My motor NEVER used to flood. You could fire her up, shut her off after 10 seconds and then fire her up again anytime, no problem.

Then I pulled the injectors last fall and shipped them off to be cleaned and balanced (maintenance) and she's never been the same since.

She started flooding when I put the injectors back in, so I sent them off to be redone. I put them back in when they returned, and the flooding continues. Now here's the sitch that has me puzzled...


Say I've been driving and now finally get home. I flip the fuel cut-off switch and wait for the car to die. Now, I wait about 5 seconds and then crank the car again. She'll spin, catch and run for about a second or two and then die again. If I don't do that crank, five'll getcha ten that the motor floods the next time I try to start it.

When I go to do work on the motor that requires removing the manifolds, I use the switch to depressurize the system. Shut her off with the switch, then crank.

Now I go to the secondary fuel rail. If I remove the hose that goes from the front of the rail to the return line, nothing happens. It pops off, no gas comes from either the hose or the rail. Not a drop. Now I reach over to remove the hose between the primaries and the secondaries and gas BLASTS out. I have to wrap a rag around the hose/rail to minimize the mess.

This has me wondering if there's some kind of obstruction or other funky thing in the secondary fuel rail. Whatever it is, I'm thinking that it and not the injectors is responsible for my new flooding problem.

I do have a spare secondary rail, but it's going to be a few days before I'll have a shot at swapping it in. In the meantime, I thought I'd pick brains here.

 

Dude, thats odd....How is the car running in general?

 

Perfectly.

 

there is never pressure in the return line.... and there is always gas between the rails. even if you de presurize it.

 

Sounds like low compression...

 

I didn't want to hear that.


How do you associate low compression with this?

 

Well, sounds like your fuel system is holding pressure (as in the injectors arent leaking). thats the next logical step for a hard start problem. Compression tests tell alot about the health of the motor.

 

Last time she was checked was about a year ago - it was a quickie test and she was blowing mid 90s. All even pulses.

 

Does your fuel cut switch cut the fuel pump or the injectors? Dumb question, but I had to ask.

Low compression motors flood more easily b/c they don't seal very well and thus don't move much air during cranking (in the most basic sense). How fast does your engine turn over?

Floding is almost always caused by low compression. You can take "flooding" injectors out of a worn engine and they'll never flood on a reman. Perhaps it is time to start budgeting fr your rebuild.

 

The switch is patched into the gang plug under the dash (killing the pump, I assume.)

I understand about low comp motors being prone to flooding, but I'd like to know why there's this charge of gas still in the line, and how that supposedly correlates to low comp. I'm not making the connection. Plus this problem manifested pretty much overnight, right after the temp injectors (on loan to me) went in while my own were being done. I suspect that its happening at the time of this swap may only be coincidental.

It's my suspicion that as the car sits this charge slowly pushes past one or more injectors and down into the motor, washing away oil and ruining compression for the next start...

Is the secondary rail supposed to be a straight, empty tube? Or is there a valve or similar device in there? How the hell can I disconnect a hose on one end and get nothing but suffer a discharge of fuel when I disconnect the other end?

 

There is no correlation to the low compression and the fuel line pressure.

Verify your fuel cut-off switch is cutting fuel pump voltage. A test light will be easiest here.

 

That's what I thought. She's got boatloads of power, which further adds to my skepticism about low comp...


Which I would use at the fuel pump plug at the rear speaker tower? You wouldn't happen to know which wire I should check? nm, I'll check them all.

 

Just checked Kevin's site.


The switch kills the pump.





Note the last part. It is expected (yes, I'm being cautious in my wording ) that *all* remaining fuel in the line is consumed. Well, not in my boat.

 

Whoops - missed this (been up all night.


Start-up is otherwise perfectly normal. Lots of spin and motor sounds 100% normal. Using the switch she'll catch within 3 seconds (if the switch wasn't previously used for shutdown.).

