Starting question for the pros...

[Citizen]

Should be an easy one for the pros out there….

I have owned 3341 for about 10 years now. Except for one episode when it wouldn’t hot start, which turned out to be a bad accumulator, the old-girl has started right up first time, every time.

But today I went out to the garage to start and run it for a while, and this time it started but died in about 2 seconds, and would not restart. Acted like it had no fuel. So I put some starter fluid down the throat, and it started right up and ran fine for some 30 minutes. I shut it down, and it hot-started it right up again, just like always.

I let the car cool down, and got exactly the same routine when I tried to start it again. Ran for about 2 seconds, then quit, but started right up after a shot of ether, and then ran fine.

Each time I tried to start the car, I could hear the fuel pump run trying to prime for a few seconds, then stop, which I think is normal.

Question is, am I looking at a impending fuel pump problem? Or is this a loss of fuel rest-pressure? Doesn’t seem to be a hot-start problem at all. The fuel pump is the new DMCH combo unit, which I put in about 2 years ago, I think.

Any thoughts/advice? Thanks in advance.

Thomas

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[DMCMW Dave]

This one bites me once in a while (we often have cars sitting around with seriously low gas tanks), sounds like a dumb question but how much gas is in the tank?

The reason I ask I that the car will start with almost no fuel pressure due to the cold start valve, but it won't run that way. The fact that you got it to run for 30 minutes would tell me this isn't the problem but I thought I'd ask.

Sounds like the pump has a hard time starting, I'd check things like the RPM relay, the wiring at the pump, and wiring at the inertia switch. Also check the wiring connections on the ballast resistors and coil. Sounds unrelated but believe me it happens.

[Citizen]

This one bites me once in a while (we often have cars sitting around with seriously low gas tanks), sounds like a dumb question but how much gas is in the tank?

[SNIP]

Sounds like the pump has a hard time starting, I'd check things like the RPM relay, the wiring at the pump, and wiring at the inertia switch. Also check the wiring connections on the ballast resistors and coil. Sounds unrelated but believe me it happens.

It has slightly less than 1/2 tank of gas.

I didn't think to check the RPM relay, or the wiring, since the pump seemed ok. Funny you should mention the inertia switch, because I think it has been broken for a while now (I noticed it several months ago). Not broken as in the car won't start, broken as in the car keeps running in either position.

I'll also check all the fuel related wiring. This weekend is about done for, so this will have to wait until next weekend...I'll report back.

Thanks Dave.

Thomas

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[David T]

It has slightly less than 1/2 tank of gas.

I didn't think to check the RPM relay, or the wiring, since the pump seemed ok. Funny you should mention the inertia switch, because I think it has been broken for a while now (I noticed it several months ago). Not broken as in the car won't start, broken as in the car keeps running in either position.

I'll also check all the fuel related wiring. This weekend is about done for, so this will have to wait until next weekend...I'll report back.

Thanks Dave.

Thomas

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This can take some time to rule out things. Generally speaking, an intermittent problem is usually of an electrical nature but it can cause a fuel problem (the fuel pump doesn't run) or an ignition problem, no spark. The place to begin is to inspect some critical places in the electrical system like:
The fuseblock especially fuse #7
The inertia switch (make sure it has a splotch of white paint and is mounted on the footwell wall).
The plug and the connections right by the fuel pump
* The connectors and the terminals on the ballast resistor (this is the one I am betting on. The terminals on the ballast resistor are steel and they rust making a bad connection).

[Citizen]

This can take some time to rule out things. Generally speaking, an intermittent problem is usually of an electrical nature but it can cause a fuel problem (the fuel pump doesn't run) or an ignition problem, no spark. The place to begin is to inspect some critical places in the electrical system like:
The fuseblock especially fuse #7
The inertia switch (make sure it has a splotch of white paint and is mounted on the footwell wall).
The plug and the connections right by the fuel pump
* The connectors and the terminals on the ballast resistor (this is the one I am betting on. The terminals on the ballast resistor are steel and they rust making a bad connection).

