89 GTU Bogs down while accelerating when warm
03-11-06, 06:42 PM
#1
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89 GTU Bogs down while accelerating when warm
I drive my car all week at speeds under about 45, but for some reason on the weekends I go on the highway and drive around 80 and the car warms up and after maybe 5-10 minutes of driving the check engine light comes on and the car starts boggin down as soon as you press the accelerator. I took an exit and was driving around on some streets and if I ease the accelerator up it doesnt give me any problems but as soon as I try anything but gently easin it up it bogs down again. Searched forums under bogging, accelerating and came up without anyone having an identical problem.
03-12-06, 07:19 AM
#3
Originally Posted by Shaughn
I drive my car all week at speeds under about 45, but for some reason on the weekends I go on the highway and drive around 80 and the car warms up and after maybe 5-10 minutes of driving the check engine light comes on...
03-13-06, 06:48 PM
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Ok I pulled the ecu code and got 17 as the only code. says something about the feedback system. Oxygen sensor output remains o.55v for 10 seconds after F/B system operation beginning.
03-17-06, 11:21 AM
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Yeah i was looking at the description and it didnt seem like that code would do it but I reset it and tested it again and I only get code 17.
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03-23-06, 09:14 PM
#11
Opinions are like........
Since you replaced the o2(straight out of S5 FSM),
you need to :
test electrical connections(is strong o2 signal making it to ECM) or is the signal shorted?
test o2 during acceleration(.5-1 volt) with multimeter at the sensor and ECU.
test o2 output during deceleration(0-.4 volt which is your error being .55v or more).
replace/test plugs/wires/coils/ignitors(complete combustion)
check for vacuum leaks(all hoses, intake, manifold gaskets......)
bad injector(get them cleaned/tested) or run a tank of FI cleaner(like BG44k).
and lastly(defective ECM), swap with known good from another vehicle.
Don't confuse limp-home mode with engine that chokes because of electrical or mechanical issues when warm. The ECU can read an error but doesn't know what is causing it.
Also, check the water thermosensor and thermostat. Make sure engine is coming up to temp(thermostat) and the ECM knows it (thermosensor). A couple of Radioshack resistors can confirm this. Swap a 'hot' spec resistor(see FSM for thermosensor specs) on a cold engine to try to create the problem. Use a 'cold' spec resistor on a hot engine when problem occurs to see if it disappears simply by inserting resistor in place of thermosensor.
A bad TPS or MAF can also cause similar issues.
Clean all wiring harness connections and grounds.
you need to :
test electrical connections(is strong o2 signal making it to ECM) or is the signal shorted?
test o2 during acceleration(.5-1 volt) with multimeter at the sensor and ECU.
test o2 output during deceleration(0-.4 volt which is your error being .55v or more).
replace/test plugs/wires/coils/ignitors(complete combustion)
check for vacuum leaks(all hoses, intake, manifold gaskets......)
bad injector(get them cleaned/tested) or run a tank of FI cleaner(like BG44k).
and lastly(defective ECM), swap with known good from another vehicle.
Don't confuse limp-home mode with engine that chokes because of electrical or mechanical issues when warm. The ECU can read an error but doesn't know what is causing it.
Also, check the water thermosensor and thermostat. Make sure engine is coming up to temp(thermostat) and the ECM knows it (thermosensor). A couple of Radioshack resistors can confirm this. Swap a 'hot' spec resistor(see FSM for thermosensor specs) on a cold engine to try to create the problem. Use a 'cold' spec resistor on a hot engine when problem occurs to see if it disappears simply by inserting resistor in place of thermosensor.
A bad TPS or MAF can also cause similar issues.
Clean all wiring harness connections and grounds.
04-01-06, 11:20 PM
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My '89 GTUs is doing the exact same thing....hasn't kept us from winning the big races, but it sucks to be hammering down an autocross course doing 50mpg on the high end of 2nd gear and the car just sputtering and bogging.......
