Detonation advise/ info is often spoken about here also is poor running both intemittent and worse.

 

My own experiece of testing fuel makes and manufacturers has been inconclusive...the Shell optimax as one subject matter, although I tried this for some 200 miles of use I was never totally convinced and reverted back to the usual unleaded.

 

Now in two years of ownership of my present zed running 14 psi etc etc I have NEVER EVER knowingly suffered from detonation regardless of where I got my petrol from.

 

I deal with many zeds either suffering from detonation or have in the past and often a poor level of service can be a contributing factor, but a positive answer between why one zed running in all the same way as another zed will detonate when the other does not has not fully been answered.

 

Petrol and its poor quality in this country is always a concideration and I do actually advise owners to use as much as possible the same source of fuel that they are happy with and then if a problem occurs then some recourse maybe possible.

 

All good advise, but I have found myself in the very same dilemor this weekend and wonder what others opinions may be.

 

Right having had an early(ish) finish Friday headed home in the zed stopping off for £30 (was nearly out) of unleaded from my normal supplier, (last two years) as I only live 1 mile from this garage I did not notice any problem.

 

The next day the zed started very strangely something it has never ever done, it was reluctant to fire, did eventually after a couple of goes and seemed ok. However as soon as I joined the main road I knew if felt strange, hunting a little , not a misfire more like a manul in too high a gear for the road speed. I had a 20 mile journey ahead so waited till it was warmed up and hit the gas on the motorway, initially it pulled ok upto to 14 psi and away...all ok I thought slowed by traffic ahead I was traveling at about 60mph on a light throttle, as I gently increased speed I was very aware by a noise my zed has never done Detonation! I lifted off and tried again...major detonation???? however if I floored it no detonation just full boost and away, so only detonation when changing from a light throttle to a slightly more open throttle.

 

I assumed at that point some pipe may have dislodged and the mixture was running well lean but still had full boost available???

Trying it again (still in traffic) found the detonation could be induced at about 7psi so too much boost not a problem. At this point the traffic cleared and soon was doing 70 mph no detonation I could hear ( maybe to much wind / road noise) how ever I did floor it to see, suddenly the car made a de-accelearation and dropped top a max 8 psi ! SAFETY BOOST Arghhhhhh never ever has this happened before.

 

Returning back to the workshop and got the conzult hooked up.

 

The 02 sensors where going crazy the A/F percentage was like 98% way too lean. Checked all the hoses and pipes nothing found out of place, all the other readings were correct but again the 02 sensors were bouncing all over the place even on 850 rpm`s the engine note was very odd however occassionally the A/F would pop up to 105% (shoul be 109%) and a noticable better engine note could be detected.

 

Trying to work out why my zed of all zeds would do this was getting to me....do not want to sound big headed but my zed is practically serviced every month! if not sooner out of passion.

 

As I started to doubt all my good work I noticed the petrol receipt on the passenger seat...and wondered?

 

Still had a a round trip of 120 miles to do so took the zed and rather tha drive slowly tried my best to not use the throttle opening that was causing detonation. well 125 miles to be exact later and only just under a quarter of a tank I fiiled up with optimax, at this point the car had previously dropping in to safety boost as soon as detting was audiable (some 6 times) I was stopping and resetting so I could monitor it a bit.

 

I exited the garage and made my way to the motorway some 2 miles away as I went down the slip way I was immediatly hit by the difference in the way it was, full power and less throttle, on to lane three and floor it wowwwwwwww !! no detting no safety boost just lovely power as usual?????

 

Hve now covered over 90 miles with no problems at all.

 

No doubt in mind that the fuel I had put in the previous night was either very low quality or spoilt in some way.

 

As expected the conzult now shows a perfect picture again with no odd readings.......I am now wondering how wide spread this problem may be? is any of the symptoms I have mentioned been encounted by other owners.

 

I am going back to the garage in the morning to ask the managers view on it, given that the offending fuel is gone proof is also gone but I do think a complaint should be logged after all the garage maybe been ripped off by his supplier?

 

Is there any particular departments that would deal with a customer complaint, or is trading standards not going to be interested??

 

Answered on a post card please.

 

 

Sorry for going on just wound up that £30 of fuel could of potentially harmed my engine if Nissan had not fitted the detonation circuit!

 

 

Jeff TT

Just for info Jeff the Nissan Detonation sensor is practically useless, as it only detects detonation below 3000RPM!

I know that petrol companies have alot of rules and regs they have to conform to re cross contamination ,looking for leaks etc, having said that ive also seen how much of the wrong grade goes in the wrong tank at petrol stations.

