Topic: Dog 350SE

[Denis]

Hello gentlemen

This huge silver barge of mine has become a money pit and as reliable as a Lada 

Before spending MORE money, I am going to try to see if any of you fellows can help.

The problem : the car refuses to start some of the time. When it does that, it sounds like nothing firing at all, when it eventually catches, it feels like no fuel - I have to pump the gas like some bloody old carburetted Lada to get it going and it dies so very, very reluctantly with a belch of smoke before finally catching on. The fuel filter is new, the fuel pressure regulator is new, all pipes and clamps are new/cleaned, checked, the cold start injector does its job...

I recently drove this car 250km without the slightest hint of a miss. When cold it either starts nstantly or not at all. When hot, it tends NOT to start  but it might.

I have jumpered the two ballast resistors and that SEEMS to help, but as I said, it will sometime start and run very well. Any ideas ?

As I said, this is a dog of a 350SE and quite frankly, this is the kind of thing that makes me feel that I should have sold the W116 INSTEAD of the diesel W123, which is, in many ways, a better car than the W116 

Denis

Paris, France

[Denis]

Hi big Richard

I thought I would get someone's attention with the Lada statement 

But you know, a Rolls that wont start reliably isn't worth a running Austin Minor 

Back to my beast, it's a D-jet and as I said, it can actually run very welll on the road.

I just went out this morning - it started perfectly BUT there was no residual pressure in the fuel ring. I decided to check the fuel pressure and will do more tests after lunch.

The only thing left to do is parts substitution after checking that the fuel pressure holds in the fuel ring (2 bars running, no dip under 1.5 when stopped for 5 min. ).
It could be a bad fuel pump and a pressure /volume test might show this but if so, why does it run/accelerate so well on the open road ? If the cold start injector were defective (leaking), that would explain zero residual pressure right ? worth "substitution testing".

The ignition looks great and as I said, the car runs well, I am going to do "substitution testing" of the coil also. I am mystified about the effect of jumpering the two low resistances in the ignition circuit - it SEEMS to help startup. How can that be ?

OK, big Richard, I wont say Lada anymore but I sure wish I hadn't sold my W123 diesel - one of the very best out of Unterturkheim.

Denis

Paris, France

[Nutz]

Are all the grounds/earths adequate on the D Jet,dunno,just throwing it out there.

[Denis]

Hi Nutz

The answer is YES. As I said, a DOG of a 350SE.

Denis

Paris, France

[michaeld]

I logged in just to throw in my two cents, and then I saw that Nutz had beaten me to it - and did a better job (what with his diagram) to boot.

But since I logged in and all...

I might be entirely wrong here, but whenever I have something that is intermittant (as you seem to be describing) I always worry that there's a bad electrical somethingorother involved - particularly a faulty ground.  When you've got an insufficient ground, some days the electron fairies dance and prance just like they're supposed to, and some days they wander off where they don't belong and pout.  I know Nutz's "fancy schmancy" diagram was more scientific (and useful) than my "dancing fairy" theory, but there it is.

Have you wired your electrical fuel system parts directly to the battery to test for pouting electron fairies?  I read your earlier posts a while back, and can't remember.

[Denis]

Monsieur Michaeld

Is your  "dancing fairy" theory in any way related to the Lucas theory of electricity that states : electricity is actually smoke carried in wires, the proof is taht when something fails, like a starter motor, it looses all its smoke (as can be observed) and no longer runs 

If so, I will looks onto this with my high-impedance, 20 Mhz sampling Tektronix fairy dance detector 

Hmmm... looking at grounds...once more, might help...

Denis

Paris, France

[OzBenzHead]

Monsieur Michaeld

Is your  "dancing fairy" theory in any way related to the Lucas theory of electricity that states : electricity is actually smoke carried in wires, the proof is taht when something fails, like a starter motor, it looses all its smoke (as can be observed) and no longer runs

Denis: I think that Lucas Prince of Darkness helpers are more likely to be debil-debils than dancing fairies!   

