Complete Tuneup - What needs to be done?

[Andres G]

Hello All,

I'm thinking it's time to give my SL a tuneup. The car has progressively been taking longer and longer to fire up from cold and it sometimes gives me a hard time to start up from warm. Once the car is running, the exhaust fumes smell like the mix is too rich and I am under the impression that every once in a while the timing goes off. The car has 40.000 kms on the odo and the last tuneup was done 7000 kms ago according to the previous owner service records - this was also 9 years ago.

I was wondering what will need to be done to it, as I think the symptoms I'm experiencing are the consequence of several different issues converging to attempt against the correct running of the engine. I plan on taking it over to a local mechanic that has experience with mechanical fuel injection (corvettes), and have him go over the fuel injection system, so here are my (initial) questions:

1 - Do the injectors need to be cleaned up every once in a while? How is this done? Is this something for a DI Yer?
2 - How hard is it to correct fuel/air mix ratios? Any particular hints?
3 - Distributor - Does it need a rebuild every once in a while? How can I tell what shape it's in?
4 - Plugs & Wires - Anything in particular that needs to be done here? I was planning on doing this myself sometime soon, before taking the car in.
5 - Any other areas to check on before going over to the doctor's?

Thanks in advance,
Andres G

[jameshoward]

Oh, Goody! A subject that's not likely to spark much debate, then.

I'll offer an initial view and then make way for others who know far more.

Like you I like to keep my car 'tuned' (whatever that means). I've put a lot of time and effort into getting my car to run properly over the years. Key to this for me was - initially - addressing a lack of adjustment in the FIP that made the car run rich. I sent it off (there's a long post on the site about what the guy did). Since it went to a pump 'expert' I also got him to do my injectors.

With the pump back, lines blown through, injectors refitted, all fluids changed (oil every year; brake fluid every 2; coolant every 2; clutch;steering; diff; transmission; etc), new plugs; check the resistance on the wires; check the coil; I set about JA's linkage tour. It took a while to get it right, but when I did I knew it. I had to tinker over many weeks with the mixture, but finally hit the sweet spot. Lots of fun trying to get the idle to settle, but again the linkage tour was key, followed by getting to know a lot about just how sensitive the idle air adjustment really is. I also did things like changed the air filter on the FI pump (obviously; coz it went away); put new oil in said pump (230SL); did the valves; checked the compression (which remains universally low); changed all other filters, like the power steering one; fuel; fuel tank mesh; changed the rotten fuel hoses to/from the tank, etc. Also did the cold start solenoid, which had a slight leak but which cleaned up well and has been fine ever since.

After having done all that fun stuff, I pulled by 051 dissy (my post on that is out there too, as are many others) and with advice from Dr Dan I pulled it apart and rebuilt it with new bits (didn't have the facility to properly 'test' it but it's excellent now). There's a bosch kit you can get from Dan also (I think that's where I got it); well worth it in my view, and quite interesting. After all that, it's time to do the timing and set the car to run the way I wanted. Doing the timing involves buying things like a dwell meter and a stroboscopic light, then using them. All great 'boys own' stuff.

To address the specific points you raise:

1. Don't think so but worth doing if you have need to remove them, of course. Some say a good additive (I know MB says no additives) like BG44K seems to work well.
2. Not hard provided you have the necessary adjustment. Do a search and see what others have done would be my advice.
3. Can't think that it needs to be rebuilt unless there's a problem. I did mine coz I wanted to know how it worked and wanted to paint the body. Internal consumable parts were worn and it was worth doing. Easy enough, but read about it on the site.
4. Read the plugs (Haynes manual). Check resistance on the wires (1 ohm on all; look out for a weird 5 ohm plug on cylinder 1, oft discussed; check condition of wires; use the right plugs (not resistor plugs; gap them properly; use anti seize, etc)
5. All of the above in my email, plus whatever else comes along....

I did all the work on my car myself with help from a friend along the way who knows plenty. But it's not hard. I wouldn't send my car to anyone else for work like this, because although it takes precious time, and I know it'll take me a long time, at least it's done properly, and I'd wager, better than most commercial garages would do the work. (There's no garage I've come across in the UK or Germany I'd trust without spending a fortune with someone like Kienle - just not an option). It's also part of the fun of owning the car.