Thank you Dave. I will check all those things. I didn't even think of the fuse box (I haven't cleaned my fuses in quite some time now, and I heard somewhere, probably here, that I need to clean them once per year).

T.

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[Ron]

Put your cold start valve in a clear container and see how it acts...

[David T]

Put your cold start valve in a clear container and see how it acts...

That's the one thing we can figure is working because he says the car will start and run (and then die). It is probably starting and running on the cold start valve. No need to waste time messing with that.

[Ron]

That's the one thing we can figure is working because he says the car will start and run (and then die). It is probably starting and running on the cold start valve. No need to waste time messing with that.I with you... I was thinking maybe "about two seconds" wasn't long enough to give it a fighting chance, so to speak. IE clear out any cylinders that a leaky injector(s) may have flooded/fowled..., which, on the other hand, might be what it is starting on....and it does start when manually priming it.

:dunno:Just food for thought.

[David T]

I have learned over many years of experience, the less you disturb during your trouble-shooing the better. All too often you can move or otherwise change something and it works but you really never know what you did that "fixed" it. And then the trouble reoccurs soon after again. By understanding the symptoms (the ones observed and the ones NOT observed!) we can rule out systems and some subsystems. With some further testing we try to eliminate things until we are left with the cause. Remember the basics, we need the mechanical to work (the basic piston, valves, and such) fuel and spark all working and at the correct time. In this case all of the starting systems seem to be functioning, it is what needs to work immediately after the starting cycle that things fail.

[Citizen]

... after I had a chance to get to it this weekend.

I inspected all fuses, and cleaned #1 & 7, although they looked ok. I inspected the fuel pump electrical wires/connections, and again all looked ok. Next I inspected the inertia switch. Yes on the white paint splotch, and mounted on the side of the footwell. However the switch was in the down position. So I moved the plunger up, and the engine started up fine, just like old times (which I thought the plunger should have been down).

So I’m thinking the inertia switch is bad. Not broken as in keeping the FP from running, but allowing it to keep running in either position.

Is [down = run] and [up = shutdown] normal operation for the inertia switch? Or is it the opposite?

Thomas

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[Rich]

Yes.
Plunger/button down (pushed toward the box) grounds the fuel pump, allowing pump to run when it sees voltage.
Other position opens the ground circuit, stops pump.

...Is [down = run] and [up = shutdown] normal operation for the inertia switch?....

[Jonathan]

So I’m thinking the inertia switch is bad. Not broken as in keeping the FP from running, but allowing it to keep running in either position.

Is [down = run] and [up = shutdown] normal operation for the inertia switch? Or is it the opposite?

Thomas

...

The way I think of it, is that it goes in the direction gravity is going.

If you're cruising along normally, then it points down (or sits in the down position).

If some sort of crazy accident finds you and the car upside down in the rhubarb, it still points towards gravity, but this time is up relative to the car.

The idea being it should kill your fuel pump and shut off the engine. And unlock your door locks automatically.

That was one of two recalls coming into play on the inertia switch. To move it to the side instead of on the front. Apparently a well placed whack with something hard right in the front left wheel well would get the switch to pop the plunger up and unlock your doors. Not terribly secure from a bad guy perspective.

Curious then Thomas, what do your door locks do? Is your electrical stuff disconnected at the moment? Or are they working ok with the power feature?

[David T]

... after I had a chance to get to it this weekend.

I inspected all fuses, and cleaned #1 & 7, although they looked ok. I inspected the fuel pump electrical wires/connections, and again all looked ok. Next I inspected the inertia switch. Yes on the white paint splotch, and mounted on the side of the footwell. However the switch was in the down position. So I moved the plunger up, and the engine started up fine, just like old times (which I thought the plunger should have been down).

So I’m thinking the inertia switch is bad. Not broken as in keeping the FP from running, but allowing it to keep running in either position.

Is [down = run] and [up = shutdown] normal operation for the inertia switch? Or is it the opposite?

