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280se - new to me, warm stalling!

Started by SteveDuNord, 04 May 2022, 10:57 AM

Big Tiny

None of these vacuum leaks would be enough to cause an engine stall situation.

However there could be a host of other things.

What is cold idle speed verse hot idle ?


SteveDuNord

No idea. There's no tachometer. I'm thinking of buying one of those digital rev counters.

I'm waiting on injectors/sleeves and ignition leads. Have a new rotor here, but can't find a new cap. Will be adjusting valve clearance and replacing transmission fluid.

Did an oil change and took this cold start video.

https://youtu.be/YNVCmNnNlI4


'77 280se

Big Tiny

Idle speed is fine cold, possibly around 1100 rpm.

First thing to check is fuel pressure and fuel flow.

https://k-jet.biz/tests/

SteveDuNord

Well I fitted 6 new injectors and seals. Now the car won't start.

Turns over, stuttered once, but other than that no dice.

I took off the pipes at the FD end to get them to fit at the injector ends. I've made sure to switch the ignition on and off a few times before trying to crank the engine.

Also, the air filter housing won't go back on, as if it's fouled by the pipes that I had removed and reattached.  :-\
'77 280se

Big Tiny

Always good to take pictures before removing anything so as to go back in order.

Do tests above as linked. Injectors would have always been down on the list of problems. More likely other issues.

You need to do some basic diagnostics and don't simply throw parts at the engine to no avail.

Big Tiny

Not sure if this helps, but shows my injector hard pipes.

raueda1

Quote from: Big Tiny on 29 May 2022, 10:45 PMNot sure if this helps, but shows my injector hard pipes.
Not related to the problem, but that's a BEAUTIFUL engine!
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

SteveDuNord

#37
Quote from: raueda1 on 06 June 2022, 09:31 AM
Quote from: Big Tiny on 29 May 2022, 10:45 PMNot sure if this helps, but shows my injector hard pipes.
Not related to the problem, but that's a BEAUTIFUL engine!

You could eat your dinner off it!

Meanwhile, I've checked the spark plugs to see if they were wet. Changed them with a new set that I'd accidentally bought in duplicate.

Bought a spark checker which didn't fit properly, so got my neighbour to hold it while I cranked the engine and electrocuted him.  ;D He must have held the metal sleeve of the HT lead. Oops... Incidentally, the bosch HT leads I bought don't fit my Bremi distributor. And the bosch Rotor I bought was the wrong sort (non rev limiter type). But I digress.

Managed to straighten out the FD hard lines, so I can now get the air box back on.

I noticed the new rubber injector bushes I bought (Febi branded) were different from the originals, so I'll try them with the old injectors tomorrow, and if that doesn't work I'll try the old bushes and old injectors. Just to rule it all out.

I'm trying to avoid a fuel pressure test as it's too complicated and I'm lazy.

'77 280se

Type17

Regarding the stalling, have you checked the CO/mixture? - on any K-Jet car I've had, a weak mixture causes hot stalling when selecting gears.
Obviously, with a vacuum leak, the mixture will be weakened by unmetered air, but if fixing the leaks hasn't helped much, it could be just a bad air/fuel setting.
It could also be a low system pressure - I had that issue with a Mk1 Golf GTI (also K-Jet) - needs a properly-plumbed pressure gauge inserted into the plumbing in the right place (or a Bosch specialist) to check it, but not usually an expensive fix (re-shimming a return valve in the Metering Head).

PS: I knew that car (to see) at shows in Dublin - looks similar to mine, and had a fairly similar registration number (see my sig below)
'76 350SE in Silver-Green

SteveDuNord

Quote from: Type17 on 07 June 2022, 07:50 AMRegarding the stalling, have you checked the CO/mixture? - on any K-Jet car I've had, a weak mixture causes hot stalling when selecting gears.
Obviously, with a vacuum leak, the mixture will be weakened by unmetered air, but if fixing the leaks hasn't helped much, it could be just a bad air/fuel setting.
It could also be a low system pressure - I had that issue with a Mk1 Golf GTI (also K-Jet) - needs a properly-plumbed pressure gauge inserted into the plumbing in the right place (or a Bosch specialist) to check it, but not usually an expensive fix (re-shimming a return valve in the Metering Head).

PS: I knew that car (to see) at shows in Dublin - looks similar to mine, and had a fairly similar registration number (see my sig below)

Well fancy that! It's no show car at the moment, needs a few paintwork bits sorting out. But I'll be attending to those after I get it running right.

I'll definitely look into the possible fixes you mentioned. Thanks.

Meanwhile... I popped the old injectors back in and the car started pretty easily.

New ones are BOSCH 0 437 502 047 (brass)
Old ones were BOSCH 0 437 502 010 (grey colour)

Apparently the brass ones are the newer versions, but still compatible. 

I've just checked the injector holders (the rubber bush) and apparently I bought the wrong ones. I'd mistakenly identified my engine as the 185bhp unit, when it's the 177bhp version. Huh.

Tomorrow I'll refit new injectors with the old sleeves. OR buy some new sleeves that actually fit. Doh.



'77 280se

Big Tiny


[/quote]Not related to the problem, but that's a BEAUTIFUL engine!
[/quote]

Thanks, this car actually sat for 14 years before I bought it. Mechanics gave up getting it running and now I have been over the whole system it runs flawlessly.

Unfortunately without actually do a proper diagnosis its hard to tell what's going on. I always start at the fuel tank and move forward. Fuel strainer, filter, pump, tank return line etc.

Need to know fuel flow, fuel pressure etc. You can buy cheap fuel pressure kits on Ebay which are just fine for a DIY'er.

SteveDuNord

Well, BigT, before replacing the injectors today, I decided to mess with the fuel distributor.

I read about refining the sensor plate, and wondered how exactly you determine the point of deflection. I couldn't 'feel' the resistance as I plunged the plate by fingertip. Not exactly.

So I peed about with the mixture screw, trying to get it just right.
Next thing you know, I'm screwing it twenty turns this way and that.

Started the engine, and ended up with this...


The plate was very stiff. So I guessed I'd massively overtightened it.
No amount of adjustment would fix it.
So I had a brainwave and cracked one of the fuel lines, which relieved the pressure.

Managed to get the sensor plate back to normal, turned the engine over but it stuttered and died.

The plate was stiff again.  :-\

I called it a day.

Thoughts?
'77 280se

Type17

I found this pic, from Terenure Classic Show in 2013


'76 350SE in Silver-Green

SteveDuNord

Quote from: Type17 on 10 June 2022, 02:03 PMI found this pic, from Terenure Classic Show in 2013




That is so cool, thanks!

Incidentally, that hat is still resting on the parcel shelf.

I turned the engine over again today but it dies before I can adjust the mixture screw. Gah.
'77 280se

SteveDuNord

Delighted to say I finally got the engine running again today after my ill fated air/fuel adjustment attempt.

Am now trying to fine tune the mixture screw to achieve maximum vacuum. Not quite there yet, but maybe after a good run things will improve and I can go from there.

Then I can have another go at fitting the new injectors, this time using the old holders.

After all that I will by a shut off valve for my vacuum kit and do all the fuel pressure checks. Phew.
'77 280se