I'm Getting a 16v Tomorrow!

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docchevron
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Post by docchevron » Tue Nov 28, 2006 3:27 pm

Er, not quite matey!
D6C's were designed to run leaded fuel.
The valves and seats are hard enough to cope with unleaded but the burn qaulity of unleaded is sh!te compared with "REAL" fuel.
All valvers must run 98 octane, except the DFW valvers with nasty cats etc...

running 98 / 99 octane fuel gives the car the power it was designed to unleash! Running 95 will effect how it runs.

I know some guys run them on 95 unleaded and report no adverse effects but mine runs like a bag of sh!t with standard 95, runs hot too.
98 / 99 octane, it runs smooth, cooler, has more go and doesn't pink if you rag it.
Goes really well 102 octane! :D , very expensive though :cry:

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Chris G
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Far too many BX's, a bus, an ambulance a few trucks, not enough time and never enough cash...

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Post by Way2go » Tue Nov 28, 2006 3:38 pm

docchevron1472 wrote: All valvers must run 98 octane, except the DFW valvers with nasty cats etc...
The info quoted is from the Citroen Drivers Handbook that comes with the car, not the Haynes BOL. :?

Would Citroen publish this wrong? :?
1991 BX19GTi Auto

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docchevron
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Post by docchevron » Tue Nov 28, 2006 3:45 pm

Would appear so!
I stand to be corrected but Citroens own technical bulletin dated 1990 says all engines run unleaded *98 RON only in 16 valve....

Since at the time 98 RON unleaded was not available in the UK I take this to mean that the valver should run leaded, as I've been told by many valver officiardo's??

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Far too many BX's, a bus, an ambulance a few trucks, not enough time and never enough cash...

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Post by Way2go » Tue Nov 28, 2006 4:04 pm

docchevron1472 wrote:Would appear so!
I stand to be corrected but Citroens own technical bulletin dated 1990 says all engines run unleaded *98 RON only in 16 valve....
My info may supercede this as my car was registered October 1991 and this is the actual handbook.
Perhaps there was a change in that next model year?
No publication date given but for those that can interpret the code on the back cover, it is BX-GB 3001 :D
1991 BX19GTi Auto

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Post by RobC » Tue Nov 28, 2006 4:25 pm

To clear things up:

There are 3 versions of the 16v engine/management system:

1987 - 1990 phase 1 with motronic ML4.1 system
1991 - 1993 phase 2 with motronic M1.3 system (+knock sensor)
1991 - 1993 phase 2 + cat with motronic M1.3 system (+knock sensor and lanmda probe)

the changeover directly correlates with the change in interior from monza (dark blue/grey striped) to le mans (red/grey/black) interiors. it DOES NOT correspond with the change in exterior styling, which took place midway through the G plate (1989).

As far as octane rating is concerned, the ML4.1 is probably best only run on high octane fuel, as doc suggests. it was originally designed for leaded fuel.

Anything with M1.3 can be run on 95 octane, since it incorporates a knock sensor that adjusts the timing to suit the combustibility of the fuel. (interestingly when i took my valver to bristol 2cvs and asked about the knock sensor, and why my ecu was telling me i had a knock sensor fault, they tried to fob me off by saying it was a sensor to do with the alarm system!!! i tried pointing out that the ecu wouldn't care about some sensor to do with the alarm but they were having none of it so i left it and did my own research!)

BX Bandit's new valver therefore is perfectly suitable to run on 95 octane unleaded. performance will be a little down though, but it will do no harm to the engine.

Personally i always try and fill up with 99 octane fuel from tesco's (only about 90p per litre!)
1991 Citroen BX 16v

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Post by jeremy » Tue Nov 28, 2006 4:35 pm

But are the valve seats appropriate for unleaded. The recommendation sertainly in late 1989 was leaded only for 16 valves - and at that time 'Super Plus' unleaded was available - although not necesarily from Total.

Interesting atricle here:

http://www.pumaracing.co.uk/unlead01.htm

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Post by Kitch » Tue Nov 28, 2006 5:22 pm

Mines a 1991 car and the handbook says to run it on 4star. My brochure from the same era also states that all models except the 16v run on unleaded.

