engine knocks when hot under acceleration
Thread Starter
Joined: Jun 2007
Posts: 2
engine knocks when hot under acceleration
It is officially summer in Phoenix and my stock 94 GT hates the warm weather. After about 10 minutes of driving the engine will knock loudly under any type of acceleration. The more gas I give it the more violent the knocking and the more sluggish the response. I only really notice it to the point of being a nuisance during the summer months. We have oxygenated gasoline Nov - Mar and I'm wondering if that is decreasing the problem.
I have taken it to several shops, but they have not been able to pinpoint the problem... they probably haven't had the patience to let it run enough for the problem to reproduce in an obvious way. No engine codes. I've done the obvious with no real improvements: higher octane, fuel additive, tune up, fuel filter, fuel pump, injector clean, mass air flow clean.
It has been getting progressively worse over the last 4 years. Any suggestions on how to find and fix this?
Thanks for the help.
I have taken it to several shops, but they have not been able to pinpoint the problem... they probably haven't had the patience to let it run enough for the problem to reproduce in an obvious way. No engine codes. I've done the obvious with no real improvements: higher octane, fuel additive, tune up, fuel filter, fuel pump, injector clean, mass air flow clean.
It has been getting progressively worse over the last 4 years. Any suggestions on how to find and fix this?
Thanks for the help.
Thread Starter
Joined: Jun 2007
Posts: 2
RE: engine knocks when hot under acceleration
oil = 5w30. various throughout the years 10w30, 10w30 full synthetic, 5w30 synthetic blend
miles = 140k
oxygenated gasoline = to add an oxygenate, such as Ethanol, to the gasoline... more environmentaly sound...impove air quality... blah, blah, blah
Thanks for the tip. I'll check those sensors.
miles = 140k
oxygenated gasoline = to add an oxygenate, such as Ethanol, to the gasoline... more environmentaly sound...impove air quality... blah, blah, blah
Thanks for the tip. I'll check those sensors.
1st Gear Member
Joined: May 2007
Posts: 133
From:
RE: engine knocks when hot under acceleration
Knock or ping is simple, its called pre-ignition, you need to retard the timing a few degrees. Actually thats how to set the timing, advance the timing until it pings, then retard it 2-4 degrees and you have found the optimal timing for the engine with the current gasoline your running.
5th Gear Member
Joined: Jun 2005
Posts: 3,986
From: Michigan
RE: engine knocks when hot under acceleration
Ok first off since your in AZ you should be running a much thicker oil. Since its (Im assuming) 100* 20w50 would be just fine and give your engine the protection it NEEDS for those kind of temps.
Second, what thermostat is in there? Because of the temps you shold be running a 180* T-stat. Also, make sure your cooling system is working properly. If your engine temp is too high it'll cause it to detonate.
Also, an intake cleaning service to remove the carbon build up on your pistons wouldnt be a bad idea either. Get some UNLEADED racing gas (100 octane +) and see if it goes away. If it does you have a lot of carbon build up on the pistons which has increased you compression ratio.
Check the timing, if its where its supposed to be leave it alone and try the other stuff I said.
-P.
Second, what thermostat is in there? Because of the temps you shold be running a 180* T-stat. Also, make sure your cooling system is working properly. If your engine temp is too high it'll cause it to detonate.
Also, an intake cleaning service to remove the carbon build up on your pistons wouldnt be a bad idea either. Get some UNLEADED racing gas (100 octane +) and see if it goes away. If it does you have a lot of carbon build up on the pistons which has increased you compression ratio.
Check the timing, if its where its supposed to be leave it alone and try the other stuff I said.
-P.
5th Gear Member
Joined: Jan 2006
Posts: 3,926
From: Puerto Rico
RE: engine knocks when hot under acceleration
10W30 will be fine for that engine at those temps.....+ it will prevent a lot of dry startups...FYI..
When you said "No engine codes".....did you mean code 111 (System Pass) KOEO and KOER?....
