1G 91 tsi dies when i hit my brakes or lights

[robert gsx1]

Hey every one,
Ok i was driving home from work and hit a big pot hole and my battery hit the hood and arced on it and my car died a had it towed home now it will start but if i turn on lights ior hit my breaksd it dies or mpi relay starts clicking if i dont use any thing it runs if i rev it past 35 it starts bogging and check engine light comes on and relays click i cant figure it out help thanx every one

 

[Spoolin92GSX]

Sounds like it cooked the ECU.

 

[steve]

Sounds more to me like the battery is dead or isn't charging anymore after shorting out to the hood.
What is the voltage when you car is running?

 

[robert gsx1]

Ill check voltage and things in the morning but if was the ecu would it still start and idle just fine no check engine light until i step on my breaks or turn on lights or the cooling fans kick on And i get the 5 sec CEl when i put the key in and it goes off like it should GRRR i love my dsm's but electronics just confuse me thank u everyone for you advice keep it coming

 

[2literbeatsV8]

First question...why no battery tie down?

 

[autodsm]

I think your battery and/or alternator are toast...could be the ECU but i would start with the battery and alternator.

 

[Dayonaise]

just had the same issue yesterday, car would start but as soon as i pushed the brakes it would drop idle and i would get a CEL but only for about 5 seconds. I changed my battery and it went away immediatly
Hope this helps

 

[gotclutch23]

I will almost bet its the battery. Id go battery,alternator, then ecu

 

[buhay6]

If it is the ecu send me a pm and I can hook you up with a ECU. But I'm really doubtful its the ECU

first question...why no battery tie down?

......+1

 

[robert gsx1]

Ok i just got the new alternator in new belts everything is hooked up correct voltage checks out at idle and under load new ecu i start it and try to turn on head lights or hit my break lights she dies i dont know what to do

 

[PotatoFlakeSTi]

Ok i just got the new alternator in new belts everything is hooked up correct voltage checks out at idle and under load new ecu i start it and try to turn on head lights or hit my break lights she dies i dont know what to do

You didn't say if you did anything w/ the battery.

 

[constant_proj21]

Try a different barrery. If that doesn't work, take your ECU out and take a peek at it. Or if you have a friend with a 91-94 (going off your profile car), then you can give theirs a try.

 

[steve]

Ok i just got the new alternator in new belts everything is hooked up correct voltage checks out at idle and under load new ecu i start it and try to turn on head lights or hit my break lights she dies i dont know what to do

Actually, this really doesn't tell us anything that is actionable. You've kept all the important information to yourself.

The first thing you can do is start describing that happens in a way that permits others to help. Steps taken, measurement values, tests preformed, results, these are the things that turn whining into diagnosis.

 

[robert gsx1]

OK i have a new battery,new alternator good ecu from my buddy.
Now the car starts up fine idles fine but as soon as the cooling fans kick on or i hit the breaks or use anything electrical it dies i checked the relays coil pack mpi relay, and igntion relay,
Now a few people said that my battery arcing on my hood wouldnt do what i described no matter how bad it arced but electronics are not my fortay so i cant call it. My next step would be pull the wiring harness and replace it unless some one has had this happen and knows what it is .
And thanx everyone for your insight on this

 

[Anubis_4_99]

Check all your ground wires, i had a VERY similar issue on my N/T and it was my intake ground.

 

[GSTurbo1]

Check to make sure your alternator is charging. My advice would be to take alt and battery out and get them tested.

 

[weebz1]

Check all your ground wires, i had a VERY similar issue on my N/T and it was my intake ground.

That's what I was going to suggest too. Also check voltage at your alt. then at the alternator fuse in the fuse box and then the battery to make sure they are all the same values.

 

[steve]

My next step would be pull the wiring harness and replace it.

Why would that be your next step?
What is leading you to think that will fix the problem and not create a bunch of new ones?

Get out your voltmeter, the measure the voltage when the car is running and when you hit the brakes. Report the voltages please and where you are measuring at.

When the car dies, is the check engine light on?
Are the brake lights actually working?
Do you hear the MPI relay click when it dies or afterward?

You also said the headlights cause it to die, do they turn on?
What's the voltage with them on?
Will the car start with them on?

I know that you answered some of these in your first post but you have since changed the battery, alternator, and ECU so it's time to revisit the symptoms.

The idea behind diagnosing problems is to develop an idea of what might be going and then start testing to prove or disprove that idea. The idea I'm still exploring is that the voltage is dropping

 

[Anubis_4_99]

BTW, don't just visually inspect and dismiss a wire because it looks ok. My intake ground looked ok, but i wiggled it a bit and it just separated from the terminal, once that happened i saw it was horribly corroded on the inside and 95% of it had broken free from the terminal.

I would also listen to steve, pulling the wiring harness is a major step from a possible little problem your overlooking because of not taking the time to go through the process of elimination.

 

[rrussell]

You can mark this up as resolved.

I help out a friend that was looking for another 1g DSM for his son. We went and looked at this car with the electric issues and bought it for 1k.

Check all your ground wires, i had a VERY similar issue on my N/T and it was my intake ground.

It turned out to be poor grounds. The most important one was the ground from the intake to the fire wall was fried and MIA. We did a test with just a good set of jumper wires all running off the ground battery terminal. With one lead going to the factory middle ground fire wall bolt and another going to the engine side motor mount. Well it fix the problem instantly. Runs and drives awesome!!!

So we went and installed new ground cables, fire wall to intake and pass side fire wall to battery

I just wanted to share this because its fixed now and if anyone has this type of issue it should show up under the heading on this forum. (this is how I found the problem from doing a simple search on this site).

Thanks guys for all the input!!!