ive heard of people putting a fuel pump cut switch in for starting. well most people press the switch before they start the car which means that the injectors have already let the fuel out and use that fuel to start the car (i think) well if you press the switch before you turn the car off and let it run out of fuel the car will stop itself that way the fuel line pressure will be low and not force out the injectors. the only draw back is that the low fuel pressure in the rails might tend to boil is this the case? personnaly i dont like fuel sitting around in my engine.
any ideas?

 

When I had a cut switch in my NA, I flipped the switch to on a second after cranking the starter and it started everytime this way. I didn't use it to shut the car down, I just turned the key off and when the motor stopped running, I flipped the switch to the off position.

 

I've never heard of it boiling. I've done both, turned the switch off to turn the car off and turned if off to start the car. Basically install it and use it as u deem necessary.

 

Sometimes I use my fuell cut-off to kill the engine. Keeps gas out of the rotors after shutdown and helps startup.

 

i know in a piston engine to much petrol cause "bore wash" the petrol takes the oil off the bore and causes excessive wear on start up. i recon rotories are even more prone to this but thats my .02 cent plus 12.5% gst

 

Instead of mucking around with switches, fix the actual problem. Remove the injectors and get them professionally cleaned.

 

Well, Mine doesnt have a problem... But a fuel cut-off is a good idea... Just in case.


Rat

 

We all know this is the way to fix the flooding problem, but some ppl can't afford(money or time) to have their car down while their injectors are off getting cleaned. Not to mention the price difference, maybe $5 for the switch and some wire with 15 mintues of down time versus over $100 to get the injectors cleaned and the down time ranging from 1-2 weeks.

If the car is stored during the winter, have them cleaned during that time. Until then, the switch will get you by.

 

NZ, I know you give great advice and know your stuff, but I would be a little more careful about making statements like that, because not everyone has the same problem.
I've said it before, and I'll say it again. I replaced ALL 4 injectors with NEW mazda injectors. I still have the same flooding problem, which needs me to use the fuel cut switch. I could have low compression, but I had that checked by Mazda and was told that it was good (bastards didn't actually give me any numbers ), this is why I am going to get it checked again. If compression is still good, then I'm at a loss as to what is causing the problem. Other than this (and a bad Idle), she runs perfect!
I just live with it.

 

I think that NZconvertable is right on the money.

his suggesttion to have hte injectors cleaned is THE way to fix the fuel flooding problem.

If your car needs the fuel cut switch after replacing/rebuilding the injectors, then you should....

STILL FIX THE PROBLEM.

Its just another problem, thats all.

Also, if I paid for a compression check, and some *** came over to me and said that it was "good" and expected me to pay for it..

I would just tell him I "paid" and leave.

You got ripped.
I would go back and tell the manager to re-do the work.
give you real numbers.

Either that or go get a piston compression checker and remove the schrader valve and check it yourself.

Its insanely easy.


By the way, i think your problem lies in a thermosensor somewhere.

Either that or your TPS has a bad spot near idle.

 

Hey, don't get me wrong, I agree that you SHOULD fix the problem, but what the actual problem is, well that's another question.

It may be insanely easy for a lot of people to do their own work, and believe me, I'd like nothing more than to be able to do it, but I'm the sort of guy that NEEDS to be shown what to do. Just call me a gutless chicken.

I think you're right about my idle being a TPS problem. I'll get the 'good folks' at Mazda to check that and the BAC and for vacuum leaks etc...

As for the compression, I should have said something, but I didn't. That's my bad. I won't make that mistake again.

 

how much did you pay for the compression check? you can buy a gauge for 5/8th of fark ool. there are heaps of write-up's about how to do it and i think some have pic's, it's harder to drive the car that check the compression. give it a go,

 

how exactly do you do a compression check on a rotary to make it accurate with the piston compression checker?

we removed one of the spark plugs and put it there and just turned the ignition.