Finally, I can't stress the degree to which I used this site extensively throughout. The likes of JA, Naj, Dan, and others make life very easy. Sad but true, I always read up on each job here before doing it, and always had either print outs or web access. Have a think about doing it yourself before you decide to send it away. It really isn't hard and it's very satisfying to get right. My eternal thanks to Peter van Es for making the site - and therefore my car - what it is,

JH

PS - there's a sort of logical order of the way to do things; my post has managed to ignore that fact. Mostly. 

[jameshoward]

I'm surprised this thread hasn't drawn many comments.

I think a few years ago it would have been a hot topic by now. An assumption, of course, but it does seem as though the flavour of the debate has moved on.

Merely an observation.

[Mike Hughes]

There are three basic items that must be checked IN ORDER when performing a proper tune up on any gasoline engine:

1.) Compression

2.) Ignition

3.) Fuel Delivery

The rest is just down to the details of how to perform the checks and and necessary adjustments.

Do these steps out of order and you will probably misadjust a critical component needlessly!

[ja17]

Hello Andres and James,

*This is a work in progress, be prepared for some additions, corrections and feel free to comment.
1-30-10   correction "E" service interval (12,000 miles)
1-30-10  additional information
1-30-10  added info, job #s corrections etc.
1-31-10  more additions and corrections etc.
2-02-10 more additions and corrections etc.

The topic is a very good one and well worthwhile. It is very complex also. I hesitate to make a responce until I give it some good thought. A tune-up procedure would be a good addition to this web-site and the technical manual. James has made a lot of good points already.

Most shops classify tune-ups as major or minor. Mercedes-Benz published standard maintenance and tune-up procedures in shop manuals and a copy of "Mercedes-Benz Service Booklet" was included in the owner's books with each car. This booklet, described the maintenance and service to be performed at certain mileage intervals. They were described as "A", "B", "C", "D", "DZ", and "EZ", services. Different tune-up and maintenance procedures were to be performed and then recorded in these booklets. The items to be serviced at the different services is listed in the booklets. All owners should become familiar with these booklets. The manuals have mileage stamps and a place for the service shop to initial and stamp the booklet. Lubrication service, spark plug changes, transmission fluid changes, differential fluid changes along with many other things are covered in the booklet. The services  are designed to keep your Mercedes running and dependable for as long as you want to own it. Preventative repairs on the alternator, starter and electric fuel pumps are also perscribed at certain high mileage intervals ("EZ" Services). There are also a few items like brake fluid and coolant which should be changed on a time schedule instead of mileage schedule. Take a look at it. Hopefully it is still with your car.
Now, these "Service Booklets" did tell what should be done and when, but gave very little detail on how to do it. This information was to be found in the BBB or other Mercedes-Benz Factory Shop Manuals such as "Maintenance Manual Passenger Cars USA Version" which was another fairly large and complex Blue Book. It deals with describing the maintenance and tune-up procedures listed in the owner's "Service Booklet". The one I use most was published in 1977 and covers almost forty diffent models including the W113 280SL. It describes how to perform about 100 basic service, maintenance and tune-up procedures various models. The dealer technicians would recieve a work order for the particular service to be performed. It listed the items to be covered and the actual procedure number which was described in detail in the Factory Workshop Maintenance Manuals.

I am also sure many shops and owners have choosen to use their own list of procedures for maintenance and tune up over the years.

I like to follow the service schedule and procedures in the owner's "Service Booklet" and also add some items of my own. The "E" and "EZ" services are the "major services" while most of the others are basic lube service with some other checks.

 "A" (first inspection 800 to 600 miles), and "B" (at 3,000 miles). These are minor  services when the vehicles were new.  "C" services occured every 3,000 miles and are minor lubrication and check services between and during D and"E" services  which came up at every 6,000 mileintervals. The "D" Service was a minor tune-up along with all the items of a "C" Service.  The "E" Service was the major tune-up and was an lot of work. The "EZ" service is every third "E" service and more preventative items were added to the standard "E" Service.

The sequence was C,D,C,E,C,D,C,E,C,D,C,EZ....etc . One of the alphabetical services would come up every 3,000 miles.  There may be some slight variation of this sequence depending on the year of your W113. 

