regards

Fred R

I worked on a car that ate 5 of them (spacer missing on the manfold mounts for the fuel rails causing them to be pushed down too far into the manifold, knocking off the caps). Might gum up the cat converters a little until they completely burn up.

thx all.

Roger.....we tried the shop vac but no go.......perhaps if the suction end was narrowed that would give a more concentrated vacuum.
Also tried a modified coat hanger with gum.....it moved the p cap so we now cant see it.

I have my OEM FIs that can be used and we're also looking at new Ford FIs to replace the refreshed units. The final decision to remove the intake is with the owner but I'll try some other avenues first.

thx Fred and yes its an auto.

I did the flex plate release wouldn't be surprised if I was the fist to do so since factory. The flex plate bolt was then retorqued to spec.

I believe more inspection is required on TT related matters.....I am talking w/Constatine.

I dont know why or what happened but do have a gut feel the whole bad vibes are coming through the drivetrain and not an engine related issue.