xeccentric

iTrader: (2)

First thing first. This is a 91 s5 na=>t2. ive had this thing for years and barely came across the problem.

So after driving my fresh rebuilt engine to break it in for about 30 miles, my car shut itself off and wouldnt start up normally again.

This is a ported motor and i figured the lumpy idle was attributed to the port but i guess i must have been wrong. While driving on the freeway the car would shut itself off because the idle would drop to 0 and i had to restart it while rolling down the freeway.

Later on in the evening on my way home i was driving down a street when my tach died, so i figured that i would drive by ear to not over rev, a couple more blocks down the care shuts down.

it refuses to start normally and when it did, it backfires a bit then dies right away. My gauges went haywire and even when the key is in the on position and the motor is off the temp gauge shoots up to hot right away and my oil pressure needle fluctuates. The voltmeter stays at 8 volts or less and the power in the car acts like it too.

I thought it might just be a bad ground. But it wouldnt explain why my tach died. Could my TPS be off?

Has anyone encountered anything like this? Or have any thoughts? I need to get the car running soon

HAILERS

Alternator not putting out or bad battery. Not enough power to run the ECU/engine.

xeccentric

iTrader: (2)

See I had a secondary battery that i put in and it was fully charged. It still acted the same way which leads me to believe that its neither of the two. The voltmeter marks 8v on the fresh battery as well

no_luck

iTrader: (3)

umm do you have a digital multi meter ?
maybe you should check out the battery and see that its good.

also a bad alternator could ground its self out or the voltage regulator in the alternator could only be putting out the bare minimum.

xeccentric

iTrader: (2)

That wouldn't explain the tach dying out though, would it?
I read that it could be caused by a faulty secondary coil.
it's been raining lately though so im going to have to wait till it clears up

HAILERS

I'm fairly sure the ECU kills the trail coils when the battery/alternator are not putting out and the available voltage gets tooooo loooooowwwww. I'm not sure of the given figure, but I've seen this happen on my car when the battery /alt was not putting out and the voltage got too low. Tach recovered when the alt/battery got up to the right values.

I can't PROVE this thru the FSM/manuals. Just personal experience yrs ago.

no_luck

iTrader: (3)

its also happend to me..
i dont know if the battery or the alternator that was the culprit but i was driving on my marry way and i next thing i know im bogging couldn't rev past 3k and slowly went down further till it stalled. i replaced the alternator and battery at the same time since you arent sopposed to install a new alternator with a dead battery

xeccentric

iTrader: (2)

Imma hop on this soon then, i guess its time for an FD upgrade eh?

-Crash-

My battery just took a **** on me yesterday, I bought a brand new one from kragen, now my car runs a whole hell of a lot better, loads more power, and yea the storm was crazy here right lol, I'm glad I have a garage!

xeccentric

iTrader: (2)

I figured that the care would run off the reserve capacity of the battery though. The battery light didn't turn on to indicate that there was something wrong with the charging system. Then again I believe that the light only turns on when the alt is completely dead. Not when its just running a lower voltage. but who knows.

sharingan 19

iTrader: (16)

Dummy lights are exactly that. And a car won't run off a battery alone for very long ESPECIALLY at night.

xeccentric

iTrader: (2)

So I got around to testing the alternator today on a bench tester and it was putting down 14.1-14.6 volts. So I cant for the life of me figure out whats going on. I changed the trailing coil as well because i happened to have a spare and wanted to rule it out.

In any case, might this be the cause of a faulty ECU? And is there way to test it as well.

Let me recap whats going on:

First the Tach died while driving
Then the car just died,
-Batteries we discharged, but i recharged them. Holding voltage fine.
-I retensioned the belts to make sure they don't slip.
-When I turn the key, the car turns and then struggles, and my tach, voltmeter, and temp gauge start jumping up and down.
-Coolant buzzer went off but corrected itself when i added like 1 quart of distilled water.


there's spark, there's gas. Don't know if theres enough of each.

If anyone has any suggestions of where to start looking, or what to look at. Please feel free to share some advice. I need to get this car running and smogged by the end of may.

I'm going to do a compression test soon using the ghetto way of doing it. (Reg compression tester and watching for bouncing needle)

beefhole

iTrader: (29)

How do the terminal wires look, any corrosion? Check the 2 main grounds also: body (driver strut tower), and the engine (starter).

xeccentric

iTrader: (2)

Everythings grounded properly as far as I know Ill double check ad report in. I forgot to mention that my alarm goes off randomly too. The stock alarm.

HAILERS

The alt may show fourteen volts on some sort of rigged up bench test, but what does it read on the car with car running. All the alt needs is the white/blue wire to have batt power on it for it to put out on the car with engine running.

Even a alt with bad regulator will self excite if the reg is bad. Self excite by reving the engine up over idle speed.

xeccentric

iTrader: (2)

Well there lies the problem. The car won't start at all. Which is why I'm going to do a comp test soon. I'm not sure what caused this at all.

xeccentric

iTrader: (2)

Is there any specific way of checking the ecu? Or is it just checking it per the fsm?

HAILERS

Spinning the engine over with the starter should result in small bumps of the tach needle as you try to start the car. If so, then most likely you have spark.

Now you need gas. Jumper the fuel pump check connector and turn the key ON. You should hear the pump running and fuel going thru the fuel rails.

Or spin the engine over with the starter and see if there is spark on one of the lead sparkplug wires if you hold that wire approx 1/16' out of the bore of the coil assy. Should spark. Proving again you have spark.

All you need is spark and gas.

xeccentric

iTrader: (2)

I have spark. I gotta check for the fuel. i'm fairly confident i do have fuel. I'm going to jump the fuel pump tomorrow to see if it comes on, then im going to pull off the manifold to see if the secondarys are shooting into the manifold. I'll post results asap. I'm off to work for now

xeccentric

iTrader: (2)

When checking resistance on tps sensor. Do i test the sensor side plug or the harness side?

xeccentric

iTrader: (2)

On top of that i cant hear my fuel pump relay click. but i cant locate the jumper wire to see if the pump is working either

xeccentric

iTrader: (2)

What have we learned today? When it seems to be the most obvious, It is. Check for melted grounds. -_-

xeccentric

iTrader: (2)

Here's another one cause I don't want to open another thread. Is the speedometer only run by the cable to the tranny? Or something else? My car stays at 20 mph while at idle and only goes up when rolling (duh). But as I'm even going 10-15mph my gauge marks 50-60. Any ideas?