I know I read something about this somewhere on these message boards, but I can't seem to find it. I think the advice given was pretty worthless anyway (I think someone said 'just give it more gas. heh.'), so I might as well throw it out there again.

Has anyone else noticed mild preignition once their car is warmed up? I get it at the usual places, maintaining speed going uphill, if you gently stab the accel. while idling you get a little rattle as the RPMs pass through 3k, etc. I don't notice it at higher RPMs, only in the 2500-4000 range or thereabouts. Of course, with cam, con rod bearings, etc in mind, this concerns me. Normal? I'm guessing 'no', but I wanted to check with everyone first.

I am running 93+ octane and I've tried a couple of different brands. I even tried an additive, just in case. I don't think it's the fuel. I'm actually wondering with the head temp is normal. I thought I might have some carbon buildup/hotspots on the head, but I wrung it out pretty well the other day and I still have that annoying rattle intermittantly. I know my CBR used to ping a little if I didn't rev it once in a while, but I think I've ruled that out.

Thanks

 

My S2000 doesn't ping at all even on really hot days (running 98 octane Aus fuel, which someone said was equivalent to your 93+). I did however recently sell my old Celica which had the 3S-GE 2L engine, and that thing pinged for years on all kinds of fuel. It drove me crazy and despite checking absolutely everything (including all the EFI sensors, injector flow etc) I never found the cause until just before I sold it.

Basically, it was gumming/coking up in the top end. I had run endless fuel injector and upper cylinder cleaner through it and driven it hard to no avail, but since getting my Subaru WRX, I'd discovered the availability of some stuff that you actually run into the air intake system. Subaru specifies that you use it every service in their engines. Half goes in with the engine hot but switched off (you have to disconnect a convenient vacuum hose on the manifold somewhere, and it sprays in), you then leave it 5 mins, start the engine and run the other half can through. It killed the severe pinging on the Celica in one go, and the idle speed went up by 300rpm. I had to manually set it lower. Subaru just calls the stuff simply "Upper Cylinder Cleaner" and there must be other brands on the market. This might not solve your problem but it's a cheap and harmless thing to try.

 

rattle? as in a feeling or a sound? Pinging sounds like marbles in a tin can. You should it was pinging? Cuase if it was, you should be taking it to the dealer... my car doesn't ping...

-Shing

 

I'm intimately familiar with ping. It's ping, but very subtle. I wasn't sure if I was being over sensitive about it or not because it's VERY quiet. I mean, I've put weight kits in distributors before that caused massive preignition, this is not on the same order. it's very subtle, but it's definately ping. I guess I'll run by the dealership tomorrow and have them take a look...

... Which provides a nice segue to my primary problem with my car: The dealership. I don't like to take it in there 'cause they abuse vehicles. I've seen those freaks go racing in and out of the garage and rediculous speed in customers cars. From what I understand, they wreck a couple each year too. The other day, my G/F was in there with her car and a service guy was on the phone with a customer explaining how to handle the rental car and telling her that they would pay for it because the mech wrecked it. Nice. A week later, there was a state trooper in there questioning some punk about an accident he had in a customer car. Of course, I don't like to leave my car in there. Last time I did, there was 20 miles on it when I got it back ('97 Prelude SH). They said the needed to 'Road Test™' it. Is that what they are calling it these days?

My point? I wish there were some place I could take my car and KNOW that it wasn't going to be abused.

 

I've just remembered, doesn't the S2K have a knock sensor? It should retard the ignition if it detects pinging. Maybe yours is dodgy? I'd still try the upper cylinder cleaner I mentioned.

 

I would assume you are correct. I think most vehicles with electronic ignition are equiped with a knock sensor, but I could be wrong.

I wonder if there's something that I could buy at the auto parts store that does the same thing. I had a friend that used a ford product on his mustang that does the same thing, it sounds like. It foamed and he sprayed it in his carb with the motor off and let it sit. Then, he ran the engine to about 2k and sprayed it in the carb until it almost stalled, then stopping. He used the whole can. Does this sound familiar? Lots of smoke? Perhaps it's the same stuff. Do you remember what who made it or where you found it? Was it a Subaru product or did they just say "Go get it at trak"?

Thanks
J

 

Sounds like the same stuff to me - same procedure, smoke etc. With an EFI car you have to just detach a convenient vacuum hose and spray it in. The stuff I had was branded Subaru and I bought it from the dealer for about AUD$15 (USD$7.50). It made me feel like a fool for chasing that pinging for years when the fix was so easy. The Toyota dealers had no idea what the problem was despite stuffing around with my EFI and making the car run strangely. I wouldn't let your Honda dealer play with it until you've tried this. I'm guessing that there are other brands on the market but I've never seen one myself. I guess that prudence dictates that you ask Honda if it's OK first, but I can't see it damaging anything.

 

Also for cleaning the combustion chamber you can use water,which has to be sprayed into the intake with the engine running at 2-3000 rpm. You have to be carefull not to over spray because it can break con-rods pretty easy. It's very effectine though....

 

Just thought you guys might want to know that I had 3 service guys listen to this one. 1 guy said it sounded like ping, the other 2 said it was just valve and/or FI noise. I guess that'll have to do for now, but it sure sounds like ping to me, just quieter. The reason that the two guys said it could not be preignition is because it would make that noise in neutral under no load. Hmm. I can remember some really agressive weights that I put in my Buick 231 distrib that caused it to ping off idle in neutral. Anyway, it does have a detonation sensor and the two guys that know the most about s2k's said it was not ping, just engine noise.

Of course, while one guy was listening to it and playing with the gas pedal, he noticed a knock that he said sounded like con rod noise (read: BAD) while bliping the throttle from idle to about 3500. After driving the car a little, we decided it was clutch noise as we could not get the car to make the noise when the clutch was engaged(in neutral), only when the clutch was disengaged. It sounds like knocking when you increase the engine speed. You can actually feel it in the accel pedal. He said this is because the engine mounts on the car are not very shock-absorbant and you can feel everything. Of course, you can also HEAR it, but once you engage the clutch in neutral (standing still) or driving in any gear, it doesn't make the same sound. Strange. Anyone noticed this?

 

Sorry about your ping but those of us in the know have to know some specifics: MY 00 or 01?????