320SL Won't Start

[Jetset]

Hello to all, I have a problem with our 1998 320SL and have just registered on the forum to get some guidance on what may be wrong.

The car was locked away in the garage for the Winter of 2007 and due to Summer not appearing in 2008 the car never saw daylight. Yesterday I elected to charge the battery up and run the engine, however, I can't get it to start. I'm a competent DIYer, and armed with a Haynes manual (which I don't yet have for the SL) I'll tackle more or less anything - except in-depth engine work!

So anyway, here's what I've done so far :

Fuel - checked, and plenty of it flowing under pressure at the fuel rail.
Plugs - checked, good sparks on all.

If I pour a small amount of fuel down the throttle butterfly-valve housing then the car will start and run for a few seconds until that fuel is used, and then stop.

Any ideas what I should try next.

Additionally, although the remote key battery is good, (2 batts at 3.2V each) it won't lock/unlock the doors, and there's no red or green lights in the rear view mirror housing as there was previously.

 

[Quick Silver]

Disconnect battery earth strap for 60 secs then reconnect that should cure the remote locking , Modern unleaded fuel goes stale and goes jellyish over a long period of time if not used , drain and refill with fresh fuel and wash out the fuel filter with clean fresh petrol or replace the filter.

 

[television]

Another thing that you can do after reconnecting the battery

Cars as of 12-94 with part number 210 820 21 26,
210 820 22 26 also 210 820 27 26 and 210 820 28 26 also 210 820 32 26 point remote key at receiver in interior mirror. press remote button momentarily twice, turn key in ignition lock to position 2 within the next 30 seconds.

or

Cars as of 01-94 with control modules 202 820 40 26 and 202 820 43 26. Switch on ignition with folding key within next 30 seconds

Welcome to the forum

 

[Jetset]

UPDATE - Thanks for the advice so far. I put 10 ltrs of fresh fuel in the tank, disconnected the fuel feed line at the injector rail and cranked the engine to flush around 5 ltrs of fuel through the sytem and back into the fuel can, so the fuel is good. I then checked the voltages on the injector plugs and all were OK, but I noted yesterday when I cleaned the plugs that they were damp with fuel so I suspected the injectors were OK anyway.

I reconnected everything and turned the engine over, still no start. I again poured a small amount of fuel down the throttle butterfly valve housing and tried the engine again. As before it started and ran well for a few seconds but stopped when that small amount of fuel was burnt off.

So I'm still no wiser, what next??

On the remote locking issue, I disconnected the battery for at least 60 seconds, reconnected it, pointed the remote at the interior receiver, pressed the button twice and then turned the ignition to pos II within 30 seconds - still nothing. As I said before the remote batteries are of good voltage and I'm getting a light on the key when I press the button.

More suggestions please.

 

[Ellsy Tanners]

I think the imobiliser is the key here, if your not getting your green led then its not decacitvated and is not allowing it to start.

 

[Jetset]

PROBLEM SOLVED - For whatever reason (grasping at straws perhaps!) I elected to check all the fuses in the engine bay fuse panel, and lo and behold I found fuse 15 (Air Conditioning Control Unit/IR Remote Control) blown. I replaced the fuse and got a red light in the rear view mirror housing, so I pressed the remote control button to get a green light and the car started.

So as Ellsy said it must have been an immobiliser issue.

I turned the car off to resecure all the bits I'd been messing about with in the engine bay, and noted a small whirring/whining noise from a cricket ball-sized unit attached to the top of the offside suspension turret. My initial thoughts was that it was the alarm siren, but whatever it was doing caused fuse 15 to blow again, so I disconnected it temporarily, replaced the fuse, and got the car running again. Whilst the car was getting up to temperature I noted that the heating/air con control panel wasn't behaving as it should, so my thoughts turned to the cricket ball type object, which I reconnected. It started whirring again but this time it didn't blow the fuse, and the heating/air con control panel began working correctly so I guess the unit has something to do with the heating/air con system. I must get a Haynes manual as this would have told me what it was.

However, all is now well.

 

[Quick Silver]

But why did it start when you ingested fresh fuel fuel pass the the throttle butterfly and run till the fuel was exhausted ? I'm now confused ! I'm glad you got it sorted anyway .

