legacycentral bbs

Been a while since Ive been able to work on my car. Torrential rain and a death in the family have kept me from getting anything done. get back to it.

As you recall in the last episode of my car wont <bleep>ing run, I drove my car to work and the next morning it started. ran for about 1-2 seconds, then died.

It turns over freely but makes no effort to start. It did the same thing about 2 months ago. a couple hundred dollars and a new fuel pump later I find out it jumped time. I kind of assumed it did it agaon. WRONGO!. Timing is dead on.

Not sure if it is related or not but about a week befor the car stopped running My Cruise controll stopped working.

Car has a full tank of gass.

Can some one give me a few starting points to check out. Im gonna pull the plugs and see if I have spark once the sun is up and id like to have a couple of other ideas in my head when I go out there.

thanks in advance.

You can do a very ghetto check for spark by just unplugging a spark plug wire from the coil and watching the coil. The spark will arc out of the coil tower onto the intake manifold.

Check if the ECU is powering up -- the Check Engine light should come on when the ignition is switched on.

Listen to make sure the fuel pump is priming -- right after you turn the ignition on, you should hear the pump run for a second or two.

You can also check for fuel pressure by pulling the hose off the outlet of the fuel filter, but this will spill fuel if there is pressure. If you do this, wear eye protection and ideally gloves as well.

This may seem dumb, but also make sure your air filter isn't completely clogged or anything, and that there aren't any vacuum leaks.

You might also try disconnecting the MAF sensor and seeing if it starts -- I believe your 90 4EAT ECU is capable of running (badly) without the MAF sensor.

A safer ghetto spark test would be to remove the plug, attach the lead and ground it by laying it on the block. This is a big no with some 2-stroke marine engines as if you get it wrong (don't have the plug grounded at all times) you can take out the computer, but fine in this case.

Steve

lets see. Check engine light turns on. Cant hear the Fuel pump, but i never have been able to. Air filter is about 6000 miles old so should be good unless i sucked a racoon into my snorkus, Tried the *unplug the coil* thing but couldnt see a spark.

Gonna try undoing the sparkplug and grounding it later. ill check the fuel pressure and the MAF then.

You should be able to hear the pump if you put your ear against the front passenger-side bottom of the trunk. You can put the ECU in test mode to make it cycle the pump on and off.

But if you're not getting spark, that's definitely a problem. Do you have an analog multimeter you can use to check the cam and crank angle sensors? And an ohmmeter to check the coil pack?

Wait -- unplug the coil? You mean you pulled one spark plug wire from the coil, right?

unplugged a sparkplug lead, aye thats what I meant.

And unfortunatly due to divorce and theft im down to a pretty basic 50 piece tool set. Gonna have to go buy a spark plug socket. But I want to check the sparkplug for spark before I assume the worst.

You might just see if a local shop will give you an old spark plug that they might have lying around.

If sparkplugs are anything like other parts around here they will want more for it than a new one.

Aircleaner looks good.

But I dont seem to have any fuel. Toggled the ignition on and off a few times. pulled the fuel line off the fuel filter, put the line BACk on the fuel filter, Put the ECU in test mode, took the line off the fuel filter. no fuel. tore the carpet out of the trunk and pulled the inspection plate. The Fuel pump doesnt seem to be working.

All of my Fuses seem intact.

whats next?

Check for power at the fuel pump's wires (I think I recently posted the exact wire colors actually). If there's power, then the pump's kaput. If not, then something in the wiring is.

Pump is a brand new (2 month old) Bosch unit with a lifetime waurentee. I suspect the problem is Electrical.

I did pull the inspection plate in the trunk so Ill check the wires tomorrow after work.

Yes, it could very well be in the wiring. In particular, there's a connector under the rear seat that seems somehow prone to failure, so look at that.

If the pump was replaced only recently, though, it might be worth checking that it was installed correctly.

Subyluvr had to replace that connection under the seat as his fizzled out. I know there is a thread around here somewhere with detailed instructions on how to bypass the plug.

Also, check that the ground wire is good.

bought a Digital Multimeter.

The Black wires(ground) give good continuity checks with the frame.

The plug under the seat looks to be in good condition.

Not getting any readings on the voltmeter from any two of the wires but my batterie died so its currently on the charger.

Working on the assumtion that it IS an electric problem. Ground good. conection under the seat good. what is my next step?

Brain salad surgery. What if I ran a power line from a keyed ignition source to the fuel pump? Grew up on vintage 1974 model vehicles where doing that kind of home wiring job didnt pose a hazard to any high falutin computer parts.

You really should check for voltage across the pump's wires when it's connected, so it's loading the circuit.

But if those connections are all good and it is an electrical problem still, the next thing to check is the fuel pump relay.

Concerns about just running a wire from an ignition-switched circuit to the pump:

1) That circuit probably doesn't have enough spare capacity to power the pump.
2) Depending what circuit it is and how things are fused, you may end up in a situation where an electrical problem in a noncritical system (like the cigarette lighter) could disable the fuel pump.
3) You lose the safety feature of having the ECU run the fuel pump only when the engine is running or otherwise necessary.

Fuel relay, Ill check that after the battery charges. any pointers?

Just follow the information in the FSM... and I've described some of this stuff very recently in anothe thread...

8 minutes on hold and the local stealership needs a part number before they can give me a price on a replacement relay....

They're not willing to look the part number up for you? Useless.

82501GA240 is the number they need. It lists for a lot of money, though, so you may want to see if someone (like Blackbart) can send you a good used one cheap.

According to them they need the part number before they can look up the part.... anyways. im not very enthused about doing business with them.

Their idiots...

ok... starting to get back into this whole working on automotive electronics thing.

A relay is essentially a High power swich with a low voltage trigger right?

So *IF* the relay was bad, I should be able to check it by removing the relay and running a Jumper across the primary power connections and have the fuel pump work.

Is this correct? Once again im not used to cars with computers that go "pop" when exposed to static electricity so im a bit paranoid of moving forward on my own.

Low current trigger. The coil draws a small amount of current and closes the contacts, which can carry a large amount of current.

Yes, you can test it that way. If it works, then either the relay is bad or whatever is powering its coil is bad.

The wire colors going to the contacts are yellow and black-with-red-stripe.

I stand corrected. Kinda punch drunk after a long shift at work. Ill give it a try when the sun comes up. thanks Vrg3