Hi there,
I've got a Bx 16vmk1, withe the same engine, XU9J4, and got the following nasty problem.
A cold start, no problem. After a period of 50 seconds or a drive of a mile, it runs like s...
It hears like it go round on 3 cilinders at idle, The engine is bouncing, and has a bump between 2000 and 2500 rpm constantly. Like The ECU cannot manage the info of the sensors,
The power is there, i can use the 160 HP force, but when driving in traffic at about 50 km/hr (30 mp/h) it is just f...

Does anybody know the answer?

Normal things like plugs, rotor arms, ISCV, Injectors, Coolant temp switch, have been replaced. Also the Voltage recording to program CAPS measured at the ECU is good.

Thank , Jonne
The Netherlands

Is the throttle switch adjusted right? So that its clicking when the butterfly is released?

Try www.bx16v.com for more info too. But reckon someone on here must have had the same issue.

i'm with Kitch on this one.

recently my Mi16 wouldn't start on it's own and even when i got it jump-started,
it wouldn't idle properly (2000-2500rpm) and it ran roughly.

got it sorted simply by adjusting the throttle position switch (TPS) or all things!

Yeah though the only thing is he said "It hears like it go round on 3 cilinders at idle" which a sticking or badly adjusted throttle body or TPS wouldn't cause. Could it be coil or ignition amp?

Yeah but he might be confused into thinking its missing when its jsut running very lumpy....probably because the air/fuel mixture isn't ride for idling.

Most Mi's run really lumpy on idle anyway....I thought mine had uber high lift cams at first!

I remember my first mi being very lumpy at idle once the engine reached normal operating temperature - then I realised it was running lean and screwed the thingy in on the afm and hey presto it idled nice.

But a coil is good or no good, right?
This problem drive me crazy!
Greeting, Jonne

The ignition module can also be bad when it gets warm, and it works great when cold..

Isn't ignition module had id replaced. For 40 seconds it runs great, after that just bad. going to replace the ignition leads by new ones.

Have you done a fault code check on the ecu?

A year and a half later and it's still not sorted?!?

The problem is still the same. It's not that i you use the car everyday, it's just for the fun
I (we) have a C4 110 HDI, Ford Focus Wagon 1.6, and a bx 16v mk1.
I drive about 500 km a year in the BX!
Trying to change the HT leads for a normal price, but in Holland there aint cheap for this engine. From Beru about €80. And still just to find out if this solves the problem.
Let y Know.

Greetings from Holland,
Jonne

Did not sort it out yet.
Sounds a bit like the sound fragment recently posted by another member.
Now new problems arrived.
i let the oilventilatoin out in the free air, resulting in a vacuum in the inlet. Alle the sparkplugs were black, so all the cilinders burn the same amount of oil.
After this "test" i replaced the spark plugs by new ones, equim rfc62ls3, like it should, but is running way to rich.....
Returrned the air fuel measurment by 15 notches. Have no power in the high revs,
have to check:
fuel pressure
Injectors.
Any ideas, please post....

lumpy idle, to much fuel.... released the relay to the fuel pump, and after 15 seconds the idle became so smooth, like it have never ever did.
So blocked return hose, bad fuel regulator, or otherwise leaking injectors....
Let it know.

did not sort it out yet.
It's a strange behaviour, horsepower is great, so the compression should be great, only the idle is bad. or a small leak between to cilinders in the headgasket.
changed the injector's by another ones, which were ultrasonic cleaned, but brought no differance.
Suggestions anybody, although it's no 405mi16?

^i've had to shorten your username.

also, please introduce yourself here:

http://forum.405mi16.com/index.php?showforum=15

thanks.

ECU?? would be worth tyring a known good one if possible

Go thru loom THOROUGHLY and check for shorts-sounds simple, but a cut/nick can fudge things right up, they did for my 16v- and replace/clean ALLthe earth cables/connectors too. Try swapping the afm with someone elses 16v that is running fine. Try getting it reset to factory isnt easy, its not supposed to be messed with from factory. You have probably tried all this, but we mucked around for weeks with my 16v, adjusting this and that, still no luck, till dad went thru the loom and found 3 breaks in it!!!!! Fixed em, and it was smooth sailing-now we have to go back and try and reset everything that got buggered up trying to solve the issue!!!

will try to check all the cables, especially from the relais from the right front wing to the ecu, maybe (hope) sort things out.
the strange thing is that many suffer the same problem with this type of engine, so hoped i get the answer maybe here......
Greetings from Holland