300E starting problems

[300E Mike]

For further info, I have had the ECU out and checked that no damp had got into the casing (it hadnt, although damp had destroyed the internals of the original ovp relay) and have also cleaned all the pins of the multiconnector block with contact cleaner and treated the ECU pins in the same way. Was also VERY careful not to touch the board or pins of the ECU, as I know just how easily static in your body can affect these components. I learnt this MANY moons ago by killng a brand new PCB for a central heating boiler by not earthing myself out and then touching the terminals as I fitted it! Ooops but hey, once bitten, twice shy and all that!!!

 

[grober]

There are 3 things fed by the OVP in an 89 car [tho you have always to to wary of revision dates! ]- the cis-e unit, the abs unit and the idle speed valve !!! might be worth temporarily disconnecting the ABS unit or the the idle speed air valve in turn just to see if they aren't affecting the voltage going to the CIS-E unit. There is a diode/diodes in these OVPs which might be toast by now if there are "spikes " in the system.
Certainly worth changing the seals since they are probably "getting on a bit" now. goes back to dieselman's suggestion of a manifold leak.

 

[television]

There are 3 things fed by the OVP in an 89 car [tho you have always to to wary of revision dates! ]- the cis-e unit, the abs unit and the idle speed valve !!! might be worth temporarily disconnecting the ABS unit or the the idle speed air valve in turn just to see if they aren't affecting the voltage going to the CIS-E unit. There is a diode/diodes in these OVPs which might be toast by now if there are "spikes " in the system.
Certainly worth changing the seals since they are probably "getting on a bit" now. goes back to dieselman's suggestion of a manifold leak.

Thank you for waking me up, as I said earlier when the OVP relay is faulty there will only be 7.5 volt on pins 87 so this is easy to test-

With the OVP in, measure the voltage on pins 87 and they should be 12v and also check on both side of the fuse on top.

Owing to the difficulty of reaching the pins, it would be interest to see what happens if you bridge 30-87 on the relay with a wire

 

[Dieselman]

At the end of the day you only require three things to make the engine fire up, compression, spark of high enough voltage and correct timing and fuel/air mixture.

You can check the compression easily enough and you can check the spark power and timing easily enough.

It doesn't matter what may be before the ignition as long as it can supply both these requirements.
The flash tester and timing light will test thre HT side more than adequately.

I'm sure your problem is either weak spark or lack of fuel caused by either vacuum leak or distributor fault.


Always start at the symptom and work backwards towards the cause, not the other way round.
Use a vacuum gauge to determine the state of vacuum when running and spray brake/carb cleaner round the joints as a test.

This is a problem not disimilar to KLP SEC560 which was a vacuum leak caused by the EGR valve. Try blocking all the vacuum take-offs an see then.

 

[300E Mike]

Hmmm. will give all the helpful suggestions a go soon (if it ever stops raining, the joys of living in the lake district in winter!!) I am currently also trying to aquire a written off s320 (1999 model) at a reasonable price at the moment as a back up plan for transplanting the running gear into my old girl. could make an interesting conversion without too much difficulty (I hope!!) As the W124 has plenty of engine bay space. I think worst case will be having to alter the sump pan and possibly engine and gearbox mounts? Maybe not though as I believe that this was the same engine as fitted to the later E320 Which, although it was a V6, should go in to the older shell without too many nightmares? (unless I'm sadly misinformed?) :bannana:

 

[MBManInKen]

I am currently also trying to aquire a written off s320 (1999 model) at a reasonable price at the moment as a back up plan for transplanting the running gear into my old girl.

How would that work? You would need to transplant all the electronic kit, the W220's data network, etc. Perhaps not entirely theoretically impossible, but surely near impossible from a practical POV?

 

[300E Mike]

Having been an electro mechanical engineer for as long as I can remember, I can see where you are coming from with having to transplant all of the electrical equipment also but not beyond all possibility at all, as most control systems have dedicated wiring harnesses etc and it is "simply" a case of removing them from the accident damaged donor and installing them to the subject vehicle, connecting to appropriate points of the existing harness as required. As I have said, this is also simply a back up plan for if I cannot succeed in making the existing powerplant run correctly, some older parts are now becoming difficult and/ or prohibitively expensive to source so why not upgrade the power train to something a little newer?

 

[Ian B Walker]

I just want to get this right. You want to put a V6 into a 124? You may suffer from steering box problems. The way around that is to fit a steering rack from a later car, preferably a CLK. This mounts just behind the front cross member, you will have to fabricate two brackets. You will also have Torsion bar problems too as it will hit the sump of a a V6. There is a way round this too. Place a 25mm spacer on the chassis to torsion bar bracket. Nice to know you know all about electrics, fancy a job on a project I am undertaking Guaranteed to keep you busy for a couple of weeks.

