Help have problems don't know what to do
 

I have a 1984 Mazda rx7 gsl 1.1L it's been having this problem since I got it which is it randomly dying while driving sometimes surging and was dying at idle fuel pump is fine it's carberated btw I'll start it and usually when it's warm it has this problem of like foot steady on the gas and running great that randomly dies or sputters and bogs out like it instantly loses all fuel but it shouldn't be the fuel pump and filter are fine, I have so far done distributer cap and rotor and had it timed perfectly I got new spark plugs a new msd coil don't know what to narrow it down to I'm pretty sure it's not the fuel pump because it primes just fine and when turning the key there is no problem with getting fuel out of the hose, don't know what it could be the ignition wires are fine, if this helps at all the problem has just been getting worse and worse since I had it, it first started just slightly losing power now it just straight up dies and won't start for a good 20 minutes until it cools down a little I'm assuming some days it will drive great othernit won't make it out of the drive way I have a repair Manuel doesn't really help with this one, just looking for advice on where to go from where I am

It used to die randomly at idle but I'm pretty sure we fixed that with timing just did it today I'll have to see for sure, rand great for a while then just crapped out and died

Problems include loss of power then dies sometimes hesitates might have just been tuning then it also when the rpms are coming down it like doesn't go right down it takes an minute and sounds like it's sucking air and having a hard time newer thing that's occurred but when you rev it it tends to do the sucking thing around 4 - 11/2 rpms,

Sounds like the issues could lie in the carburetor. I would rebuilt it, setting the floats to factory spec and replace the fuel filter as well.

You will also want to check for vacuum leaks as a larger leak can cause stalling and rough running or erratic idle. Remember, these rubber lines are 33 years old and can be very brittle.

Did you use NGK plugs, BR8EQ-14? If not you should. Did you replace both the leading and trailing coils?

If this is happening only after warming up or running for a period of time and the interval seems to
be getting shorter and shorter, it could be a bad leading igniter. You can swap them on the dizzy
real quick to determine if the symptom follows the igniter.

I would check the simple things first. I know you said the fuel flow was good. It may appear fine
at idle but suck at higher rpms or driving due to sludge picked up in the tank. Make sure you put
a new fuel filter on. Also as suggested, verify there are no vacuum leaks. This is the number one
reason for idle stability and decel problems. A bad brake booster can look like a leak as well
but thats not very likely.

I already have replaced the fuel filter hadn't done anything but the ignightors could be the issue I'll check those

Bad leading coil.

No it's a brand new coil like two weeks old

Not bad coil
 

not a bad coil its brand new

Yes
 

Yes I did use those plugs and what is the best way to check for vacuum leaks ?

So firstly, I see you have a second thread highlighting similar issues - to get the best help and to avoid confusion please try to keep everything in one place :icon_tup:

Just to clarify, after your timing adjustment is it still stalling at idle? Did you adjust the idle speed and mixture? I just want to narrow things down and see if you are having the issue all the time or just under high load?

Back to super simple basics, when you checked the fuel pump - did you check both flow rate and pressure?

I know you said you replaced the fuel filter but is it still clean now? If your tank has/had an excessive amount of crap in it, then it will already be clogging the filter back up. In which case, you can be sure that your carb is full of junk as well and likely needs a clean and rebuild. So if your filter is dirty already; I would get your tank cleaned and then run some Seafoam and see if that can clear the carb before rebuilding, you might get lucky. Usually carb rebuilds introduce more issues than they fix so I would avoid doing it until all other options have been looked at. However if your filter is still nice and clean ignore this!

As for vacuum leaks - I would start by just replacing all the hoses. As stated above, they are old and need to be done anyway.

Almost everyone ruins their carbs when they rebuild them.

Unless they grew up working on carbs. :lol: :lol: :lol:

All these noobs destroying their Nikkis.

It takes some experience in working with carburetors and the correct tools to do the job properly IMO. I have two sonic tanks dedicated to carburetor parts cleaning, a special dial caliper for float adjustment, brass cleaning wheels, compressed air, and several kits on hand. I spend in upwards of six hours or more rebuilding a Nikki. There is a learning curve to these carbs and once you've done a few properly and learned how to set and adjust them properly then you have no worries. But as Jeff mentioned, most people do more harm than good when then open up the car and attempt the rebuild. We could go on for some time about the aspects and quality of the aftermarket carb sets as well as the needle quality in said sets.

There is a test procedure in the FSM for testing you igniters. They can and will fail. If you would like me to post the procedure I can. You can also go to Foxed.ca and download the FSM for your 7.

Um, it's the seats that must be avoided. The needle quality is fair and can go into stock seats if necessary (if stock has hardened tips), and properly burnished with a spoon. Never adjust your floats. Never blindly set them with the little paper measuring tool that comes in a kit. Chances are better than good that the factory setting on them is still perfect.

If the carb has never been opened then yes Jeff you're correct on the float adjustment. I use a digital dial caliper to measure the float height per the FSM. I've had carbs that people have gone through where the floats were improperly adjusted so much that the engine was starved for fuel and the person sold the car because they could not get it running right.

The needle quality in the kits is alright. Seat quality I have seen varies. I've seen some poor machining and I've seen small amounts of burring on new seats. Just makes me wish that the original kit was still available.

The thing about the floats is most folks adjust them dry and then put them in the carb and even
make sure they fill to the mid point of the glass. Which you'd think is all good, but what a lot of
folks don't do is make sure the drop is right as well. Too little drop, not enough gas, too big a
drop and you get flooding and inconsistent bowl levels. Its very picky sometimes. It also
depends on how "smooth" the pressure to the seats are as well. If the pump pulses a lot or
the pressure bounce too much as the seats open and close, that can be another issue that can
make it a pain to dial in.