Here is my "E" Service list (major tune and service) I am sure we can fill in with some more items. The "E"  service is carried out at 12,000 mile intervals.

Items I have added myself to the list will be noted with an *  (ja17)

These are all "E"Service procedures,  (12,000 mile)  except as noted ;

1.0) Test drive car and note any problems, noises, vibrations with the engine, suspension, transmission,
     or  differential. heater and AC systems (job #098 and #099)

2.0) Record vehicle information (chassis #, engine #, distributor #). The transmission # and differential ratio are
       optional. Keep the recorded information for future use and for ordering parts. *(ja17)

3.0) Check and clean all fuses and  battery connections. *(ja17)

4.0) Check and adjust all V-belts (job#756) replace all belts at  every other "EZ" service  ( 60,000 miles) (job #757)

4.5) Check battery and add distilled water if needed (job #821)

4.6) Check charging system output  * (ja17)

4.7) Check   (job #895), recondition or replace the alternator at every other "EZ" service (60,000 miles) (job #15)

5.0) Check main fuel filter (check tank screen & elec fuel pump screen if  main filter has a lot of dirt or rust) *(ja17).
    (replaced main fuel filter at "EZ" service 30,000 miles) (job #840 and #849)

5.1) Check the  fuel pressure and volume output of the electric fuel pump

5.2) Replace or recondition the electric fuel pump at 60,000 mile intervals (job #07)

7.0) Remove and read the spark plugs after the test drive

8.0) Check the engine compression while still warm (job #751)

9.0) Remove the valve cover, loosen the radiator cap and re-torque the cylinder head bolts while the engine is still
      warm. * (ja17) Note****  (review all the pro's and con's of this procedure)!

10.0) Examine the timing chain, chain tensioner, and chain guides for wear or damage. (record the camshaft
        I.D.  number)

11.0) Check condition of ignition system (if a scope is being used,  job #832)

11.1) Use an ohm meter to check all the spark plug wires ends, also check the coil wire and its ends. *(ja17)

11.2) Identify the ignition to see weather it is original standard, original transistor, or non-original. Verify that the
        correct coil, points and ballast resistor are being used. *(ja17)

11.4) Lube distributor with two drops of oil in the capsule on the side also at the felt under the rotor and apply some
        grease on the distributor cam for the contact points rubbing block (important)  (job#779)

11.5) Examine distributor and check the centrifical advance and vaciuum cell. *(ja17)

11.6) Replace ingnition condensor every other "EZ" services (30,000 mi)

11.7) Replace ignition points and set dwell (job #773)

11. examine, clean or replace ignition rotor  every other "EZ"service (30,000 mi) test resistance with ohm meter

11.9) examine, clean or replace ignition  Distributor Cap every other EZ"service (30,000 mi)


12.0 ) Adjust engine valves on a cold engine (job #753)

13.0) Examine the valve seals with a flashlight. *(ja17)

14.0) Check vertical timing gear for excessive free-play *(ja17)

16.0) Replace and gap spark plugs with non-resistor type if possible. (job #770)

17.0) Check to make sure that the valve cover hold down straps are not too close or rubbing against the camshaft   
      before re-installing the valve cover. (this condition can cause a mystery "tapping" noise) *(ja17)

18.0) Check or replace the valve cover gasket. If it is soft and pliable it can be re-used. Test the rubber gasket by
          bending it sharply,  if the rubber is good, it should not crack or break. *(ja17)

23) Clean the main engine air filter  (replace at the main air filter at every other  "EZ" Service every 30,000 mi)
      (Job #202)

23.5) Check power steering fluid level (job #134), check all hoses. Clean or replace the power steering filter (replace
         filter at "EZ" Service 30,000 mi)

24.0) Check or replace the injection pump air filter (replace at "EZ" Service 30,000 mi job #806)

24.5) check or change the injection pump oil if yours is an early injection (non circulating oil) pump. (job #800)    
         (change at "EZ" Service 30,000 miles *(ja17)

25) Set the ignition "static timing"  

26) Start the engine and set the dwell  Job #781, #782) then re-set the ignition timing at speed ranges with a timing
     light. (job #773, #772 and #774 for USA cars with ignition changeover relays)

27) Check and adjust all engine linkages (job #904, job #798) & (linkage tour) , speed solenoids (job #793),
    vacuum dash pot (job #796),  &  venturi switches.

