Carbon issues...Tried everything under the sun...I think
07-13-2010, 08:33 PM
#1
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Carbon issues...Tried everything under the sun...I think
Any advice you can provide would be greatly appreciated. Here's a synopsis of my problem and what I've done so far.
1986 2.4L EFI, RUNS RICH, CARBON ON TAILPIPE END, NEW ENGINE (same symptoms before after engine change due to rings and oil consumption). REPLACED ALL EGR COMPONENTS, MASSIVE CLOGGING (CARBON), REPLACED ALL VACUUM LINES, AIR METER, ALL AIR/WATER TEMP SENSORS, TPS (ECU code reported by mech),O2 SENSOR (numerous times). Runs and sounds like original engine did for 20+ years on initial start till about 5 mins past normal warmup temp then has higher pitch to engine above 2000 rpm on warmer temp days. Sounds normal during winter/cold days after warmup. No accel, a/c idle up,any other probs etc. Only continued carbon and higer pitch/possible air/fuel mixture problem. Then replaced air intake valve, removed and cleaned throttle body (found clogged vacuum ports), Reset TPS to spec's. High idle resulted. Required full decrease idle adjust. Near wits end. (Also new exhaust manifold,entire exhaust system,catalytic converter,new air filter, distributor cap,rotor and plugs/wires (within last year). New a/c up valve, cold start injector valve. No air leaks air filter to throttle body. Timing and valves recently adjusted, all ignition components checked out ok and still ran at high idle speed. Worried that have fixed carbon build up related probs but still haven't resolved buildup source. Fuel pressure regulator replaced. Carbon went away. Then had hard starting when warm engine, ok on cold starts. Realized vacuum line to VSV to FPR not connected. Reconnected. Carbon returned, suspect bad VSV. Apparently after engine change and before prior mech misconnected fuel pressure regulator to VSV to intake chamber vacuum line and had line from cruise control to FPR (discovered by no cruise control). VSV lines were routed intake chamber to VSV back to intake chamber. Reset intake chamber vac line to cruise control, Intake chamber line to VSV then line to FPR. Down to VSV or ECU even though normal ECU ops with no codes when checked. Yikes!!! What now?
1986 2.4L EFI, RUNS RICH, CARBON ON TAILPIPE END, NEW ENGINE (same symptoms before after engine change due to rings and oil consumption). REPLACED ALL EGR COMPONENTS, MASSIVE CLOGGING (CARBON), REPLACED ALL VACUUM LINES, AIR METER, ALL AIR/WATER TEMP SENSORS, TPS (ECU code reported by mech),O2 SENSOR (numerous times). Runs and sounds like original engine did for 20+ years on initial start till about 5 mins past normal warmup temp then has higher pitch to engine above 2000 rpm on warmer temp days. Sounds normal during winter/cold days after warmup. No accel, a/c idle up,any other probs etc. Only continued carbon and higer pitch/possible air/fuel mixture problem. Then replaced air intake valve, removed and cleaned throttle body (found clogged vacuum ports), Reset TPS to spec's. High idle resulted. Required full decrease idle adjust. Near wits end. (Also new exhaust manifold,entire exhaust system,catalytic converter,new air filter, distributor cap,rotor and plugs/wires (within last year). New a/c up valve, cold start injector valve. No air leaks air filter to throttle body. Timing and valves recently adjusted, all ignition components checked out ok and still ran at high idle speed. Worried that have fixed carbon build up related probs but still haven't resolved buildup source. Fuel pressure regulator replaced. Carbon went away. Then had hard starting when warm engine, ok on cold starts. Realized vacuum line to VSV to FPR not connected. Reconnected. Carbon returned, suspect bad VSV. Apparently after engine change and before prior mech misconnected fuel pressure regulator to VSV to intake chamber vacuum line and had line from cruise control to FPR (discovered by no cruise control). VSV lines were routed intake chamber to VSV back to intake chamber. Reset intake chamber vac line to cruise control, Intake chamber line to VSV then line to FPR. Down to VSV or ECU even though normal ECU ops with no codes when checked. Yikes!!! What now?
07-13-2010, 08:51 PM
#2
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The 02 sensor controls the air fuel ratio, and if its bad it can cause the problems your having. You said that you had a code coming up for the 02 sensor, have you replaced the 02 sensor ?. When i got my 86 4Runner i went through it and replaced a few sensors, not because they were bad, but because they were 24 years old and had over 300.000 miles on them, and the 02 sensor was one of them. So if your 02 sensor is original with a lot of miles on it, then just replace it.
Last edited by myyota; 07-13-2010 at 09:15 PM.
07-13-2010, 09:31 PM
#3
Registered User
Any advice you can provide would be greatly appreciated. Here's a synopsis of my problem and what I've done so far.
1986 2.4L EFI, RUNS RICH, CARBON ON TAILPIPE END, NEW ENGINE (same symptoms before after engine change due to rings and oil consumption).
REPLACED ALL EGR COMPONENTS, MASSIVE CLOGGING (CARBON), REPLACED ALL VACUUM LINES, AIR METER, ALL AIR/WATER TEMP SENSORS, TPS (ECU code reported by mech),O2 SENSOR (numerous times).
Runs and sounds like original engine did for 20+ years on initial start till about 5 mins past normal warmup temp then has higher pitch to engine above 2000 rpm on warmer temp days.
