Check engine light off under load?
Trio3b
09-23-2012, 09:16 PM
1993 PA with a good strong 3.8L with 271k miles. Before all this, the engine would crank and run a few sec then stop. Figured out it was definitely losing coolant into AND out of engine at upper intake manifold /throttle body joint and also suspected idle air valve.
.Replaced upperintake manifold (goofy plastic was indeed leaking).. Pulled off throttle body , cleaned gunk out of idle air valve. Pintle and seat look OK. Not sure about TPS but it does seem to vary resistance as it's turned and MAF is new. Now she idles and runs very nicely. Acceleration seems weak but that's probably b/c I've been cranking around town in the Camaro while fixing this. THERE IS NO HESITATION OR STUMBLING upon acceleration.
Pretty sure I replaced PCV valve properly and torqued manifold correctly. Now check engine light is on intermittent. When it IS on and stays on for any length of time (5-10 minutes), I notice it will go out under heavy acceleration then come back on as engine returns to low load condition.
Poked around for any vacuum stuff I forgot but don't see anything and I don't hear any hissing or whistling.
Autozone doesn't do OBD1 checks any more and I got rid of my code scanner last year.
Any ideas appreciated.
.Replaced upperintake manifold (goofy plastic was indeed leaking).. Pulled off throttle body , cleaned gunk out of idle air valve. Pintle and seat look OK. Not sure about TPS but it does seem to vary resistance as it's turned and MAF is new. Now she idles and runs very nicely. Acceleration seems weak but that's probably b/c I've been cranking around town in the Camaro while fixing this. THERE IS NO HESITATION OR STUMBLING upon acceleration.
Pretty sure I replaced PCV valve properly and torqued manifold correctly. Now check engine light is on intermittent. When it IS on and stays on for any length of time (5-10 minutes), I notice it will go out under heavy acceleration then come back on as engine returns to low load condition.
Poked around for any vacuum stuff I forgot but don't see anything and I don't hear any hissing or whistling.
Autozone doesn't do OBD1 checks any more and I got rid of my code scanner last year.
Any ideas appreciated.
yaz4real
09-23-2012, 11:38 PM
Thought OBD I could be checked by reading the flashes between code 12 by using the paper clip.
Trio3b
09-24-2012, 09:54 AM
Thought OBD I could be checked by reading the flashes between code 12 by using the paper clip.
Forgot about that. Yes the paperclip shows bad throttle position sensor (tps)
Thanks
Forgot about that. Yes the paperclip shows bad throttle position sensor (tps)
Thanks
yaz4real
09-24-2012, 12:18 PM
Your symptoms are classic tps. Sometimes cleaning connections and cleaning by removing from the throttle body however most people R&R. Easy to clean and try to save some $$$
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