 

Honestly, the fuel cut-off switch is a GOOD IDEA! as previously stated I have one, and I have no flooding problems. But lets be honest, RX-7s FLOOD. Pure and simple, they are prone to flooding. So having said that, putting the switch in on the off chance that the car floods, saves me from potentially having to pull my plugs to unflood the car, in a parking lot, on the bad side of town, in the rain...etc....

So go ahead and bash fuel switches (NZ and Sniper X) all you like, and make sure that you have a good time unflooding your FC when it happens, and it WILL happen. Keep a spark plug socket handy!!

Rat

 

Fair point, but too many people here (I don't mean you specifically) suggest this as a way to fix the problem, which it does not. There are other problems caused by dirty injectors besides flooding. If you think your cars running even near 100% with dirty injectors, you're wrong. I switch is a good way to start a flooded engine, but just becasue you fit one, doesn't mean you should just forget about the injectors. They should be taken care of as soon as practical.
BTW, injector cleaning should be overnight at most, not 1-2 weeks!

 

Have you replaced the transistor in the ECU that fries and causes idle and hot start problems?

Diagnosing and Correcting TurboII Idle Problems (it's at the bottom).

 

So, now its okay to have a fuel cut-off switch?

 

Hey Z, thanks for pointing out the ECU fix. I glanced over that 'cause at the time I didn't have a TII. John

My brain is a little fuller now.

 

I never said it wasn't. I said don't consider this a fix, because it's not. It just masks one symptom of the problem.

 

Off the top of my head, here's some things that can contribute to flooding problems -

- Poor low-speed compression on the engine
- Slow starter
- Weak battery
- Worn plugs/plug wires
- Vacuum leak
- Bad/worn water temp sender
- Leaky injectors

ANY of those things can cause flooding. There is NO simple fix for flooding problems - it isn't just "clean your injectors and your problem will be solved". The majority of the flooding problems I've seen have been from worn, high-mileage motors, which is an expensive proposition to fix. It's also hard to justify spending a big chunka change on a new motor or a rebuild when a $5 switch will keep you going. And, there's nothing wrong with that - I'm a firm believer of waiting until the engine is DEAD before trying to rebuild/replace - get some more useful life out of the engine first. An engine build or swap is a very complicated process, especially for a beginner, and you can end up with far more problems than you started with.

My daily driver, an '86 base, NEVER floods at ALL. It has 174,000 miles on the chassis and about 20,000 miles on the engine that I built. I have NEVER had the injectors cleaned, save running injector cleaner through on occasion and using quality gas. Why does it never flood? Because all the systems on the car are healthy, and the motor pulls 20+ inches of vacuum at idle with the 6-ports open - that's one tight bastard.

Anyhow, long story short, there is NO end-all, be-all fix for flooding problems. It can take a long time of troubleshooting systems to figure out where the cause lies, and many times there are multiple problems that are all contributing. Put in a fuel pump switch, use it if the car floods, and go enjoy the car.

Dale

 

that link that was posted about idling problems is GREAT i'm printing it out as we speak, im' going to have an afternoon of fun with this.


and as far as the weak battery and stuff, well the other day from cranking so much my battery died, i'm going to go test it and see whats up, maybe getr a new one.

 

Just pickin on ya!...

 

that link to the ecu repair sounds good, but i have no bac or anything else, seems to idle ok.

i pulled the ecu out and it has a gizzmo chip in it and written all over the case, are these chips anygood? do the change the fuel map?

 

Sort out the injectors first. Dirty injectors isn't the only cause of flooding problems, but it is the most likely. Even if it's not, your 15+yo injectors are due for a clean anyway and this will improve performance. Get them done. Ray Carter (aka Gizzmo Electronics) does a lot of ECU work. You'll need to talk to him to see what was done. I'll see if I can find a contact.

 

Other than the low compression, these are all simple problems that are easily diagnosed and fixed, and they should be fixed whether flooding is a problem or not. But it's still a fact that leaking injectors is the most likely cause. And how does a vac leak cause flooding? Does a new car have flooding problems? No, so something is wrong and it can be repaired. There are very few cases of incurable flooding.
A switch is a good idea, just in case (I have one), but there's no way I'd just accept having to use it all the time.