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93 Chevy wont start


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jimpower
User

Jul 8, 2010, 4:13 PM

Post #1 of 24 (7454 views)
93 Chevy wont start Sign In

Have 93 chevy truck 5.7 L , truck died like it run out of gas (I wish - not the problem) will turn over but fuel pump not operating
When you turn the key get no power to fuse (ecm-b 20a - should be hot get nothing) - pump relay - fuel pump in addition the service engine soon light does not come on when key in run during self test and unable to get anything thru OBD (swapped out bulb with known good one still nothing)
Have checked all fuses - pump relay - oil/fuel pressure switch and pump all are operational when powered directly from + terminal
Seems the pump relay fuse not receiving power - have the standard Haynes manual but shows 1 orange wire when in fact there are 2 grey? so did continuity check from fuse to relay to pump and wiring there is good,not sure what the relationship is between ecm-b and service engine light but it must be telling me something. ECM wire ?
Any help would be appreciated dont think it is a component feel like it is a power supply problem


Hammer Time
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Jul 8, 2010, 4:42 PM

Post #2 of 24 (7448 views)
Re: 93 Chevy wont start Sign In

If your not getting power at either side of the fuse with the key on check the fusible links at the starter.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



jimpower
User

Jul 9, 2010, 1:33 PM

Post #3 of 24 (7431 views)
Re: 93 Chevy wont start Sign In

First thanx for quick response ,is this the puple starter solonoid wire? if so where is it fused, looks like it runs from starter directly to ignition in cab I have checked for pwr with key turned to on and no voltage present cant see anything physically wrong and dont see where it is fused


Hammer Time
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Jul 9, 2010, 1:51 PM

Post #4 of 24 (7427 views)
Re: 93 Chevy wont start Sign In

No, the purple wire is the starter trigger wire. Your looking for red wires attached to the main terminal along with the battery cable. They are special fuse wire that will melt internally. Pull on each one and see if any stretch.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Jul 9, 2010, 1:52 PM)


jimpower
User

Jul 9, 2010, 2:52 PM

Post #5 of 24 (7417 views)
Re: 93 Chevy wont start Sign In

OK that makes more sense to me have positive cable with 12gauge orange fusible link - this carries on to junction box could not strech orange link - at junction box checked all other links specifically black link attached to red wire and it does not stretch (does this go to alternator ) will keep looking thanx again


Hammer Time
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Jul 9, 2010, 3:05 PM

Post #6 of 24 (7415 views)
Re: 93 Chevy wont start Sign In

There should be more than one. One will be for the alternator and others power other things. Look at the back of your fuse box too and make sure nothing is wrong there.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



jimpower
User

Jul 9, 2010, 3:48 PM

Post #7 of 24 (7410 views)
Re: 93 Chevy wont start Sign In

Really not having much joy -at junction box with key on have power to all fusible link wires -including red wire and voltage at the other end at alternator still cant get power at ecm-b fuse either side with key on and no service engine soon light on bulb check could it be a bad ecm?


Hammer Time
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Jul 9, 2010, 3:52 PM

Post #8 of 24 (7407 views)
Re: 93 Chevy wont start Sign In

If you have power coming into the fuse box, just follow the bus bar to find out where your losing it. If that fuse is dead, others should be also unless the fuse box is bad.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



jimpower
User

Jul 9, 2010, 4:04 PM

Post #9 of 24 (7404 views)
Re: 93 Chevy wont start Sign In

The fuse I have been checking with no power to it is under hood at junction box for fuel pump relay it has 2 grey wires going to it but have no idea how to trace its power source wiring diagram shows 1 orange wire going to it which has me confused am I going down the wrong path where does this fuse get power from ? is it not supposed to be hot at all times?


