R107 how to set up a new fuel metering unit

[Robbiz]

I have replaced to fuel metering unit on my 1979 R107 350 v8 and can't get it to run. Ideas

 

[grober]

Djet or Kjet? try reading this rather lengthy thread on a W115 coupe restoration for some links/explanations
Mercedes W114 250 Coupe - help!

or try this set of videos.

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[Robbiz]

Djet or Kjet? try reading this rather lengthy thread on a W115 coupe restoration for some links/explanations
Mercedes W114 250 Coupe - help!

or try this set of videos.

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For more detailed information, see our cookies page.

Accept third party cookies

Kjet

 

[grober]

Lots of stuff out there on how to adjust these systems. Since these systems are essentially hydraulically powered [by fuel pressure] and air flow controlled ----first port of call would be checking for system fuel pressure and injector output.

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[Robbiz]

Thanks, that's what I am thinking but before I replaced the unit I had 5 bar of pressure from the fuel pump to the unit but only 1 bar coming out, hence the replacement.

 

[RaceDiagnostics]

On the K Jet system there is only one user adjustment, the fuel mix screw, everything else is fixed, have you checked the WUR is functioning properly, all the procedures for test are in the workshop manual?

If you have bought a re-manufactured fuel distributor it should already be tested and working.

PS the pressure from the fuel pump should be more than 5bar.

 

[Robbiz]

On the K Jet system there is only one user adjustment, the fuel mix screw, everything else is fixed, have you checked the WUR is functioning properly, all the procedures for test are in the workshop manual?

If you have bought a re-manufactured fuel distributor it should already be tested and working.

PS the pressure from the fuel pump should be more than 5bar.

The new metering unit is a refurbished original, I've returned it once and they say it is working perfectly. However if I put the old one back on the car fires up right away.

 

[Robbiz]

The new metering unit is a refurbished original, I've returned it once and they say it is working perfectly. However if I put the old one back on the car fires up right away.

 

[grober]

Somethings not matching up between your car and their test rig---- highlight sections and scroll down to cis injection system on menu below
Untitled Document
lots of info e.g.
https://www.startekinfo.com/StarTek/outside/11883/PROGRAM/Engine/107/M117_45/073-205.pdf

 

[Robbiz]

Many thanks to all.

Rob

 

[grober]

Let us know if you find the solution. good luck

 

[Robbiz]

I think the issue may be my Fuel metering unit is an original cast iron version and the replacement is an alloy version. I'm sure it shouldn't make difference but can't think of anything else!

 

[grober]

There is mention of a fabric diaphram between the upper and lower halves of the distribution unit with the adoption of the alloy upper body in that pdf I linked to.
https://www.startekinfo.com/StarTek/outside/11883/PROGRAM/Engine/107/M117_45/073-20
Are you aware of its presence /absence In your set up? There is mention of the importance of the position of this diaphram in relation to very small metering hole from the lower to upper body to make sure its not occluded[ blocked] in this detailed rebuild PDF for a porsche 928 slightly different set up but may have useful pointers??
Wayback Machine

taken from this link
Rebuild 380SL Fuel Distributor