Vehicle Application Listing Approved For SAE 5W-20 Motor Oil
• 1993-1996 1.9L Escort/Tracer
• 1995-2000 2.0L Zetec Contour/Mystique
• 1999-2002 2.0L Cougar
• 1997-2002 2.0L Escort/Tracer
• 1998-2002 2.0L Escort ZX2
• 2000-2002 2.0L Focus
• 2001-2002 2.0L Escape
• 1993-1997 2.3L Ranger
• 1993-1994 2.3L Mustang
• 1993-1994 2.3L Tempo/Topaz
• 1998-2001 2.5L Ranger
• 1995-2000 2.5L Contour/Mystique
• 1999-2002 2.5L Cougar
• 2001-2002 3.0L 4V Escape
• 1996-2001 3.0L 4V Taurus/Sable
• 1993-2002 3.0L (Vulcan) Aerostar/Ranger, Taurus/Sable (Flexible Fuel and Gas)
• 1995-2000 3.0L (Vulcan) Windstar
• 1993-1994 3.0L (Vulcan) Tempo/Topaz
• 2000-2002 3.0L 4V Lincoln LS
• 1995-2002 3.8L Windstar
• 1993-1997 3.8L Taurus/Sable, Thunderbird/Couger, Continental
• 1994-2002 3.8L Mustang
• 2002-2002 3.9L 4V Lincoln LS
• 1997-2002 4.2L (SPI) F-150 (under 8500 GVW only), E-Series
• 1996-2002 4.6L 2V Mustang
• 1992-2002 4.6L Crown Victoria/Grand Marquis
• 1991-2002 4.6L Town Car
• 1994-1997 4.6L 2V Thunderbird/Cougar
• 1996-2002 4.6L 4V Mustang Cobra
• 1995-2002 4.6L 4V Continental
• 1993-1998 4.6L 4V Mark VIII
• 1997-2002 4.6L 2V Triton F-150/250 (under 8500 GVW only), E-Series, Expedition
• 1993-1999 4.9L E-Series, F-Series
• 1993-1995 5.0L Mustang/Mustang Cobra (Canada)
• 1993-1993 5.0L Thunderbird/Cougar (USA)
• 1997-2001 5.0L Explorer/Mountaineer )
• 1993-1996 5.0L E-Series, F-Series, Bronco
• 2000-2002 5.4L Excursion
• 1997-2002 5.4L 2V F-150/250 (under 8500 GVW only), Expedition, E-Series, E-350 Chassis/RV/Cutaway
• 1998-2002 5.4L 2V/4V Navigator
• 1993-1996 5.8L E-Series
• 1993-1997 5.8L F-Series, Bronco
• 2000-2002 6.8L Excursion
• 1997-2002 6.8L E-Series, E-350 Chassis/RV/Cutaway
• 1999-2002 6.8L Super Duty F-Series 250 HD/350/450/550 Motorhome
• 1993-1998 7.5L All Vehicles
Exceptions
2001
3.3L Villager
3.9L Lincoln LS
4.0L Ranger, Explorer/Mountaineer, Explorer Sport, and Explorer Sport Trac
2002
2.0L HP Zetec SVT Focus
3.3L Villager
4.0L Ranger, Explorer/Mountaineer, Explorer Sport, and Explorer Sport Trac
NOTE:
IF VEHICLE IS NOT LISTED IN THIS APPLICATION, SAE 5W-30 OIL IS RECOMMENDED. REFER TO TSB 99-8-16.
• 1993-1996 1.9L Escort/Tracer
• 1995-2000 2.0L Zetec Contour/Mystique
• 1999-2002 2.0L Cougar
• 1997-2002 2.0L Escort/Tracer
• 1998-2002 2.0L Escort ZX2
• 2000-2002 2.0L Focus
• 2001-2002 2.0L Escape
• 1993-1997 2.3L Ranger
• 1993-1994 2.3L Mustang
• 1993-1994 2.3L Tempo/Topaz
• 1998-2001 2.5L Ranger
• 1995-2000 2.5L Contour/Mystique
• 1999-2002 2.5L Cougar
• 2001-2002 3.0L 4V Escape
• 1996-2001 3.0L 4V Taurus/Sable
• 1993-2002 3.0L (Vulcan) Aerostar/Ranger, Taurus/Sable (Flexible Fuel and Gas)
• 1995-2000 3.0L (Vulcan) Windstar
• 1993-1994 3.0L (Vulcan) Tempo/Topaz
• 2000-2002 3.0L 4V Lincoln LS
• 1995-2002 3.8L Windstar
• 1993-1997 3.8L Taurus/Sable, Thunderbird/Couger, Continental
• 1994-2002 3.8L Mustang
• 2002-2002 3.9L 4V Lincoln LS
• 1997-2002 4.2L (SPI) F-150 (under 8500 GVW only), E-Series
• 1996-2002 4.6L 2V Mustang
• 1992-2002 4.6L Crown Victoria/Grand Marquis
• 1991-2002 4.6L Town Car
• 1994-1997 4.6L 2V Thunderbird/Cougar
• 1996-2002 4.6L 4V Mustang Cobra
• 1995-2002 4.6L 4V Continental
• 1993-1998 4.6L 4V Mark VIII
• 1997-2002 4.6L 2V Triton F-150/250 (under 8500 GVW only), E-Series, Expedition
• 1993-1999 4.9L E-Series, F-Series
• 1993-1995 5.0L Mustang/Mustang Cobra (Canada)
• 1993-1993 5.0L Thunderbird/Cougar (USA)
• 1997-2001 5.0L Explorer/Mountaineer )
• 1993-1996 5.0L E-Series, F-Series, Bronco
• 2000-2002 5.4L Excursion
• 1997-2002 5.4L 2V F-150/250 (under 8500 GVW only), Expedition, E-Series, E-350 Chassis/RV/Cutaway
• 1998-2002 5.4L 2V/4V Navigator
• 1993-1996 5.8L E-Series
• 1993-1997 5.8L F-Series, Bronco
• 2000-2002 6.8L Excursion
• 1997-2002 6.8L E-Series, E-350 Chassis/RV/Cutaway
• 1999-2002 6.8L Super Duty F-Series 250 HD/350/450/550 Motorhome
• 1993-1998 7.5L All Vehicles
Exceptions
2001
3.3L Villager
3.9L Lincoln LS
4.0L Ranger, Explorer/Mountaineer, Explorer Sport, and Explorer Sport Trac
2002
2.0L HP Zetec SVT Focus
3.3L Villager
4.0L Ranger, Explorer/Mountaineer, Explorer Sport, and Explorer Sport Trac
NOTE:
IF VEHICLE IS NOT LISTED IN THIS APPLICATION, SAE 5W-30 OIL IS RECOMMENDED. REFER TO TSB 99-8-16.
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