27.5) Lubricate linkages (job #415) use light oil or graphite solvent.

28) Identify and check the engine starting devices with engine cold and with engine hot if applicable *(ja17)

29) Set injection pump mixture and set idle (idle speed and CO job #798)

30) Test drive

31) Drain engine oil while hot/warm

31.5) Drain oil cooler if applicable.

31.6) Replace engine oil, oil filter and seals, (job #151)

31.7)  Check to make sure that the critical upper housing seal is in place These seals do not come in the filter kit and
        must be orded separately. They do not have to be replaced every filter change but should be replaced
        occassionally so they are fresh and soft. *(ja17)

36) Automatic transmissions check fluid level  (job #120),  change filter and fluid and gasket at "EZ" Service 30,000)
     (job #170 and #174) also a good idea to re-torque the transmission valve body bolts  while open *(ja17)

36.3) Drain transmission fluid while hot/warm (drain the torqeu converter and the pan)

36.5) Automatic transmission, check the rubber transmission cooler hoses at the radiator bottom.*(ja17)

36.6) Standard transmissions check the fluid level (Job #121 )

37.0) Check the shift linkage ends on all types (job #525 automatics linkage rod adjustment if needed)

33) Check fluid level in rear axle (job #180)

**Important all drain plugs should be either left out altogether or installed "tight" with their new seals. Never temporarily install a drain plug finger tight, thinking you will come back to tighten it. If you forget to come back and it falls out later you have a real problem.

39) Change the oil in the differential, check the axle boot and seals for leaks. (job #130)

41) Check suspension for wear.

42) Check the drive shaft for wear (flex disc, universal joints etc)

43) Lubricate Chassis (job #250)

43.2) Lubricate door hinges (job #350),hood cable (job #395),  hood hinges  (job #395), trunk hinge, and engine linkages, door latches (job #393)

43.5) Lubricate all key locks with graphite (may save you an expensive steering lock/key failure some day) *(ja17)

44.0) Check drive shaft and flex disc. Grease driveshaft

45) Check for any fluid leaks

45.1) Visual check of fuel system for leaks and condition of hoses (job #041)

45.2)Engine coolant should be changed every two or three years reguarless of mileage (coolant becomes acidic with
      age. MB factory coolant is formulated for Mercedes engines and has a PH suitable for them. (job #991).
      
45.3) Check cooling system level (job #990)

45.4) Pressure check cooling system for leaks at "EZ" service (30,000 miles) (job #038)

46) Adjust  clutch free-play if applicable (job #501) check for leaks (job #045)

46.5) Check fluid level of cluch hydraulic  sysem (job #510)

47) Check for any loose bolts

48) Check front wheel bearings and replenish grease in caps (job #388). Check bearing end play (Job #630)
      Only if repacking of all grease or repairs are needed (job#631)

50.0) check brake fluid level (job #700), check for leaks check brake rubber hoses  (should be replaces with new
        every 10 years)  flush and replentish brake fluid seasonal, change every 2-3 years (job #702)

50.2) Disc brakes...Check for leaks and wear (job#711) .Check Brake calipers(job #703), pads (job
       #707)  and rotors (job #709).  Clean and rotate pads (job #707)

50.5) Drum brakes..... Clean and check. Scuff brake shoe surface and drums with emery cloth (job #719)
        adjust shoes (job #705)  

50.7) Hand brake   lubricate and adjust (job #706 and job #097)  adjustment at rear wheels (job #009),

51) Rotate tires (job #986, #983) torque wheel bolts (job #988) check tire pressure (job #987)

52) Check exhaust system, hangars, etc.

53) Check Battery and connections. (job #821)

54) Check windscreen wiper system, windshield washers  (job #099)(job #065)

54.5) Check function of all lights (job #099)

55) Check front axle toe-in and camber  (job #625)

55.3) Check steering play (job #025)

55.5) Check tightness of steering box bolts on frame (job #924)(job #922)

56) Check rear axle camber  (job #627)

57) Treat rubber door seals (job #476) and other rubber seals *(ja17)

58) Check AC level and function (job #484)



More to follow getting late!!! This is a work in progress, be prepared for some corrections and additions!

