Intake manifold cleaning and chasing the elusive hot engine "ping"
01-06-2009, 08:10 AM
#1
Senior Member
Thread Starter
Join Date: Oct 2004
Location: Pretoria - South Africa
Posts: 1,205
Intake manifold cleaning and chasing the elusive hot engine "ping"
Long story:
In South Africa we don't have either EGRs or O2s so I don't know how relevant this all is going to be for you guys on the other side of the pond but here goes:
My VG with about 300K km has had only one fussy and meticulous previous owner before me, and yet I have been "plagued" by a mysterious "pinging" or "spark knock" effect when the motor is hot (intake manifold reaches more than about 63C) that apparently only myself could hear.
I have tried many a suggestion including retarding timing, better fuel, worse fuel, no fuel, decoke snake-oils, fuel additives yada yada yada ............ no change.
Then over December I decided I will consume a six-pack while removing and cleaning the whole of the IM.
So - this is what I found when I removed the upper intake.
Strange things I notice in those pics:
1. Cylinder 6's tract is the cleanest
2. Funky black "crystals" present on the lower intake surface
3. Lots of crud on the aluminum goose-neck intake section
4. Nice thick layer of crud behind and on the TB and butterflies themselves.
Net result of all of this cleaning and restoring everything to a nice and shiny clean surface with carb cleaner, then acetone and then engine degreaser finally? .............................
1. Way higher idling (1400rpm in park) - had to reset idle speed by major amount of IACV adjustment (bypass valve needed closing of about 4 whole turns).
2. No detectable change in throttle response or anything else like easier starting etc as this motor has imo always been silky
3. The irritating "hot engine ping" is GONE (2 weeks now)
Now this motor has never been "opened"/"touched" in its 300K km.
I cannot explain/attribute the presence of the hot engine "ping" I experienced to the condition of the IM I had, but obviously it has a major affect on either timing or mixture in the absence of EGR and O2 when our engines run off of a simple fuel and timing map in the ECU.
Anybody else with comparable pictures of the same exercise on their motors?
Thoughts as to the mechanism causing the presence of my "hot engine ping" with an apparently "dirty" IM?
Warnings on my part:
If you look at the IM's top you can see that both the PCV and the Booster line is effectively connected to the IM side feeding cyls 1,3 and 5 - iow stuff like Seafoam is going to be cleaning only half the IM and cylinders when used as directed. (yes there are 2 minute slots connecting the two halves of the IM via the PCV channel cavity but they are positioned such that little or no flow is possible from the rear to the front)
IMO the proper application method of eg Seafoam to the IM on the VG would be to fit a T-piece to the 2 vacuum lines that is found to be plugged on the TB on the MAF side of the TB - this will allow the throttle itself to be used to govern and draw Seafoam from a container via the opening of the small port in the venturi next to the butterflies - in guaranteed equal amounts to both the front bank and the rear bank of IM
In South Africa we don't have either EGRs or O2s so I don't know how relevant this all is going to be for you guys on the other side of the pond but here goes:
My VG with about 300K km has had only one fussy and meticulous previous owner before me, and yet I have been "plagued" by a mysterious "pinging" or "spark knock" effect when the motor is hot (intake manifold reaches more than about 63C) that apparently only myself could hear.
I have tried many a suggestion including retarding timing, better fuel, worse fuel, no fuel, decoke snake-oils, fuel additives yada yada yada ............ no change.
Then over December I decided I will consume a six-pack while removing and cleaning the whole of the IM.
So - this is what I found when I removed the upper intake.
Strange things I notice in those pics:
1. Cylinder 6's tract is the cleanest
2. Funky black "crystals" present on the lower intake surface
3. Lots of crud on the aluminum goose-neck intake section
4. Nice thick layer of crud behind and on the TB and butterflies themselves.
Net result of all of this cleaning and restoring everything to a nice and shiny clean surface with carb cleaner, then acetone and then engine degreaser finally? .............................
1. Way higher idling (1400rpm in park) - had to reset idle speed by major amount of IACV adjustment (bypass valve needed closing of about 4 whole turns).
2. No detectable change in throttle response or anything else like easier starting etc as this motor has imo always been silky
3. The irritating "hot engine ping" is GONE (2 weeks now)
Now this motor has never been "opened"/"touched" in its 300K km.
I cannot explain/attribute the presence of the hot engine "ping" I experienced to the condition of the IM I had, but obviously it has a major affect on either timing or mixture in the absence of EGR and O2 when our engines run off of a simple fuel and timing map in the ECU.
Anybody else with comparable pictures of the same exercise on their motors?
Thoughts as to the mechanism causing the presence of my "hot engine ping" with an apparently "dirty" IM?
