Loud clatter - possibly injection pump????

[Ed Riefstahl]

Greetings everyone,
My 230sl is still on my Quick Jack lift, but nearly ready to put wheels on it.

Today I started the car for the first time in 8 months. It started first hit of the key. There is a very loud clatter, possibly from the fuel pump. I didn't let run, but shut it off immediately. I looked extensively for anything that might be hitting. I cranked the engine with coil disconnected, not any abnormal sounds.

In the last week I disconnected and removed the relays on the drivers fender to paint under them and reinstalled them. I also put new motor mounts on the car, which did raise the engine a bit.

I also changed the main fuel filter, because I had to remove it to swap the motor mount. I've changed it before in the past, but it's been a few years.
I did fill the canister with gas before reinstalling in from the top side, but for sure there is some air in the system.

I don't ever recall having this issue in the past with a MB gas engine. I also don't recall ever having to purge the system on these fuel injected gas cars. Most of my fuel injection experience is with w123 MB diesels, where you need to any time you change filters.

Before I damage something I'm asking for some input from you nice folks out there.
Any comments / suggestions / help is greatly appreciated.

Ed Riefstahl
Erie, PA

[ja17]

Check the oil level in the IP first.

[Pinder]

Also check that the back of the engine / pipe that goes to the intake is not hitting the firewall as you said you replaced the motor mounts and its possible it sits higher in the engine bay. Also had you at any point removed the valve cover? you didn't over tighten that? there is a possibility to over tighten it and as mentioned by Joe in this forum that doing so can make the valve cover hold down clamps rub the cam and make a knocking type of sound.

[Ed Riefstahl]

I'll be checking the car out more thoroughly tomorrow. Didn't have anymore time Friday.

There was definitely nothing hitting anywhere on the exterior of the engine. This sounds much more like pretty significant valve clatter. It sure didn't have it last fall.

Joe may be on the right track. Somehow in my mind I was thinking I must have done something recently while working on the car to cause this and totally slipped my mind to check the oil in injection pump oil.

While on the subject, I'm not sure what the rest of this group uses for oil, (whole nother subject) but I use Shell Rotella 15-40. I've been using it in my diesel tractors and older cars for many years because it's one of the only oils left that still contains zinc, which has been removed from most oils due to catalytic converter damage.

I'm curious to know what others on this list use in their SL's and how many have switched to synthetic. Also curious if you use the same oil in the injection pump?

BTW, I did replace the gear lube with synthetic in the differential after rebuild, but I also put new seals in it.

Thanks again for your comments.

Ed Riefstahl
Erie, PA

1966 230SL (Ms Magoo)
1970 280S (Miss Daisy)
1989 300SE (Majestic)
1999 BMW Z3 5 speed
1991 BMW 318I 5 Speed
1997 Toyota Paseo Convertible - Red 5 speed (have you ever seen one?)
1997 Ford Ranger step side (Mater)
2023 Mazda CX 5

[Ed Riefstahl]

Good morning folks,
I had a chance to pull the injection pump dipstick this morning. Oil level is normal and oil isn't very dirty. However it does have a slight varnish smell and feels pretty thin, which makes me think I need to change it.

I've never changed the injection pump oil since I've owned the car and for the life of me I can't find a drain plug. I've even searched the archives on this forum to no avail. I did remove the plug on the side of the pump just below # 1 injector line, but it seems too high to be a drain and nothing came out anyway, so I replaced it.

I've done nothing up front recently such as remove distributor, valve cover etc. only replaced motor mounts. It sounds like a severe detonation or valve clatter, however doesn't sound like it's coming from under valve cover and seems higher pitch.

Could air in the lines cause this?

Thanks for any suggestions.
Ed Riefstahl

[BobH]

Hello Ed, i believe you need to draw the oil out through the dipstick hole, there is no drain plug, use a syringe or similar

I can't answer your noise question, as i'm mechanically challenged, so hopefully someone experienced will comment

I must admit i find your posts inspirational, considering what you've both been through this last year

Carry on the good work, and best wishes to you and your wife

[Cees Klumper]

I once forgot I had left a 27 mm socket and wrench on my crankshaft bolt and started the car that way. Point being maybe a foreign object like a small wrench or screwdriver is making this noise somewehere? Small but still possibility.

[Ed Riefstahl]

Hello again,

After checking oil level in the pump, I had my wife start the car so I could be under the hood. This was probably the 4th or 5th time I started the car. This time it clattered for a brief second and shut up completely.

I guess it had to be the air in the pump from changing the fuel filter. What a terrible loud racket it was making. Bad enough to make me really nervous. I don't recall ever having this happen in the past on any of my older FI cars.

I removed the oil with my Mighty Vac and in the process of replacing it. Not really sure if I should use something other than conventional oil, but plan to put Rotella in for now.

