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cherrywood12
07-15-2013, 08:31 AM
Hey All, 2002 Prostar 209 with 350Chevy ... will turn over and want to start running but shuts off as soon as I turn key back ... new battery, new dist cap and rotor, plugs newer... can hear fuel pump prime and see fuel going into carb from EFI as motor turns over ... all gauges respond ... have good spark to dist ... checked 50 amp reset ... check fuses under dash .. any ideas ... thanks!!

coz
07-15-2013, 08:36 AM
Hey All, 2002 Prostar 209 with 350Chevy ... will turn over and want to start running but shuts off as soon as I turn key back ... new battery, new dist cap and rotor, plugs newer... can hear fuel pump prime and see fuel going into carb from EFI as motor turns over ... all gauges respond ... have good spark to dist ... checked 50 amp reset ... check fuses under dash .. any ideas ... thanks!!

Sounds like the IAC (idle air control) valve. Had that same problem and picked up the part from NAPA.

cherrywood12
07-15-2013, 08:37 AM
Thanks .. will give it a shot

cherrywood12
07-15-2013, 10:07 AM
COZ, just went to Napa and they had hard time finding a cross reference on the part I need .. 2002,350 chevy with EFI ...what is the best way for the to get me the correct valve?

André
07-15-2013, 10:15 AM
NAPA 21755 will do on older TBI,not sure about your but i think it will do...
Not sure it is the cause of your problem...
Bad ECT could also cause not enough gas to start when cold...
Would it start when adding starting fluid...

cherrywood12
07-15-2013, 10:28 AM
I can see the gas coming out of injectors and it turns right over to start but just dies when key is turned back to on position.

JimN
07-15-2013, 11:04 AM
Hey All, 2002 Prostar 209 with 350Chevy ... will turn over and want to start running but shuts off as soon as I turn key back ... new battery, new dist cap and rotor, plugs newer... can hear fuel pump prime and see fuel going into carb from EFI as motor turns over ... all gauges respond ... have good spark to dist ... checked 50 amp reset ... check fuses under dash .. any ideas ... thanks!!

Push the clip on the safety switch. If it sounds like it's firing (test this with a timing light) when you crank and the spark stops when you stop cranking, your lanyard's clip has deformed and isn't pushing the button in far enough.

cherrywood12
07-15-2013, 11:17 AM
replace IAC ... same problem

JimN
07-15-2013, 11:31 AM
replace IAC ... same problem

Test before replacing. The proper range for the resistance of the ECT is widely available.

Aukanaii26
07-15-2013, 12:20 PM
I am having the same problem with my '84 prostar with a 351. I am assuming its electrical but haven't had time to test it, spent all weekend trying to figure it out. Rebuilt the carb, changed plugs, rebuilt ignition switch. I am clueless interested to see what you find. I am going through the starting circuit Tuesday afternoon or Wednesday.

cherrywood12
07-15-2013, 01:18 PM
ok .... just went out and the thing cranked right up I did jiggle safety switch ... idles like before ...
I wonder if something had to reset when I replaced IAC?

JimN
07-15-2013, 01:23 PM
I am having the same problem with my '84 prostar with a 351. I am assuming its electrical but haven't had time to test it, spent all weekend trying to figure it out. Rebuilt the carb, changed plugs, rebuilt ignition switch. I am clueless interested to see what you find. I am going through the starting circuit Tuesday afternoon or Wednesday.

Check the safety switch. Does the voltmeter move when you turn the key to ON? If not, check the switch.

Starting curcuit? Does it crank, or not fire?

JimN
07-15-2013, 01:25 PM
ok .... just went out and the thing cranked right up I did jiggle safety switch ... idles like before ...
I wonder if something had to reset when I replaced IAC?

The IAC closes when the key is turned off and opens a fixed amount of steps. This is called a 'stepper motor' and the ECM is instructed to open it so it will start easily next time. When an IAC is replaced, it sometimes needs a few key ON/OFF cycles to get it to the correct position. The ECM doesn't "know" where it is, it just sees a voltage drop or current peak when closing it, then opens whatever number of steps.

cherrywood12
07-15-2013, 01:38 PM
ok went out again and was not starting and wiggled safety switch and would start ... can I bypass this switch or would a local store have one?

Jerseydave
07-15-2013, 01:42 PM
ok went out again and was not starting and wiggled safety switch and would start ... can I bypass this switch or would a local store have one?

You can bypass it until you get a new one. (some owners never use the kill switch and bypass it permanently by I wouldn't recommend this)

JimN
07-15-2013, 01:50 PM
ok .... just went out and the thing cranked right up I did jiggle safety switch ... idles like before ...
I wonder if something had to reset when I replaced IAC?

Press on the pin in the switch with your thumb- if it works every time (before it gets too sore), replace the lanyard. The plastic relaxes over time, with heat.

cherrywood12
07-15-2013, 01:56 PM
pulled switch and jumped connection .... started every time

cherrywood12
07-15-2013, 02:06 PM
thanks guys ....
gunna start a new thread on my speedos not working

thatsmrmastercraft
07-15-2013, 02:09 PM
pulled switch and jumped connection .... started every time

:woohoo::woohoo::woohoo:

JimN
07-15-2013, 02:11 PM
thanks guys ....
gunna start a new thread on my speedos not working

What about the rest of the gauges? If they're flaky, it may be the MDC box or its ground wire. If the speedos are the only bad ones, look at the transom- paddle wheel, or pitot?

cherrywood12
07-15-2013, 02:45 PM
replaced paddle wheel.. no change .. what is pitot?
took to dealer ... they swapped boxes and box was good ... fuel gauge is only one that acts funny all the rest are good.

JimN
07-15-2013, 02:54 PM
replaced paddle wheel.. no change .. what is pitot?
took to dealer ... they swapped boxes and box was good ... fuel gauge is only one that acts funny all the rest are good.

A pitot might look like this-
http://www.westmarine.com/webapp/wcs/stores/servlet/Product2_11151_10001_348216_-1____ProductDisplayErrorView#.UeRFB6z7aVo

They're usually black on a MC. Uses a vinyl tube to pressurize a membrane at the front. Doesn't apply to yours, apparently.

Check the ground for the MDC.