96 TA

Car is detonating while under load, I can rev it fine with no detonation while in "N" but as soon as I put it in drive and excellerate at normal speed I can hear the detonation.

So how can I fix this? Thanks.

shoebox

Use higher octane fuel and/or check to be sure the EGR system is working.

96 TA

Ill use some octane booster, I already us 93 gas which is the highest it goes around here.

How do I check the egr? Is there an egr delete kit I can just use to eliminate the egr completely?

Also, I was wonder if it would help to buy a Air-Temperature Module http://www.slponline.com/view_product.asp?P=63010 Does anyone think this would help since it would advance the timming?

Injuneer

If you can actually hear knock, you have serious problems. The stock programming is capable of pulling up to 15-degrees of timing advance to eliminate audible knock. There's absolutely no rational explanation of a "stock" LT1, running on 93 octane, getting audible knock.

Have you ever had it scanned to see if the PCM is pulling timing in response?

Why do you want to eliminate the EGR? It helps reduce detonation under certain operating conditions, like lugging the engine in the wrong gear.

Then you want to consider an "Air-Temperature Module" because "it would advance timing"...... too much timing can cause detonation.

You need to find out why your "stock" setup is acting the way it is, not attempt to band-aid it by deleting the EGR or adding a resistor to the IAT sensor.

96 TA

Looking at the issue I understand the ATM would be the wrong way to go, I was thinking of that because it causes the PCM to read a 35 degree air temp, and since my issue is more when the car is warm I thought something might be had to have the ATM. Im aware of the 15 degrees of timing pulled by the pcm and if I would have put the two together it wouldn't make any sense to add timming if the PCM cant pull enough of it. My bad

I didn't know EGR would help with the detonation, my car is a A4 so there isn't much of an issue having it in the wrong gear, but regardless I was planning to remove it later when I finally get to the exhaust. Ive done it before on a 96 LT1 with no issues but that was a while ago and cant remember to a "T" how I did it.

I don't want to "band-aid" anything but I have a guess that age has set in to my nearly 200,000 mile LT1. Currently im saving to install a new motor so any advice I can do to help my motor last as long as it can is welcome. So far octane boost is one and an inspection of the EGR is another, if removing it isn't in the best interest then I wont due it but it was just a question I was asking. Do you have any sugestions?

Injuneer

You may have issues with the timing signals/pulse patterns from the Opti being corrupt.

96 TA

So replacing the opti is a possible solution? Do timing chains every need to be replaced on these engines, I know they get loose but could it affect the timing to this degree (detonation).

DelSoto

sorry to revive such an old thread but was wondering if changing the opti helped. I have this same situ but cannot find my knock. I purchased a cable and using Datamaster, I am looking to see what it is doing. It does not show any timing getting pulled and while running and hearing the knock, I see no increase in the knock count. I suspect my opti as well. When the thing warms up it will barely turn > 1500 rpm and pops out the exhaust.

ricehammer

May be bad gas. Mine pinged like crazy after 10gal of 93 Citgo once (actually every time I went to #$%tgo). Instead of octane booster, which may give you a couple tenths of an octane, try a few gallons of 110 octane Sonoco or CAM2 and add it to what you have. Then start buying your 93 somewhere other than where you are now. Worth a try.

DelSoto

I have had 5 tanks through it with same results from 3 diff places

shoebox

If you are hearing actual detonation and not getting any increase in knock count, something is wrong with that picture.

DelSoto

could my opti be a cause perhaps? I posted in another thread my problems with the stumbling popping out of the exhaust and won't rev over 1500 rpm when it warms up but after cooldown it runs fine again. I am at the end of things I know to look for and try. 1 shop wouldn't look at it. Another never heard of an opti. 2 others couldn't find anything or wanted to start replacing parts I have already replaced (in some instances twice).

97bowtie

Sounds like O2 sensors.

DelSoto

Replaced 3 tanks of gas ago

JP95ZM6

Bad Knock Sensor? If it knocks and is not showing knock counts, sounds like the car can't hear the knock.