Need advice from any MX6 gurus out there

**mykl-s** · 4-7-06, 2:41

Hi all,
I'm having a pinging problem and it's driving me crazy. The problem began shortly (but not immediately) after my exhaust manifold studs were replaced. The pinging starts at around 3000rpm in second or third gear at around 1-3 pounds of boost and goes away if I give it more throttle. If I pass through 3000rpm while not boosting, there is no pinging.
I have replaced the throttle body boot (which was starting to show its age), checked the plug gap and reduced it from 1.05mm to 0.95mm (plugs are clean), replaced the distributor cap, adjusted the timing from 10 deg advance to 8 deg advance and checked the leads.
The leads are spiral wire with resistances of 1.45, 1.2, 1 and 0.75 Ohms and the lead from the coil has a resistance of about 1.5 Ohm. There are no obvious leaks in any of the piping on the intake side, I am running 98 octane fuel, standard boost and have 260000km on the clock.
The pinging seems to be worse in cold weather and strangely reducing the ignition timing from 10 deg to 8 deg seemed to make it a little worse!
If any gurus out there can point me in the direction of the cause of the problem, you may just save my sanity! Thanks.

Mike

**mykl-s** · 4-7-06, 2:58

Just a thought.... could a dodgy throttle position sensor or egr position sensor cause the problem?

**heyitsmikey128** · 4-7-06, 18:26

ok look by 8 and 10 degrees advanced you me 8 degrees BTDC (Below Top Dead Center) right. Ok well detenation is caused becuase you not igniting the fuel fast enuff before the piston reaches the top of its stroke and thats when it detinates moving it from 10 to 8 is WORSE because you igniting the fuel later not giving it time to combust. My timing was off the other day and i was detinating. I moved it to 10 and the prob went away.

And what kinda plugs are those there is alot of plugs that don't work right with our cars.

I don't kno a whole lot about fuel but 98 octane is HARDER to ignite than 93 or 91. I dont know if this would cause it (kinda dout it) but if someone else has an opinion on high octane fuel then you can shoot.

And no im almost positive the throttle position sensor is your problem and i KNOW you egr isnt causing that, its just annoying.

and also your wires can cause this problem.

**magik8** · 4-7-06, 19:40

Are you using premium gasoline?

**automan** · 4-7-06, 21:58

Quote:

Originally Posted by heyitsmikey128

ok look by 8 and 10 degrees advanced you me 8 degrees BTDC (Below Top Dead Center) right. Ok well detenation is caused becuase you not igniting the fuel fast enuff before the piston reaches the top of its stroke and thats when it detinates moving it from 10 to 8 is WORSE because you igniting the fuel later not giving it time to combust. My timing was off the other day and i was detinating. I moved it to 10 and the prob went away.

And what kinda plugs are those there is alot of plugs that don't work right with our cars.

I don't kno a whole lot about fuel but 98 octane is HARDER to ignite than 93 or 91. I dont know if this would cause it (kinda dout it) but if someone else has an opinion on high octane fuel then you can shoot.

And no im almost positive the throttle position sensor is your problem and i KNOW you egr isnt causing that, its just annoying.

and also your wires can cause this problem.

Generally, if a knock sensor "hears" pinging, it will retard the timing, not advance it. I think mykl is on the right track by retarding the timing a bit. I recall reading a service bulletin that advised service techs to inform customers of non-turbo MX6s to avoid using higher octane than was recommended because of drivability issues. Have you tried lower octane fuel?

**magik8** · 4-7-06, 22:05

Not sure if 98 octane is "premium" or not over in Aus...

**mykl-s** · 4-8-06, 2:01

98 octane is the top premium grade we have in Aus. Our other grades are 91 and 95.

**cam22t** · 4-8-06, 2:44

You shouldn't be pinging on the fuel your running. The problem has to be elsewhere.

Why do you suspect your TPS ?

Reason why i am asking, is becasue. If you know there is a problem with it, then fix it 1st. I would assume that the factory ecu is using it to sense load.

**mykl-s** · 4-9-06, 0:08

I'm not aware of any problem with the TPS, just systematically going through considering what it might be. I've ruled out plugs, leads, distributor cap, intake piping leaks, fuel, air filter blockage, fuel filter blockage, etc. Could be a dirty injector I guess, but I've run a couple of bottles of injector cleaner through also. The EGR seems to be working when I test it in neutral. It's got me stumped!