Strange problem with 129sl, 1991

[eggy91sl500]

Fitted lowering springs today, all fine there, But since getting the car off the ramp, the fuel pump is sqeeling its head off when driving,
It's a16 port diagnostic connector.
Fault code 17 is showing up in port 8.
(distributor ignition,
HFM sequential multi port fuel injection /ignition system.

Pressurised engine control.

Any suggestions what to look for.

Thanks

 

[LostKiwi]

I'd be having a good look at the pump. It may just be coincidence.
Also check there's no pinched fuel lines.

 

[eggy91sl500]

Thanks again kiwi, I was thinking about a squished pipe from the pump, as it is pretty close to the jacking point, so will have to get the car up on my own ramps and get a better look.

 

[eggy91sl500]

Update, can't see any damaged pipes.
Car seems to be getting far too much fuel, fumes would knock you out,

I cleaned the crank sensor (looks pretty new)

Previous owner has fitted s, steel pipes from the manifold to the back box, so no cats, but can't see any 02sensors.

 

[eggy91sl500]

Sorry still bringing up code 17 in port 8.
As I delete the code, it comes on as soon as I start the car.

 

[LostKiwi]

The O2 sensor is about halfway down the car (if fitted). Where the cat would have been.

 

[eggy91sl500]

Nothing on there, no hanging wires.

I have ordered a new fuel filter, and might just try a new Fuel pressure regulator.

This has me stumped.

 

[LostKiwi]

The connector for the lambda is a plug in the side of the transmission tunnel. If it's been unplugged the connector should still be there.

 

[eggy91sl500]

Will have a look at it tomorrow, spend the day checking everything and let you know how it goes

 

[mioba]

You mention the crank sensor (looks pretty new). Was this replaced by you previously. It could be a cheapo aftermarket part and Mercs just donlt like cheapo aftermarket parts.

 

[eggy91sl500]

Today, s update.
Took the car back to the mechanic (mate) found out its wasn't the fuel pump sqeeling, there's a type of valve on the front +rear anti roll bars, like a hight adjustment thing, and the rear one was pressurising the steel pipes that run up below the driver side, also the pump at the ASR was hot, we disconnected the rear one (well broke it) now no noise, and no heated ASR.


Any idea what this thing is.

Thanks

 

[LostKiwi]

Pictures might help?

Doesn't sound like anything I've seen on mine?

 

[eggy91sl500]

Wouldn't know how to put on pics, lol
Just about my limits here now.

 

[LostKiwi]

Do you have a switch like this on your console below the radio?

 

[eggy91sl500]

No mate, I will get pics tomorrow and my wife will put them on for me.

 

[eggy91sl500]

Just found out, the valve I'm talking about is for self levelling suspension, but previous owner has done away with it, and fitted sachs shocks, so I shouldn't need to use this system,
Am I correct.

 

[LostKiwi]

Was never aware of 129s having self leveling without having ADS (hence the question about the switch).
Looking at the parts catalogue it appears there may well be a model with rear self leveling only as well as the full ADS implementation. A VIN decode may tell what yours had.

 

[eggy91sl500]

Sorry mate, yes I have that switch you posted also one beside the switch for turning the lights on, think on my last 129 this raises the front.

Vin wdb1290662f014751

 

[LostKiwi]

Ah that makes sense now. That switch is ADS - the forerunner to SBC on the 230.
Someone at some point has removed ADS (not too surprising given lack of skills in general garages plus cost of components though it's a shame as it's not a bad system).

 

[eggy91sl500]

So do you think that it will be OK to just leave it as it is (disconnected) the steering seems to be working fine.