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  #1  
Old 06-21-2002, 07:25 AM
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350 SDL Injector Pump Damaged By Mechanic?

I have a 350 SDL and had the seals on top of the pump to the injector lines replaced by a mechanic. When I go the car back it had a rough idle.

Another mechanic has looked at the problem and concluded that the first mechanic probably damged one or more of the pins in the openings in the top of the pump where the seals were installed.

The rough idle (actually more of a dead miss) goes away at about 1200 RPM and it runs fine otherwise.

Mechanic says pump has to be rebuilt to cure the problem as there is no known source for the pins alone. If a pump rebuilding shop can get the pins why can't we?

Does anyone know of a source for the pins in question or a possible alternative cure for the rough idle, all of the obvious has been checked out.

Thank you.
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  #2  
Old 06-21-2002, 09:55 AM
moedip
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Don't waste your time. If you paid a mechanic to do the job - he should have done it right - The first mechanic should pay for the damage he caused - no if ands or buts about it. If he won't - talk to a lawyer. A call from the lawyer will give him the nudge to repair his damage. If it doesn't - get it fixed and sue him for the costs. Of course - that is if the second mechanic was RIGHT! Injection pumps are highly precision and expensive to fix - you are talking real critical tolerances here and the mechanic really has to know his pumps to disassemble in spotlessly clean environment - just like an automatic trannny.
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  #3  
Old 06-21-2002, 01:26 PM
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Location: Gainesville FL
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Thats a great idea. Car don't work, get a lawyer. I guess I'll just retire.

I have resealed hundreds of pumps and for the life of me I have no clue from your description what he did wrong. Never seen no pins, noway.

Why was he there in the first place? Has anyone determined which cylinder is misfiring? If he did something that caused a problem as described it should be easy to pick the cylinder.

If so check the archives or ask Donnie which cylinder catches the carbon off the EGR valve and make sure your cylinder isn't that one before you make accusations.

It would be best that you let the first tech analyze the problem. All of us will be in a real state if proof of malfeasance comes by only the chronological fact that he worked on the car and now it has a problem.

Someone needs to find the problem. I suppose in the US legal system a good lawyer can get your money whether your case has merit or not. I can't imagine anyone paying any money till the solution is found. How much would you pay?
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Steve Brotherton
Continental Imports
Gainesville FL
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33 years MB technician
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  #4  
Old 06-21-2002, 02:34 PM
moedip
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Steve - didn't intend to make you angry. My remarks were intended for those "mechanics" who don't know what they are doing on a car - but try it anyway without knowing proper procedures causing problems - NOT PROFESSIONALS - LIKE YOUR SHOP. The post said "When I go the car back it had a rough idle." If the FACTS are TRUE then I stand by my post. Would your shop have ever let a car out with a rough idle? Not only do I doubt it - I think you would lose sleep if something like that happened in your shop, unless, of course you noticed the rough idle problem and made the customer aware of it and he decided not to proceed. If your staff damaged a part accidently or otherwise and did not fix it at no charge to the customer you'd jump out of your skin first. Professionals like yourself are highly trained and treat customer's cars like you would your own. But hey - we are all human and things happen accidentally - and that is when a real mechanic will stand behind what he did. I AM NOT advocating making the guy pay for something he did not do. If the customer had another problem immediately after and it was something the mechanic did not touch - the CUSTOMER should pay for the additional work.If the original "mechanic" damaged the pump - HE should pay. If not - the legal system should be used to resolve the problem. Please don't take my post wrong - I was not attacking Mechanics - I was attacking "mechanics" - and they are out there and sometimes the legal system is the only way to deal with them. A Pro does the work and deserves to get paid a fair price for the work and the customer deserves a quality job for his money. My humblest apologies if I offended you - It was not intended or implied.
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  #5  
Old 06-21-2002, 03:35 PM
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No problem, I just train myself to react to violence and I consider the legal system to be tantamont to violence.

I prefer the diplomatic front, jus tell him your friend Guido will visit him if he don't get it right. (bg).
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Steve Brotherton
Continental Imports
Gainesville FL
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33 years MB technician
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  #6  
Old 06-21-2002, 03:39 PM
moedip
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YOU know Guido??? His brother Antonio is a good friend of mine!!!
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  #7  
Old 06-21-2002, 04:37 PM
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By pins, might the second mechanic mean the delivery valve needles?

Sixto
91 300SE
87 300SDL
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  #8  
Old 06-21-2002, 07:13 PM
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stevebfl:

Thank you for your reply.

I have had this 1991 car since new and know it's history.

Car did not have a rough idle until the injector pump seals were replaced.

Two other MB mechanics have now told me there are some delivery valve needles (pins-I think I have this right)/springs in the injector pump that can be damaged or improperly reinstalled during the procedure which can result in a rough idle condition.

One of the two mechanics has since worked on the problem and has concluded it is an injector pump problem.

Is there anything unique about the 350 SDL injector pump delivery valve needles (pins) and springs or are they common to the other MB injector pumps? Can the springs be accidently installed upside down?

Thank you.
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  #9  
Old 06-21-2002, 07:37 PM
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smoke gets in your eyes
 
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While you're waiting for Steve, here's what little I know...

- I don't think it matters which way the spring goes.

- It might be possible to install the delivery valve (pointy thing) upside down but it would require a lapse on the part of the installer.

- The delivery valve carrier has a groove suggesting that there's a top and bottom end. I don't know what the effect would be of installing a carrier upsidedown.

- I don't know how you can upset the internals of the pump by doing something wrong while replacing the delivery valve seals and o-rings.

Sixto
91 300SE
87 300SDL
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  #10  
Old 06-22-2002, 09:27 AM
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I was real busy at work yesterday and now am at home. The needle and spring check valve arrangement isn't used on later pumps. Its my recollection (I haven't personally done this job in a number of years although we do them all the time in the shop. I meant to look it up before I left but my WIS locked up trying to print 202 evap removal insts for a freind in Tampa. I left the hour glass cranking and will seewhats happened when I get back.

Its my impression that the later cars have an encapsulated pump element check valve. There are plenty of things that went wrong including the posibility that a major leak from the brass seal will defeat the pump element check valve and cause a misfire by preventing filling of the line in question.

Another possibility in the pump is dirt. The pistons are driven upward by the cam in the bottom of the pump; sort of like valve in the engine. The pistons go back down due to spring force, also like valves. Like valves they can stick for various reasons.

All of this speculation is based on the fact that a particular cylinder is misfiring. If a problem occured due to the repairs this would most likely be the case. If the engine runs rough with random misfires the causes would be different and not as likely to be the result of repair.

As I stated before, diagnsosis requires identifying the condition and if a misfire the exact cylinder misfiring needs to be identified. If that cylinder is the one nearest the EGR valve, I would do a compression test. The problems with the 350 motor seems to be a compression loss due to the piston rod bending when a large chuck of carbon winds up in the space between the piston and the head and the engine has momentum.

If a single cylinder misfire is identified and the compression is uniform to within 10%. The pump should come back apart on atleast that cylinder to view the seals and assembly for correctness and I would crank the engine by hand and view the piston of the pump going up and down.

The real unfortunate part of all this is that everything you do on a diesel takes so much time and there is so little real diagnostics available.
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