Air pump failure - any option to remove /disable the pump?

[500Espot]

Postby gsxr on Wed Mar 18, 2009 2:13 am

My E420 air pump had been noisy, and this morning it seized up. Fortunately it happened immediately after I backed the car out of the garage, so I heard the ugly noises from the clutch, and shut off the engine. I disconnected the wire to the clutch, which allowed me to drive the car, but unfortunately the computer knows the pump isn't functioning and it triggers the dreaded Check Engine light.

In case you haven't looked, the price for rebuilt pumps is obscene... $350-$500, plus a core charge. The stupid thing only runs for 1-2 minutes after a cold start, and the only purpose is to help the catalyst heat up faster (which I could really care less about). The bearing is fine, I could leave the pump in place. The non-catalyst engines have an idler pulley in this location but the cost would be ~$250 USD plus S&H to order the bracket+pulley from Germany. But the bigger problem is the computer not being happy, and triggering the CEL on the dash.

Does anyone know how to fool the computers into not knowing the air injection is disabled? Better yet, an EPROM chip for the LH module from a non-catalyst version? I'd sure like to avoid the ~$400 repair bill (and several hours labor to R&R the POS).

:down:
Dave M.
Boise, ID
1995 E420 (W.I.P.)
1994 E500 (Q-ship)
1993 300D (Sportline)
1987 300D (Sportline Stage 2)
1987 300D (R.I.P)
Click here for my website photos, documents, and movies.

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Postby NIIBE on Wed Mar 18, 2009 3:02 am

?????

?I had also removed my Air pump and am driving over 3years.
I have just plugged EGR holes by custum made blind plug and plate.
I do not do any modification according to ECU.

I think it would not cause by air pomp failure.

NIIBE

gsxr wrote:My E420 air pump had been noisy, and this morning it seized up. Fortunately it happened immediately after I backed the car out of the garage, so I heard the ugly noises from the clutch, and shut off the engine. I disconnected the wire to the clutch, which allowed me to drive the car, but unfortunately the computer knows the pump isn't functioning and it triggers the dreaded Check Engine light.

In case you haven't looked, the price for rebuilt pumps is obscene... $350-$500, plus a core charge. The stupid thing only runs for 1-2 minutes after a cold start, and the only purpose is to help the catalyst heat up faster (which I could really care less about). The bearing is fine, I could leave the pump in place. The non-catalyst engines have an idler pulley in this location but the cost would be ~$250 USD plus S&H to order the bracket+pulley from Germany. But the bigger problem is the computer not being happy, and triggering the CEL on the dash.

Does anyone know how to fool the computers into not knowing the air injection is disabled? Better yet, an EPROM chip for the LH module from a non-catalyst version? I'd sure like to avoid the ~$400 repair bill (and several hours labor to R&R the POS).

:down:

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Postby gsxr on Wed Mar 18, 2009 3:05 am

NIIBE wrote:?????

?I had also removed my Air pump and am driving over 3years.
I have just plugged EGR holes by custum made blind plug and plate.
I do not do any modification according to ECU.

I think it would not cause by air pomp failure.

NIIBE


Niibe, what LH module part number are you using? How do you keep the Check Engine light from triggering? That's my main problem!



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Postby 195910 on Wed Mar 18, 2009 1:20 pm

gsxr wrote:
Niibe, what LH module part number are you using? How do you keep the Check Engine light from triggering? That's my main problem!





Hi GSXR,

Had issues with this pump too, the bearing got shot, luckily someone here got the bearings for these. completely useless thing!.
We don't have the Check engine light.

195910

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Postby gsxr on Wed Mar 18, 2009 2:57 pm

I wish mine was just a bad bearing. AFAICT, the bearing is fine, it's the pump internals that are shot. It doesn't turn smoothly like it should, it intermittently locks up. By comparison, the pump on my E500 turns very smoothly by hand. Stupid pump!



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Postby gerryvz on Wed Mar 18, 2009 6:06 pm

Bearing.

Bite the bullet.

Replace pump with rebuild.