Lucas was one of two bad "features" of all postwar British cars - of all market and engineering levels; the other "feature" was the mandatory, no-cost "option" of the oil drip.

It is rumoured that Lucas once tried to build a computer but, having failed to make it leak oil (or smoke!), abandoned the project.   

[Papalangi]

First off, you may need to look into the Lucas PN 530433 replacement wiring harness smoke.
http://www3.telus.net/bc_triumph_registry/smoke.htm

Have you measured voltage at the coil while cranking?  If the jumpered resistors help it start, the start terminal on the starter might be part of the problem.  Either the contacts in the solenoid or the wire itself.  Could also be the key switch itself.  Try measuring the voltage at the coil as shown in job 07.4-125.

Michael

[Denis]

Hi fellows

Back to reality. The voltage at the coil, terminal 15 is not 12v but is not supposed to be. I checked and tested the two resistors and switched to a known good coil.

Still no go, but spark present. 

 I finally got the car sputtering by madly pumping the accelerator pedal, and it stuttered to life. Good, with a fuel pressure gauge installed betwen the cold start valve and the fuel rail, I went to check the fuel pressure with the engine running (smoothly). Zero bars... ...OK, I figured there was air trapped so I cranked the engine to move fuel up the gauge line up to the disconnected gauge head, refitted the head and started the engine. Still 0 bars...

By now, I figure that the fuel pump is defective. It can pump enough volume at some silly pressure to get the engine running but nowhere near the 2.1 bars required.  What else would explain this ? The defective pump will also not allows a help pressure in the fuel rail - if I disconnect a neoprene fuel line, there is some pressure but not two bars. This is attribute to either the check valve in the pump being defective and/or the pump being worn enough that it will not develop much pressure.

Any other idea before I order a fuel pump ?

(Sigh)....sparks....electric fuel pumps...(sigh) (dream of diesel)...

Denis

Paris, France

[Nutz]

So you've done a pressure and volume test? How many liters do you get in 30 seconds?

[Denis]

Hi Nutz

It pumps a half liter per 30 seconds but that is just unrestricted flow. When connected, it seems incapable of raising significant pressure depite the new FPR 

Sounds like a worn pump to me, don't you think ?

Denis

Paris, France

[Papalangi]

Yea, it does sound like a pump gone bad.  The wife's car had the wiring at the pump go bad and the car would stall sometimes.  That is until the wires burned off.  At the pump.  In the tank.

Michael

[Denis]

Just a question.

Do I need to buy the D-jet pump or can I use the later, and much cheaper, K-jet pump ?

After all, I just need anything that fits and will pump 3 bars or so and deliver volume, which is usually not a big problem. It is easier for me to get a 380/420/500 W126 pump than a W116 part.

Bye for now

Denis

Paris, France

[Nutz]

No,you have to use a D Jet fuel pump.You can also find one on a;

W111/108 with V8
R107 up to 1975

[michaeld]

Denis,

Re: your earlier question concerning the rationale behind my earlier post: It's "where there's smoke, there's fire," NOT "where there's smoke, there's fairies!"

I'm not certain whether the conventional flow theory (positive to negative) or the electron flow theory (negative to positive) of electron movement is correct, but I have convinced myself that fairies must surely be involved in the process.  Something is dancing around in them wires!  Oh, sure, the more rationalistic among you say its just the negatively charged portion of atoms, but there's been too many times when my (so-called) "electrons" showed they had minds of their own!  Hence, the dancing fairy theory of electrical flow.  The trick is to appease the fairies so they do not become angry with you and decide to go off in some unwanted direction to pout - and if you make them REALLY mad, they will wave their magic fairy wands and flat out melt something!  I've seen it with my own two eyes, I have!!!

Not knowing the intricasies of K-jet and D-jet relationships, I can only agree with Nutz that you should stay "au naturale" (Sorry, alll; it just seemed like a good way to express remaining completely stock to a guy from Paris) so that you eliminate any chance for some unknown variable rearing its ugly head. 

I wish you good luck with your 350, Denis.  I hope it's the pump, after all; and not some ticked-off fairies!