405 Pings, Please HELP!!!!!!!!!!

DavidNCL

New member
Fellow Frogger
Joined
Aug 5, 2003
Messages
2
Location
Newcastle
I have a 405 (93 model, petrol engine)that pings under load. I am running the car on 96 octaine fuel and have taken all the normal precautions to fix this problem; cam belt, injector cleaning etc.

I am at a loss, if anyone has any sugestions could you let me know it would be a great help.

Thanks
 
stick a bottle of octane booster in it next time you fill up and see how you go
if it cures it then run it on 98octane fuel after that
 
Thanks for the reply.

I have been running the car on BP Ultra which is suposedly 98 octaine and it still pings under load, i have even thrown some race fuel (av gas) in it with little improvement.

I am down two to thoughts
1. The Chip

2. The mechanical advance in the dizzy may not be doing the right things creating an uneven advance curve.

Once again if anyone can help please let me know.
 
I thought the 405 8V engines had a full fuel/ignition ECU? ie the distributor is empty.
 
Pinging can be caused by several or a combination of factors including, but probably not limited to:

mixture too lean;
engine overheating or hot spots;
ignition timing too far advanced;
dizzy worn out, causing erratic ignition timing;
spark plug grade too hot;
air intake too hot;
fuel octane too low;
heavy carbon build-up in the combustion chambers;
etc, etc.

I had severe pinging problems with my 504, but it now seems to be cured. I tackled the problem from a number of angles; in the end it turned out that there were several contributing factors.

spanner :)
 
DavidNCL:
Thanks for the reply.

I have been running the car on BP Ultra which is suposedly 98 octaine and it still pings under load, i have even thrown some race fuel (av gas) in it with little improvement.

I am down two to thoughts
1. The Chip

2. The mechanical advance in the dizzy may not be doing the right things creating an uneven advance curve.

Once again if anyone can help please let me know.
The talk of "Avgas" is a worry. That stuff contains lead I was told, in which case you haven't done the cat any favours.
I have a 16V that makes weird noises on Ultimate that we're trying to sort at present, so it's not the be all to end all in fuels, however, my son has a BX 1.9 TZi which I think would have the same motor as yours, in which case, the distributor can be moved to adjust the spark. His was doing the same when he bought the car but by using a strobe timing light I retarded the spark & it's been right ever since.
Finding the hole in the housing to see the flywheel mark is a bugger as you have to plough through a pile of wires & pipes on the Cit, but it's at the front slightly right of centre and through the bell housing. Before you go to too much trouble looking for the timing mark, just check that there are two bolts attached to a plate & screwed into the engine holding the distributor. If so, then the distributor, hence the timing is adjustable.

Alan S
 
how mony km's has it done ???
give it a redex treatment and see how you go
don't be afraid of the initial smoke that mey exit the rear of the car
 
An excellent and cheap method, of cleaning carbon deposits from within an engine, is Steam cleaning, Remove the air cleaner, start the engine and bring rev's up to 3 1/2 to 4000 then pour or squirt approx 300ml of water, slowly into the Carby or Throttle body. Voila' all done.
This is one of the positive effects of water injection, the internals are always spotless, another is it is an excellent cure for Pinking, because it lowers the temperature in the combustion chamber thereby lowering the flash point temp', removing the need to go to a higher octane fuel or the need to use additives.
renault_ cheers!
 
frogs4ever:
Pinging can be caused by several or a combination of factors including, but probably not limited to:

mixture too lean;
engine overheating or hot spots;
ignition timing too far advanced;
dizzy worn out, causing erratic ignition timing;
spark plug grade too hot;
air intake too hot;
fuel octane too low;
heavy carbon build-up in the combustion chambers;
etc, etc.
To add to frogs4ever's list you could also think about:

dead lambda sensor
clogged / dead cat
low fuel pressure (dying fuel pump?)
lean mixture
clogged fuel filter
blocked canister or defective fuel return valve
defective temperature sensor
defective coil
emmission control system issues

Cheers

Rod

<small>[ 06 August 2003, 11:23 AM: Message edited by: Rod Hagen ]</small>
 
Blocked EGR valve?

My 405 pinged on 87 RON+MON/2 fuel so I've been running it on 92 octane (again, RON+MON/2) which has cured it. Interestingly, when I lived at 1050 m above sea level, it NEVER pinged. But now at 10 m ASL, it needs high octane. It is at 300,000 km now. I should check the EGR valve but I don't know where it is on the 405....assuming it has one. Exhaust Gas Recirculation suppresses pinging.

<small>[ 06 August 2003, 12:22 PM: Message edited by: M. Tippett ]</small>
 
..............and nobody agrees that the timing could be out? roll_lau roll_lau roll_lau roll_lau roll_lau roll_lau

Alan S :confused:
 
I think we all agree that the timing could be out, Alan. It pops up in a few of the answers above. Mind you, unless someone has actually fiddled with it, or there is a mechanical problem with the dizzy or a problem with the computer or emission gear, its really pretty rare for timing to change.

Another possibility that hasn't been mentioned might be a high level of accumulated condensation or other crap in the fuel tank.

Cheers

Rod
 
With prolonged use, the lead in the avgas will poison both the cat and the lambda sensor. A short burst is OK, but don't get caught. The fine is now $10 000!
 
My 405 had recently had a new cam belt fitted, before I bought it.
It was gutless and pinged like mad. - Problem = Cam timing out by a tooth.
Line up the holes in the drive sproket and cam gear. Not too hard
 
Dirty injectors can also be the cause of pinging, and from what I have seen no amount of Spitfire or whatever will fix, despite the adverts. The injectors must be removed and ultrasonically cleaned and the spray pattern and output checked on a test rig.
 
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