Help please. My R129 won't start.

[Monkeytrousers]

from

Mercedes: cold start injector..power during crank..controls…

I have a Mercedes 1990 R129 500SL. The cold start injector is getting any power during crank. I have no luck in - Answered by a verified Mercedes Mechanic

www.justanswer.com

Might help to take a photo of your electrics and post it on here.
While injection system problems are a distinct possibility I am mindfull you appear to be having some random electrical probs as well

Thanks again guys.
Excellent video & diagram.
Going to go through the fuel system over the next couple of days and fingers crossed I'll get the car to fire up.
Got a new fuel filter coming tomorrow and going to put some fresh petrol in.
I'll let you know how I get on.
Thanks again guys.
All the best.
Glyn.

 

[mikrt]

I'd be tempted to get a friend with a bigger vehicle to give me a tow and bump start it. And keep pulling for a minute after you get sign of life.

 

[Doodle]

I'd be tempted to get a friend with a bigger vehicle to give me a tow and bump start it. And keep pulling for a minute after you get sign of life.

That would be quite some trick to bump start a 500

 

[Deleted member 149005]

Especially an auto.,.

 

[SL300-24]

I would change the dizzy caps, rotors, and seals even though you have cleaned the old ones. Pull the plugs, probably flooded by now and replace them too and I would think you will fire her up. I doubt it will be the injection, I don't think that you have covered the basics properly. These things eat dizzy caps when left standing make sure your battery is FULLY charged too before you attempt to start it.

 

[Monkeytrousers]

I would change the dizzy caps, rotors, and seals even though you have cleaned the old ones. Pull the plugs, probably flooded by now and replace them too and I would think you will fire her up. I doubt it will be the injection, I don't think that you have covered the basics properly. These things eat dizzy caps when left standing make sure your battery is FULLY charged too before you attempt to start it.

Hi SL

I would change the dizzy caps, rotors, and seals even though you have cleaned the old ones. Pull the plugs, probably flooded by now and replace them too and I would think you will fire her up. I doubt it will be the injection, I don't think that you have covered the basics properly. These things eat dizzy caps when left standing make sure your battery is FULLY charged too before you attempt to start it.

Hello SL500.
Thanks for the advice.
I'm gonna go through the fuel system this weekend & try that first.
I've been through the ignition and it seems ok, but I could be wrong.
There seems to be a good spark at the plugs and they are new ones I've just put in last week.
It's also got a new battery on which I have just given a full recharge & I've cleaned the dizzy's & rotor arms which looked pretty good to be honest.
The only thing I haven't done is check the coils with a multimeter as not sure how to.
Thanks again for your time.
Glyn.

 

[Monkeytrousers]

Hello there again.
Just a quick update to say I've pulled all the injectors out and it looks like 2 off them were leaking, so hopefully that's part of the problem. Given them a proper clean & may need to replace 2 or more.
Also cleaned the fuel distributor which didn't seem that bad.
Next up's the fuel filter if I can manage to get to it once I've sussed out the jacking point from behind. (Ooh err missus, young maaaaan!!!) I'll let you know if it's successful.
Thanks again so much to everyone who's helped.
This forum's the best.
CheeRS guy's.
P.s. God, these things are a complicated pain in the ar*e.
But I'm guessing that's what gives the satisfaction when we get it right.

 

[Monkeytrousers]

Hello there again too everybody who's tried to help me with the problems I'm having.
Sorry for the late reply but I've not been well enough to crack on with the old girl.
Just started to work on her again, but she's still not playing. I'll let you know how I get on if that's ok.
Also whilst I'm on here, doe's anybody know if the 3 holes in the air flow sensor plate should be clear. Mine seems to have 2 clear & 1 blocked.
And has anybody had problems with the Fuel Pressure Regulator???
Thanks again guys & hope everyone's well.

 

[ivan1983]

Just to confirm is the fuel pump running after the initial priming?
Guess it's hard to check in the short space of time it's running?
You could try bridging the fuel pump relay so it runs all the time to rule out the fuel pump not running after priming.

 

[amazighman]

After you try to start it , are the spark plugs wet or dry when you remove them?

You could do a pressure test on the fuel system to see if the pump is working at correct pressure.
Flush the fuel system and purge it with an airline

Send your injectors to be checked and refurbished...

Check there is no vacuum leak anywhere on intake pipes after MAF.

 

[grober]

POST UP your VIN number
have you got an aftermarket alarm/immobiliser?
have you got an EZL ignition unit?

 

[grober]

ADDED to above

K6JRF Auto Page

K6JRF Auto Page

My Mercedes S500 Coupe

www.k6jrf.com

 

[Monkeytrousers]

Hello again guys.
Sorry for the late reply but not been well enough to get under the car until yesterday.
I've drained the fuel out and it looks like varnish & also there was quite allot of debris that came out as well.
Gonna fit another new fuel filter today if I can but just wanted to ask if there's anyway I can clean the fuel tank whilst in situ.
I've seen some posts online that say it can be flushed using water but that sounds a little bit strange to me.
Also I know its probably a silly question but I'm guessing the arrow on the filter points towards the back of the car.
Thanks again guys, you've all been brilliant.
All the best.
Glyn

 

[alabbasi]

Don't add water. You'll never get it out. The allow represents fuel flow so it should be pointing away from the tank

 

[Monkeytrousers]

Hello there Alabbasi.
Thanks for your reply pal.
Would you suggest running fresh fuel through it then until it runs clean?
The filter has been removed & I've blown through the tank and also through the lines that come from the fuel distributor with compressed air.
Thanks again for your advice.
Glyn.

 

[alabbasi]

Hello there Alabbasi.
Thanks for your reply pal.
Would you suggest running fresh fuel through it then until it runs clean?
The filter has been removed & I've blown through the tank and also through the lines that come from the fuel distributor with compressed air.
Thanks again for your advice.
Glyn.

I suggest directing the fuel pump inlet pipe to a jerry can with fuel in it and removing the tank from the equation. If you can get the car to run using a jerry can, then i would take the tank out and have it professionally cleaned. Unless you saw rust, a full tank of fuel will eat away at the varnish and burn it off slowly.

When doing this, make sure you block the fuel tank exit hose as the return fuel will go back to the tank.

If you can't get the car to run, you'll need to focus your attention elsewhere. Probably back to the Fuel pump, fuel distributor or injectors.

 

[Monkeytrousers]

Hello again allabassi.
Thanks again.
There was rust & debris coming through yesterday but I've flushed it through with some clean fuel and its coming through pretty clean with no more rust.
I've also taken all the injectors out again and cleaned them.
I'm going to pull the fuel dizzy of tomorrow & clean that again.
Would you try it with new fuel & filter OR get the tank professional cleaned first.
Thanks again pal & all the best.
Glyn.

 

[219]

That would be quite some trick to bump start a 500

Entirely doable as long as not for a flat battery

 

[219]

Especially an auto.,.

MB autos can be easily bump started : up to 30mph in neutral - drop into drive , or even 3 .

it is in the owners handbook

 

[219]

Hello there again too everybody who's tried to help me with the problems I'm having.
Sorry for the late reply but I've not been well enough to crack on with the old girl.
Just started to work on her again, but she's still not playing. I'll let you know how I get on if that's ok.
Also whilst I'm on here, doe's anybody know if the 3 holes in the air flow sensor plate should be clear. Mine seems to have 2 clear & 1 blocked.
And has anybody had problems with the Fuel Pressure Regulator???
Thanks again guys & hope everyone's well.

If by fuel pressure regular you mean the fuel accumulator under the car , these are a common fail point .