Replaced/added all kinds of grounds, fresh engine (less than 2500 miles), TPS and timing set, new NGK wires, known-good coils, new O2. Some things we have NOT done is have a proper ground for the exhaust, checked the OMP, checked any tems sensors, and pulled codes from the ECM.
-JW
Replaced/added all kinds of grounds, fresh engine (less than 2500 miles), TPS and timing set, new NGK wires, known-good coils, new O2. Some things we have NOT done is have a proper ground for the exhaust, checked the OMP, checked any tems sensors, and pulled codes from the ECM.
-JW
04-02-06, 12:37 AM
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Edit-- should have read "50 mph". Tired, sorry :-P
Just ran out and checked for codes, also Code 17....using the 1300cc.com guide as reference that's also Feedback System. Guide says that long flash (on for a second or more) means a unit of "10"... looks like a Code 17.
We replaced the O2 sensor with a new Bosch one when the motor was rebuilt, but it was running poorly and when it was breaking in it was running very rich and shooting fire, also some bad wiring with the Split Second programmable signal calibrator it was running veeeery rich. Could have easily torched the O2...I am searching for a local store that has a new O2 sensor before my race Sunday morning hehe.
Also, I have heard more than once that those trashed braided ground straps at the mufflers are for grounding the exhaust system. We had removed them (of course), and relocated the O2 bung behind the first cat when the REPU header went on there (long story, class rules make me keep both cats without relocating them), there may not be a sufficient ground for the O2.
I plan on being beneath the GTUs tomorrow to try to remedy both of these problems.
OTOH, I am getting (off the stock gauge) a reading of less than 12v at idle and apparently a tick under 14v under power/revs, and with a voltmeter I am showing 12.67v with the engine off and 12.14v at idle, 13.87v at higher rev. All new grounds, original 190K alternator, Mazda Competition main and alt pullies, Odyssey PC545 battery (11lbs). Idle voltage concerns me, any input?
-JW
Just ran out and checked for codes, also Code 17....using the 1300cc.com guide as reference that's also Feedback System. Guide says that long flash (on for a second or more) means a unit of "10"... looks like a Code 17.
We replaced the O2 sensor with a new Bosch one when the motor was rebuilt, but it was running poorly and when it was breaking in it was running very rich and shooting fire, also some bad wiring with the Split Second programmable signal calibrator it was running veeeery rich. Could have easily torched the O2...I am searching for a local store that has a new O2 sensor before my race Sunday morning hehe.
Also, I have heard more than once that those trashed braided ground straps at the mufflers are for grounding the exhaust system. We had removed them (of course), and relocated the O2 bung behind the first cat when the REPU header went on there (long story, class rules make me keep both cats without relocating them), there may not be a sufficient ground for the O2.
I plan on being beneath the GTUs tomorrow to try to remedy both of these problems.
OTOH, I am getting (off the stock gauge) a reading of less than 12v at idle and apparently a tick under 14v under power/revs, and with a voltmeter I am showing 12.67v with the engine off and 12.14v at idle, 13.87v at higher rev. All new grounds, original 190K alternator, Mazda Competition main and alt pullies, Odyssey PC545 battery (11lbs). Idle voltage concerns me, any input?
-JW
04-05-06, 01:27 PM
#14
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Well the check engine light stopped coming on and the ecu doesnt kick into limp mode. The only thing I could think of is that when I replaced the O2 sensor I didnt reset the ecu then did reset it but still had the same problem. Drove it for about another week and all the sudden it either realized it was fixed or something else.
04-05-06, 02:01 PM
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I replaced my O2 as well and then added a ground to the exhaust pipe, reset ECU, and viola no more problems.....well, there is that uncontrollable oversteer.....
-JW
-JW
04-09-06, 01:57 PM
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Well I thought problem solved but I jumped in the other night and headed down the highway and it started the same problem all over again. How did you add a ground to the exhaust pipe.
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