Idling speed reduced and lumpy - Mikey Jay
The car has had a complete new exhaust. The idling speed appears to be half what it should be and is lumpy. This suddenly happened. RAC man whipped out the plugs and they look fine. He apologised for not having exhaust gas analyser but they don't carry them. The carb controls all seem to be free, nothing sticking as far as I know. Engine seems to run fine through rest of the range. If someone knowledgeable could give me a few pointers as to what to look for next I'd be most grateful. When I got back to london (in a tight parking space), I could smell dreadful exhaust fumes in the car and underneath but the parking space may have caused this. The fumes at idle seemed really bad though. I put my hand over the exhaust to check for leaks and I couldn't detect any. Could there be a leak in the vacuum pipes? This car has a lot of rubber tubing around the carburettor. Engine in good nick generally btw.

Idling speed reduced and lumpy - bell boy
it could well be a pipe off
the lambda has not been plugged back in
it connects electrically to the downpipe exhaust

sorry cant think of anything else
Idling speed reduced and lumpy - mike hannon
'Carb controls'?
How old? Which engine?
Idling speed reduced and lumpy - Mikey Jay
Its a 12 valve single ohc twin constant depression carb type non catalyst 1992. The point is carburettors don't usually suddenly lose their settings do they? I could smell fumes through the heater fan when stationary. Could a leak in the exhaust front section cause a reduction in revs at idle?

Idling speed reduced and lumpy - David G.I.Davies
From your description of fault,I'd suggest you have one or more leaking diaphragms in the carburetters.Each carb. has a power valve diaphragm and an accelerator pump diaphragm.You have to remove the carbs. and invert them to inspect these,so it's a time consuming job.As you say there is an awful lot of small bore rubber piping and it's worth checking this,but I don't think a broken vac. pipe could cause excessive richness,it would tend to make engine idle a little too fast or stall.

David Davies
Idling speed reduced and lumpy - bell boy
a nightmare then if its 92 with the rear wheel steer and all its gubbins and people moan at engine moanment
good luck and thanks for the engine update details :-)
Idling speed reduced and lumpy - SaabFanatic
You should start by checking out Honda's own workshop manual here:

Idling speed reduced and lumpy - Chuckie888
Blocked EGR
Idling speed reduced and lumpy - Mikey Jay
Thanks guys for taking the trouble to reply. Haven't had a chance to proceed further with the fault. Will check egr first. Don't like the idea of stripping a kehin carb down, so hope this is a last resort. Definetely a fuel problem.


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