 

This is how I understand it. The inside surfaces of all engines is covered with a very thin layer of oil. This oil helps seal the piston to the cylinder or rotor to the chamber. This seal is what lets compression build up. At start-up there's quite a lot of fuel injected in to get the engine to fire up. This has the effect of washing some of that oil off, lowering the compression pressure. In a healthy engine there's still enough compression to allow the engine to fire. In an engine with low compression, that oil that's washed off lowers the compression to where the engine can't catch. It just spins and won't start.

Saying the engine is flooded probably isn't strictly correct, but by disabling the fuel system you can crank the engine over enough to get enough oil onto the seals to rebuild enough compression to start the engine.

You should be able to see why leaking injectors also causes flooding. Fuel leaking into the engine washes all the oil away, killing compression even in a healthy motor. If the injectors aren't leaking, then low compression must be the next possibility.

 

There's a touch of ignorance in some of the above posts. When you use the fuel cut switch to depressurize the rail it does not completley depressurize the rail pressure unless you rev the engine up to above three grand and then floor the pedal as the rpms drop.

If you just idle the car and turn the pump off, the car will die....but you'll still be left with approx 20psi in the rail. Sorry but I've had a pressure gauge attaced to my fuel lines for the last four days and I've been watching what I described above on two different cars. One of those been there done that things.

 

THIS is what I wanted to know!

Thank you!


Do you know what it is inside the fuel rails that is trapping the fuel? Are there valves or similar devices?

 

the fuel is traped between the FPR and fuel pump... that is there job.

 

How can it be trapped by the FPR? It's only a restriction, not a check valve. It's always open to some degree, so it shouldn't be able to hold any pressure.

 

but when the car is turned off normaly it should keep full pressure in the rails.... it must close up as soon as the pressure drops below what it should be.

 

You might be right. Looking at the picture of the FPR on page F2-49 of the FSM, it looks like fuel pressure is what holds the FPR open, with the vac signal opening it further or closing it a bit to regulate the upstream pressure. Below a certain pressure (~20psi it seems) the spring holds the FPR closed.

Interesting what you learn when you look a little harder.

 

First off, my apologies for not posting a final thank you in here. All of the info was much appreciated.


Tonight I did a 3 hour visit with my mechanic, going over all the new rotary stuff I've collected since the last time I saw him. Renesis pdfs and the like (and of course the vid of those guys pulling the Storm out of the snowbank. )

Anyway, just before I left he poked around the hood (as I talked about the continuing flooding problem.) Here's what he found:

- all 4 plugs were cleaned 24 hours ago. When he pulled them he said that the trailing ones looked fine, but the leading ones did not. He pointed to a small, clean 'ring' at the innermost edges of the electrodes (I can chop a pic if anyone's having trouble with that description) and said that the last time he saw that pattern on a plug the rotor was about to go...

He also said the leading ones looked as though the motor was running rich. The thing was, the trailing plugs looked fine. So it looks like the leading plugs aren't doing their job. Not doing it well enough, anyway...

I checked my log book and it turns out that the plugs have been in there since May of last year. I hadn't replaced them since b/c the electrodes are all still 100% and I've been keeping them clean by soaking the business end in carb cleaner at each oil change. They seemed to all be just fine (age aside.) So perhaps the leading plugs are both simply past their prime and in need of replacement.

- I did a resistance test on the L1 wire (all high tension leads are OEM, the leading ones are the 'long' pair.) The 87 FSM says 16k/m. I got 7.7k. Is a lower resistance a desirable thing, or is it time to go shopping?

- he suggested replacing the leading coil, and I do have a spare I saved from my last 7. I plan on doing FSM tests on both before swapping, if only for amusement.


So it looks as though there's a chance that my flooding is due to poor ignition on the leading plugs rather than a dying motor. I can't tell ya what a relief that was to hear. I only hope that it proves to be true.

 

bump

 

This is funny because I'm experiencing the same problem of flooding and some of the comments I got were quite unusal to say the least. I plan to check mine out with the same trouble shooting. I hope this is all there is to this as well...