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Post by BX Bandit » Tue Nov 28, 2006 6:44 pm

Gor Blimey - so much info to absorb....

Kitch: The tappett rattle is there hot or cold - but it's not too severe. There is another rattle when cold. I haven't a clue what it is but could it be the hydraulic pump? It needs a trained ear in the bay whilst the engine is started. Having said that, it didn't make the noise this morning and it started well and ticked over nicely too. Much better than when I picked it up so it either likes being run or is enjoying the V Max - probably a bit of both. Its got Castrol Magnatech :x in at the moment so as you say, it needs some decent oil.

Rob C
re: cambelt rattle. i've had mine tensioned and adjusted on many occasions when i've been worried about the rattling noise, and each time it comes back from the garage still rattling a little bit when cold. as the engine warms up it expands and the rattle goes away. don't worry too much about it - if john witty who builds gary's racing BX says the tension's fine, then i believe him...

when i looked at the car i remember that other noise you were talking about though - sounds like a high pitched scraping noise, coming from the back of the engine, when cold right? never heard that before on a 16v. however it's definitely not
a) cambelt
b) tappets
c) HP pump
There are two noises that bother me: The noise on start up which as you say is not a), b) or c) above to Doc can give a good ear when he come over. The other noise is at around 2000 rpm and it sounds as if the belt is shredded and flapping on the inside of the cover. Belt looks good tho' but I haven't checked the tension - maybe its a bit loose and just exhibits that at 2000 rpm? I agree that something may not be right but it's all part of the fun as far as I'm concerned :lol: :wink: 8)

Also
1987 - 1990 phase 1 with motronic ML4.1 system
As far as octane rating is concerned, the ML4.1 is probably best only run on high octane fuel, as doc suggests. it was originally designed for leaded fuel.
BX Bandit's new valver therefore is perfectly suitable to run on 95 octane unleaded. performance will be a little down though, but it will do no harm to the engine.
Mine is a 1990 so it should have the ML4.1. Is there any way of telling?
If it is ML4.1, then surely mine would 'prefer' higher octane??

The nearside front footwell was like a swimming pool this morning so I cleared the drainage tubes from the sunroof and took out the front and rear carpets which are good condition but soaked. There is also mould under the rear seats....I'll put a fan heater in and leave the sunroof and windows open a crack for a few days.

DocChev was spot on with his radiator spot - it started leaking today!!! Just glad it got me home!!
have some balls
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Post by RobC » Tue Nov 28, 2006 8:12 pm

there are two easy tests to discover whether you're on ML4.1 or M1.3. confusingly ML4.1 is the earlier version despite being a higher number...

1. Are the 2 relays in the engine bay (next to the offside sphere) or under the driver's seat next to the ecu? If it's the latter you've got M1.3.

2. (slightly easier!) check the interior trim - is it le mans (red/grey/black/white) or monza (dark blue/grey stripes)? if it's le mans, you've got m1.3. i've yet to hear of a 16v with le mans interior that's also a ML4.1 car. Are you SURE yours is 1990? remember H reg cars were both 1990 and 1991 :wink:

and of course, (2) only works if the interior is original...

2000 rpm rattle is classic cambelt rattle. you'll find that if you play with the cambelt cover at that rpm the noise will go away. your belt may well be perfectly tensioned, but the cambelt covers have a habit of fouling things up.

FWIW My manual says unleaded's fine for the 16v, as does the 1991 brochure that came with it!
1991 Citroen BX 16v

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Post by cavmad » Tue Nov 28, 2006 8:51 pm

BX Bandit wrote:Gor Blimey - so much info to absorb....

Kitch: The tappett rattle is there hot or cold - but it's not too severe. There is another rattle when cold. I haven't a clue what it is but could it be the hydraulic pump? It needs a trained ear in the bay whilst the engine is started. Having said that, it didn't make the noise this morning and it started well and ticked over nicely too. Much better than when I picked it up so it either likes being run or is enjoying the V Max - probably a bit of both. Its got Castrol Magnatech :x in at the moment so as you say, it needs some decent oil.

