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Premium Member 2002 R170 SLK V8 5.0
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Do like I said make up a Jumper Wire with 4 Wires, twisted and taped into one, stick a croc on the single end if you wish, that is the end you will attach to B+, wire the 4 separate ones into the other relays output wiring plug(s), (i.e direct into Fuel Pump Wire and the other 3 wires at the connectors) ;)

You are thus eliminating K40 and powering up all Circuits except Horn direct from Battery + and can now see if the darned thing cranks and starts when you turn the Key, if it does, then we can go from there ........................

Best to turn Ignition Switch on, then attach power to Battery, then quick smart back to Key and turn it to Crank, (we don't want Drive Auth to think it's being hot wired and create a red herring) :(

I think we've already had a few of those ;)

Use an assistant on the Key if you must, but it won't hurt the Fuel Pump to run for 30 - 60 seconds without Cranking the Motor ;)

There is several good reasons I am asking you to do this, and I think it will at least Crank then, but if all else is good you can expect it to start up too, if it does, drive it up and down your drive slowly !!
 

Premium Member 2002 SLK320
Joined
810 Posts
Where does the signal to fire off the relay to close come from?whatever feeds that is not closing the relay.
Your question demonstrates the limitations and frustrations of fault finding the traditional way. According to the wiring diagrams on the R170 DIY page (page 24/73), the signal to operate the fuel pump relay comes from the engine control module. What inputs this control module uses to decide to operate the relay is not apparent from reading wiring schematics.
I would follow Dave's recommendations if I were you.
 

Premium Member 2002 R170 SLK V8 5.0
Joined
4,165 Posts
Especially since we have very likely ruled out dud ECU, Key & DAS / RF by fitting another set (of course SDS will confirm that for certain) ;) .......................

But, in the abscence of SDS .....................

All along I have suspected a power failure or earth, so now I want to take K40 and Wiring TO K40 out of the equation completely, and simply simultaneously Power the 4 Vital Circuits at the Wiring FROM the K40 ;)
 
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Premium Member 2002 R170 SLK V8 5.0
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the signal to operate the fuel pump relay comes from the engine control module. What inputs this control module uses to decide to operate the relay is not apparent from reading wiring schematics.
Thanks @Australian

I forgot to answer that ...............

That is part of ME ECU Programming Strategy .................

ME ECU sees Ignition On when K40 fires a 12V at it via one of the Relays, ME ECU then starts the Pump via it's Relay in K40, if Engine isn't cranked or started within 20 seconds ME ECU then shuts off Pump via the Relay.
If you then crank the Starter ME ECU now starts the Pump again via the Relay, and if she starts up ME ECU then keeps the Pump Relay engaged, ME ECU detects a running Engine via CPS input and maybe others ;)

Clearly as the Relay and the Pump are not engaging I'd bet a case 'o' Beer that that Engine ECU has a power feed voltage missing, which is why when he pushes on Relays he can hear the likes of Throttle Butterfly or Air Valve motors initialising.

* I also said a way back that that pushing on Relay Contacts is a bit of a pointless test although it has given me some insight here tbf ;)

This isn't Rocket Science, it's an MB Car ;)

With those Circuits "hot wired" If the darned car now Cranks and likely then will start, (perhaps after a few tries), anyone wanna bet me more beers that a new K40 from MB will cure it ??????????????????????????????????????????????

I also mentioned Ignition Switch but that got discounted "because other stuff worked" :cry: .......................
I would test it if the 4 hotwire doesn't work, how hard is it to make a simple test lamp from a 21 Watt Bulb, Multimeters are as I said, a waste of time on MB's when checking Power Circuts, because of all the Voltages that feedback from all the Electronics on board .........................

:rolleyes:
 

Registered 1998 SLK230
Joined
86 Posts
Discussion Starter #45
Ok,maybe my thick head may understand your relay bypass suggestion now. I did not catch that the intent was to skip 4 k40 relays. My head was thinking 4 wires of 1 relay and that made no sense.

I am In no hurry as rainy winter has descended on WA state and the conventional solution has been rather fun for me, but proven frustrating to those that have it or spend the money to use at a shop. If no luck comes my way, I鈥檒l get a tow trailer rented and take a day off work to have a shop sds it.


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Premium Member 2002 R170 SLK V8 5.0
Joined
4,165 Posts
I鈥檒l get a tow trailer rented and take a day off work to have a shop sds it.
Surely that will cost you more than buying the SDS ?