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Postby Glen on Wed Mar 18, 2009 7:50 pm

gsxr wrote:I wish mine was just a bad bearing. AFAICT, the bearing is fine, it's the pump internals that are shot. It doesn't turn smoothly like it should, it intermittently locks up. By comparison, the pump on my E500 turns very smoothly by hand. Stupid pump!





My money is on the bearing but if yours is okay, then just gut the pump and leave it connected so the computer thinks its there.

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Postby gsxr on Wed Mar 18, 2009 7:56 pm

Glen wrote:My money is on the bearing but if yours is okay, then just gut the pump and leave it connected so the computer thinks its there.


I was wondering about that. Doesn't the computer look at the O2 sensor readings, to determine if the pump is operating? If not, I could connect a dummy solenoid so it sees an electrical load - that's simple. I thought it would be more complicated. Hmmm. I'll check into that. Anyone have a junk pump they can loan me for an experiment?

About the bearing - at least one of the bearings is replaceable. A guy on Benzworld did that as a DIY, but I think it was the pulley bearing, not the internal pump bearing(s). The pulley (with clutch disengaged) rolls very smoothly, it's the pump center shaft that is iffy. I turned it by hand and had to use a wrench to "crunch" past whatvever was hold it up, and this morning on a cold start it ran normally (that is to say, audibly - it hasn't been quiet in the 1000 miles that I've owned the car). I still need a long term fix, either disable or replace, and I'm shooting for the cheap/free option if possible!



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Postby 195910 on Wed Mar 18, 2009 8:04 pm

Can we use a shorter drive belt and bypass the pump?

195910

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Postby gsxr on Wed Mar 18, 2009 8:25 pm

195910 wrote:Can we use a shorter drive belt and bypass the pump?


No, due to belt routing, a pulley is required in that location. Non-catalyst M119 engines have an idler pulley & bracket mounted in that position, as mentioned in my first post. My main problem is keeping the computers happy. I don't want a CEL on all the time, and I also would prefer not to pull the bulb, but that is an option....



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Postby J. M. van Swaay on Wed Mar 18, 2009 9:00 pm

If the e420 pump is similar to the one on my wife's 94 E320 wagon, you might be able to repair the internals. I attached a picture of what all the parts look like. This one was making noise, I disassembled, cleaned, regreased, reassembled and reinstalled. It's been working quietly now for some time............

J. M. van Swaay

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Postby omegabenz on Thu Mar 19, 2009 3:00 am

gsxr wrote:No, due to belt routing, a pulley is required in that location.



That can be arranged by making a mounting boss, and making/retrofitting a pulley.

I borrowed this pic from your other thread:


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Postby gsxr on Thu Mar 19, 2009 4:26 am

well, (1) I believe it's not worth the R&D, when there are factory parts available for ~$250... and (2), based on the routing diagram below, I'm fairly certain it can't be done without totally changing the belt routing (and belt length), both things I would not want to do. ROI = zero.

I'll be happy if I can disable the thing and make the computer not throw a code. But I'll also look into just taking the pump apart, cleaning it up, and putting it back together. A free fix would definitely be in my budget!


You do not have the required permissions to view the files attached to this post.
Dave M.
Boise, ID
1995 E420 (W.I.P.)
1994 E500 (Q-ship)
1993 300D (Sportline)
1987 300D (Sportline Stage 2)
1987 300D (R.I.P)
Click here for my website photos, documents, and movies.

===================================

Postby will_968 on Thu Mar 19, 2009 5:37 am

gsxr wrote:No, due to belt routing, a pulley is required in that location. Non-catalyst M119 engines have an idler pulley & bracket mounted in that position, as mentioned in my first post. My main problem is keeping the computers happy. I don't want a CEL on all the time, and I also would prefer not to pull the bulb, but that is an option....





Mine was replaced with the non-cat idler and pulley. Didn't do the job myself (garage did it), but I've no engine light on, and they didn't tell me they needed to do anything to stop it coming on.

