Help w/Diagnosis

Supradrew · 05-28-2005, 12:27 AM

I have a 91 supra and it has the non-turbo (duh) i have had a miss in one of the cylinders. we put all new tune up parts on it and replaced the radiator and the thermostat and the belts. well, it's no longer overheating, but it still has the miss. #4 cylinder as best we can tell. also, we couldn't get the rotor off? No smoke, compresion test says it's ok, but has a consistant miss? any thoughts would be helpfull...

KingDiamond · 05-28-2005, 03:03 AM

What octane gasoline are you running. If your only running 87 octane, you may have a piece of carbon on that cylinder that is preigniting the gasoline and then when the spark plug fires and ignites the unburned fuel or exhaust the two flame fronts will collide causing a ping or knock. Possibly acting as a mis in the one cylinder you are talking about.

KingDiamond · 05-28-2005, 03:05 AM

In other words if your only running 87 octane, try running a higher octane like 89 or 93. Also what kind of spark plugs did you use as replacements. What Brand, what are they produced out of, platinum, etc..

Supradrew · 06-01-2005, 05:51 PM

It's been properly diagnosed. #4 injector was broken. Bosch replacement $82.00. Phew ~ Thx for your thoughts.

KingDiamond · 06-01-2005, 06:17 PM

glad you found the problem, and it turned out to be relatively inexpensive problem.

05-28-2005, 12:27 AM	#1
Supradrew Stock Join Date: May 2005 Posts: 2	I have a 91 supra and it has the non-turbo (duh) i have had a miss in one of the cylinders. we put all new tune up parts on it and replaced the radiator and the thermostat and the belts. well, it's no longer overheating, but it still has the miss. #4 cylinder as best we can tell. also, we couldn't get the rotor off? No smoke, compresion test says it's ok, but has a consistant miss? any thoughts would be helpfull...

05-28-2005, 03:03 AM	#2
KingDiamond 12psi boost Join Date: Apr 2005 Location: West Milford, NJ Posts: 357	What octane gasoline are you running. If your only running 87 octane, you may have a piece of carbon on that cylinder that is preigniting the gasoline and then when the spark plug fires and ignites the unburned fuel or exhaust the two flame fronts will collide causing a ping or knock. Possibly acting as a mis in the one cylinder you are talking about.

05-28-2005, 03:05 AM	#3
KingDiamond 12psi boost Join Date: Apr 2005 Location: West Milford, NJ Posts: 357	In other words if your only running 87 octane, try running a higher octane like 89 or 93. Also what kind of spark plugs did you use as replacements. What Brand, what are they produced out of, platinum, etc..

06-01-2005, 05:51 PM	#4
Supradrew Stock Join Date: May 2005 Posts: 2	It's been properly diagnosed. #4 injector was broken. Bosch replacement $82.00. Phew ~ Thx for your thoughts.

06-01-2005, 06:17 PM	#5
KingDiamond 12psi boost Join Date: Apr 2005 Location: West Milford, NJ Posts: 357	glad you found the problem, and it turned out to be relatively inexpensive problem.