Thanks for all your comments and suggestions.
Have a great weekend.
Ed Riefstahl

[Ed Riefstahl]

Hi folks, here's the latest update.
I filled the pump with straight 30 weight. I figured it had to be close to what they would have used in the 60's. I used a hand held pump type oil can with the same hose I used to siphon old oil out. I poured the old oil into a glass jar to see if there was any foreign material. There was none.

I started the car up and it clattered for a second then quieted right down. I let it run a minute, shut it off and started it again. Same thing clatter like a spoon inside of a tin can or on a fan blade. I let the car run a bit and all of a sudden out of nowhere it starts up again. Sometimes it will run as quiet as a mouse, even if I rev if up. Other times, even after warmed up, it will start clattering for no reason.

It sounds like it's coming from the rear of the injection pump. I'm in the process of pulling the electric solenoid off the rear of the pump, just to see what I can see. It sure sounds like something came loose inside the pump the noise way it comes and goes.

Very puzzled at the moment.

Ed Riefstahl

[ejboyd5]

Chances are very slim that the noise comes from the injection pump.  Considering what you have described, I would suspect timing chain tensioner problems.

[ja17]

Yes, It could be the chain tensioner. Some times the engine fan forces engine noises to the rearward. Dirty engine oil can cause the tensioner to lose prime until the engine is started. A worn/stretched timing chain can aggravate the problem.

[Ed Riefstahl]

It makes noise as soon as it fires, like a chain rattle does, only nastier metal against metal. It always makes the noise every time on start up and usually goes away in a couple seconds. However sometimes as it sits there purring as nice as you please, out of nowhere it starts making a terrible sound.

I had a chance to use my stethoscope this time while my wife started the car a few times. Turns out the sound was not coming from the injection pump or up front as in timing chain / tensioner. It appears to be coming from bell housing / fly wheel / torque converter area. My wife was inside the car and also said it sounded like it was coming from the transmission. keep in mind I'm pretty hard of hearing, so that doesn't help matters.

I'm wondering if a fly wheel bolt came loose or starter isn't disengaging all the way. At any rate, something is hitting something me thinks.

I actually have a new starter that's been waiting to be put on. The car is still on my lift, so I guess I'm not ready to put the car back on the ground yet.
I'm actually sweating a little less at the moment, thinking it's probably not the IP.
That was really making me nervous. At least it has nice clean oil in it now.

Thanks again for your comments and suggestions.
Have a great weekend.

Ed Riefstahl

 

[Cees Klumper]

Loose flywheel bolt or similar makes sense - I would recommend not running the engine again until you have found the issue. You don't want a loose metal item get launched in such a way as to 'grenade' your engine or transmission ...

[Ed Riefstahl]

I had a chance to check out the flywheel bolts. Not exactly my idea of a great way to spend Saturday evening, but this is really bugging me. So, my wife said lets go out and check those bolts and kept me company and handed me tools.

All bolts were tight and nothing unusual, so I pulled the starter because the sound sure seems to be coming from the rear of the engine. The starter looks fine too. I'll install the new one because I have in on hand and it's a real bear to get off.
I used about 2 ft of wobble end extensions. Wow, were those bolts tight.

I hate having to start the car up, but the noise is so sporadic that it's hard to trace where it's coming from. I plan to pull the valve cover when I get a chance and check timing chain & tensioner and rockers etc.

Thanks again for suggestions.

Ed Riefstahl
Erie, PA

1966 230SL (Ms Magoo)
1970 280S (Miss Daisy)
1989 300SE (Majestic)
1999 BMW Z3 5 speed
1991 BMW 318I 5 Speed
1997 Toyota Paseo Convertible - Red 5 speed (have you ever seen one?)
1997 Ford Ranger step side (Mater)
2023 Mazda CX 5

[rwmastel]

I had a chance to use my stethoscope this time while my wife started the car a few times.

Can you continue to stethoscope your way around during more startups?  Sounds (pardon the pun!) like the best way to find the source.

[Ed Riefstahl]

Hi Rodd,

I really have no other choice at this point, but to start it up again. As of this morning I've now changed IP oil (wasn't low), checked all flywheel bolts and removed starter. (have new one to put on). I've removed and thoroughly inspected the chain tensioner and chain guides. Everything looks perfect. I'm currently adjusting the valves before putting cover back on.

The sound is like someone putting a spoon in a fan blade, and seems to be coming from the rear of the engine. My wife who operated the key, said it sounds like it's under the transmission tunnel. I will put the new starter on the car and have no choice but to start the car again.

After some more research and checking past postings on this forum, I'm seriously thinking I may have an issue with the torque converter. It sounds like it's coming from the rear of the engine and that's the only thing I can point to. Baaaaahumbug.

I can hardly believe I've gone thoroughly through the car in the last 9 months, from entire cooling system, charging system, brake system, differential etc. I start the car up and it sounds like it's going to explode.

BTW, the car has great oil pressure and runs and sounds great when the clattering stops or until it starts again.

