0110-M-P

iTrader: (10)

I won't lie, I'm new to the FB scene and carburetors in general. I just picked up a 82 GSL last saturday with a known intermittent problem. The car will random start stuttering under throttle (not heavy, just normal driving) and eventually stall. Pull over...wait ~5 minutes...start it back up and it drives fine again until it will eventually stall. The stalling and sputtering feel like it is either running out of gas (like a dying fuel pump) or running extremely rich and flooding. I haven't pulled the plugs when this happens yet (no tools when this has happened), but I can see that fuel is still in the carb when it dies.

Just for the hell of it after I bought it I replaced the ignition coils with spares that came with the car and replaced the spark plugs with NGK BUR9EQ's from my FD (just to get fresh plugs in it). Neither affected the issue at all. The fuel filter looks new and I was told the fuel pump had been replaced recently.

It really seems like it is probably a carburetor tuning thing as of right now, but I thought I would pose the problem here to see what everyone thinks as well.

Kentetsu

Check the connections on the ignitors, and you should probably go ahead and swap out the fuel filter, which is the usual suspect for this type of issue...


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DivinDriver

iTrader: (15)

Ignitor connections, yeah, or perhaps they were installed without heatsink paste and are overheating. Coils have also been known to have opens/shorts that expand as they heat.

If it's not fuel, next two guesses are usually ignition or vacuum. Could be a vacuum leak that opens as things heat up & expand, but they usualy need longer than 5 mins to cool back down again.

0110-M-P

iTrader: (10)

I just replaced the fuel filter...no dice. Also, I don't think it is a problem with something being heated up anymore. I got it to do it after driving only 2 miles today and it only happens when under consistent load...4th and 5th gear acceleration specifically.

Could it be a carburetor tuning problem with everything running excessively rich? I'm so used to seeing a wideband in the car with me that not knowing my exact AFR really screws with my head now.

Kentetsu

I wonder if it could be an issue with the shutter valve? You could try wiring it open, and see if the resolves the issue. If you don't know what I'm talking about, just run a search on the term "shutter valve" and you will find a wealth of information. Good luck...

axle

I had the exact same issue when I bought my 81 the fuel pick up in the gas tank was plugging up cleaned the tank replaced the screen as mine was riped and it solved the problem

0110-M-P

iTrader: (10)

I will look into the shutter valve thing...

This is what I was thinking earlier today, just didn't feel like messing with it today. Maybe I will drain the tank and take a look tomorrow.

speedracer_not

running outta gas? they your plugs will be red

too much gas or weak spark, then your plugs will be black.

happy plugs have a nice tan

one other thing might be the fuel flow is blocked after 5 minutes of running. So check pull the fuel line and check the flow rate when the car stalls. I had a 914 that did the same thing, first it was a vacumm leak, then it was the insulator under the distributor had a crack that would expand when things got warmed up.

0110-M-P

iTrader: (10)

It is definitely a clogged fuel pickup in the gas tank. Took everything apart today and yea...its bad. The pickup strainer mesh was torn and the pickup tube extremely dirty.

Anyone know where I can find a new pickup strainer?

axle

no not right off hand but you can use window screen and rap it around then jb weld it just don't go to crazy or it will continue to plug up on you if your tank is rusty might want to do a fuel pump volume test to while your at it just to be safe

0110-M-P

iTrader: (10)

Still can't find a replacement for the strainer....any other ideas. I might consider making my own, but that will be a last ditch effort.

bliffle

Unless you can scare up a pickup on the Classifieds section here you will probably have to visit an auto junkyard or fab your own. I'd guess that all the RX-7s in your area suffer the same thing (prolly caused by bad gas from the pipeline) so you will have to fab your own.

Clean everything up and solder your pickup together (JB Weld and any other epoxy will eventually deteriorate immersed in petrol). If possible, silver-solder things together for greater vibration resistance (soft solder may vibrate apart).

I saw a couple weeks ago that some guys published pix and everything on how they fabbed pickups. Looked pretty good. You might try a search.

0110-M-P

iTrader: (10)

It looks as if I am going to have to do something custom at this point. I did find out this bit of information though from the JB Weld website...

0110-M-P

iTrader: (10)

I just finished completely cleaning the pickup/return tubes, but still have not found any sort of replacement for the strainer that sits in the tank....and I have been looking hard. I called Mazdatrix and they told me there was no replacement other than sourcing a good condition used one, which I can't find.

This isn't something that I would truly like to do, but is there any reason that I can't just neglect the intake strainer and let the fuel filter catch everything since it is before the pump? Then replace the fuel filter more often. Either that or run two fuel filters in a row?

I really want to put the gas tank back in tonight and this strainer thing is really starting to bug me. I would repair the original strainer, but I can't find any epoxies or other sealants that will hold up submerged in gasoline.

Kentetsu

If I were in your shoes, I'd skip the strainer. Like you said, the filter should grab anything that comes through anyway. Just make sure nothing really big gets in there and cloggs the line itself. As long as you keep the gas cap on, and buy your gas from reputable stations, I'd think you'd be alright.

bliffle

Yeah, I'm with you guys. Forget the strainer. If it were me I'd see if I could find some old-fashioned copper window screening (sometimes a custom window outfit or a very old Hardware store, or an electronics place that keeps it around for Faraday boxes) and fashion a gross filter easily, or I'd fab up just a simple baffle to keep rocks from clogging the pickup tube. And I'd silver-solder it with MAPP gas in a cheapo propane torchhead, just because I LIKE silver-soldering (my bicycle frame is all silver soldered steel and it's lasted perfectly ever since I designed and built it 30 years ago).

My experience with epoxy is that fuel wouldn't dissolve it but fuel would deteriorate the bond to metal so that the joint would leak fuel. YMMV.

One thing that worries me is that eastcoast guys seem to have a lot of trouble with crappy gas.

7aull

iTrader: (2)

so.
what's plugging up the strainer?
Bet your insides of your gas tank are disintegrating into the fuel. Might consider pulling your tank, chem-dunk at a rad shop, re-line with POR15 tank seal kit. Your start-stall-OK-in-5-min routine was identical to my prob before tank cleaning...
Stu Aull
80GS
Alaska

0110-M-P

iTrader: (10)

Yes it is bits of inside the gas tank. I decided last night after some more research to go ahead and buy the POR-15 tank reseal kit. Then I won't feel the need to install the pickup strainer. The tank really isn't in that bad of shape internally, so I think that the supplied solvents will do the job and an acid dip is necessary.

bliffle

Sounds good.