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Adapt And Overcome!
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Discussion Starter #1 (Edited)
:dunno: So im pretty sure I have a short. When I unplug the neg cable from the battery and put a test light between the neg wire and the battery post the bulb lights up! There is 12.7V between the negative cable and the negative post on the battery. Now I've left the test light hooked up between the two negatives and pulled every fuse and relay under the hook and on the interior by the door. the light didnt go off! Ive check all my wiring under my truck and under the hood. unhooked the alternator which it keep the battery charged so its working! Unhooked the plug that connect all the wiring to the rear of the truck. I dont have any dash lights on what so ever. all the lights work. If i give it a jump it fires right up no problem and runs just like new. if i turn the truck off it will start one time after I turn it off but after that the truck just cranks and refuses to start! It has 35k miles on it. had it tuned up and all that 2 months ago. New fuel pump and filter. New Maf sensor.My battery is 2 days old and workin great.

My main concern is how is it possible for my negative ground wired and the negative on the battery to create 12.7V which is directly proportional to the Positive reading I got.

any help would be highly appreciated

***Really would like to figure out what the problem is bc my wife is nagging me to get her car back lol!
 

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lol i take im screwed lol this sucks really

No your not, thats not the problem. What you are doing with the test light is completing a circuit so the bulb will light. and the 12.7 you have on the ground wire to the terminal to the post is whats known as the "voltage drop".. What are the symptoms are you experiencing ? Maybe my self or someone on the forum can help.
 

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Adapt And Overcome!
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Discussion Starter #4
No your not, thats not the problem. What you are doing with the test light is completing a circuit so the bulb will light. and the 12.7 you have on the ground wire to the terminal to the post is whats known as the "voltage drop".. What are the symptoms are you experiencing ? Maybe my self or someone on the forum can help.
Hey, thanks for posting. I under stand the whole voltage drop and stuff. well actually im just learning that stuff bc im in the middle and switching jobs so im out htere in the electronics course in 29 palms ca. Problem im seeing is the circuit shouldnt be complete when the ignition is in the off position.

sysmptoms-
-will crank/no start
-spray fuel in Tb starts up
-put a set of cables on the battery for a sec starts up
-once started and turned off it will start once
- theres a draw off the battery when the ignitions off
-once started runs great everything works no problems
-once u let it sit it will not start again
-battery about a week old
-last battery was only good for 1 month had it tested(12 v and .02amps)
Its completley tuned up since i was going to drive it to 29 palms but decided to ship it. I had a complete tune up done and everything.

Like i said it runs just how it should once started.
Still trying to find out what it take the power away
 

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NOS make light brighter!
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1,480 Posts
You had to have missed something. Not a mechanic; but isn't there a couple things that are hooked up through fusible links, and do not feed through the fuseblock?

Good Luck.
 

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Adapt And Overcome!
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1,118 Posts
Discussion Starter #6
You had to have missed something. Not a mechanic; but isn't there a couple things that are hooked up through fusible links, and do not feed through the fuseblock?

Good Luck.
Ok it has somthing to do with my alarm which i have a new prestige alarm. The battery was died on my had it test it was a POS so got a new one. When i have the test light between the neg post and the neg wire the light flicks when i mess with the alarm the it stops the alarm makes some beep noise then flicks again. I just dont know if my alarm got reset bc the battery was completely drained while it was sitting waiting to be picked up to be shipped to me? idk but i know im on the right track. kinda thinking could be some kinda passlock crap who knows! Thanks
 

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NOS make light brighter!
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What did you make your connections with? Solder, crimps, wire nuts? When moving the harness, is there movement between the connectors and the alarm's brain?
 

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Adapt And Overcome!
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1,118 Posts
Discussion Starter #8
What did you make your connections with? Solder, crimps, wire nuts? When moving the harness, is there movement between the connectors and the alarm's brain?
no i had it done by a shop in nc im in 20 palms now but they soldered everything together and its done nice so i still dont get why i have draw at the ignition when the key is off position
 

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NOS make light brighter!
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The alarm is going to draw current while the car is off. How much, I cannot tell you. The paper work to you alarm should give some indication as to the current consumption of various sensors and the brain while in use. After adding up all of the amperages, check the amperage at the battery.
If you get a reading higher than it should be, completely disconnect the alarm. Take a reading again, and see it there is anymore amperage being drawn at the battery. If there isn't any, than it is isolated to the alarm and its parts. Do an amp draw on each individual part and track down the offensive sensor or whatnot. If each individual piece is normal, than check the amperage at the main connector on the alarm's brain. Calculate the difference between the draw at the battery and right at the connection. It shouldn't be much at all, as the voltage drop over such a short length of wire (assuming it is mounted near the firewall) should be minimal to none. If you found a difference, than check any hot wires along that bundle for shorts. Keep in mind when testing amperage that you only check the hot wires. running the ground within the clamp will level out any inductance reading, causing the meter to read low or zero.
 

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Adapt And Overcome!
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1,118 Posts
Discussion Starter #14
well now its hard to start once started will run but rough.then after about 15 min it dies and is hard to start. when you drive it and press the gas it boggs down somtimes dying.

what parts are good-
-tps
-fuel filter
-fuel pump
-icm
-camshaft sens changed 2000 miles ago
-cap n rotor
-plugs wite
 

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fuel pressure regulator? fuel pump relay? are you getting the GM signature ful pump sound when you turn the key to the on position with out starting it?

TO me it sounds like your alarm has nothing to do with it. An alarm does not do anything with fuel at all. unless they hooked up an fuel shutoff on the pump wires. i have never seen this done as a "normal" alarm install though.
 

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Adapt And Overcome!
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1,118 Posts
Discussion Starter #16
fuel pressure regulator? fuel pump relay? are you getting the GM signature ful pump sound when you turn the key to the on position with out starting it?

TO me it sounds like your alarm has nothing to do with it. An alarm does not do anything with fuel at all. unless they hooked up an fuel shutoff on the pump wires. i have never seen this done as a "normal" alarm install though.
Fuel pump just replaced about 2k miles ago. fuel pump comes on with the loud whine.

3 tries to start
runs but cant put gas pedal down or it bog down and/or die
run about 15 min die
start it right back up
run 15 die
wont start after that until it sits for a while
then hard to start approx 3 tries min to start
 

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i think 1 of the engine management sensors is acting up,

i had a similar thing with a Dodge, its would start,run and drive perfect, only when it came up to normal operating temperature it died and didn't fire back up..

turned out it was the camshaft position sensor along with the crank position sensor.. both were bad,.. replaced them , truck ran fine.

if i were you, do some tests, measure your fuelpressure cold and hot, and your ignition-signals, maybe its a bad ignition switch and get a read-out of the ecu..
 
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