Thanks for the comments,

Ed Riefstahl
1966 230SL (Ms Magoo)
1970 280S (Miss Daisy)
1989 300SE (Majestic)
1999 BMW Z3 5 speed
1991 BMW 318I 5 Speed
1997 Toyota Paseo Convertible - Red 5 speed (have you ever seen one?)
1997 Ford Ranger step side (Mater)
2023 Mazda CX 5

[rwmastel]

It sounds like it's coming from the rear of the engine and that's the only thing I can point to.

As mentioned above, maybe it's the side-to-side metal air tube between the engine and the firewall?  Stethoscope that thing.

[Cees Klumper]

As an alternative to starting her up, two tips:

- turn the crankshaft by hand; like one does after replacing a timing belt or chain, to make sure there's no interference. You control what happens
- if that does not produce results, only crank the starter but remove the fuel pump fuse and the coil wire, so the engine cranks but cannot start running

Those would be safer ways to get at the issue than actually running the engine. I am just concerned for you.

[JohnnyC]

Greetings, I haven’t read this entire thread, but have you done a cylinder compression check? Perhaps something located at the aft engine internals is broken or defective. And, I assume the transmission has oil in it.

Cheers and God Bless,
JohnnyC

[Ed Riefstahl]

Hello again guys,

Hi Rodd, I just went out and rechecked the tubes again. They are securely attached to the engine. I can't even move them the slightest bit and they are no where near the firewall. you can't imagine how badly at this point I wishing it could be something simple like this.

Cees & JohnnyC, I've already done this. I've turned the engine by had and cranked it without spark. It sounds perfect in every way.
When the car runs, and clatter stops, it sounds perfect. I'ts been a couple years since I've done compression check, however I know my engine and it's not a bottom end, wrist pin, or valve noise at all or even close to those sounds.

This sound resembles the noise of something hitting something that is rotating. A very rapid fire sound. Remember putting things in the spokes of your bicycle when we were kids.

Today I thoroughly inspected and adjusted all the valves and replaced the valve cover after cleaning it with aluminum cleaner. Everything looked perfect and very little adjustment. I also installed the new starter on the car and now it does nothing at all, starter won't even activate.

Beyond frustrated at this point, so I will take a break for now. I may address the starter issue tomorrow. I'll make sure I have power to it and probably jump across the solenoid to see if it cranks. I should have hooked 12 volts to it before installing it. New starter, didn't really think I needed to. I sure hope I don't have to reinstall the old starter. It's a real pain to swap out the starter without dropping exhaust.

Not sure what could be in the torque converter, but sure sounds like that's where it's coming from. When it's running again I'll get under the car with my stethoscope while my wife starts the car. I wouldn't do this except it's on the lift with all wheels off the car.
Thanks again for all the suggestions.

Ed Riefstahl
 

[JohnnyC]

Actually, a loose spark plug can produce clanking sounds when combustion initiates. Found this troubleshooting an early BMW once, I was very surprised by the strange sound it made. I think this caused a lean condition (sucking in more air) resulting in detonation, producing the clunk/knocking sound.

BTW, only one plug was loose, in-line 6 and cylinder 6.

Cheers,
JohnnyC

[ja17]

I did have a 230SL in for service about forty years ago. It did have an intermittent, rotating, clattering sound coming from the injection pump. Sounded like the flyweights on the governor clattering against some thing. Never found out exactly what it was. I did some adjustments on the injection pump and it went away. Use a "vibrations stethoscope" to probe around for this type of noise. A vibration stethoscope has a solid shaft instead of a hollow sound pick up. You can also use an extra long screwdriver with your ear against the end of the handle. Vibrating and rattling noises transmit up the solid shaft. You can even hear your injectors squirt with this technique.

[Mike Hughes]

There should be plastic debris screens on the bell housing. it not present, it is possible for a bit of gravel to be projected into the bell housing.  Sounds just like one of those Fisher-Price wheeled pop-corn popper toddler toys until it is finally flung out or removed. My XJ6 was missing a similar screen, but it has had one for some years now after such an incident.

[Ed Riefstahl]

Hi Joe,
Yep, great trick using a long screwdriver. I learned this in the 70's working as a mechanic. Unfortunately, I now have significant hearing loss and can't even use my hearing aids, with the stethoscope.

I plan to have someone with better hearing help me diagnose where the sound is coming from. I have no choice at this point but to start and run the car to pinpoint where the sound is coming from.

Thanks for suggestions and comments,
Ed Riefstahl

1966 230SL (Ms Magoo)
1970 280S (Miss Daisy)
1989 300SE (Majestic)
1999 BMW Z3 5 speed
1991 BMW 318I 5 Speed
1997 Toyota Paseo Convertible - Red 5 speed (have you ever seen one?)
1997 Ford Ranger step side (Mater)
2023 Mazda CX 5