Try that Hot Wire trick, I'm very confident it will at very least run the pump and allow it to crank, but likely it will start so you can get a listen to the motor, after all, there is no risk, when you turn ignition on your K40 should always be applying 12V + Battery Power to those circuits ;)

And besides that we all wanna know if it will Start and Run before next spring :ROFLMAO:

And if for some reason it doesn't I'll have a deeper delve and see if I can suss it out for ya, I'm not just guessing here, I have a fair old reputation for sorting out many Mercedes via Forum posts ;)

HTH ;)
 
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Premium Member 2002 R170 SLK V8 5.0
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BTW, you do realise that if you have SDS myself or someone else can Team Viewer it at a mutually suitable time and diagnose it for you ?

You then get to watch what the TV'er is doing so you can understand how to work it yourself, or you can read my noobie guide and get the basic gist ...................

The other thing with this is, you may take it to a shop, they plug in SDS and find it's not communicating, because ME ECU is not getting the power it should, so then you're paying by the hour or wasted the Trailer and the 1 - 2 hrs SDS time ...............................

It honestly makes no sense to me for you to just chuck down the toilet $300 - $500 + $$$ for your day off, or waste of a days holiday when you and the guys on this Forum can fix this together ;)

:)
 
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Registered 1998 SLK230
Joined
86 Posts
Discussion Starter #48
Kind of reluctant to post more. No luck with the wired bypass Dave suggested.

Still no sds and that may end the generous help I鈥檝e gotten due to my 鈥渟tubbornness鈥

I did find a shop that did a scan and reported they could not 鈥榬each鈥 the ecu. Got a brake lamp code which makes sense as that was a previous owner issue getting him pulled over three times by the same cop.

After careful review of wiring diagrams, all three technicians showed my where the PSE is in the alarm/security system as a key part of it running. $615 for new on the shelf 1708000248 pse. A few 鈥渨orking, clean, functional鈥漮nes on eBay for 200. I know mine is completely destroyed and was planning on replacing to get central locking working, but have read on here cars are running with PSE removed, so question if it really can stop the cranking process.


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Premium Member 2002 R170 SLK V8 5.0
Joined
4,165 Posts
I'm gutted for you, and this is gonna sound harsh, but intended to help .....................

I did say to beware of a Garage, I am almost certain that they did not use SDS and even more certain that they don't know much about MB's, and how they work.
PSE is in the Alarm / Security System yes, but it has NOTHING to do with Drive Authorisation, you can take the PSE out of the car and it will still start !! (that is one of my clues that they have no clue)

The fact that they can't even communicate with the ME suggests that there is a Power / Earth missing, did you / they try both ECU's even without swapping the Theft Relevant Parts that go with it ?
It can still communicate despite not having the correct Drive Auth ;) (second clue) ................

That set you bought, which came from who knows where originally, might be dud, wouldn't be the first time I've had dud stuff sold by dishonest EBayers ???????????????
(NOTE that is not any form of slight on the member here that sold it to you, he bought that set in good faith !!)

Finally, did the Garage use SDS I seriously do not believe they did ;), sounds to me like they are just another Garage that doesn't know that it is essential, and that purports to know it all, then takes your money for an inept opinion / guess etc etc ?

SDS would walk them through guided testing for a lack of comm ;)

You must be at the point now that you could have bought the SDS, certainly that Garage have wasted your money if the best they can come up with is a Brake Lamp faulty 馃ぃ (likely the Bulb Holder connections btw)

Go through the Wiring Diagrams at the ME ECU Plug(s), Car on Charger / Maintainer, Ignition on, use a Test Lamp with a bulb not LED, has it got all the main Powers and Earths at the ME ECU Plugs ?

Use a test lamp with a Bulb, not a Multimeter, and do it with the ME ECU unplugged ;)

EVERY TIME I HAVE ANY CAR WITH AN ME ECU THAT DOESN'T COMMUNICATE IT IS ALWAYS ................

In most common order for a Mercedes ..................

Motor Relays, (in your case K40)

Dead ECU

Wiring (inc Fuses and Ign Switch) from Grounds or Battery / Ignition On Power to Relays

Wiring (inc Fuses) from Relays to ME ECU

Wiring to Diagnostic Socket from ECU

Or in this instance it could be they were using a :poop: Diag Machine, but that said even an old Snap On with the correct 38 pin lead will communicate in some fashion even tho it won't tell you an awful lot, nothing like the SDS will :p ;)

Stick the bloomin car in an Airplane and bring it here :D :D :D

Keep reporting back, despite what you may think this isn't rocket science ;)

Finally ..................

WA is Washington yeah ?

I may be able to find someone nearby you with SDS and knowledge, or alternatively try posting a new thread in the regional section asking for someone with SDS ;)

Don't know if the Mods / Admin can think of a fellow member who can help ya out ;) @jbanks15 @LeonardoDaBenz @Avel Du @savcom @WoZ53 ????????????????????

My Geography is :poop: btw 馃ぃ

I do honestly hope this helps ;)
 

Super Moderator (UK)
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I don't know of anyone in Wa, but changed link to the regionals for Wa.
Best place to ask for regional help.
 

