bad engine ground?

tak209
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bad engine ground?

Postby tak209 » Thu Feb 07, 2013 6:58 pm

my car starts and shortly dies after it starts. i had this problem in my old corolla and it ended up being a bad ground. how can i test if this is the case here?

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HASport AE86
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Re: bad engine ground?

Postby HASport AE86 » Thu Feb 07, 2013 7:07 pm

check the circuit open relay and the AFM. If the relay goes bad it will supply fuel for cranking but wont keep the fuel pump running after the engine starts, letting the engine run out of fuel and die. The relay operation is also controlled by the AFM. The relay doesn't kick on until it sees that the flapper door on the AFM is moving and the engine is cranking. A bad AFM will cause the engine to not start at all. There is a ghetto way of grounding this signal wire out to trick the ECU. I would start with the circuit open relay (aka fuel pump relay) first though.
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tak209
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Re: bad engine ground?

Postby tak209 » Thu Feb 07, 2013 7:11 pm

when i open the flap on the afm i can hear the fuel pump turn on... so i think thats ok then right?

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Re: bad engine ground?

Postby tak209 » Thu Feb 07, 2013 7:12 pm

and when i crank i get fuel also

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Re: bad engine ground?

Postby HASport AE86 » Thu Feb 07, 2013 7:16 pm

AFM is working fine then. The circuit open relay is behind the glovebox, yellow connector 5 pins. It's actually two relays in one. Half of the relay runs the fuel pump during cranking, the other half runs the engines after cranking. So if one half of the relay fails the car will only get fuel when cranking and then the pump shuts off. Unplug the relay and jump the blk/red and blue/blk wires with a spare piece of wire. This bypasses the relay all together and supplys a constant 12v to the pump. If the car runs, you know its the relay.
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tak209
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Re: bad engine ground?

Postby tak209 » Thu Feb 07, 2013 7:29 pm

nope still does the same thing. :/

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Re: bad engine ground?

Postby tak209 » Fri Feb 08, 2013 12:42 am

how can i check if its the engine ground?

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Re: bad engine ground?

Postby ethergore2 » Fri Feb 08, 2013 8:45 am

tak209 wrote:how can i check if its the engine ground?


Check to see if there is a secure connection on both ends and check the continuity of the ground wire from both ends.

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Re: bad engine ground?

Postby tak209 » Fri Feb 08, 2013 2:25 pm

ok there is continuity... and it is secure on the chassis so i am guessing this isnt my problem?

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Re: bad engine ground?

Postby ethergore2 » Fri Feb 08, 2013 4:00 pm

That's what I would guess. To diagnose your problem now I think we need more clues. Can giving the engine gas keep it going? How long does it run after it starts? What does it sound like? When did the problem come about?

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Re: bad engine ground?

Postby tak209 » Fri Feb 08, 2013 4:50 pm

i am currently in the middle of a engine swap. i put a aw11 gze in my corolla and it wont start. i have the cam timing right and the distributor is in the right spot. but it doesnt stay running. here is a video i made of what its doing.


http://youtu.be/6fFyS97pofM

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Re: bad engine ground?

Postby tak209 » Sat Feb 09, 2013 6:03 pm

bump

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Re: bad engine ground?

Postby allencr » Sat Feb 09, 2013 10:43 pm

tak209 wrote:ok there is continuity... and it is secure on the chassis so i am guessing this isnt my problem?


Yes, that is not your problem because we see that it has enough enough capacity & continuity to be able to run the starter, but that any other connections can only be guessed at.

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Re: bad engine ground?

Postby flowisode_zero » Sat Feb 09, 2013 10:51 pm

Its quite a rare possibility, but check your EFI relays. I had one die on me at a gas station (car would only crank), then less than 24hrs later the second one took a dump (car would start, then die off immediately).

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Re: bad engine ground?

Postby tak209 » Sun Feb 10, 2013 1:59 am

ok will do. thanks guys.

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Re: bad engine ground?

Postby Zenki85 » Wed Feb 13, 2013 9:32 pm

Check the 15 fuse for the fuel in the kickpanel inside. Found out which on it is. it might be blown and the fuses on the battery terminal
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Re: bad engine ground?

Postby tak209 » Fri Feb 15, 2013 11:10 pm

i figured it out. i didnt run a wire from the ecu... i dont see how i missed it. lol

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Re: bad engine ground?

Postby JaySee » Thu Dec 04, 2014 4:40 pm

tak209 wrote:i figured it out. i didnt run a wire from the ecu... i dont see how i missed it. lol



Im having the same problem with my car only difference is that it started happening after i had a guy swap the harness. By any chance do you remember what wire was it that you forgot to connect ? or any other things you noticed? all my relays and AFM are fine

thanks!