Will

'93 Mercedes E500
'94 Porsche 968 Sport
'08 Audi A6

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Postby gsxr on Thu Mar 19, 2009 4:30 pm

will_968 wrote:Mine was replaced with the non-cat idler and pulley. Didn't do the job myself (garage did it), but I've no engine light on, and they didn't tell me they needed to do anything to stop it coming on.


Hmmm. I would LOVE to know how they managed that trick. You sure the CEL bulb wasn't removed? You still have an O2 sensor and catalysts, right?



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Postby need2speed on Thu Mar 19, 2009 6:48 pm

I think will is in Dubai, where non-cat models were available so they have both the parts and experience for this conversion. Say Dave, do you have p/n's for the non-cat pulley set-up? Maybe my next project...

need2speed
500E500 owners motto: "Lead, follow, or better yet, get out of the way."

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Postby omegabenz on Thu Mar 19, 2009 7:08 pm

gsxr wrote:well, (1) I believe it's not worth the R&D, when there are factory parts available for ~$250... and (2), based on the routing diagram below, I'm fairly certain it can't be done without totally changing the belt routing (and belt length), both things I would not want to do. ROI = zero.

I'll be happy if I can disable the thing and make the computer not throw a code. But I'll also look into just taking the pump apart, cleaning it up, and putting it back together. A free fix would definitely be in my budget!





My point was that it can be done -whether that can be cost effective or not, that is up to the owner. Maybe S500R on MBworld is doing that delete to his racing engine/race car.

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Postby gsxr on Thu Mar 19, 2009 7:10 pm

Non-cat pulley setup is found in EPC for Euro 124.034, Group 20, subgroup 045, callouts 74 and 80. Actually, it looks like the bracket (Sheave Pulley Console) comes with the idler pulley! Cool, that makes it easier - and cheaper, too:

119-230-03-42

Some different length bolts may be needed to attach it, you can see them in the EPC drawing.



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Postby gsxr on Thu Mar 19, 2009 7:20 pm

omegabenz wrote:My point was that it can be done -whether that can be cost effective or not, that is up to the owner. Maybe S500R on MBworld is doing that delete to his racing engine/race car.


Almost anything can be done if you put the time, effort, and $$$ into it. The question is, is it worth it, and does it make sense. In this case, it really does not. The factory solution is simple, cheap, and retains the stock belt length as well.

:spinsmile:

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Postby brams on Thu May 07, 2009 8:18 pm

Dave,

I'm jumping in late on this thread I know but my Euro E500 has the pump disconnected and it does not log a code in the LH module, my guess that on your car being US, that LH also does not log a code, I reckon that would be done by the diagnostic module which US cars have.

If you measured the resistance of the clutch and then put a resistor across it that might do the trick, you might want to use a big wattage and maybe stick it to a heat sink though in case it gets hot, I'd guess the windings of the clutch are lower resistance, maybe 10 ohms or less. Might pay you to use a 12v bulb instead.

I doubt that the O2 sensors are used to measure the effect of the pump working, seeing as the pump is used to oxidise the exhuast to light the CAT's off quicker then it stands to reason that the O2 sensors would not be feeding back for the same reason (they are not hot enough to work).

Glad you mentioned the bracket, I've been looking all over for that. As I want to throw the pump in the bin on my car.

95 E500 Limited

 

[pesuazo]

Re: Air pump failure - any option to remove /disable the pum

Sorry to revive this old thread, but I would like to know where I can get the idler pulley mentioned in this thread.

I want to remove the air pump and place an idler pulley in its place (if one exists and can be purchased).

Thanks.

PESuazo

 

[J. M. van Swaay]

Re: Air pump failure - any option to remove /disable the pum

You can simply remove the magnetic clutch disc from the front of the pump. There is an allen key hole in the end of the pump shaft, insert key to hold shaft while using wrench to remove nut. With the clutch disc removed, you will have the equivalent of an idler pulley because the pump internals will never turn. (the internals only turn when the magnetic clutch is active thereby magnetically connecting--or clamping--the internal drive shaft to the the pulley that the serpentine belt drives. If the clutch disc isn't there, there is nothing to magnetically clamp)

I recently replaced the pulley bearing on one of my cars and I purposely left the magnetic clutch disc uninstalled. I'm experimenting to see if I get a CEL. If the pump is electrically disconnected, I know you will get a code but I'm not sure what triggers it. If the computer looks for a lean condition, I expect I'll get the code again. If the computer looks for electrical load when the magnet is active, I should not get a code because the magnetic will still activate but it just won't cause the internals of the pump to turn.......

