| I've recently had a detonation issue at crusing/low boost levels. At least I think it's detonation. It seems to happen much worse when it is hot outside. The car is my DD so I'd like to figure this out. To start, I have just a pop charger and boost jets with Ashpec ECU for CA (91 octane). I have never had a problem with detonation until more recently. I don't really drive the car hard much but just once in a while. I started to hear detonation when pulling in 3rd a few months back. I didn't have a garage and wasn't home for months at a time and so I just didn't drive hard when I did drove it. Figured I'd change plugs and check timing and such when I had a chance. However, now it seems to be detonating at very low boost. In fact it is any time the boost goes positive when it is warm out. Say, after 10-15 min of driving in 80 degree weather. I'm honestly scared to drive it. Luckily I have a friends car for a while. What I have done/checked with limited skill or knowledge: Replaced plugs - PFR6B-11B and gapped at .035 Cleaned air filter Checked fuel pressure which seemed ok according to what Ash says. But I only checked at idle because I didn't want to drive around with detonation. I replaced the fuel filter anyway. Checked compression. The range was 142-149 psi but it seemed to take too long to build pressure. 12-13 cranks. I did not do the oil in the cylinder test but the built pressure seemed to hold indefinitely. I adjusted the timing which was at ~17 to right on 15. This was done at an idle of around 700 rpm. I had to adjust the idle as it usually idled higher at 1000 rpm. I also adjusted the TPS which was not off by much. I have not tested for boost leaks. I read that a faulty engine temp sensor could cause the car to lean out the air/fuel mixture so I cleaned it and the connector which was corroded. At first I thought it helped because I did not hear any detonation when I test drove it afterwards. But today I drove it when it was hot out and after it warmed up it was detonating again any time the boost was higher than 0 psi. This is from a BLITZ turbo timer/boost gauge not the stock gauge. I also tried to clean the connector to the CAS. The detonation is still there. Has anyone had detonation at low boost? I have not checked the EGR operation yet, mainly because it seems difficult to get to the vacuum hose to check. Could that be an issue? According to Ash it seems it could but I have not read any posts with people saying a faulty EGR caused detonation. The engine runs smooth, especially after the plugs were changed but it does have 193k on it. Any help or suggestions would be appreciated.
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