Thomas

...

If it runs with the plunger up that means either:
The switch is bad
The switch is not hooked up (or jumped out).
The problem could certainly be related to this so you should try to get that switch to work.

[hmcelraft]

The wires on the inertia switch are on the bottom ? - which is the correct position.

[Rich]

Yes.

Plunger on top, wires/plug on bottom.


The wires on the inertia switch are on the bottom ? - which is the correct position.

[DMC5180]

If it runs with the plunger up that means either:
The switch is bad
The switch is not hooked up (or jumped out).
The problem could certainly be related to this so you should try to get that switch to work.

My suspicion would be the wires at the inertia switch are not in the correct position.

The fuel pump circuit is (N/C) with plunger down.

The door lock circuit is (N/O) with plunger down.

When the plunger is up the opposite it true.

Swap positions between the Black/purple and the Brown/pink double wire terminal at the inertia switch.

[Bitsyncmaster]

My suspicion would be the wires at the inertia switch are not in the correct position.

The fuel pump circuit is (N/C) with plunger down.

The door lock circuit is (N/O) with plunger down.

When the plunger is up the opposite it true.

Swap positions between the Black/purple and the Brown/pink double wire terminal at the inertia switch.

Good thinking. Would guess his ECU for the door locks is disconnected also.

[DMC5180]

After rereading this thread from the top. Thomas said, the FP ran with the switch plunger in both positions. If this is truly the case, then David's suggestions would be more plausible.

A photo of the switch and wire connections would helpful here.

[Citizen]

Would guess his ECU for the door locks is disconnected also.

Yep, good call. The door locks haven't worked since I got the car. And to tell you the truth, it never bothered me. I manually lock the doors anyway, and I was always a bit worried about getting locked in.



After rereading this thread from the top. Thomas said, the FP ran with the switch plunger in both positions. If this is truly the case, then David's suggestions would be more plausible.

A photo of the switch and wire connections would helpful here.

Here is a picture. A little blurry (sorry about that) but should do.

35844

And the car just now started up just fine, did not die, with the plunger up.

Thomas

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[DMC5180]

Boy, it's really tough to get a handle on it from the photo. The extra tape wrap seems suspicious.

Can you try again much closer.

Also did you try starting with the plunger down?

[Citizen]

Boy, it's really tough to get a handle on it from the photo. The extra tape wrap seems suspicious.

Can you try again much closer.

Also did you try starting with the plunger down?

Here's a little better shot.

35845
Yep, tried plunger down. It started up ok this time, but I might not have let the car cool down enough (let it sit for about an hour). I will try again with the plunger down tomorrow evening, so it will be completely cold.

[DMC5180]

Nothing stands out, so after you try it cold tomorrow. We can go from there pending the result.

[Jonathan]

Is there any way that the connector could be on incorrectly? Like in such a way that it is off by 180 degrees and you've reversed the functionality? Like plunger up now provides a ground and plunger down does not? I've not taken one apart before to know how they work inside and I don't have the replacement recall version on my own car.

See photo of the old and new beside each other:

35849

Also, if the problem is actually electrical in nature, having the engine cold or hot shouldn't matter, right? If this is affecting things, it would be only coincidental, or is there some aspect of the fuel pump running or ignition system working that is dependant on the car being cold? If it works cold and not so well hot, it could be a mediocre connection on the ballast resistor perhaps that gets worse when it gets hot?

[Citizen]

I got around to trying to start the car with the plunger down, and this time it started up, and stayed running. First cold, then hot. So now I'm a little embarrassed that may have asked for help prematurely, if so, sorry to have wasted everyone's time (although I did not originally to suspect the inertia switch, and posting this thread led me there). Whatever, it looks like I have a bad switch, so I'll replace that, and try not to bother you guys again until my next quandary.

Thanks everyone!

Thomas

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[Jonathan]

No apology necessary. If any suggestion or idea gets you thinking about something else that might be causing the problem, then that's not a waste of time for me. Glad you got it sorted out.