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St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'13- '14
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93 wont start - H72 code - UPDATED
Turn the key, and it sounds like it wants to go. engine turns but doesnt fire. Everything was working fine til today. It seems to be getting fuel but the spark (according to the guy at the body shop) is not there. So I ran the code thing (paper clip trick) and got a code H72 in section 9.
Any idea what would be the cause of this?
Last edited by vetteweiser; Sep 13, 2004 at 06:17 PM.
I was hoping that my 95 shop manual had some info for you it does not. You may want to call a dealer and see if they would answer that question for you good luck
I had the same problem with my 93 about a month ago. I made all the checks as per the vette manual. It pointed to 2 things. The Opti and/or the module. Since I wasn't sure if the opti was any good or in what shape it may have been in I ventured to change the Opti, the water pump, all the hoses, and the thermostat. I also added vacuum venting to the Opti (I will post photos eventually). When I attempted to start the engine it did not. I then had a friend lend me the module off of a firebird and it fired up right away. Soooo, if you are so lucky and can get a spare ignition module make the test. You may get away with just changing the ignition module. This will take 10 minutes to do.
St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'13- '14
Cruise-In IV Veteran
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Cruise-In VI Veteran
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Cruise-In VIII Veteran
is that the ignition module on the passenger side of the engine that has two wires leading into it, one with a black connecter one with a gray connector??
that's the one. It sits next to the coil, held with 2 screws. Don't attempt to check with an ohm meter, if it isn't bad it will go bad. Try to get another module unplug yours and plug in the other module. If the problem is your module the engine should start.
no problem, anytime. When you do try, let me know the results.
Oh, by the way I had the same code and a few others. Don't know how they tie up with this problem. Maybe someone else can tell us.
St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'13- '14
Cruise-In IV Veteran
Cruise-In V Veteran
Cruise-In VI Veteran
Cruise-In VII Veteran
Cruise-In VIII Veteran
Here is an interesting twist. The car will crank but not start in Park. Put it in Neutral, and NOTHING. It acts like it would act if the car was in R D 3 2 or 1.
Sounds like the park/neutral switch may have a prob but not likely your no spark problem. I just wanted to point out that the "H" in your code is for "History" so you may have had a little dimmer trouble at one time and the code 72 is stored but is unlikely anything to do with the current no start issue. You can unhook the neg post of battery for a bit to clear that code, then check and see if it ever returns.
The ignition module may be the answer, if you can swap it with another at no cost to test it then do so. You should also consider the VATS and do a search on VATS related troubles. If you have a sprare key with new pellet it may be worth trying after clearing code. Just my .2 cents. Good luck.
Turn the key, and it sounds like it wants to go. engine turns but doesnt fire. Everything was working fine til today. It seems to be getting fuel but the spark (according to the guy at the body shop) is not there. So I ran the code thing (paper clip trick) and got a code H72 in section 9.