1.8 Si Flat spot when revs are low

[440man]

My 440 with a B18U engine has developed a fault that only happens when the engine reaches normal running temp.

When the revs are low and I begin to accelerat it hesitates for fraction of a second before the revs reluctantly increase and if I let it idle the engine cuts out altogether. It will start again with no problem, but its a bit worrying when attempting to pull away from a junction.

I've recently replaced the stepper motor and the rotor and distributor cap to resolve another problem.

Any ideas please?

[sandythecaddie]

what's the year , milage, any service history?

[440man]

Originally Posted by sandythecaddie

what's the year , milage, any service history?

Hi Sandy,

1995, 74K and agents to 35k and me for the rest

Hi ive had the same problems and if you don't do something now it could get worse trust me!
1. check throttle position sensor plug, found under the airbox feed tunnel. check conections of wires as one of mine had frayed!! also to check are the inlet and exhaust gasket or head gasket. done by checking the compression very simple if you have the right tools and know how! exhaust gasket is very fiddly to change as small hands or a engine lift help. for some bolts a degree in reflexology helps. also check air filter (unlikely) and use a fuel injection additive from halfords etc (£5-20) every 6000 miles or so. other probs i had were the catalyst had gone (exh. gasket. fuel thrown in to down pipe and burning on the cat!!) head gasket is a garage job unless you have specialist tools if bad things have gone wrong.
2. i also experienced high revving and big idle fluctuation.

hope this points you in the right direction.
if you get it right your engine will be flying, it really will make a differance

steve
1996 440 1.8 si

[440man]

Originally Posted by 440man

Hi Sandy,

1995, 74K and agents to 35k and me for the rest

Hi Sandy,

Your an absolute STAR!! - the old girl is running as good as new again and all for 20p's worth of rubber pipe.

Thanks very much mate, I would never have found it on my own.

I can't imagine how with the limited knowledge I have, but if I can ever help. please give me a shout (so long as its not money!!),

Cheers,

Tony

[sandythecaddie]

hi Tony, glad to hear the old girl's running right again. if you need help just shout or email

[Mark480]

What did the problem end up being? It'd be good for a reference if anyone else is experiencing similar problems!

[sandythecaddie]

hi Mark480, i'll try to describe as best as i can, at the rear of the throttle housing are small about 2'' in length braided/rubber hoses which through time perish. they may look ok but thats all.replacing these hoses is cheap and easy and well worth the effort.
the one that leads to the air pressure sensor is very important and inside the small hose there should be a small brass insert approx 1/4'' diameter with a hole @ 0.5mm (mine does anyway) replace this into your new hose and refit.
symtoms of perished hoses include; rough idling, poor acceleration, cutting out, black sooty spark plugs(ecu compensating for weak mixture) poor fuel consumption, tempers flaring at junctions and roundabouts.
and a wee extra note, remember to check all coolant hoses when the engine is hot as any bulgeing of hoses will be easier to spot and it's always better to replace a hose at home than an engine 100 miles away.
cheers for now S

[Mark480]

Excellent Sandy!

I have the 1.8i single point and will check that tomorrow! It's reasonable milage at 54k miles. It's well looked after, never sees above 3k revs, regular full services and all the rest of it! Just recently it's been a little hesitant to start, not that it takes a few attempts it just means holding the key turned for 4 or 5 seconds instead of 1!