[merl]

great post   would help if the type of fluid, ie auto trans fluid power steering, brake, etc., currently recommended or used was also listed.   thanks merl

[jameshoward]

Merl,

There's always going to be a good amount of debate it seems about fluids. FWIW, I use:

10W40 in the engine (semi-synth, and for diesel engines)
Same oil in the FI pump (my car is a 230 so has a separate supply)
ATF (DII) in the transmission (mine's a manual but ATF is what MB state should be used) and power steering
Castrol (TQ I think) Diff oil in the diff (i.e. can't remember what that was, but it's only very rarely that it's changed) - a search here will provide a wealth of detail, I'm sure.
Standard DOT3 brake fluid for brake and clutch
Coolant - MB coolant for Alu engines would be perfect but was very expensive when I priced it in Germany, so I went with a generic coolant for Alu engines made by BASF in Germany.
Occasional shot (few hundred ml) of 2 stroke oil in a full tank of fuel now and then
Highest octane unleaded in the tank (I think we have 99 in the UK branded as Ultimate) with a bit of unleaded fuel additive (personal choice; most don't bother but I've got a few bottles to use up).
Standard grease on all 270 odd grease nipples and in the front wheel bearing hub covers once in a while
Standard oil on the door, boot, bonnet and all other hinges, and on the dissy (2 locations: felt patch a-top the thing under the rota arm (a drop off the dip stick is easiest) and a drop or two in the little oil location on the side of the dizzy that rotates to reveal a little hole.
Battery grease on the battery terminals (top up the battery once in a while if it needs it)

Can't think of anything else right now.

JH


 

[Peter van Es]

Someone ought to add this to the Technical Manual here: http://www.sl113.org/wiki/Maintenance/Start as a separate TuneUp page!

[Andres G]

Oh Wow! Great input from all here!

I am so thankful for this information... I will take the time to add it to the Technical Manual as soon as I can.

I have already scheduled a visit to the local FI specialist and will provide him with as much info as I can gather from here.

Thanks again.
Andres G

[abe280SL]

Andre,
I have a Gunsen CO analyzer use to cost less than $170. It alllows you to adjust your fuel injection pump at idle to a CO between 3.5-4.5%.  I can't live without it.  There is a knobb in back of the FI pump...clockwise makes it rich..counterclockwise lean.   You will learn little tricks like disconnecting the rod to the FI pump...if you open it up then (more fuel while air intake stays same) and it accelerates it means you are too lean....if stalls..too rich.  You can then do the opposite...open the air throttle  while the fuel pump stays the same... if you add air and it accelerates it means too rich in fuel..if stalls you were already to lean and stalling by adding more air.
I also use dwell angle rather than gap in the points...it is a more "real" reflection of what is actually going on..IMHO.
Have fun
abe

[glenn]

Andres,  The most 'general' problem I've experienced on my 20 or so FI'd 6s has been idle speed fuel mix.  Either too rich or too lean at too high an idle.  This assumes timing, valve adjustment, CSV, fuel pump pressure and flow, solenoids, butterfly, etc are OK. 
   After all this is OK--- set idle speed to 750 rpm by---

1. Get engine warmed up.
2. Disconnect linkage rods at FIP and venturi 
3. Adjust idle air too max rpm (more air raises rpm if rich, less air raises rpm if lean) for FIP setting.
  Note rpm
4.Adjust FIP knob toward 800 rpm(stop engine first, don't adjust knob with engine running).  CW if rpm below 800.  CCW if above rpm.
5. Repeat 3 and 4 until rpm is 800.
6. Screw in idle air screw to 750 rpm.
7. Connect linkage rods.

PPP Pleasant Pagoda Perambulations

[jameshoward]

PPP - Perambulations?! What you're suggesting is heresy, Glenn!  

[glenn]

Perambulate---to move around and about with elan and class.  As in driving a Pagoda. ..

[jameshoward]

It's from the Latin 'perambulare' (I think that's the spelling) which in English is 'to walk,' hence my original comment, but I wont split hairs.

PPP rules regardless.