Warnings on my part:
If you look at the IM's top you can see that both the PCV and the Booster line is effectively connected to the IM side feeding cyls 1,3 and 5 - iow stuff like Seafoam is going to be cleaning only half the IM and cylinders when used as directed. (yes there are 2 minute slots connecting the two halves of the IM via the PCV channel cavity but they are positioned such that little or no flow is possible from the rear to the front)
IMO the proper application method of eg Seafoam to the IM on the VG would be to fit a T-piece to the 2 vacuum lines that is found to be plugged on the TB on the MAF side of the TB - this will allow the throttle itself to be used to govern and draw Seafoam from a container via the opening of the small port in the venturi next to the butterflies - in guaranteed equal amounts to both the front bank and the rear bank of IM
01-06-2009, 11:04 AM
#3
01-06-2009, 03:10 PM
#4
if your IM made that much difference im guessing the outside of your engine is just as dirty get it steam cleaned it will help lower engine bay temps also im pretty sure you were suppose to use specific TB cleaner it might have something to do with the your idle still not falling back down. also u never wanna use seafoam ever in your life theres just too many horror stories
one product nobody has yet to trash (or have their car trashed by it) is this:WYNN's V.I.C
i would also check out your exhaust manifold studs leaking exhaust can really heat up the engine
(just "guessing" but you probably have a lil oil seepage coming from your dipstick if the engine is dirty and/or leaking exhaust this is prabably broken as well)
i bet south africa gets pretty hot u might wanna consider exhaust wrapping
one product nobody has yet to trash (or have their car trashed by it) is this:WYNN's V.I.C
i would also check out your exhaust manifold studs leaking exhaust can really heat up the engine
(just "guessing" but you probably have a lil oil seepage coming from your dipstick if the engine is dirty and/or leaking exhaust this is prabably broken as well)
i bet south africa gets pretty hot u might wanna consider exhaust wrapping
01-06-2009, 03:33 PM
#5
if your IM made that much difference im guessing the outside of your engine is just as dirty get it steam cleaned it will help lower engine bay temps also im pretty sure you were suppose to use specific TB cleaner it might have something to do with the your idle still not falling back down. also u never wanna use seafoam ever in your life theres just too many horror stories
one product nobody has yet to trash (or have their car trashed by it) is this:WYNN's V.I.C
i would also check out your exhaust manifold studs leaking exhaust can really heat up the engine
(just "guessing" but you probably have a lil oil seepage coming from your dipstick if the engine is dirty and/or leaking exhaust this is prabably broken as well)
i bet south africa gets pretty hot u might wanna consider exhaust wrapping
one product nobody has yet to trash (or have their car trashed by it) is this:WYNN's V.I.C
i would also check out your exhaust manifold studs leaking exhaust can really heat up the engine
(just "guessing" but you probably have a lil oil seepage coming from your dipstick if the engine is dirty and/or leaking exhaust this is prabably broken as well)
i bet south africa gets pretty hot u might wanna consider exhaust wrapping
01-06-2009, 08:11 PM
#6
Senior Member
Thread Starter
Join Date: Oct 2004
Location: Pretoria - South Africa
Posts: 1,205
if your IM made that much difference im guessing the outside of your engine is just as dirty get it steam cleaned it will help lower engine bay temps also im pretty sure you were suppose to use specific TB cleaner it might have something to do with the your idle still not falling back down. also u never wanna use seafoam ever in your life theres just too many horror stories
one product nobody has yet to trash (or have their car trashed by it) is this:WYNN's V.I.C
i would also check out your exhaust manifold studs leaking exhaust can really heat up the engine
(just "guessing" but you probably have a lil oil seepage coming from your dipstick if the engine is dirty and/or leaking exhaust this is prabably broken as well)
i bet south africa gets pretty hot u might wanna consider exhaust wrapping
one product nobody has yet to trash (or have their car trashed by it) is this:WYNN's V.I.C
i would also check out your exhaust manifold studs leaking exhaust can really heat up the engine
(just "guessing" but you probably have a lil oil seepage coming from your dipstick if the engine is dirty and/or leaking exhaust this is prabably broken as well)
i bet south africa gets pretty hot u might wanna consider exhaust wrapping
The only factually correct and sensible item in your whole post is your name because the forum handles that properly automatically for you.
01-06-2009, 09:31 PM
#8
yeah my thoughts were..... (read earlier post)
01-07-2009, 07:38 AM
#9
if your IM made that much difference im guessing the outside of your engine is just as dirty get it steam cleaned it will help lower engine bay temps also im pretty sure you were suppose to use specific TB cleaner it might have something to do with the your idle still not falling back down. also u never wanna use seafoam ever in your life theres just too many horror stories
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