Help please. My R129 won't start.

[Monkeytrousers]

That looks like the right battery for your car. If your car starts by spraying ether into the intake or gasoline then you don't have a spark issue. As I suggested earlier, get a little bit of gasoline and pour it into the intake to get it running and keep dribbling fuel bit by bit to see if it will continue running. This will eliminate some guess work around whether it's ignition related / immobilizer etc.

Is the engine in post #14 your engine? If so, it's not CIS , it's the later EFI engines which had wiring harness issues. CIS cars had a fuel distributor with hard steel lines going to the injectors.

Before you buy injectors, you need to determine which injection systems you have.

Hi Alabbasi.
Thanks for the reply.
No that's not mine unfortunately but mine is the mechanically fed with mechanical fuel distribution engine.
This is a pic of mine.
I don't if it matters & I kno I'm taking up allot of your time but just thought I'd ask if anyone knows if the 3 holes in the air flow sensor plate in the pics should be clear as it looks like 2 are clear on mine & 1 isn't.
Thanks so much to everybody who's helping me.
Glyn.

 

[Monkeytrousers]

That looks like the right battery for your car. If your car starts by spraying ether into the intake or gasoline then you don't have a spark issue. As I suggested earlier, get a little bit of gasoline and pour it into the intake to get it running and keep dribbling fuel bit by bit to see if it will continue running. This will eliminate some guess work around whether it's ignition related / immobilizer etc.

Is the engine in post #14 your engine? If so, it's not CIS , it's the later EFI engines which had wiring harness issues. CIS cars had a fuel distributor with hard steel lines going to the injectors.

Before you buy injectors, you need to determine which injection systems you have.

I will try it with fuel into the air intake tomorrow.
I've got a fire extinguisher somewhere so once I find it I'll give it a go.
Thanks again pal.

 

[Will]

If it’s been sitting for that long, your best bet would be to drain the tank and flush the fuel system through. You will have twin fuel pumps, you might find they don’t like sitting around in the old fuel either, and can seize up or struggle to run properly.

If you have the CIS system they are quite fussy on system pressure, and the fuel metering unit and/or injectors could also be clogged.

Remove the plastic panel that covers the fuel pump package, remove the feed pipe that goes into the fuel pumps and you can easily drain the fuel into a container that way. Depending on how quickly the fuel flows out will also tell you if the strainer in the tank is blocked.

Refit the pipes, re-fill with fresh fuel, then remove the main fuel feed pipe fitting that goes into the fuel distributor, jump out the fuel pumps and pump some fresh fuel up to the front end. I’d then leave the pumps connected for a while to circulate fuel back to the tank and keep it flushing for a couple of minutes.

Probably the easiest way to purge some of the old fuel out. If it’s still not running after that, it’s likely you’ll have to clean out and overhaul some of the other K-jet stuff - eg fuel metering unit etc.

 

[Monkeytrousers]

If it fires than dies after a short while, could it be a faulty MAF (Mass Air Flow) sensor?

Hi greenmanslk.
I will try to have a look tomorrow at the MAF sensor.
Can these units be serviced or is it a replacement job pal.
Thanks again.

 

[alabbasi]

Hi Alabbasi. Thanks for the reply. No that's not mine unfortunately but mine is the mechanically fed with mechanical fuel distribution engine.

OK good, after cranking the car to get it started, get a 12mm flare and crack each line open on the top of the fuel distributor (spider looking thing) to see if a little bit of fuel bleeds outs. This will tell you if you have fuel pressure and if the fuel is nasty. Also with the ignition in the on position, push down on the flap and let me know if there's resistance (not too hard).
Also let me know if you hear a whining sound (like bag pipes)

Your injectors may be gummed up. This is common and they are basically brass nozzles that can be freed up with a combination of compressed air and brake clean in a spray can. I can probably talk you through it.

 

[Monkeytrousers]

If it’s been sitting for that long, your best bet would be to drain the tank and flush the fuel system through. You will have twin fuel pumps, you might find they don’t like sitting around in the old fuel either, and can seize up or struggle to run properly.

If you have the CIS system they are quite fussy on system pressure, and the fuel metering unit and/or injectors could also be clogged.

Remove the plastic panel that covers the fuel pump package, remove the feed pipe that goes into the fuel pumps and you can easily drain the fuel into a container that way. Depending on how quickly the fuel flows out will also tell you if the strainer in the tank is blocked.

