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Rough running

Need some advice regarding the BX. It's a 16v (ie the Mi16 engine), with the early management meaning no cat or knock sensor.

The car doesn't like pootling around at low revs. For example when doing 30 in 4th (2ish krpm) and just feathering the throttle the car starts juddering, eventually leaving you kangarooing down the road. Lift off and it coasts along fine, put your foot down and it accelerates fine. Same thing at 40 in 5th. Also when cruising along the motorway at around 3.5krpm the problem isnt there but occasionally you can feel a slight misfire. But it pulls really well still when you put your foot down - cleanly all the way to 7+krpm.

So far I've changed the plugs for the recommended NGK triple electrode jobbies, put on new HT leads, rotor arm and dizzy cap. Plus it's already had a new coil Put some injector cleaner through. Tried octane booster and then 99RON fuel. Quickly cleaned the air flow meter and it's connections. Also quickly cleaned the throttle butterflies. Nothing has helped.

The previous owner (or his mechanic) seemed to be a bit of a bodge artist - I've found a few things missing or not done up tight so with this in mind, any suggestions as to what to try next? I'm gonna give the AFM and throttle body a proper clean this weekend. Possibly recheck all the wiring connections. But it's starting to annoy me now as it's a right pain to drive into work!

Any (decent) advice appreciated.

Cheers

Carl

Reply to
Carl Gibbs
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I was expecting Ken to get in there first with a comment about chav'd up chocolate biscuits, but well done you've beaten him :)

Reply to
Carl Gibbs

Carb icing? :-)

Right. I'll get m' coat.

Reply to
AstraVanMan

If it's got a TPS which is a pot, check for smooth voltage output throughout the range and that it's correctly set. Next I'd check the fuel pressure.

Reply to
Dave Plowman (News)

The first thing to do is check service items..............sounds like the sort of problem that may well be caused by something very simple. My guess would be plugs/leads.

k
Reply to
Ken

Nice one. Idiot

Reply to
Carl Gibbs

Mi16 engines dont like cheapo plug leads, and also have you changed the fuel filters?

k
Reply to
Ken

They definately weren't cheapo leads. I haven't changed the fuel filter as I think it's been done recently. May give it a try anyway though.

Reply to
Carl Gibbs

Other thing that can cause this sort of problem is dirty injectors..............Halfrauds injector cleaner just doesnt work, but if you can get hold of the Forte stuff from a good garage, then thats a great deal better.

k
Reply to
Ken

I think I used Wynns. But I'm toying with the idea of taking the car off the road for a week and sending the injectors away for a proper clean with

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£50 ish quid for all 4, so not too bad at all

Reply to
Carl Gibbs

I'd save your money. The injectors on my SD1 are 20 odd years old and have done 150000 miles plus. They don't normally benefit from cleaning - not like the older mechanical type. A look at the plugs might give clue if one or more wasn't quite up to spec, though. IMHO you have a more fundamental problem.

Reply to
Dave Plowman (News)

OK Dave, I'll keep trying and see what happens.

Cheers for the advice guys.

Reply to
Carl Gibbs

I reckon you could have a good crack at cleaning them with a household ultrasonic cleaner anyway.

Reply to
Doki

You've checked every single hose and trunking (apart from water ones) carefully? Air leaks are a common thing to upset an injection system.

Reply to
Dave Plowman (News)

Yep, best I can. Got a bit of spare time this weekend though, so gonna give it a proper going over.

Reply to
Carl Gibbs

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