Our survey said UH-OH :wink:

Regarding your rattles do you think the engine may want a flush and then new (best quality) oil and filter? I`ve certainly found this helps on non BX`s (as well as adding Wynn`s or similar oil addative) and in fact my Calibra is a different car altogethr since doing the above and changing the plugs. The only thing I didn`t do was have the engine flushed though this is on the cards.
It`s already much less rattly and drives 70%+ better now.
Vauxhall apologist.

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Post by BX Bandit » Tue Nov 28, 2006 10:04 pm

1. Are the 2 relays in the engine bay (next to the offside sphere) or under the driver's seat next to the ecu? If it's the latter you've got M1.3.
As I have just removed the carpet I did find some curiosities not present in the TD.....
An electrical gizmo box under passenger seat...ABS Cont unit???
An electrical gizmo box under drivers seat...ecu?? And yes, there were 2 relays fitted.
So that means I have an M1.3.
I also have a le mans interior (very comfy!) which would further support M1.3
Date of registration and purchase is 29 Sept 1990. So maybe late '90s also means M1.3??
So, in theory I can run 95 or 99 octane without any problems...???

CavMad, an engine flush has been mentioned in passing (Doc I think) and could well be in the running. I am tempted to go to town and do a full engine recon/rebuild..it's really the only way of knowing what you've got under the hood for sure and will be a good way of getting to know the engine which is currently completely alien to me...have to see, could be £££££££££££££££££££ :roll:
have some balls
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Post by RobC » Tue Nov 28, 2006 10:13 pm

yup, sounds like you've gotta M1.3 there matey.

one last check, just to be sure though, is if you find a black sensor with 2 wires coming out of it screwed into the engine block right next to the oil filter - that's yer knock sensor and it only came with the M1.3.

interesting that yours is a late 1990 with phase 2 engine - i had (briefly) a 1990 H reg that had the monza velour and had ML4.1 (i.e. phase 1). Maybe mine had been hanging around for a bit before it got registered, whereas yours was hot off the production line and straight onto the road! 8)
1991 Citroen BX 16v

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docchevron
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Post by docchevron » Wed Nov 29, 2006 3:29 am

That follows, my valver has ML 4.1, no knock sensor and hates 95 RON.

Jeremy, although Super plus was available in the early ninties, it was 97 RON not 98 RON. Or at least it was in every forecourt in the southwest I ever visited!! :lol:

The plug under the bonnet should have told me Bandits motor had the knock sensor.... I must be getting old!

I'd still rather run 99 octane though....

I know V power is crap but if you cant get Tesco's finest your a bit stuffed !
A few Tesco's stores round here dont do 99 RON so occasionally, when I get "caught short" I have to fill up with costimax / V power or whatever it's called this week! Car doesn't seem to mind it though....

Cheers
Chris G
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Far too many BX's, a bus, an ambulance a few trucks, not enough time and never enough cash...

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Post by Mike E (uk) » Wed Nov 29, 2006 7:58 am

" I know V power is crap "

I disagree, my 16V runs very nicely on it. costimax seems OK too.
Not tried the 99 tesco type yet.

The Alloy cylinder heads all have hardened steel valve seats.
So it is not the lack of lead you have to worry about, just the lack of octaine if you want max performance.

Mike

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Post by BX Bandit » Wed Nov 29, 2006 10:05 am

is if you find a black sensor with 2 wires coming out of it screwed into the engine block right next to the oil filter - that's yer knock sensor and it only came with the M1.3.
Did you mean oil filler? Yep, there's a little thingy connected to inlet manifold and air inlet duct. So mines an M1.3 which means it doesn't mind which fuel its on? I must say tho' it does seem alot better on the v-max but it could be cos' its had a good run instead of standing around??
Why do recon Vmax is crap docco? I think the local Texaco will do super unleaded (98 ron???) and I'll check Tesco - it's a big store so they probably do, although I'm not keen on lining their pockets any further truth be known - daylight bluddy robbery that lot!!

Need to focus on the TD cos its MOT tomorrow!!!!!
have some balls
1990 BX 16V Platinum Grey
1990 BX TZD (with A/C) Pink
1990 BX TGD White
2003 Audi A6 2.5 TDi
1960 Morris Minor Clarondon Grey
1971 Triumph 2000 Auto Valencia Blue