Hope this makes sense.

J. M. van Swaay

 

[gsxr]

Re: Air pump failure - any option to remove /disable the pum

JM, thanks for performing this experiment... I've always wonderered if your method would work to disable the pump. If the computer doesn't look for a lean condition at the O2 sensor, it should work perfectly.

 

[pesuazo]

Re: Air pump failure - any option to remove /disable the pum

I am having the same issue, the bearing on the pulley went bad, hence I have to remove the pump and change the bearing. The pump itself is good.
The horrible sound of the bearings happens without the clutch being engaged, hence the issue is the idler bearing on the pulley.
Question:
Did you have to remove the fan in order to get the air pump out?

Thanks,

PESuazo

 

[pesuazo]

Re: Air pump failure - any option to remove /disable the pum

Found the article to remove the pulley while the pump stays in place.

Will try this weekend.

The idea is just to replace the bearing on the pulley, may be able to save myself a lot of work by leaving the pump in place.

See attached the article.

 

[J. M. van Swaay]

Re: Air pump failure - any option to remove /disable the pum

Yes, the pulley can be removed without removing the pump. It does however take some plier/screwdriver/snap ring plier gymnastics to get the snap ring off. If you don't have one, a good snap ring removal tool might be a good investment. Make sure it works for larger snap rings because the smaller tools don't provide enough opening or strectch to get this ring off. (Ask me how I know...........)

J. M. van Swaay

 

[pesuazo]

Re: Air pump failure - any option to remove /disable the pum

Well decided to take the pump out from the bottom, but the moment I removed the alternator, I realized the problem IS the alternator. Bearings are completely shot!!. It has about 1/8 inch play, and when I spin it, sounds horrible and grinds (although spins sort of freely). The air pump spins smoothly and no sound. Go figure.
I will quote the repair, if close to a new one, I will just replace it.

 

[need2speed]

Re: Air pump failure - any option to remove /disable the pum

FYI, my local dealer has the complete 119-230-03-42 air-pump delete Sheave Pulley Console for CDN $400 (their price). I can ship at cost or on your FedEx account, etc.

 

[diaconovic]

Re: Air pump failure - any option to remove /disable the pum

Hello , there is two version of the air pump delete console
listed in the 124.036 section.

For the 119.974
Up to engine number 5781 , you'll need A119 230 02 42.

Beginning at number 5782 , A119 230 03 42.

For the 124.034 owners , only the 03 42.

 

[500AMM]

Re: Air pump failure - any option to remove /disable the pum

Hi Patrice.

This was really great info!
Out from the EPC is these PNs the bracket only. I guess the pulley, bolts etc.. are standard MB parts.

Since we don't have the Engine Check Light on the EU models, we don't see the fail code. However, the fail code do still exist in the system, but does this affect the engine running in some way or the cats?

-arnt-

 

[Christian_K]

Re: Air pump failure - any option to remove /disable the pum

164€ + Tax in Germany... In my opinion to expensive if you just could remove the clutch and stuff from the original pump.

 

[500AMM]

.
So, finally I concluded to buy the air pump replacement bracket - A 119 230 02 42. This bracket will go on my '92 so it has the early type pulley for 8-slot serpentine belt. The bracket for the later type 6-slot belt is A.........03 42, but the early type will fit on the later engines with the belt running on the inner 6 slots on the pulley. I haven't sorted out the bolt sizes yet, some of the excisting bolts on the air pump bracket is reused, and so far I think one longer bolt is needed. The EPC views are shown in post #10.

Find enclosed some pics. The third last image show a PN which doesn't appear in the EPC, and I guess it is for the mounting bracket only, but the entire bracket is only sold as a complete assembly. The second last image shows the bracket in the approximate mounting position. The air pump delete operation will be done some time next year.