Refit the pipes, re-fill with fresh fuel, then remove the main fuel feed pipe fitting that goes into the fuel distributor, jump out the fuel pumps and pump some fresh fuel up to the front end. I’d then leave the pumps connected for a while to circulate fuel back to the tank and keep it flushing for a couple of minutes.

Probably the easiest way to purge some of the old fuel out. If it’s still not running after that, it’s likely you’ll have to clean out and overhaul some of the other K-jet stuff - eg fuel metering unit etc.

Hi Will.
I will try and get under the old girl tomorrow and see what I can find out and get back to you if you don't mind.
Thanks again so much for your time and expertise.
Glyn.

 

[BlackC55]

Back to basics first.

If you have a spark, is it bright blue? Even if you have a spark it might not be a good one.

 

[BlackC55]

I have had this issue on a few 129's. The spark is not strong enough. Look in your distributer caps for corrosion.

 

[Monkeytrousers]

OK good, after cranking the car to get it started, get a 12mm flare and crack each line open on the top of the fuel distributor (spider looking thing) to see if a little bit of fuel bleeds outs. This will tell you if you have fuel pressure and if the fuel is nasty. Also with the ignition in the on position, push down on the flap and let me know if there's resistance (not too hard).
Also let me know if you hear a whining sound (like bag pipes)

Your injectors may be gummed up. This is common and they are basically brass nozzles that can be freed up with a combination of compressed air and brake clean in a spray can. I can probably talk you through it.

Hello again allabassi.
Thanks again mate.
Brilliant info.
I will try and go through the process you've described tomorrow and fingers crossed I might get the old girl fired up
Thanks again so much to everyone who's contacted me.
Absolutely brilliant response.
Thanks again guys.
Glyn

 

[Monkeytrousers]

I have had this issue on a few 129's. The spark is not strong enough. Look in your distributer caps for corrosion.

Hi blackcC55.
Thanks for your reply.
I've had the dizzy's and rotor arms off and given them a good clean.
To be honest they weren't bad at all to start with.
I've also been through all the earth contacts in the engine bay & the battery and cleaned & refitted.
Thanks again pal.
Glyn.

 

[Monkeytrousers]

Hi blackcC55.
Thanks for your reply.
I've had the dizzy's and rotor arms off and given them a good clean.
To be honest they weren't bad at all to start with.
I've also been through all the earth contacts in the engine bay & the battery and cleaned & refitted.
Thanks again pal.
Glyn.

Sorry I meant to say also I'll get out there tomorrow and check what the spark looks like.
Thanks.

 

[Monkeytrousers]

Hi blackcC55.
Thanks for your reply.
I've had the dizzy's and rotor arms off and given them a good clean.
To be honest they weren't bad at all to start with.
I've also been through all the earth contacts in the engine bay & the battery and cleaned & refitted.
Thanks again pal.
Glyn.

Sorry I meant to say also I'll get out there tomorrow and check what the spark looks like.
Thanks.

 

[BlackC55]

Maybe take the dizzy's off first. 10 min job to check them.

 

[BlackC55]

Maybe take the dizzy's off first. 10 min job to check them.

FYI the fuel injection system on these early 119 engines are usually very very reliable.

 

[Monkeytrousers]

Maybe take the dizzy's off first. 10 min job to check them.

Hi BlackC55.
I've given the dizzy's a proper good clean.
New ones were fitted just before it was put away several years ago.
That's one of the first things I did but didn't make any difference.
Thanks again pal.
Glyn.

 

[BlackC55]

They corrode still. Especially if they have not been used.

 

[alabbasi]

Hello again alabbasi....

As I still have a couple of hours left in the day, I thought I'd hunt around the house garage to see If I have the parts laying around to explain what needs to be done and I did! So I thought I'd put a quick and dirty video together to explain how to clean the injectors. It's very rough but you should be able to get the idea.

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[Sicario]

This is what its all about people, collective knowledge...

 

[Monkeytrousers]

This is what its all about people, collective knowledge...

Wow that's brilliant pal.
Can't thank you guys enough.
I'll go over it tomorrow and let you know how I get on.
Thanks again so much to everybody who's shared there wisdom with me.
Brilliant, absolutely superb response.
CheeRS.

 

[grober]

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