problems magically disappear?
Thread Starter
Instructor
Joined: Jun 2003
Posts: 200
Likes: 0
From: Tempe AZ
problems magically disappear?
Last week, my poor 85 sputtered like crazy, had no throttle response, and I got high off how rich it was running. So I went out of town over the weekend and let it sit in my garage. Came back, and its a whole new animal! When I stomp on it, it picks right up and actually revs without throwing a fit. fast too. What could cause this? I'm wagering that in a couple days of daily driving its gonna go back to being a slug, cause this sort of thing happened a long while ago. Typically, its always a slug.
things i've done: trickflow 195cc alum heads
things that've happened:
-ran into a mountain, body damage, hood don't open
-replaced o2 sensor 4 months back (still running rich)
-hacksaw'd off the mufflers and rear y-pipe (hangers broke)
-thrashed the interior
-rear main seal leaks (no surprise)
-random engine codes, usually for low voltage to fuel pump (?), maf/iac code, runs rich code, tps code, and i forgot the other one.
ideas why it likes to take long naps?
things i've done: trickflow 195cc alum heads
things that've happened:
-ran into a mountain, body damage, hood don't open
-replaced o2 sensor 4 months back (still running rich)
-hacksaw'd off the mufflers and rear y-pipe (hangers broke)
-thrashed the interior
-rear main seal leaks (no surprise)
-random engine codes, usually for low voltage to fuel pump (?), maf/iac code, runs rich code, tps code, and i forgot the other one.
ideas why it likes to take long naps?
Melting Slicks
Joined: Sep 2003
Posts: 3,326
Likes: 1
From: I live at www.domesticlugnuts.com I sleep in PA
Re: problems magically disappear? (brdd)
It probably hacked up a furball.......... :lolg:
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: problems magically disappear? (Corvettaholic)
First off open the connector in the Or wire near the battery for a minute to clear the codes.
You might also carefully look into the MAF while someone shuts off the engine; if the sensor wires don't glow bright red for 2sec, replace the MAF burn-off relay. If ok, clean the contacts to the MAF; if the code comes back and no faulty ECM, replace the MAF.
If code 52 comes up just after startup, replace the FP relay; if it comes up later, replace the oil pressure switch.
The TPS code may go away with the MAF code but you can check the TPS voltages at base idle and at WOT to see if all is well.
You can use the ECM's field test mode (explained on my site) to see if the ECM is going/staying in closed loop mode; if not (since the O2 sensor is fairly new, replace the coolant temp sensor in front of the engine umder the TB.
You might also carefully look into the MAF while someone shuts off the engine; if the sensor wires don't glow bright red for 2sec, replace the MAF burn-off relay. If ok, clean the contacts to the MAF; if the code comes back and no faulty ECM, replace the MAF.
If code 52 comes up just after startup, replace the FP relay; if it comes up later, replace the oil pressure switch.
The TPS code may go away with the MAF code but you can check the TPS voltages at base idle and at WOT to see if all is well.
You can use the ECM's field test mode (explained on my site) to see if the ECM is going/staying in closed loop mode; if not (since the O2 sensor is fairly new, replace the coolant temp sensor in front of the engine umder the TB.
Thread Starter
Instructor
Joined: Jun 2003
Posts: 200
Likes: 0
From: Tempe AZ
Re: problems magically disappear? (FX GS)
I think after I run those tests and nothing comes up, gonna get the poor thing checked for a hairball problem. maybe you guys are on to something...
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