constant probs

[AB 0]

i have not long owned my 90' 1.8 16V it started sticking revs and hunting on idle when i got it. for some reason i unplugged my idle valve and it ran lovely for about 2 weeks. now it seems to have lost some of its pull, very dull through the rev range could this be causing this or has something caused it to go into set up mode that i have heard a few people mention. Any help here would be wonderful.

[stevemac 0]

Clean your idle valve with either petrol of carb cleaner, then plug it back in (may sort your idle problems out).

 

1.8-16v has Bosch K-Jetronic injection. This is system is fully mechanical & has no setup mode.

 

If the engine still doesn't run properly,after sorting the idle valve out -

Does it start okay from cold ?

Does it run okay when hot ?

Does the external fuel pump (under floorpan next to OSR wheelarch) buzz when you switch the ignition on, before you start the car ?

Is this pump noisy when the engine is running ?

[AB 0]

ok the car starts fine from cold and runs fine when hot. the pump is noisy on start up but not noisy when running.

[stevemac 0]

Does it "hunt" on idle when the engine is warm, cold or both ?

 

I suspect that it may be dragging air in from somewhere - check your inlet manifold for cracks & gasket condition.

While the engine is idling, spray some WD40 along the inlet manifold gaskets - does this make a difference to the idle. If it does - you've found the problem.

[steve_16v 0]

If the fuel pump is noisy when the engine is running does that mean it needs replacing? My car feels a bit underpowered at the moment but I'd put that down to a slightly blowing exhaust, will a new fuel pump help? It idles fine btw.

[Supercharged 2]

If the fuel pump is noisy when the engine is running does that mean it needs replacing?

 

Maybe but how old is your filter?

[steve_16v 0]

If it's the one you can see when the cars on ramps it looks like it was changed recently. No idea about the one in the tank.

[stevemac 0]

Right - this info is unique to Bosch K-Jetronic injection (1.8-16v & possibly 2.0-16v) :-

 

Noisy external fuel pump while the engine is running means that there is a resistance somewhere in the fuel system.

 

As Steve says, fuel filter is 1st place to start - should be changed every 2 years & lives next to the fuel pump. Make sure it's fitted the right way round - there's an arrow on the filter body, indicating the direction of flow.

 

2nd cause is the internal fuel pump inside the fuel tank. When this internal pump stops working, the external pump struggles to pump the fuel up out of the tank & also pressurise the fuel system at the same time. The knock-on effect of this dead internal pump is that the fuel pump relay (in the fusebox) will begin to "burn out". This relay burning out is gradual & the car will randomly cut-out while driving. Eventually, the relay will die alltogether & the car will not run.

 

So - if your external fuel pump "buzzes" quite loudly while the engine is running, sort it out asap before it gets expensive.

[steve_16v 0]

thanks for the info, I'll get the filter changed this week and pray it sorts it out, changing fuel pumps doesn't sound like fun.

[stevemac 0]

Changing the internal fuel pump is dead easy - fairly cheap too, around £25 from memory.

 

It fails from time to time because it's completely submerged in fuel for all of it's life.