Ongoing idle issue

First off car is EG 1600 lump running standard Kjet set up as from factory…

Ok, so my low idle problem still remains. originally I though this problem was just when warm. Maybe the increased RPM from cold is just disguising it instead.
So the car has now had the timing set to factory setting of 0 degress and the CO and idle set accordingly.
Ignition is strong with blue spark on all cylinders.
Unable as yet to find obvious air leaks.

Main latest symptons:-
Idle is pulsing, I.e. the revs sit at say 800, but lower to about 750 before returning to 800 again in a rhythm
Also she starts the off button fine, but when I 'blip' the throttle to de-illuminate the battery light, the revs go up fine but then drop right down to about 300rpm sometimes stalling before creeping back to pulsing idle.
This is the same when driving/easing off approaching junctions.

It's a 1600 EG so no idle stabilisation valve or anything posh like that. When the lights/fan/electrics are on the revs drop more and the problem is greater.
The WUR has good resistance and voltage getting to it, I would like to pressure test is but can't warrant buying a gauge at the moment.
Anyone experienced similar of have any suggestions?
 

This sounds similar to mine, ended up the fuel pump was failing, then it seized!

ppc229w said

This sounds similar to mine, ended up the fuel pump was failing, then it seized!

I just looked at the prices of pumps, not too bad.
I'd just be gutted to buy one fit it and find that the problem still there.

How did you know for sure your pump was seized?

had the issues you have then one day wouldn't start, took off the pump and connected to a battery and it would not work
May be worth borrowing one if you can to try

ppc229w said

had the issues you have then one day wouldn't start, took off the pump and connected to a battery and it would not work
May be worth borrowing one if you can to try

 

Thanks for the info… What was you car like when running under load? Did it rev up ok and drive ok? Mine is, it's just a problem at ambient and idle.

Is the timing defiantly 0 deg in the Haynes manual?

Had similar with a 1800 (rebored to 2000) and I linked it to the electrics/grounding. Is it made worse when the lights, radio and wipers are on? Mine still very very occasionally does it but sorting my grounding out improved it massively. Didn't change with new injectors, turning up by stealth racing, new metering head, warm up regulator….spent all that and then it improved with the grounding. Moral of the story from mine is sort the grounding of the electrics first and then try the rest!

lakesk8 said

ppc229w said

had the issues you have then one day wouldn't start, took off the pump and connected to a battery and it would not work
May be worth borrowing one if you can to try

 

Thanks for the info… What was you car like when running under load? Did it rev up ok and drive ok? Mine is, it's just a problem at ambient and idle.

Ran fine once out on the road, lumpy and hunting on start up

You are using super unleaded petrol?
800 rpm is a little low they should be at 900 to 950 rpm.
Have you checked the rubber o ring on the idle screw as they do go flat and let air in after time.
Old one with new o ring next to it


New o ring fitted with old next to it.

shepp said

Is it made worse when the lights, radio and wipers are on?

Yes it is, cleaned a lot of earths when car was rebuilt. Will have a closer look at the fuel pump soon. Maybe the earth in that is causing problems.
Thanks for the input…👍🏻

Sounds identical to mine. Mine does it very rarely now, say 1/50. Being affected by electrical demand points towards electrical/ground. I keep meaning to check my alternator as well as I have never checked it/bushes. Good luck!

Ok people, gotta be fuel pump related… Pump used to prime when ignition was switched to position 1. Now it's definitley not priming.

So car is up in the air and I'm looking at the pump? Is it the round one nearer rear? Or square one nearer front. Can't find any wiring at round rear one. I know ones the accumulator, but which one? 

Any ideas please?

the accumulator has no wiring ,if you look under the rear seat you will see a small hole where the wiring leads to the fuel pump,normally its sits in a metal type case.

Try this
partsbase.org

Ok found some pumps online… Found a Bosch one for 90 and the cheapest non branded ones are 40.

Is it worth getting the Bosch one?

not all the relays will prime, i think its somethign to do with the fact some coils send a single spark when ignition is on may trigger the relay?  main thing is the pump runs while its cranking over, if this happens then the relay is ok.

has yours had the fuel relay bypass socket fitted above the fusebox? the early ceramic fusebox is prone to burning out the fuel pump power pin on the fusebox as its not man enough

rubjonny said

not all the relays will prime, i think its somethign to do with the fact some coils send a single spark when ignition is on may trigger the relay?  main thing is the pump runs while its cranking over, if this happens then the relay is ok.

has yours had the fuel relay bypass socket fitted above the fusebox? the early ceramic fusebox is prone to burning out the fuel pump power pin on the fusebox as its not man enough

Thanks Rubjon. Definitely got the bypass socket, got photos somewhere will dig them out when I'm in the computer. Can I test the voltage/resistance at the pump and determine if the pump is bad that way?

you could try jumping the relay socket, only trouble is the fuel pump wire isnt fused as its in the relay itself so i would make a jumper wire with a fuse in it just in case.

have a look at your AAV and WUR wiring in the bay too if either of these short it'll pop the pump fuse.

the 2 pins on the pump relay are 30 for the live and 87 for the pump power, loop your fused wire between those and the fuel pump should come on

Thanks rubjonny…Looking at Haynes, it states the jumper method with inline fuse. It suggests disconnecting the return feed from the fuel distributer and placing it in a 1000cc measuring glass. Then bridge for 30 secs with the ignition on while someone holds the glass. It says 'the amount must be at least the minimum quantity given in the specification. If not pump or accumulator/ filter is at fault.'

Btw does anyone know where I should be looking for the specified amount???

Anyway, I'm gonna change the fuel filter before I  run this test… Watch this space 

you should have a chart in the haynes somewhere, might be a couple pages in. I can see it in the bentley its got a straight line showing delivery volume vs voltage at the fuel pump.

9v it says 335ml, 10.5v it says 547ml and 12v it says 760ml