Hi all, Long time no post... (Feb) Getting detonation underload at low revs? Also getting it as it comes on boost. My first guese is the O2 sensors but I hope it ain't cause the cost more + they are a Pain in the ass to remove. Anoyone heard of a temp sensor causing this I also have a high idle problem. Still exists after replacing the TPS. Maybe they are all screwed! Cheers, Danny
Do diagnostic test .... I suspect code 34 - dud det sensor would cause detonation as described. Try to keep in a higher gear and avoid loading the engine as detyonation can be extremely damaging!
Exactly what I've got at the moment...idle, detonation, the works... I've bypassed the det sensor as it failed a couple of months ago, I've also developed a knock at cold start in cylinder 5 or 6... Any ideas?
"a knock" ?? or lifter noise .... tic, tic ....? Noises are hard to diagnose over the 'net, but more specific description may help.
not lifter noise...more hollow than lifter noise... kinda like a little man under the plenum occasionly tapping it with a mallet. :LOL: also who can describe the noise of detonation best...I'm getting a fast rattle, the ol' chain gun from DOOM1 at around 4000rpm in 1st and to a lesser extent in 2nd. Turn the boost down and it dissapears in 2nd but still there in 1st.
Sounds like detonation, but >>> >>> "at cold start" ? :wacko: What is the actual timing set at? See Tech Index re Detonation, it may help you understand the symptoms/causes.
Rob... When I put my boost up with .9mm jets I got this perculiar tic tic tic high in second and pretty much through all of third, fourth etc. It was a very distinctive ticking noise - what could this be?
Scott ... Dunno what the tic, tic is, unless lifter noise or zorst leak ... Detonation, aka pinging, is quite pronounced and usually experienced with a hot engine under load. Some describe the noise as marbles rattling around in a tin, I liken it to continuous 'pinking'-type sound [until accelerator released]. A glance in RV mirror will usually show black zorst fumes bellowing out. Good idea to check actual timing ~ using direct coil pack connection, NOT inductive connection as this can be 1 - 2 degrees out.
pinging or detonation sounds like loose coins or marbles rattling in a tin can. It is normally irregular and best heard coming through the firewall. It can happen under load (or with too much boost) or as in my case under light throttle at about 2500 revs. Its causes are many, but usually caused by either a lean condition or increased cyclinder temps (caused also by lean conditions or hot spots). Cheers
Can detonation occur when the engine is cold, just started, just driven off and that rattling sound is heard at 4000rpm. Never heard it in 3rd or 4th, even under WOT and 16psi. What else could rattle when accelerating in 1st or second?