 

[television]

But why did it start when you ingested fresh fuel fuel pass the the throttle butterfly and run till the fuel was exhausted ? I'm now confused ! I'm glad you got it sorted anyway .

My thoughts as well

 

[Jetset]

Puzzling indeed. I'll remove fuse 15 later on and see what happens.

 

[television]

Its worth cleaning all of the fuses with a good cleaner,non drying, its possible that you just touched another that had a bad connection

 

[Jetset]

That's a good point TV.

So, with the the driver's window down and bonnet open, I locked the car using the remote, removed fuse 15 and then turned the key. The engine turned over and the indicators started flashing, but no start. I then did as before with a small amount of fuel down the throttle butterfly valve and turned the key again. The engine turned over with the indicators flashing again, and as before the engine started for just a few seconds until the above fuel burnt off. Strange n'est pas!

It may be just one of those things I suppose. :-?

I'm now going to make sure I start and run it once a month when not in use.

 

[Jetset]

Malcolm - from what I've seen of the website so far you appear to be quite the Oracle, so could you (or anyone) tell me what the cricket ball-sized object is that I mentioned earlier? it's attached to the top of the offside suspension turret inside the engine bay. I've looked through the parts diagrams on the Russian website but I can't find it.

The reason I ask is that it doesn't sound at all healthy. As I said earlier, it blew fuse 15 which in turn contributed to the starting problem, and now it's making a constant noise (with the ignition on or off) which sounds like there's some electrical arcing going on inside it, the noise doesn't even stop when I lock the car up.

 

[television]

For the 129063 it is the alarm,,55 in the link

http://www.detali.ru/cat/oem_mb2.as...GA=722.607&CT=F&cat=44F&SID=82&SGR=525&SGN=23



On a RHD car its on the near side

 

[Jetset]

Thanks Malcolm, that's exactly the right part.

As ours is a 129063 why is the unit not pictured in the 129063 alarm system diagram HERE, and yet it is pictured on the 129064 diagram link you gave?

Must find a price for a replacement, doing a rough calculation from the website it looks to be around £130. The unit does have a couple of screws on either side but when you remove them it doesn't seem to make internal access any easier, but I'll have another try.

 

[television]

You are in the wrong section, go to the main page,then 82 then 540

 

[Jetset]

Hi Malcolm, the link I gave above is to the following page :

Model = 129063
Catalog = 515
System = 82 ELECTRICAL SYSTEM
Illustration = 540 BURGLARY ALARM SYSTEM AND INFRARED CLOSING SYSTEM

....and as you can see the cricket ball-sized alarm unit is not pictured.

The link you gave above goes to the following page where the alarm unit is present and correct :

Model = 129064
Catalog = 44F
System = 82 ELECTRICAL SYSTEM
Illustration = 525 BURGLARY ALARM SYSTEM

Strange!

 

[television]

Changes often took place before a model change.
The 129063 change took place in 08-08 where it became the 129064 and V6 engine, and this have been the case with the alarm, unless it has been updated, thats all I can think of

 

[Jetset]

Malcolm, could you clarify your comment above about when the change from 129063 to 129064 took place - 08-08?

Looking at the parts diagrams it appears that under 129063 the alarm system would activate the car's horn whereas on 129064 there is a dedicated siren unit. Our SL was registered in August 1997 and is a 129063 so I'm puzzled why it has the 129064 siren fitted!

 

[television]

The change was when MB introduced the V6 engine, and 17" wheels became standard, that was in 08-1998 and the car from this point on was the 129064.

What could have happened was that the original alarm went faulty and it was updated, or the alarm system was updated during 1997 during manufacturing.

The same thing happens on later cars like the 230475, where the Comand went wide screen and the D2B bus went over to MOST, I believe that the new SL 06-2006 is still a 230475

 

[Quickbrit]

Would that not indicate that the imobilising system on a Merc is fuel pump related?

Cut the fuel, cut the ability to run. Simple but effective.

MikeE
Just my 2c's

But why did it start when you ingested fresh fuel fuel pass the the throttle butterfly and run till the fuel was exhausted ? I'm now confused ! I'm glad you got it sorted anyway .