Car started last week, yesterday, but not today....
 

what's up everyone
obviously from the title, you know what i might need help with:D

well, finished rebuilding engine 2 weeks ago....car started fine...then started it a week ago and drove it around for 20 minutes, no problems.....yesterday, it took me three tries until the car finally started....today replaced air filter and spark plugs......guess what? doesn't start.....there is spark and the AFM is connected, all vacuum hoses and spark plug wires are connected and snug......car cranks but no go.....did something else not associated with what i replaced go bad?

i'd appreciate any advice fellas.....been working on this car for several months, and i'm almost there, geez!!!! oh the torture!!!! http://www.pelicanparts.com/support/smileys/splat.gif

oh and also, what should the battery level be when i turn the ignition? mine is at about between 11 and 12, is that enough to start the car? because when the car ran, it was at
a little above 14

I had a problem like this. The engine would crank and crank and crank and crank but no start. I replaced the ignition switch and it started right back up

do you hear the fuel pump from the back of the car? i recently had a problem similar and it ended up being a dme relay

Spark and no fuel? If you nave spark your ignition switch is working as well as the first set of contacts in the DME/fuel pump relay and the reference sensor.

As with the question posed above; do you hear the fuel pump run during the cranking and/or for a little bit just after you stop cranking? If not then either it's the fuel pump fuse, second set of contacts in the DME relay or the fuel pump itself. Wiring at the fuel pump can give problems too.

check the cannections on the speed & flywheel sensors on the firewall right behind the intake manifold. When mine were messed up it did the same thing

The battery at rest, car not running and no draws on, should be somewhere around 12.6v to 12.8v depending on the type of battery you have.

So, if you are down in the 11v area this is not so good. When you turn the starter that is going to suck a large amount of current and knock system voltage down. Since we have electronic brains there is a point when the brain will cease to work. I think that is something around/under 10 volts.

To test if this could be the problem jump your car to a good battery and see if she fires up.

hmmm....so how does the fuel pump sound?, when i turn the ignition it sounds like a very cute little eenie weenie motor is running.....a slight humming sound maybe.....hmmm....

That is what a fuel pump sounds like.

"Turn the ignition"??? Meaning cranking the car? The fuel pump will run only when the car is cranking or running. That wiring sound with just the key on is the fresh air fan.

hehehhehe .......... the wiring sound is more than likely the fresh air fan.

Check to see that your rotor is not coming loose.........

Any way for you to check fuel pressue?

well i don't have any tools to check fuel pressure, but i'm sure that would help narrow down the possibilities....what would i need and where could i find them?

You need:

1. Jumper for fuel pump relay: An inline fuse holder with 10 or 12 gage leads, 1/4 spade terninals crimped on leads (trim to fit if needed), & fuse, what is it 16 Amp? Get from stuff Auto parts store.

2 Pressure gage to hook to fuel rail: A 60 or 100 PSI presure guage, a fuel hose to fit the nipple on the fuel rail under the nut. 1/2" I think, but you better check, & don't loose the ball behind the nut. a barbed fitting to connect the hose to the guage to the hose. 2 hose clamps. Hose from auto parts store, rest from hardware or plumbing store.

hey guys, just trying to follow the dme inspection steps on clarks garage.....
does anyone know what the resistance/rating on this diode is? i plan on replacing it.....http://forums.pelicanparts.com/uploa...1110960343.jpg

Why? For less than $30 you can buy a whole new relay.

Just take it into almost any electronics shop, and they should be able to match up something that will work for you.
There is no resistance to diodes, the only 2 values that matter are their current rating, and what reverse voltage they can take.

It doesn't look like there is anything wrong with it though....

No that diode is just to isolate the relay-coil from the power-supply. The problem with these relays going bad are with the mechanical contacts corroding. The solder joints on the circuit board is pretty marginal as well. There's a way to replace these two relays with solid-state power transistors.

oh, sorry for the confusion, the picture is from clarks garage.... ;)
but anyways, yes socal, i called a local dealership, and a new one's 37 bucks, i guess i could buy it cheaper online, but i "need" it now.....:D

Should be able to get one from a local shop that caters to the BMW/Porsche crowd for less.

A diode lets current flow one way & stops it the other. You can ohm it one way then swap the leads to check. If you buy the relay, go ahead & fix this one for a spare, if the diode checks bad. Diodes are cheap, about $1.