 

If you report it to the garage they are obliged to look into it, but it is very difficult in some cases, your best bet is get a can and put a pounds worth in it, and then follow the trading standards route.

 

But if they have had a tanker scince you filled up your proof may get diluted.

 

Trading standards dont mess about eitheir, i had a woman complain of a short measure once trading standards came in and turned me over, luckily our paperwork was all in order so i was in the clear.

 

Also if you report it to the station itself, if they are not on the level it will give them a chance to cover their tracks.

A good reason NOT to bridge the det sensor with a resistor me thinks - could well have saved your engine Jeff ;)

I had a bad batch of fuel from BP once, pretty much exactly the same symptoms - had to drive like a real wuss until it was run through. This must have been bad because my ECU is actually setup for regular unleaded.

My neighbour has a tuned new STI scooby and wanted even more than its present 300bhp from it but the guy who will remap the chip to win another 30bhp insists he fits a knock link first. He showed the gizmo that just arrived through the post. It has a piezo sensor to fit to the engine and a gauge with coloured leds to show the degree of detonation. It appears that this knock microphone is much better than the stock one that loses sensitivity after 3000rpm where the real damage can be done.

 

Anybody here tried one?

Originally posted by WillieO

My neighbour has a tuned new STI scooby and wanted even more than its present 300bhp from it but the guy who will remap the chip to win another 30bhp insists he fits a knock link first. He showed the gizmo that just arrived through the post. It has a piezo sensor to fit to the engine and a gauge with coloured leds to show the degree of detonation. It appears that this knock microphone is much better than the stock one that loses sensitivity after 3000rpm where the real damage can be done.

 

Anybody here tried one?

 

my mates got one on his STi too, must be a scooby thing! ;)

Also have has a similar occurance after filling up at esso one day, give it any throttle and the engine sounded like a diesel :(. Next fill up was ok though.

 

Can you get these dett meters for zeds? I do get concerned about knock 'cos my dad always fills with standard fuuel but its a jap so really should use premium :(

The only system I know of is the J&S system but it is very expensive and difficult to install!!!

Zedparts sell this one..

 

 

The Integral knock meter is a unique tuning tool which displays knock condition. The knock meter taps into the OEM knock sensor together with a secondary microphone mounted in the engine bay, for improved noise discrimination. Detonation shows up as a high frequency signal on knock sensors, and cannot be identified simply by hooking up a voltmeter or LED to the sensor. The Integral knock meter correctly interprets and discriminates this signal, and displays it as a easy to read LED bar graph.

 

We recommend using the knock meter together with wideband O2 gauges when tuning fuel and timing maps. We also recommend the knock meter by itself as a low cost (and superior) alternative to EGT gauges.

 

Cost: $254 US Dollars = £162.75 British Pounds

 

Have a look at the site: Zedparts-Gauges

 

Not sure if there is a supplier in the UK, but they are made by Integral Ltd in Japan... http://www.integral-ltd.co.jp/index.html They make a range of matching meters:

I have been filling at the same shell station for the whole year I have owned the old thunder and have had problems only once. After a previous thread, I went for a chat to the cashier guy (always works the night shift, usually the time I drag myself away from the office) and he said that optimax is delivered only once in every 3 deliveries, as it occupies the largest tank under the forecourt and the owner gets a discount for buying in larger quantities (?)

 

He said that some customers had complained of poor performance, pinking, etc (mostly Nova drivers) with one fill up but that the dealers could find nothing wrong with their cars. It seems that fuel quality is taken as a national level and no-one ever thinks that a problem with their car can originate from the fuel put into it.

 

Trust the Zed to show it up so plainly but after reading the thread last week, I will certaily be checking to make sure the fuel going into my old thunder is fresh....is really quite scary...

Defo know Andy is right on this one, seems bridging the det sensor is for use in a test only situation.

 

Jeff TT

the new Apexi S-AFC-2 has a knock sensor built in amongst other things.

Originally posted by Jezz_S13

the new Apexi S-AFC-2 has a knock sensor built in amongst other things.

 

AFAIK that only taps into the existing sensor though - so fairly useless since the sensor is only good up to around 3000rpm - dangerous detonation tends to occur under high load/high revs....

 

All IMO of course ;)

 

CheerZ,

 

Andy

Mmm, how much is a sticky onny sensor that will be pluginable to the S-AFC 2?

I have an S-AFC2 ready to go on to my Zed and wondered if I could get an uprated knock sensor that will read all through the rev range or the range pertinant to a Zed.

 

Olly.