Sounds normal during winter/cold days after warmup. No accel, a/c idle up,any other probs etc. Only continued carbon and higer pitch/possible air/fuel mixture problem.
Then replaced air intake valve, removed and cleaned throttle body (found clogged vacuum ports), Reset TPS to spec's. High idle resulted. Required full decrease idle adjust. Near wits end. (Also new exhaust manifold,entire exhaust system,catalytic converter,new air filter, distributor cap,rotor and plugs/wires (within last year).
New a/c up valve, cold start injector valve. No air leaks air filter to throttle body. Timing and valves recently adjusted, all ignition components checked out ok and still ran at high idle speed. Worried that have fixed carbon build up related probs but still haven't resolved buildup source.
Fuel pressure regulator replaced. Carbon went away. Then had hard starting when warm engine, ok on cold starts. Realized vacuum line to VSV to FPR not connected. Reconnected. Carbon returned, suspect bad VSV.
Apparently after engine change and before prior mech misconnected fuel pressure regulator to VSV to intake chamber vacuum line and had line from cruise control to FPR (discovered by no cruise control).
VSV lines were routed intake chamber to VSV back to intake chamber. Reset intake chamber vac line to cruise control, Intake chamber line to VSV then line to FPR. Down to VSV or ECU even though normal ECU ops with no codes when checked.
Yikes!!! What now?
1986 2.4L EFI, RUNS RICH, CARBON ON TAILPIPE END, NEW ENGINE (same symptoms before after engine change due to rings and oil consumption).
REPLACED ALL EGR COMPONENTS, MASSIVE CLOGGING (CARBON), REPLACED ALL VACUUM LINES, AIR METER, ALL AIR/WATER TEMP SENSORS, TPS (ECU code reported by mech),O2 SENSOR (numerous times).
Runs and sounds like original engine did for 20+ years on initial start till about 5 mins past normal warmup temp then has higher pitch to engine above 2000 rpm on warmer temp days.
Sounds normal during winter/cold days after warmup. No accel, a/c idle up,any other probs etc. Only continued carbon and higer pitch/possible air/fuel mixture problem.
Then replaced air intake valve, removed and cleaned throttle body (found clogged vacuum ports), Reset TPS to spec's. High idle resulted. Required full decrease idle adjust. Near wits end. (Also new exhaust manifold,entire exhaust system,catalytic converter,new air filter, distributor cap,rotor and plugs/wires (within last year).
New a/c up valve, cold start injector valve. No air leaks air filter to throttle body. Timing and valves recently adjusted, all ignition components checked out ok and still ran at high idle speed. Worried that have fixed carbon build up related probs but still haven't resolved buildup source.
Fuel pressure regulator replaced. Carbon went away. Then had hard starting when warm engine, ok on cold starts. Realized vacuum line to VSV to FPR not connected. Reconnected. Carbon returned, suspect bad VSV.
Apparently after engine change and before prior mech misconnected fuel pressure regulator to VSV to intake chamber vacuum line and had line from cruise control to FPR (discovered by no cruise control).
VSV lines were routed intake chamber to VSV back to intake chamber. Reset intake chamber vac line to cruise control, Intake chamber line to VSV then line to FPR. Down to VSV or ECU even though normal ECU ops with no codes when checked.
Yikes!!! What now?
07-13-2010, 09:45 PM
#4
Registered User
Okay, here's an idea for you to consider......since you've replaced the O2 sensor several times. (which brand, btw?)
Quite possibly the engine's actually running lean and the O2 sensor's working. Just because you get a code (5?) for the sensor doesn't mean it's a problem with the sensor. If the sensor's working, barring any wiring issues, it could be just detecting a problem..... a lean one. So, if it's running lean, the sensor keeps signaling the ECU to enrich the fuel mix. Over time, this correction/adjustment gets worse (you'd have to know about ECU fuel trim to really know what that means, but fuel adjustments are cumulative) due to the original problem getting worse. Have you had the injectors serviced?
Quite possibly the engine's actually running lean and the O2 sensor's working. Just because you get a code (5?) for the sensor doesn't mean it's a problem with the sensor. If the sensor's working, barring any wiring issues, it could be just detecting a problem..... a lean one. So, if it's running lean, the sensor keeps signaling the ECU to enrich the fuel mix. Over time, this correction/adjustment gets worse (you'd have to know about ECU fuel trim to really know what that means, but fuel adjustments are cumulative) due to the original problem getting worse. Have you had the injectors serviced?
07-14-2010, 07:41 AM
#5
Registered User
Like thook said, you sure it's running rich? Looking at the plugs would be the best indication of that.
Assuming it is running rich, If O2 sensor isn't Denso or NTK (NGK) that may be the problem.
Has fuel pressure been tested? What were the numbers?
x2 on injector service - witchhunter.com is the best place for that.
Assuming it is running rich, If O2 sensor isn't Denso or NTK (NGK) that may be the problem.
Has fuel pressure been tested? What were the numbers?
x2 on injector service - witchhunter.com is the best place for that.
07-14-2010, 09:06 AM
#6
Registered User
Thanks, sb5walker. You inspired me to do a lot more reading on this type of subject.....namely the "Botsched" sensor issue. I ran an interesting, educational expirament with my wife's vehicle seeing as how I had a Bosch unit on there. I haven't finished with my expirament, but I plan to do a little write up thread on the whole matter. I'll let you know when that happens, if you're interested. You're input would be welcome, when it does.
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