Can we talk fuel injectors on a M103 please?
 

I've got the battery out.

I can get all the fuel lines off.

I am having trouble with the injector "holders".

I am having trouble with the first one since the thread for the air cleaner mount obstructs the screw to release the "holder"

Also, what should I expect when I slide the injector out?

I am looking for tips/hints please.

I have done a thread search already.

Please excuse the poor quality picture.

I am terrible and re-sizing them to make them fit for the posts!

Any help would be appreciated!!! Thanks.

-Mike McKinney

The air cleaner mount should screw off. Save your self some time and buy a extended 5mm allen wrench, it should have a allen head shaped ball on the end of it, should be about 5 inches long. That will make your job easier. Also make sure your injectors have been popped, if not you will have a hell of a time getting your car started! Make sure you put new seals in too. I have done this job a few times as well as a fuel distributor. Its real easy if you have the right tools. Don't expect it to run smooth at first, it will take a while for the system to build up pressure.

term
 

"That will make your job easier. Also make sure your injectors have been popped"


What do you mean popped?

thanks,

You have to connect the injector to a pump designed to pop the injector open, its a hand pump. You will also be able to check the spray pattern on the injector.

It is funny how long it took and how long the car sat but, they are in!
 

Okay I've got them in.

I put in new injector seals along with them. The plastic 'sleaves' were in perfect condition so I did reuse them.

The difference was immediate after the second start.

The first start barely happened. It took three tries for the injectors to "spray" to life so to speak.

The problem I have now is the car idles poorly, sounds like it is on 5 cylinders and accelerates weakly from a stop.

I only drove the car around the block though.

What do I do from here? I have checked all the connections. I don't have any leaks. Will this be temporary until the injectors finally 'pop'?

I am wondering what to expect here.

The car came up to temperature fine and it starts perfectly and very strongly.

Weird thing, the idle is perfect for 30 seconds and then it sounds like I've got one cylinder that is not firing ?

I am looking for some tips, stories anything you can offer guys.

Many thanks!

Sincerely,

Michael McKinney

Is there a way I can "pop" the injectors once they are in the car?

What about a "high load" highway drive?

You were right Terminator, my car is running about as well as poop smells.

Can anyone offer me anything with the injectors in the car? Should I take them out and re-install? I don't have a pump to pop them?

I'm really stuck here guys please help.


Thanks a ton,

Mike McKinney

They pop themselves shortly after running. I put scores in without any popping.

Have you adjusted the mixture? If you have a single cylinder misfire, indentify it and find the cause.

you wouldn't be the first person I've known to get a bad injector in a new set

I just took the car out on a 50 km drive.

It still chugs in the low rpm's and has a "put put put" out of the tailpipe at idle.

The economy gauge at idle in gear is about halfway.

The car also smells of fuel slightly like it is running rich? Fuel gauge moved a bit and I only travelled 50 km.

I have not touched the mixture.

After I floor the accelerator and the rev's climb above 4 grand the car flies like it is brand new.

The car starts perfectly though and on the first crank everytime.

Have I screwed something up when putting the fuel lines on again?

I don't have any smoke coming out of the tailpipe or anything.

I've done some hard, foot-to-floorboard stomps on the highway and no smoke or anything else. Car does very well on the highway with the rev's up. Economy gauge is always at minimum unless you floor the accelerator.

I must have done something wrong here. The car just idles and drives lumpy in the low revs.

Can someone point me in a direction to look at things? I don't have any backfires or anything like that.

I need a plan of attack.

Thank you for reading and please offer anything that comes to mind.

Many thanks,

Michael McKinney

i had bad plugs, wires and rotor and had similar symptoms.
car runs like a champ now that those have been replaced.

I have replaced the spark plugs with the injectors. I forgot to report that.

I changed out the sparkplug wires with a new OEM replacement set one year ago after I ripped one of the wires changing the plugs.

The ignition cap and rotor are original.

Should I also think about the fuel pump relay at this point?

How much do these items typically cost?

I will buy new parts and only OEM of course since the car is in exceptional condition after I have taken care of those door dings that bubbled earlier this year.

I would just like to know what to look for to diagnose old parts that may not be operating up to spec any more.

Thank you for reading my posts and I look forward to any additional responses. It has been a great help so far especially reducing my own second guessing.

Many thanks,

Michael McKinney

Sometime back, I posted a picture of a test setup I made using plastic tubing. I attached six pieces of tubing to the injectors and turned on the key. I could see that some had a good spray and some didn't. I installed all new injectors. It didn't run any better. After testing again I realized that my fuel distributor was bad. After buying a salvage one that problem was cured.

I'd bet your mixture is now off from bad injectors before (leaking, to be precise), so your idle mixture is now lean. When you floor it, the computer richens the mixture.

You will need a digital VOM that reads duty cycle (Sears has several for less than $50). Connect positive lead to the #3 "hole" in the diagnostic connector on the fender (it's the one with a round screw cover with a retainer chain on it). Set meter to duty cycle -- it well read either 90 something percent or 30 something percent (I can never remember which way!).

Use a 3 mm allen wrench to push down the "key" in the fuel distributor through the hole with a rubber gromet on the air cleaner housing. Turn slightly clockwise, I beleive, to richen. Should make a big difference.

Adjust in small increments and wait 20 sec or so between measurements for the O2 sensor to stablize, or you will swing way rich to way lean, back and forth!

You smell gas from lean misfire, and the O2 sensor is swinging too much. It runs fine on startup because the O2 sensor has to heat up before it works, and the computer runs at a fixed mixture (slightly rich) until the engine and O2 sensor warm up.

Peter

Thank you Peter and Cap'n.

Peter, you post was great, very informative. I just don't understand why I need to buy the VOM? Can I just adjust on my own and see what happens?

How could the fuel distributor get out of wack to begin with? I'm a little curious as to how all these sensors interact.

Cap'n, how much did you pay for your replacement fuel distributor? New replacement distributors are an astronomical amount!

What do you think about the ignition coil?

Is it fine since it can start the car fine and on the first try (car makes the proper turn over sound and comes on to a smooth idle until it warms up)....???

Thanks again for all the posts guys.

Mike McKinney

Everytime you make a change to any part of the fuel delivery system or air flow you need to adjust mixture! It is in no way automatic on a Mechanically Fuel Injected Engine. Even changing the fuel filter requires this and going to a higher flow air filter as well. And surely changing the injectors changes how fuel flows into the chamber! Adjust air/fuel mixture using a VOM. If you have one then you do not need a new one! I have adjusted the mixture so often on my M102 motor due to changes that I have it down to a less that 5 minute process!