fuel pump

hi i have a 1975 mercedes 450sl R107 model i have changed fuel pump & relays still not firing and no buzz when turning key any ideas?

Hi unknown member,

it would be nicer if we could answer to yoru name directly.

1975 can be a D-Jetronic or KA-Jetronic car. Which one do you have? In both cases fuel pump has external control. Either by D-Jetronic ECU and relay or by safety switch and relay.

mehmet
i have the D-jetronic set up

Hi Mehmet,

please check whether EcU applies ground to pin 19 for 2 sec when you switch on ignition. And also verify that the additional cable on battery plus side is properly fixed.

ok have to do it on the weekend i read that it could be the ignition switch also? mem

where is the safety switch ? plus
whats it look like ?
mem

Hi Mehmet,

don't mess around with other sources who do not know what D-Jetronic is. Safety switch exists on KA-Jetronic cars. Please measure pin 19 and verify the addtl. wire on plus of battery. And I would appreciate Hi, Regards etc. This tries to be a polite forum.

hi Dr-Djet
Maybe i'll send the unit to a Professional to Test and Repair if you know of any one in England? please let me know thank you for your time much appreciated
all the best mem

Merhaba Mehmet,

what was the result of measuting pin 19 vs. pin 16 on ECU after switiching ON ignition? That is first thing to do.

I do not know of anyone in England who can do a test and repair even that there are many who claim they can. Anyone who repairs/verifies such an ECU must have Bosch's reference values for each function block and must be able to simulate each function block's external conditions. in principle you should be able to go to any Bosch Classic service in the UK and they can send it to factory for repair.

tekrar merhaba Dr-Djet
I did the Test i Counted Down from the Main Loom to Pin 19 & 16 Nothing happened when Ignition On and Off,Then i Counted up bottom of the plug to 19 & 16 the Power was there when switched on ignition and Not there when Switched Off. The wire On the Plus Side of the Battery is Fixed on Solid No Movement i Cannot See any Deterioration of Wire Looks Good.
best regards mem

Merhaba Mehmet,

o zaman senin ECU bozulmuş. Malesef sana. Then your ECU seems broken. Sorry for you.

hi Dr-Djet
tamam yenileme içine bakacağım
zaman ayırdığınız için teşekkür ederim saygılarımla
thank you again regards
mehmet