i recently acquired another 85 GSL-SE. recently me and my friend noticed that the car hesitates and feels like power is way too low. we thought it was old gas so we put in $15 of 89 to see if that helped once fuel level was getting close to empty. but it didnt. he then thought it was the spark plugs. turns out the guy i bought it from had no idea that the car has 2nd gen plugs. although the car does run it runs poorly. before i gave the seller the money my friend checked the compression and its at a healthy 120psi. still has everything intact when it left the assembly line including the exhaust. the clutch was replaced and only has 10k miles added in the last 5 years that it was used. later this morning i took it out for a drive to see if running the newer fuel at least helped. nothing. then as i was looking underneath the car to see if there was anything that needed to be addressed ie: leaks, rust, broken stuff, i saw that the main cat had several glowing red spots toward the front of the car(thank god for that heat shield)
my theory is that since the car still has the original exhaust intact could it be possible that the cats are clogged up so much that it creates way too much backpressure and extremely hinders the engines performance? i would also like to ask of you guys to give me any suggestions on what else could be the problem. if nothing that me and my friend try out before we check the exhaust system, we're gonna sawp out the entire exhaust from the Grey Ghost(my first 85 GSl-SE that has an apex seal spring collapse and was rebuild, but is now instorage cause shes getting readly for hibernation in another friends garage for the fall and winter) which as an RB header and straight pipe bolted to the stock muffler to Roxanne( the newer GSL-SE).
any help is much appreciated cause i dont want to have another blown motor that i have to spend another 3k for a complete rebuild and replacement of all vacuum linesand misc. just cause i have a problem i cant fix

 

I run 3rd gen plugs in mine with no issues. BR9EQ's I think.

I think your on the right track with the cat removal, then check the ignition system plugs, distributor cap and rotor. Next would suspect the fuel system. Change the basics like fuel filter. Might be your injectors are clogged.

Good luck.

 

i'll try that. but im going the safe way and use the spark plugs that are needed for my 1st gen. i am gonna try the fuel system next. after getting the fuel level down i'll replace the fuel filter and then put in fuel injector cleaner with 93.

 

does anyone think my theory is possible?

 

i also found this in the passenger side storage bin inside the original Mazda Factory Manual..... nevermind i cant seem to scan it in

 

I agree with you. Just unbolt the cat, or change out the entire exhaust and see if it runs better.

 

I agree. Whenever I buy a used car, I do a full tune-up; plugs, wires, filters, dist cap, rotor.... Do the tune up first and see if it runs better. I'd check the cats next. Let us know how turns out.

Andy

 

well when i went to change the air filter to a K&N the air box was very hard to pull off well not really but there was resistance. apparently the previous owner tried to seal the box with silicone. and he put too much to where the silicone went into the flapper door causing it to stick shut and only opens when pushed. fortunately i had another GSL-SE that is instorage so i took the air box and tube from the Grey Ghost and put in Roxanne. now it was purring like a kitten. so i went to put 93 in her along with fuel injector cleaner and ordered NGK BR8EQ14 spark plugs to pick up tomorrow. when i got home i went to clean the house up a bit for company. before they came over i wanted to get the car inspected cause apparently the sticker is 4 months expired. but then as i was turning the car on she idled for a bit and then just died! and after that she wont start. not even starting up and then stalling. she just wont start. any suggestions? my guess is that the cleaner got a hold of some "stuff" in the tank or lines and now clogged up the injectors. this is the only time i will be on my PC for a while so if possible anyone can call me. i have sprint cell phone. if you have mobile-mobile calling then you should have a problem calling long distance. my # is 254-371-8146. if not then i will check back here ASAP. thanks guys for the help

 

I had a similar situation, in that I went to check my filter and the filter gasket(material on the edge of filter) has melted sealing the box shut. After I pried it open I see some of the gasket material melted making a tar like substance in the bottom of the air filter box. None of it got into the flapper. I need to clean it out and figure out why the gasket material melted. Very strange.

cptpain, I would suspect fuel. Make sure you have fuel pressure. Oh btw lower octane gas works just fine.

 

I have the same exact problem. I just got an 85 that sat for like 3 years. got it running but she tops out at 60 and has hardly any power at all after replacing fuel filter, plugs, draining bad gas.... I got under her the other night after letting her run a little while and all the way from my cat to the freakin muffler was glowin bright red. let me know what helps. I'll try to post again after I get that thing off

 

thats what happened to me. that tar like stuff was more severe for me. it restricted the flapper from opening fullyand under WOT it wouldnt open at all.
thanx anyway guys i appreciate all the help. i fixed the problem. turns out two cables for the blaster coils (one on trailing and one on leading) were loose and were not making contact. also the Fusible link was abit loose. and i changed the entire air intake from the Grey Ghost to Roxanne because i had that tar like problem. now the car runs like it should. and with that K&N filter the intake note sounds nice under WOT. to summarize:
swapped air intake from Grey GSL-SE to Red SE( tar like substance restricting flapper door)
new spark plugs (BR9EQ14)
tightened connections on blaster coils and fusible link

 

Cool. Glad your back running good again. These are great little cars.

I wonder if the air pump is blowing hot air back into the air box?? I have no idea how it could get so hot that it's melting the air filter. I may try some heat shielding after I get it cleaned up. I'm curious if anyone else has seen this besides us?

 

probably only affects those that have only been left sitting at idle then turned off. cause thats what im assuming because the inspeection sticker was 4 months expired and the gas was smelling somewhat odd... i dont know tho could be someone was just trying to seal the box with some silicone.

 

I notice you started with 89 octane, then went to 93 when everything was running right.

Your GSL-SE is noremally aspirated, right? It'll actually run better on 87-89 octane than the higher octane stuff. No point wasting money at the pump for no gain.

 

i put in 89 when i bought it then once it got low i put in 93 and injector cleaner to get rid of some of the carbon that was in there cause when i took off the exhuast there was a fair amount of carbon from what i could see on the rotors and when i ran my finger in the housing