I bought the bracket from Speed Autoteile, Germany, €234 incl. VAT + shipping. I also requested Tom Hanson at MBCC about this bracket, but he reported it NLA in the US.

-a-

 

[samiam44]

I've. Seen threads on rebuilding pumps.928 or 944. They replaced all the bearings.
Only one is difficult.

Mike

 

[500AMM]

I've. Seen threads on rebuilding pumps.928 or 944. They replaced all the bearings.
Only one is difficult.

Mike

Mike,

None of the air pumps in my cars are bad, I'll do the air pump delete to close out one part from maintenance. The air pump is in my mind a totally redundant part running only some minutes on cold starts. It is a "green philosophy" behind the whole thing with only the emissions in mind, which was ruling in the '80/'90-ies. Today is the green budgets quite more extensive considering a components lifetime in total from production, maintenance, scrapping and recycling. So the small amount of emisson they reduce on all M119 engines over say 30 years, is peanuts compared to the consume of resources in keeping the pumps running on the cars. That's my 2 "green" cents..

It's also a nice small weight saving.

-a-

 

[samm]

Re: Stripped bolt heads on distributor rotors: How to remove?? HELP

yes those Beru are in England. Can get them when I get my smog pump delete bracket...I guess a couple of months from now...Cant wait to ge that smog pump off and throw it away!! Will figure a way to avoid the check engine light of course

ADMIN EDIT: Moved this post over from rotor bracket thread here, post #56.

 

[gsxr]

Re: Stripped bolt heads on distributor rotors: How to remove?? HELP

yes those Beru are in England. Can get them when I get my smog pump delete bracket...I guess a couple of months from now...Cant wait to ge that smog pump off and throw it away!! Will figure a way to avoid the check engine light of course

Only way to kill the CEL is to pull the bulb, or disconnect the DM. I'm sure you could find some way to get through CA emissions since the CEL is only a visual, and the pump really does nothing on a warm engine. While it's nice to ditch the pump for the weight savings and reduced clutter, it also won't boost power since it's generally only engaged after a cold start. That said, I wouldn't mind the delete bracket if it wasn't so blasted expensive!

 

[samiam44]

Re: Stripped bolt heads on distributor rotors: How to remove?? HELP

Could we simply make a run of knock-off delete brackets. Nothing golden or hard. Position the idler pulley hole so a inexpensive and common pulley assembly can be used.

Michael

 

[gsxr]

Re: Stripped bolt heads on distributor rotors: How to remove?? HELP

Could we simply make a run of knock-off delete brackets. Nothing golden or hard. Position the idler pulley hole so a inexpensive and common pulley assembly can be used.

Michael

The pulleys are available separately, and not terribly expensive. 119-200-04-70 for 8-rib, 601-200-07-70 for 6-rib.

The bracket is the hard part. There are 2 brackets, one for early engines / 8-rib (119-230-02-42), the other for late engines / 6-rib (119-230-03-42).

Both still appear to be available new according to the MB Classic site (links below), but expensive at $300-$400 USD. On the bright side, the bracket includes the pulley.

http://partssearch.mercedes-benz-classic.com/parts/A1192300242?tt=automatic
http://partssearch.mercedes-benz-classic.com/parts/A1192300342?tt=automatic

 

[samm]

I just hate the clutter and extra maintenance and more reasons that could make the car unreliabel. If I could remove the AC I would as well...

 

[samm]

Re: Stripped bolt heads on distributor rotors: How to remove?? HELP

my other car was built with no AC for UK market. Ive dealt with the summers just fine....

