Injector Replacement

[JFawcett]

Need some input on injector replacment on 87 560SL. It has been hesitating intermittently, but will accelerate and goes very well on freeway. If I step on the gas and kind of "blow it out" the hesitation stops and all is good.
I ran some K44 through it and improved the whole system very noticably.
HOWEVER (it's always something with these cars) it didn't clear it up totally.
Got an estimate to replace injectors of $1,800. Mechanic said it is not just the cost of replacing injectors, but replacing all the seals and rubber that just deteriorates when they get into the engine to replace injectors. Trust the mechanic, very honest and upfront about everything....doesn't try to upsell. Thoughts on this?

[KCM]

If the mechanic has told you $1800 without even looking at the car, go find another mechanic. To blindly give you that high a number right off the bat without doing some diagnostics is insane. Injectors themselves range from $35 to $60 each depending on where you buy them. O-rings and other injector seals, including holders, would only run another $50 or so. Check this site (Buy Parts) to get prices, but realize the mechanic will mark up the prices if he buys them. I assume he is talking about replacing misc hoses and lines which should not add up to that much.

I just installed them in a 1989 and it was a piece of cake. If you do not replace the holders, just hold them down when pulling out the injectors to prevent dislodging them. I'm not sure the injectors would cause the hesitation you describe. I would have the mechanic do a fuel pressure test. This will determine if the injectors are leaking among other things. Don't forget about the ignition system. Spark plugs may help as well. Might check the vacuum advance line to the ignition module to make sure it is not broke or plugged. Take a look under the hood and air cleaner yourself and look for obvious problems, such as broken vacuum lines, lines that have came off, wiring that is bare, disconnected wires, fuel leaks, and other stuff. These cars have a lot of junk under the hood that can deteriorate with age and heat, and can cause problems. Does it act like it is missing or does it simply not want to go like lack of fuel? Does it act up when hot, cold, or both? Being as specific as possible about the problem will help in diagnosis.

I know what you're saying about always something with these cars. Been fighting a hot start problem, and I think I pretty much have it whipped after many $$$. Nothing is cheap on these models.

[ctaylor738]

Pure BS. I removed the injectors on my 560, cleaned and pressure tested them using my ancient Bosch tester, and reinstalled them with all new seals. Even with my fumbling and bumbling, it was maybe 4 hours end-to-end. I truly don't see where the potential to break things or encounter major problems.

So $10 per hole for seals, plus the cost of the injectors, which have a list of $71, comes to $648, plus 2 hours labor at $100 since you are replacing, not cleaning/testing. Sounds like the guy really doesn't want the work, or really needs some money.

I will say, it is an easy DIY with a decent set of metric tools. Lots of posts on how to do it.

[JFawcett]

thanks for input. I am pretty mechanically inclined, but for some reason the fuel system makes me nervous. The mechanic has been servicing this car for about a year now (since I bought it) and I have never been disappointed with the work (but the prices have on more than one occasion made my eyebrows go up). The cap, rotor, wires and plugs are pretty new. I have a coil on order.

What other rubber pieces could he be talking about that would need to be replaced? I know the injectors, isolaters, o-rings.....what else?
There is a large rubber hose (guessing for Air intake) that runs up both sides of the manifold....do I need to replace that as a "since I am in there anyway?"

I will do a search on injector replacement and see what I find.

Right now I am getting a new front suspension......fun. New ball joints, control arms, re-pack wheel bearings, etc, etc. Very excited about this bill.

Thanks again!

[ctaylor738]

If you are not having problems with a high idle, I would leave the idle air hoses alone.

There are two short pieces of hose that connect to the idle air valve, and a breather hose that connects to the left valve cover. They need to be moved to get to the left front injectors, so you might want to replace them if they have cracks.

I am hard-pressed to come up with anything else that you would replace as a matter of course along with the injectors and seals. It's not like you gain access to stuff in the course of the job.

A 14mm crowfoot and a set of 6" hex bit sockets (KD Tools) will make the job a lot easier.

[JFawcett]

thanks. I think I will try myself....If I get stuck, I can always tow to mechanic.
Is there any kind of glue/lubricant/adhesive that needs to be applied to the isolators/injectors/threads? Anything other than pull out and replace?

Thanks for all the help.

[JFawcett]

Well, would you believe all this misbehaving and hesitation was caused by the COIL! I was shocked!
Replaced the coil and all was right with the world!
Can't believe it.....coil was just out of range and that made all the difference!

[KCM]

Originally Posted by JFawcett

Well, would you believe all this misbehaving and hesitation was caused by the COIL! I was shocked!
Replaced the coil and all was right with the world!
Can't believe it.....coil was just out of range and that made all the difference!

Sounds like it was your lucky day. Wish the coil would have fixed the problems on my car. Coils can act weird sometimes. They usually act up when they heat up and short out. Maybe revving up the engine got more air circulating to cool off the coil. I have heard that a bad coil can sometimes take the EZL ignition module with it, and they ain't cheap ($2000 new).