 

[LastMinute]

Mike,

Nothing is impossible, but the differences between a W124 300E and a W220 S320 are enormous. There's the obvious difference in physical layout, and the electronics are two generations apart. You may be surprised at the extent of what "simply" needs to be transplanted just to get the engine to start...

Are you perhaps thinking of the W140 S320? That had the same basic engine (M104) as the E320, so would be a significantly easier transplant than an M112 from a W220 - though even then there may be a lot of extra electrickery that could make the task less than straightforward.

Good luck - and keep us posted if you do go for a transplant!

 

[MBManInKen]

The W220 is a fully integrated environment, with a data network over which all these components communicate. Would it not be necessary to transplant the gearbox and its electronics, the whole ESP system which interacts with engine management, etc? I don't think it's just a matter of a few looms to be honest.

 

[television]

The W220 is a fully integrated environment, with a data network over which all these components communicate. Would it not be necessary to transplant the gearbox and its electronics, the whole ESP system which interacts with engine management, etc? I don't think it's just a matter of a few looms to be honest.

The ESP (1998) runs in BAS (1996) I do not think that you could add it all

 

[MBManInKen]

The ESP (1998) runs in BAS (1996) I do not think that you could add it all

Not again, Malcolm!

ESP predates BAS. Braking Assist is an additional function of the integrated system. ESP does not run "in" BAS at all.

From this site:

1995: Eine weitere Innovation von noch grundlegenderer Bedeutung wird zeitgleich eingeführt und gehört seither zum serienmäßigen Lieferumfang des S 600 Coupé: das "Elektronische Fahrstabilitäts-Programm ESP", das den Fahrer bei Fahrfehlern unterstützt, indem es sensorgesteuert durch gezielten Bremseingriff dem instabilen Moment entgegenwirkt und damit zur Fahrsicherheit beiträgt.

and

1996: Mercedes-Benz präsentiert als Weltneuheit den Bremsassistenten, eine Innovation, die der aktiven Sicherheit dient. BAS ist in der Lage, Notbremsungen zu erkennen und bei Bedarf automatisch und in kürzerer Zeit als bisher die maximale Bremskraftunterstützung aufzubauen. Der Bremsweg des Fahrzeugs wird dadurch entscheidend verkürzt.

 

[television]

Not again, Malcolm!

ESP predates BAS. Braking Assist is an additional function of the integrated system. ESP does not run "in" BAS at all.

From this site:

and

Sorry thats impossible, for a start the car needs to have ABS, BAS is an extension of this where braking can be done individually. ESP uses the BAS and cant work without BAS.


You find me one car that has ESP and no BAS the C class and the 129 are ideal examples for looking this up

 

[nick mercedes]

I have a 1989, 300E which has been laid up for a couple of years. It was laid up because the ignition module and crank sensor had packed up and I didnt really have the tipe to sort them out. It was running great prior to these parts giving up. I have now replaced these parts and it is a SWINE to start from cold!! I removed the ovp relay, and it started much easier so this was replaced (at £96 from my local merc garage!) but still poor starting. Ive checked the cold start injector and rotary idle valve (which seems to be working ok), Stripped, cleaned and rebuilt the fuel distributor and checked for any vaccuum leaks, changed the plugs, checked through the wiring etc etc. Im now at my wits end!!!! can anyone offer any advice? The annoying bit is that once it starts and has been given 5 min to warm up, it runs really smoothly and drives well. frustrating damn thing!!!! any suggestions offered will be gratefully recieved

What's the dizzy cap like?

 

[MBManInKen]

Sorry thats impossible, for a start the car needs to have ABS, BAS is an extension of this where braking can be done individually. ESP uses the BAS and cant work without BAS.

Malcolm, I am getting a bit fed up with having to have these same discussions every few months.

ABS = anti-locking
BAS = brake assist (increase braking power in emergency stop)
ESP = electronic stability programme (counteract over/understeering)

You find me one car that has ESP and no BAS the C class and the 129 are ideal examples for looking this up

My W140 had ESP but no BAS.

Mercedes started to fit antilock brakes (ABS) to their cars decades ago. Then, ASR made its entrance. ASR controls traction to avoid slip.

If you combine ABS with ASR and yaw control, you have an ESP system.

BAS is a system that recognises when the driver makes an emergency stop and then applies maximum braking pressure. This was done because research has shown that people tend not to brake hard enough in an emergency.

