Todd951968

I recently took my 951 out of 3-month storage and noticed that there is a slight pinging, under load. The car is mostly stock except for; Stage II guru chips, 3 bar FPR, reliaboost manual boost controller set at 15lbs, billet diverter valve,
and SFR test pipe. I use 93 octane.

Does anyone have advice on what could be causing the pinging? Its possible I may have accidentially re-adjusted the reliaboost slightly-the screw came out last summer and I may have screwed and mal-adjusted the thing putting it back together. Of course it ran fine afterwards and didn't start pinging until I took it out of storage.

I'm worried about blowing a head gasket or worse so any advice on what to check out would be appreciated. With the weather nice again, I can't wait to drive it.

pk951

Turn down the boost if you are pinging.

Good if you could check you're AFR. Running with 93 octane should not ping at 15 psi.

Todd951968

How does one check the AFR or set it for 15lbs? The car came with it when I bought it and so I don't have instructions and don't know how to adjust it.

Chris White

Are you running the gas that was in the tank during storage? Old gas could be the problem if nothing else has changed.

There is a ‘fuel quality switch on the DME but it is a pain to get to. Use up the old gas and then see what happens.

Chris White

johne

You check the AFR(air fuel ration) with a WB02(wide band Oxygen sensor). You do this by buying one and installing it and then using it to take readings of your exhaust gases, or by going to a dyno and paying them to do it for you. Also AFR's are expressed in terms of the ratio of air-to-gasoline. AKA 14.7:1 is stoichiometric.

To decrease/increase your boost you use your MBC(manual boost controller). Boost is expressed in PSI (lbs) or BAR.

To summarize turn you boost down until the pinging stops(maybe 14 or 13 psi will doe) then start reading the archives and learning about AFR's and how to tune your car to stay at 12:1 AFR under boost. Oh and always use premium with 951's.

-John

Todd951968

I thought it could be old gas. But after only 3 months? It was the "winter blend" of gas, though. Instead of using all the old gas, I filled it when it had about 1/4 tank of the old gas left. It did seem to improve a little. Hopefully, a complete tank of new gas will rectify things. I'll try that.

bearone

gas goes bad after a couple of weeks.

after 3 months you're lucky it started because the varnish gets the fuel pump too.

try a few tanks of chevron sul.
btdt.

87/951

johne

Orrrrrr you could try turn down your boost so you don't blow your head gasket. Then after a few tanks or whatnot you can try inching the boost back up.

-John

Bill

Another possibility is you have crude in the bottom of your fuel tank. After sitting, it could have settled at the bottom of the tank. Then when you started it up again, you clogged the in tank screen or fuel filter. Once either becomes a restriction, your engine will not get the fuel it needs and lean out.

Drain your old fuel. Remove and replace the in-tank screen. Replace your fuel filter. Even if this is not your issue, these are required periodical maintenance items. And definately not a waste of money.

Pinging can be caused by many things. Advanced timing. Intake air leak behind the AFM. Bad fuel. Too much boost (more air than fuel). Carbon buildup on the pistons and thus too high compression. Ect.

And a lean fuel mixture which can come from, a fuel line restriction/crushed line, clogged fuel filters, failing fuel pump, failed fuel pressure regulator, clogged fuel tank vent. To check for fuel supply issues, check your fuel pressure first as it is the most likely suspect and easiest to trouble shoot.

If your fuel pressure is ok, look to the other items.

TurboTommy

Really, how do you know it's pinging for sure?
The knock control system should have taken care of the situation before the human ear can hear it. If it's bad detonation, you might hear a couple of "little pinks" of you listen carefully; then nothing; accompanied by a loss of performance.
You should make sure first it isn't another sound (something vibrating; like heat shield, etc.)

Gas doesn't go bad in a few weeks; that's ridiculus. Not even three months.

bearone

well then how long is it good for?

i've had, over the years, problems with bad/old gas in cars, lawn mowers, edge trimmers and other 2/4 cycle engines.
gas goes bad, evaporates, leaves a yellow stain/varnish on/in fuel lines, injectors, fuel pump, filter and everything it passes thru.

it makes for hard starting, acceleration and reliability.

Todd951968

Thanks, I'm going to try some of the suggestions. I drove it lightly last night and didn't notice pinging, which had started when I was in 3rd gear or higher and started rolling on the throttle. It really could have been a bad tank of gas. Hell, the gas station could have put lower octane in the "premium" pump-I've heard of that thing happening before.

I thought about adding octane booster but they say to add it before filling up and the tank is now 3/4 full. I think I'll just run this tank empty and refill it and see what happens. As of now, I think its bad gas. I'm just horrified at the thought of a pinging 951 and what it could lead to.

By the way, how does one turn the boost down on the car? I have a manual boost controller (someplace) but I don't know where it is. Can you accurately adjust it or do you just turn it down a bit and gradually increase boost? Unfortuneately, I'm not that versed on the car yet. Thanks

Skunk Workz

Same goes for winter storage of motorcycles....loads of people have starting problems and rough running the first tank (3-5 month old gas). After 5 months,usually you have to disassemble the carbs on bikes because they are so clogged with residues from the old gas they hardly run at all. Unless they were drained before storage,of course..