 

[Unavita]

Only way to kill the CEL is to pull the bulb, or disconnect the DM. I'm sure you could find some way to get through CA emissions since the CEL is only a visual, and the pump really does nothing on a warm engine. While it's nice to ditch the pump for the weight savings and reduced clutter, it also won't boost power since it's generally only engaged after a cold start. That said, I wouldn't mind the delete bracket if it wasn't so blasted expensive

(95 M119/ S420)- I have read the several alternator/ secondary air injector configurations. I began the process of deleting my badly ruined pump. It was eating belts. I acquired the upper alternator bracket that is found on 90-92 cars so equipped. I acquired a new lower bracket as well. I was not able to get the 143amp alternator to fit. So I tried a 100amp from a 129. It also had the same problem. Then I was looking at the chart diagrams. (see attached at #540) Though the bracket I have is similar it juts outward on one side and is backwards ( I believe). This bracket would have the threaded side towards the outer portion of the engine which is not correct. To place it correctly the jut would interfere with the belt and fan housing.

I am searching for the correct part and any help would be appreciated. Also, the Conti 2176 belt that the EPC states is for this config is too big.

I see that there is a bracket albeit an expensive one?

Thanks in advance.

Post Script: I will ad that I have seen the idler pulley listed above and it is about a $340.00 part. It will run the standard belt.

 

[Benz]

Running a shorter belt to eliminate the air pump only works on the 6 cyl ? My engine noise is deemed to be this air pump or my alternator. After removing my drive belt the noise was no longer there. I have play up and down on the alternator. When putting a pry bar to each item to use as a stethoscope I hear the noise quite evenly in both items so I guess its process of elimination... Does anyone else sell the bracket other than mb classic if we cannot use a shorter belt.

 

[Unavita]

I should clarify that I am speaking of a W140 M119. The serp config came in 4 different variations. Smog pump beneath the passenger distributor; Alternator beneath the passenger dist.. AND there was a non- smog pump config as well.

 

[Unavita]

 

[emerydc8]

Years ago there was a string where someone rebuilt one of these pumps. IIRC, it was a lot of work and I thought to myself that it would be easier just to go to a junk yard (or Ebay) and get a used pump. There was also some discussion of how to trick the DM out so it would not set off a check engine light if the pump was not engaged on cold startup (just a bad clutch), but it was discovered that the system was a lot smarter than originally thought and no one really knew what it was looking for to keep the CEL from illuminating.

 

[Glen]

Has anyone tried replacing the air pump with an electric one like this:

Mercedes Secondary Air Pump - Bosch 0001405185

Mercedes Secondary Air Pump - Bosch 0001405185

www.fcpeuro.com

Seems like it would be pretty easy to wire up with a relay and some hose...

 

[Unavita]

In my case and as I first noticed when I repaired the pulleys a person who previously worked on the car seems to have bent the bell for the clutch fan.
Additionally, I have figured out why the tensioner is not engaging properly- my error.

 

[Unavita]

30 degrees today and warm enough to work in my (not-insulated) detached.
So- I managed to correct my mistake of using a 2076mm belt (which was routed incorrectly and wrong) which caused the tensioner to work improperly. (Note- I should and will get the .960 idler pulley).
I used yarn to measure 89.75ish inches, drove over to the parts store and grabbed three belts- on what I believe was correct and on a 1/2 inch larger and smaller. A 1/2inch is a lot of travel. I installed the first one measuring 89.5 or 2275 mm and all works well.
My suggestion is to get the right parts and do the job correctly. It took a lot to find the information for the engine without a smog pump and it's config. That is due to my inadequate search resources. What GSXR stated promptly is correct. Should do this make a not of it in your maintenance log. Cheers!

 

[Unavita]

I have not tried an electric pump but what be curious as to it's configuration.

 

[anderzen]

I was just talking to Petyo of the Kangaroos Team about this, he had a pretty built up M119 used for drifting years ago and stripped a lot of unused components including this... he essentially removed the pump and kept the bracket, then used a 6 rib pulley with a machined pieced he added onto the existing bracket. Won't be in the same location as pump was or as the delete bracket but will still work. I am planning to do a refresh on engine stand soon, will share what I come up with. I will be deleting this and EGR and simplifying anything that can be....

 

[500AMM]

That sounds interesting! It is fully possible to make a custom solution, but you may have to use a different serpentine belt length, but it's a lot of various lengths to pick from.

 

[anderzen]

yea banking on different belt length but that should hopefully be the easy part... especially with time of it being on a stand anyway, I'll do my best to come up with something good.