Super Moderator (Canada)
2012 SLK55 AMG w/P30 "Schwarzie"
Joined
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We USED to be able to search on a member's location but with the new (and improved :rolleyes: ) software, we can't (unless Jeff is allowed to--rest of us are barred).
 
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Premium Member 2002 R170 SLK V8 5.0
Joined
4,165 Posts
changed link to the regionals for Wa.
Thanks Myk ;)

I wish I could be more help to the OP now, but I'm running outta ideas without actually being there to test stuff, like I said, if he had SDS I could Team Viewer it and get a clue wots goin' on ;)
I am absolutely convinced there is Power (+ or -) missing somewhere to that ME ECU ;)

(y)
 
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Super Moderator (UK)
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Thanks Myk ;)

I wish I could be more help to the OP now, but I'm running outta ideas without actually being there to test stuff, like I said, if he had SDS I could Team Viewer it and get a clue wots goin' on ;)
I am absolutely convinced there is Power (+ or -) missing somewhere to that ME ECU ;)

(y)
Curiosity.
Where is the ECU located?
I ask because, with pse suffering damage, might it be worthwhile examining the ecu housing for similar?
 

Premium Member 2002 R170 SLK V8 5.0
Joined
4,165 Posts
HTH ;)
Where is the ECU located?
I would say in the Right Hand Side under Bonnet Equipment Box, with Fuse Box on LHS as it's a LHD, my Car is the other way round, but it will be in the same place as the K40, well mine is ;)

Here's another Question for OP .......................

Back away you said that pushing a Relay started the pump and also moved butterfly motors, (you heard a noise under hood) ..........................

Did that happen when you did the 4 wire bypass ?

If it didn't you may just have not done my bypass right, probably my fault as it's really hard to explain exactly which wires to connect to in text, and I don't have a pre facelift car here to take photos etc ;) .....................

If that is the case can you get an assistant to hold that relay down, and you try cranking it when you hear the noise ;)

You need to Turn Ign on and shout now exactly as you do at which point the helper must immediately push the relay contacts, as soon as you here the pump, turn the key further to crank ;)
If it doesn't work first hit, Ign off and try it a few times, just in case .........................

Also, if you can't get joy doing that, swap back to your original ECU / Key / DAS RF Combo, hopefully you didn't put all the Dash Trims back yet ;)

HTH ;)
 
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Registered 1998 SLK230
Joined
86 Posts
Discussion Starter #56
You鈥檝e all been very helpful and I take no issue about calling me out for not getting SDS scan. I am in Washington about 20 miles south of Seattle.

I do have another question. I talked to previous owner and he hopes I get it running soon. He did say that he felt there was a slight delay from when the key was turned to start position before it started cranking. Not much but it did not immediately crank like other cars. Could there be any chance the key switch in the start position could have a failure? I have a complete key switch still attached to a steering column and the key for it. Would swapping it out be any help?


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Registered 1998 SLK230
Joined
86 Posts
Discussion Starter #57
Pse in 鈥渢runk鈥 rear of car famous to get wet from leaking seal it plugged drain. Ecu under 鈥渉ood鈥 in front near battery. It鈥檚 sealed well and spotlessly clean.

I surely could have failed to do the 4 wire test. Noise I heard is in the front, at the pressure regulator, not the fuel pump under the car in the rear.


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Premium Member 2002 R170 SLK V8 5.0
Joined
4,165 Posts
Did you not test the Ign Switch way back when I mentioned it ?

It could be yes, but all MB's do have a split second delay to Crank ;)

What about the press relay crank over test above ? try that first ;)

EDIT :- looks easier to swap the Steering Lock assy but why not test it with bulb first ;) ;)

The noises you here, does that happen when you turn the Ign on ? or only upon pressing the relay ?

As soon as you turn Ign ON (pos 2) then you should hear pump run and a few clicks or whirrs from under the hood.
 

Registered 1998 SLK230
Joined
86 Posts
Discussion Starter #59
I surely missed ignition switch test. I鈥檒l go back and review your advice.

Key in run position always has noise from throttle body area but can鈥檛 remember if fuel pressure regulator always does or it was after relay contact. At work now, so another 10 hours before I鈥檓 under the hood again for update.

Spare ignition in the column has a 10mm bolt with a clamp that i loosened, but appears there is another form of attachment holding it in the column. Looks like an easy plug/swap if it wasn鈥檛 still in the column.


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Premium Member 2002 R170 SLK V8 5.0
Joined
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Test the original with a test bulb first here's the Ignition Switch Wiring Diagram, so you know which color wire should be powered hot in which Key Position ....

(click pic to enlarge it) ;)



Note that Pink / Red is the one that should Fire up your K40 Relays to on and Violet is the Cranking Wire that goes to ECM via Pulse Module ;)
 
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