89 corvette won't restart
Thread Starter
1st Gear
Joined: May 2012
Posts: 1
Likes: 0
89 corvette won't restart
Had injectors, ECM and ICM replaced. Won't restart, just cranks over. When we bought it went to have key made from VIN and it didn't work. Obviously different ignition. It seems like it takes about 30 minutes before it will restart. ? security issue. Any suggestions?
Heel & Toe
Joined: Feb 2009
Posts: 22
Likes: 0
disconnect the throttle position sensor, start the car, reconnect the throttle position sensor and let it "set a code" so that your check engine light is on then use the diagnostics to see what the problem is. worked for me, worth a try
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
You can get the error codes out of the ECM by doing the following:
http://corvettephotographs.com/c4vettes/codes.htm
The meaning of the codes is shown here:
http://forums.corvetteforum.com/1576116036-post35.html
The ECMs in these early C4s are REALLY STUPID. The codes are very basic failures, such as "sensor or wiring is open" and "sensor or wiring is shorted to ground". A lot of problems won't set a code. Some codes are not really problems, such as error code 42, which you will get when you disconnect the EST connector to set the base timing.
http://corvettephotographs.com/c4vettes/codes.htm
The meaning of the codes is shown here:
http://forums.corvetteforum.com/1576116036-post35.html
The ECMs in these early C4s are REALLY STUPID. The codes are very basic failures, such as "sensor or wiring is open" and "sensor or wiring is shorted to ground". A lot of problems won't set a code. Some codes are not really problems, such as error code 42, which you will get when you disconnect the EST connector to set the base timing.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The engine won't run with the TPS disconnected. The ECM thinks you're in "clear flood" mode and cuts off the injectors.
Maybe you meant the MAF? I know it will work with the MAF disconnected because I did that by accident one time. Unplugged it and forgot to plug it back in.
VATS disables the starter and the injectors. If VATS kicks in it won't crank (unless the starter relay has been bypassed).
Maybe you meant the MAF? I know it will work with the MAF disconnected because I did that by accident one time. Unplugged it and forgot to plug it back in.
VATS disables the starter and the injectors. If VATS kicks in it won't crank (unless the starter relay has been bypassed).
Heel & Toe
Joined: Feb 2009
Posts: 22
Likes: 0
then what could be wrong with mine? it's hard to start and will not idle and had a check engine light (or actually "service engine soon") so I got the code and it was "throttle position sensor voltage high" - I figured it would have a "limp mode" in case the throttle position sensor quit communicating at all so I unplugged the tps and it cranked right up. It was barely idling so I ran around and connected it back and it smoothed out idling - "smoothed-out" but still not right. It's trying to idle at 880rpm. I repeated this a few times to make sure it wasn't coincindince that tps unplug caused it to start. Sorry for the thread hijack
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
The engine won't run with the TPS disconnected. The ECM thinks you're in "clear flood" mode and cuts off the injectors.
Maybe you meant the MAF? I know it will work with the MAF disconnected because I did that by accident one time. Unplugged it and forgot to plug it back in.
VATS disables the starter and the injectors. If VATS kicks in it won't crank (unless the starter relay has been bypassed).
Maybe you meant the MAF? I know it will work with the MAF disconnected because I did that by accident one time. Unplugged it and forgot to plug it back in.
VATS disables the starter and the injectors. If VATS kicks in it won't crank (unless the starter relay has been bypassed).
IF the tps is in clear flood mode, ecm sets a 20: 1 air/fuel ratio, rather than shut off injectors entirely. not sure about other years.
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Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
will put the ECM into clear flood mode
The high idle you have is most likely due to the high TPS voltage making the ECM think you have the throttle open further than what it is is.
Check and adjust TPS volts
Last edited by vetteoz; Jun 13, 2012 at 03:04 AM.