Replaced injector and found death

[ptoro01]

Howdy everybody,

As you all know, ive been battling a rough idle, high idle, poor gas mileage, intermitent engine in warmer weather and now i know why.

I ordered and replaced 1 injector on #8 and found it quite fouled as you'll see in the picture. Replaced the plug to go with it and now im guessing that all the gas being poured into that cylinder has washed down past the pistons and the engine now squeels like a dying pig. Although when I put it into drive or reverse, the shaking has gone away, the idle is just perfect and the engine seems to purr except for that squeeling sound.

Im guessing that after about a year atleast and a good 10 000k I have burnt the rings, the valves must not be happy and I cant run the engine or it will self combust soon.

Im gonna check that to be sure with a compression test but everything seems to point towards that. If it is going to die in very soon, the car is getting parted. More on that later.

Peter

[ctaylor738]

Maybe you have it backwards? Bad rings or a worn valve guide fouled the injector?

Did the sqealing start right after you changed the injector? Or is it coincidental?

[WANT '71 280SEL]

I'll bet it's your belts...

Look at the bottom where they ride around the pulleys and see if they're "glazed" or better yet, if you've never replaced them before, why haven't you yet?

Thanks
David

[psfred]

CHANGE THE OIL! IT"S MOSTLY GASOLINE!!!!

If the oil is new (as it should be, it was diluted horribly with all that gas!), very likely it's a drive belt. If it were the bearings squealing, it wouldn't run long....

Peter

[Tomguy]

Indeed, if your engine's squealing is coming from the engine itself (metal on metal scraping) then it would not squeal long - perhaps 15 -30 seconds if you're lucky - before MASSIVE and very noticeable engine failure symptoms kick in - bellowing smoke out the exhaust, horrid clankings and clutterings, or instantaneous death. However, if it somehow IS related to that and now it's just on its way out...

Pull the plugs and turn the engine by hand. Does it hit a spot where it has very high resistance at any point, or is it easy to spin? It should go pretty easily (although not TOO easily). If you hear any scraping from the rear of the driver's side then yeah, I suppose you could THEN assume you have a shot bore, piston, rings, or something along those lines.

My #8 cyl was also dead for a period of time - about a month max, and not even 1k miles though, so I can't compare my situation with yours, BUT if the engine was not getting gas at all, then no combustion was occuring - you simply had a dead cyl. Valves can't burn if there's no burning going on in that cyl to begin with. It was basically just compressing and recirculating the intake air. The cylinder was still getting oil and, since no combustion was occuring, possibly too much oil, but that should do no harm whatsoever. I would think it's something else making that sound.

Edit: A lot of modern V8 engines actually shut off 4 cylinders, like the new Hemis with the "MDS System". It shuts off the fuel supply to them. I highly doubt they'd do this if it harmed the engine Gas can't dilute the oil (and therefore destroy the bore or rings) if there is no gas in the cylinder to begin with!

[ptoro01]

Thanks guys,

The engine doesnt shake around at all, before the car was shaking at idle, now its smooth. It was idling for about 45 seconds at least while I was trying to locate the noise from but sadly I was surrounded by 3 concrete walls with a concrete ceiling so the accoustics didnt help.

I thought about it and the constant squeeking sound really seems to be a belt or a pulley. I also talked to the mechanic at work and he made me shut the hell up cause i sounded so stupid. If it was a cylinder, it wouldnt make a constant noise but a back and forth. There is also no reason that the new injector throws a bearing because that cylinder was already getting gas and thats why the plus was black, from a constant drip. Not to mention that all the cylinders are connected by the intake manifold.

ctaylor738: The squeeling started right away. It could be the other way around, very likely as there is some black carbon in the intake.
Tomguy: There are no rattles or anything that seem to be going bad that way. I will pull the plugs and see if its easy to turn over.
psfred: The belts have been changed less than a year ago. I still dont know how to adjust the tension properly. I can push down a quarter inch on them and they have never squeeled.

Right now, tomorrow evening, I will do a compression test and see what that shows me.

Thanks for the feedback guys. You guys are helping keep the 450 alive.
Pete

[ptoro01]

Im a fool im sorry for wasting everyone time.

I did a compression test on the car and all 8 turn out to be between 145-155 psi. That reassured me and I decided to just let the engine idle, with my dad we pinpointed it to the intake. Of course I left the air box off!!! So I decided to check and see if that could be it by folding a towel into nice square, put it over the intake and the nose just muffled and then slowly the engine started rough idling and I took off the towel, stopped the engine, put the airbox back on and TA DA. She puurrrrrs on all 8.

Now I know I gotta figure out a way to flush my intake clean. It has massive carbon build up everywhere. Is there any trick to that?

Thanks everyone for your time,
Peter

[psfred]

Take it off, take it apart (get new seals for re-assembly), and scrub....

Peter

[WANT '71 280SEL]

Peter, where ya' been? I missed your posting! By far I think you are the most helpful of anyone here in any of the rooms.

Thanks
David

[ptoro01]

Thanks Peter, will do. The car may be on its last few months anyways, I dont know the plan for it yet. Financially its not viable to finish fixing it and moving to cali with it. A whole plethora of parts may be soon available to everyone here.

Peter, where ya' been? I missed your posting! By far I think you are the most helpful of anyone here in any of the rooms.

Did you mean the other Pete or me with my awesome questions of absolute nonsense?

Take care and thanks for the help,
Peter

[WANT '71 280SEL]

Now, now now... You're helpful too but I was speaking specifically to psfred who is my favorite member here.

Thanks
David

[JoeyTheB]

If you really want it cleaned, take it off and drop it off at a place
that redoes heads (or has a sand/bead blaster).

Check out this photo of mine:


I think they use a sand blaster (or bead blaster),
the same thing they used on the heads (which looked just as good).

Cost -
My manifold was done for free (came with the $700+ head job).
I did the exhaust manifolds once and paid the "minimum job fee"
of $45.

[ptoro01]

Thanks,

Very interesting you mention that because I do have one at work. Its big enough to fit a 20'' rim inside. I will try that out real soon when I have a few hours to dissassemble. Are there any tricks to taking the intake manifold off?

Thanks
Peter

[JoeyTheB]

Well, you need to remove the fuel rails/injectors (assume you have already).
Next remove the connections on the front.
Tricky part ?
Probably the connections at the rear.
Be especially careful of the vacuum port on rear pass side
where the tranny metal vacuum line ties in.
It's easy to bugger that one up b/c it's a hollow screw.
(ask me how I know...)

Mine came out pretty much as pictured, then took the fiddly bits off
for r&r. You don't have to remove the lower 1/2 to pull it out.

You'll need two intake manifold gaskets,
and probably want to replace the 8 donut gaskets
that connect the lower 1/2 to the upper 1/2.

Might want new gaskets for the throttle body,
and cold start valve.

[Aaron]

Just wanted to let you know....

The new injectors from Bosch are of a different opening pressure than the original ones that were in the car. I never recommend replacing just one, do the entire set along with holders and o-rings.

Just my $0.02 in case you experience any other running problems.