There is also EBR, which ensures that braking power is properly balanced between the front an the rear end of a car.

All these functions are logically separate, even though in terms of implementation they share of course components and software on a modern car. The systems are integrated, but that has nothing to do with their logical scope.

So, you do not need to have the logical function of BAS (brake assist) in order to have a fully functional ESP (stability control) system. ESP detects and counteracts understeer and oversteer. That does not require the function of enhancing emergency braking as per BAS, and in fact the W140 s-class had a full ESP system well before it had BAS.

 

[grober]

Me I would get the w124 working first! Suffice to say its a much simpler and cheaper car to set up than a W220. Personally with your car and todays motoring climate the engine to go for would be the straight 5 cylinder diesel 270--- C270,E270,CLK270 ---bags of torque and 170 bhp with economy with a 5 speed auto. NOT that I'm suggesting this mind!!

Moving on does your car have a rotary idle actuator or an auxiliary air device??

 

[television]

taken from
508 HO Part 4-ESP (WJB) 04-01-01


ESP Function
BAS +
ABS +
ASR +
EBR +
= ESP

BAS is switched off if:
• BAS release switch not operated
• Speed <3 km/h (1.8mph)
• No signal from stop light switch (S9)
• A BAS fault is recognized
• Request cancelled from ESP or Distronic

Just 2 things from the MB training programs I will find the document from the same source.

There were early types of systems running and I am referring to the full blown systems as we know it now.

 

[MBManInKen]

taken from
508 HO Part 4-ESP (WJB) 04-01-01

Yes, we've been there before! This is from training materials (I've got the pdfs as well) that describe the current implementation of all these systems on modern cars.

This document says bugger all about the history of these systems, nor does it imply that an ESP logical function (i.e. stability control) requires the BAS logical function.

The business about how if you disable/remove a certain component of the current implementation of these integrated circuits, you also disable another function is neither intellectually nor practically of any value.

I'll say it again: it is perfectly possible to build a car with an ESP system that has no BAS function as part of it. Even better: the W140 s-class had ESP well before it has BAS.

There were early types of systems running and I am referring to the full blown systems as we know it now.

I'm sorry, but that's another intellectually unreasonable argument as it implies that cars with ESP before they also had BAS were somehow less capable in terms of stability control than the later cars.

On a modern car, logically separate functions end up being integrated in terms of implementation, i.e. they share sensors, electronics, software, etc. That is absolutely no argument for silly statements like "ESP works in BAS" or "you cannot have ESP without BAS", both of which are absolute nonsense.

The German quotes I posted earlier represent the official timeline of these systems' development and clearly show how ESP was there well before BAS. Also, to quote Mercedes itself:

Brake Assist is integrated into the ESP® system in today’s Mercedes-Benz passenger cars. It uses ESP® technology to regulate braking pressure, making additional components unnecessary.

 

[300E Mike]

My word, I created an argument from being slightly misinformed!! sorry peeps!!!, sorry guys, didnt intend to cause any in bickering Righty ho, I did a lot more research into my idea for a transplant on 'tinterweb last night an I hereby eat a HUGE slice of humble pie. it is possible to do the transplant I was considering however, yes, my theory for taking the engine/ transmission loom from the donor and "grafting" it into my car is possible and it would indeed run and drive (after a fashion) once the steering/ suspension issues were addressed, for it all to function 100% I would effectively have to build all the systems from the donor vehicle into my car. I am now absolutely Knackered from spending hours in front of the comp last night researching this idea and finding that, whilst eminently possible, it isnt really viable, no matter how much sentimental value the car holds. I will have a go at the suggestions previously posted about getting my existing powerplant running well again as I know that the ploblems lay within the ancilliary side of things as the engine has a relatively "youthfull" 126000 miles on the clock and a full service history to go with it so mechanically it should be fairly sound. If all else fails, I will have to either consider Graeme's suggestion of a diesel transplant of some sort or if I decide to do a "autobhanstormer" kind of transplant, look out for a decent V8 engine and box (a-la 400e/500e that were popular in the U.S.) and take things from there. once again, many thanks to all, your comments are most appreciated and it doesent matter how qualified and capable I think I may be at my trade, a fresh pair of eyes and a different perspective is always helpful when trying to get to the bottom of annoying faults that were not present prior to my cars enforced lay up period

P.s. am still looking for a bigger hammer than a 28lb fencing mallet.......

 

[300E Mike]

P.p.s. It has a rotary idle actuator Graeme. seems to turn freely and operates ok if a power supply is put to the terminals though.