tick over erratic

[french dave]

hi,everyone im a new 1800es owner and delighted with the car however i have a few queries.tick over cold/hot is erratic 600/900rpm.improves greatly when you disconnect vacum advance pipe tickover 1200.any ideas?also seat belt lock mechanisum does not put on warning light carnt find switch in lock mechanisum between seats -seems to be spare wiring bulb holder under carpet - anything to do with it?oil temp gauge not working -sender?side of sump?and speedo erratic -cable or gauge? welcome feedback/solutions thanks.

[capt jack]

Hi

Sounds like your ES has pretty much the same little delights as my own!

The Bosch DJet EFI system is quirky, and it's essential that you get you head around how it works. It only controls the fuel, not the ignition, so first step is to be sure your ignition is bang on right.

Idle is notoriously difficult (ie: bloody awkward - and no-one understands the system) to even out, but I found the following helpful;

1. Disconnect the vacuum line at the manifold end and plug it off. You don't need it.

2. Renew all the electrical connections - to the injectors, pressure switch, throttle switch, temp sensors (especially the one by the thermostat), cold start valve, trigger points (on distributor), and earth point on the inlet manifold.

3. Make sure you've got the right plugs.

4. Set the points using a dwell meter if possible. Check the centrifugal weights in the distributor. Make sure your coil connections are good. Lubricate the distributor felt pad.

5. Set the timing using a strobe if possible to 10 degrees BTDC.

6. Make sure the air filter is clean.

7. Tighten up all connections to the inlet manifold. The Bosch DJet EFI system is VERY intolerant of inlet vacuum leaks.

8. Confirm that the aux air valve is working.

9. Check the resistances on the pressure switch and injectors.

10. If possible, confirm that the fuel pressure regulator is working, and that it isn't leaking.

11. Make sure your fuel pump is working properly, and the filter is in good nick.

12. Make sure that flow and return fuel lines are not partially blocked.

Get hold of a workshop manual for any B20E Volvo - you'll find it essential to understand how the Bosch DJet EFI system works. As I understand it, if you can get the idle to around 900 rpm +/- 50rpm, you're doing well.

The seat belt warning light is connected to a sensor under the passenger seat that probably doesn't work any more. Been messing around with mine today - and it still refuses to work!

Oil temp gauge sensor in drain plug. Follow the wiring back and check all connectors. Earth the gauge to check that it is functional.

Speedo cable is probably sticking.

Hope this helps

Cheers

Jack

PS: Check out your brake servo hose and one-way valve too. Leaks here will affect the idle.