Detonation problem persists
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On The Tree
Joined: Mar 2004
Posts: 175
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Detonation problem persists NEW DATA OCTOBER 4TH I had a detonation problem while on vacation see: Detonation/Ping on Vacation Trip
and I thought it would be gone when I got back to the Midwest and fueled up with the local 93 octane, 10% ethanol gas. Not so.
I’ve noticed that I’ve got pinging more often now, but most often under these conditions:
All together = Highway, Mild incline, high engine load, throttle opening to increase speed.
This was not the case before the 4000 mile vacation trip. I thought that maybe I had carbon in the engine, so I did the Seafoam soak. It did blow a lot of smoke, and was pinging LOUD when I was driving it out of the subdivision, so I know I blew a lot of carbon out.
But obviously, that’s not the whole problem. I need suggestions for why a car with only 28,000 miles will develop a ping problem!
For those interested, here is an AutoTap log showing the detonation and other pertinent details.
and I thought it would be gone when I got back to the Midwest and fueled up with the local 93 octane, 10% ethanol gas. Not so.
I’ve noticed that I’ve got pinging more often now, but most often under these conditions:
All together = Highway, Mild incline, high engine load, throttle opening to increase speed.
This was not the case before the 4000 mile vacation trip. I thought that maybe I had carbon in the engine, so I did the Seafoam soak. It did blow a lot of smoke, and was pinging LOUD when I was driving it out of the subdivision, so I know I blew a lot of carbon out.
But obviously, that’s not the whole problem. I need suggestions for why a car with only 28,000 miles will develop a ping problem!
For those interested, here is an AutoTap log showing the detonation and other pertinent details.
Last edited by fnbrowning; Oct 4, 2007 at 08:28 PM. Reason: New additions
Thread Starter
On The Tree
Joined: Mar 2004
Posts: 175
Likes: 1
Originally Posted by Cheatin' Chad
It look slike you are "lugging" the engine. You are trying to go WOT from 1100rpm??
Downshift!
Downshift!
So rather than a huge log from a lot driving I made it happen where I knew it would.
Believe me, the pinging is there at other throttle positions.
I never had any ping before now whether I lugged it or not - so this is new.
Remember, that thread I linked to in the first post. This started on vacation.
On poor Western gas, it was nearly a death rattle I had to moderate with octane boost to get me out of the mountains.
But now, after flushing the tank and returning to driving 'round my usual highways, I'm noticing a lot more pinging. Something's changed, something's wrong. . . .
Start with basic diagnostics.
Are you burning oil?
Have you done a compression check?
What do your plugs look like?
etc.
quit lugging the engine... You can permanently damage an engine by doing that once or twice.
Are you burning oil?
Have you done a compression check?
What do your plugs look like?
etc.
quit lugging the engine... You can permanently damage an engine by doing that once or twice.
Thread Starter
On The Tree
Joined: Mar 2004
Posts: 175
Likes: 1
On Saturday the 22nd, I treated my Trans-Am engine to a Seafoam soak to remove carbon. Seafoam was added the a hot running engine through the brake booster line until the engine stalled. The vehicle sat for 45 minutes. After startup, a considerable amount of white smoke was evident, which decreased to zero as the car was driven.
On Saturday the 29th, the service listed below was accomplished. The vehicle was then refueled with Shell 93 octane.
Includes compression check data on cylinders listed below:
1 - 8 - 7 - 2 - 6 - 5 - 4 - 3
153 150 150 152 151 150 153 153
Valve covers removed and pushrods checked. Also MAF removed and cleaned with Electro-Wash, a universal electronics cleaner.
8ea AC Delco Iridium plugs, gapped @ .40 Part #41-985
Wix Fuel filter Wix 33311
Wix Air filter Wix 46144
Included is the latest AutoTap data. Last time I was "accused" of lugging the engine. This time I kept the rpm's higher to avoid "lugging" the engine.
When I sent my tuner the data, shown in my post directly above, here is what he proposed.
Please give me your opinion of his suggested changes
His words in quotes:
On Saturday the 29th, the service listed below was accomplished. The vehicle was then refueled with Shell 93 octane.
Includes compression check data on cylinders listed below:
1 - 8 - 7 - 2 - 6 - 5 - 4 - 3
153 150 150 152 151 150 153 153
Valve covers removed and pushrods checked. Also MAF removed and cleaned with Electro-Wash, a universal electronics cleaner.
8ea AC Delco Iridium plugs, gapped @ .40 Part #41-985
Wix Fuel filter Wix 33311
Wix Air filter Wix 46144
Included is the latest AutoTap data. Last time I was "accused" of lugging the engine.
This time I kept the rpm's higher to avoid "lugging" the engine. When I sent my tuner the data, shown in my post directly above, here is what he proposed.
Please give me your opinion of his suggested changes
His words in quotes:
Below is a stock 2002 timing table for a vehicle identical to yours
This is your timing map. What is shown in the gray is the difference versus the stock timing map show above. As you can see, it is pretty much the same except for the wide open throttle positions. The negative values indicate how much less the stock timing value is than your current value.
I would be more than happy to reduce the areas in question in your timing map to eliminate all of your spark knock. Based on what you are doing, I would suggest that your map look like this:
Last edited by fnbrowning; Oct 4, 2007 at 08:37 PM. Reason: Clarified what my tuner said
It doesn't seem to me like your timing is excessive. Can you use
ATAP to see cylinder mode misfires? You'd like to know if this is
a one-bad-injector problem, vs a general fueling or general airflow
short-metering problem.
What is your Dynamic Cylinder Air mass value at WOT? That is
a pretty good indicator of airflow reasonableness.
ATAP to see cylinder mode misfires? You'd like to know if this is
a one-bad-injector problem, vs a general fueling or general airflow
short-metering problem.
What is your Dynamic Cylinder Air mass value at WOT? That is
a pretty good indicator of airflow reasonableness.
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You are still lugging the engine at that rpm and mph. What gear were you in for that last log? Leave the timing where it is and let the knock sensors do their job. They are not pulling the max timing they can not in PE mode. If you dont want to see any KR at that mph while accelerating, downshift. If you change the timing at those rpms and load in the tables, you won't have that extra timing for when you are in a lower gear and not lugging it. Another thing that can have an effect on it is IATs which are not in your log.
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I would suggest pulling the intake bellows, open the throttle body and make a wipe with your hand. There will be a slight amount of oil but if its flat out wet than that may be your problem. Oil consumption threw the PCV system has caused knock problems for me before. A great way to help the problem is to use a catch can. Also, one last thing. Your fuel trims look nicely tuned in however it may help to target a slightly negative fuel trim say -5%