Hammer Time
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Jul 9, 2010, 4:20 PM

Post #10 of 24 (7396 views)
Re: 93 Chevy wont start Sign In

If that has gray wires then it's inline with the fuel pump and will only be powered when the fuel pump is powered. The gray wire is the line to the pump.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



jimpower
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Jul 9, 2010, 5:05 PM

Post #11 of 24 (7390 views)
Re: 93 Chevy wont start Sign In

OK seem to be going in circles where is ECM-B mini fuse this is what powers the fuel pump correct? thought it was underhood adjacent fuel pump relay really confused now appreciate your patience


Hammer Time
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Jul 9, 2010, 5:16 PM

Post #12 of 24 (7386 views)
Re: 93 Chevy wont start Sign In

There is no ECMB fuse in that truck.
The orange wire is powered by a fusible link and the red wire by the ignition switch.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



jimpower
User

Jul 9, 2010, 5:25 PM

Post #13 of 24 (7380 views)
Re: 93 Chevy wont start Sign In

Nice shows how much I know the systym ,will chase the orange and red wires to see where I am losing power again appreciate your help have had enough for today it is miller time the first cold one is for you


jimpower
User

Jul 11, 2010, 3:32 PM

Post #14 of 24 (7364 views)
Re: 93 Chevy wont start Sign In

What fusible link powers orange wire ?
Engine turns over and have spark so dont think ignition/red wire the issue
Have continuity on orange wire up to ECM from relay
Also no SES light when ignition turnrd to run and SES light when trying to read codes at data link could this be connected in any way looks like a seperate curcuit


Hammer Time
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Jul 11, 2010, 3:43 PM

Post #15 of 24 (7361 views)
Re: 93 Chevy wont start Sign In

Your not making any sense. If your testing for power to the fuel pump relay, then you go to the relay and test the wires for power. Nobody cares about continuity or what else in the car works. Just test the wires for power.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



jimpower
User

Jul 11, 2010, 3:49 PM

Post #16 of 24 (7352 views)
Re: 93 Chevy wont start Sign In

Continuity to check for break in curcuit and to trace wires , not seeing any voltage on orange wire anywhere so trying to determine where it is being lost as everything seems to check out


Hammer Time
Ultimate Carjunky / Moderator
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Jul 11, 2010, 3:53 PM

Post #17 of 24 (7350 views)
Re: 93 Chevy wont start Sign In


Quote
Have continuity on orange wire up to ECM from relay


I don't know what your measuring but that orange wire doesn't even go to the ECM. It goes to a fusible link as I already stated. The link should be at the starter.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



fescom
Novice

Jul 11, 2010, 4:15 PM

Post #18 of 24 (7345 views)
Re: 93 Chevy wont start Sign In

Think you scared him off Hammer!!!! lol

O maybe not.

Gotta love flow charts tho.


(This post was edited by fescom on Jul 11, 2010, 4:17 PM)


jimpower
User

Jul 11, 2010, 4:20 PM

Post #19 of 24 (7340 views)
Re: 93 Chevy wont start Sign In

Well I physically followed orange wire from relay in to wire bundle where it is tied in with 2 other orange wires , the 3 orange wires are connected to 1 orange wire thru the firewall to the ECM wiring harness the starter has 2 wires purple trigger wire and positive battery cable which has fusible link attached


jimpower
User

Jul 11, 2010, 4:28 PM

Post #20 of 24 (7335 views)
Re: 93 Chevy wont start Sign In

Fescom if you have something positive to add that is fine if you just want to highjack thread because you think this is fun get a life


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jul 11, 2010, 4:44 PM

Post #21 of 24 (7328 views)
Re: 93 Chevy wont start Sign In

The branch of the wire you saw going to the ECM would be a branch of the power feed to the ECM not from it. The rest of the wire goes to a link where it's fed from. That would also be the reason that you don't have a check engine light. The same link powers the ECM. Apply power to that wire and I bet it starts right up.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Jul 11, 2010, 4:47 PM)


jimpower
User

Jul 11, 2010, 4:53 PM

Post #22 of 24 (7322 views)
Re: 93 Chevy wont start Sign In

You are correct was just about to post it went back out and jumped from the terminal to orange wire bypassing fusible link and shazam pump works and ses light on that is good to find had physically checked fusible link but wire did not strech assumed it was ok but is obviously the cause of the fault
OK Hammer thanks for the education and feedback
Cheers


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jul 11, 2010, 4:54 PM

Post #23 of 24 (7320 views)
Re: 93 Chevy wont start Sign In

Glad you were able to get to the bottom of it.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



fescom
Novice

Jul 11, 2010, 8:43 PM

Post #24 of 24 (7308 views)
Re: 93 Chevy wont start Sign In

U MEAN THIS ISN'T FUN?



WOW, BE NICE






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