Narfle

iTrader: (16)

Crap, I am a basket of problems this week. I took the car for a drive today, and it was almost overheating. Hit 230F, merging onto the highway. I had to cruise off-throttle to get the temps down, and basically coasted back to my garage.

Low coolant? No
White smoke? No
Coolant in overflow bottle? Very little
Fans Turning? Yes, working both sides on multiple speeds
Water pump working? Yes, after letting the fans run while the car is off, starting the car drops temps, so the water is flowing.
Cat back clogged? No, I can see straight through the first section with a light

I noticed secondary boost is weird, the car had been running slightly hotter for a while. Went on a hard ride the other day, just fine. I don't think I was in secondary boost much. Felt a little slow. But, when I took it out today it was up to 220+ after a couple blocks. I'm thinking I clogged my cat. What do you think?

Possible next checks
-Champagne test
-Cooling system pressure test

It's hot here, but not that hot. Don't feel comfy testing boost on another ride, because it got so hot so fast. Could idle and see if the cat(s) glow?
Also, I have run 100 octane fuel on basically a stock car. I think that's probably not good for the cats, so I had been mixing half and half when I do it. And, recently just been running 91 since it seemed like the high octane was tough on the car.

Narfle

iTrader: (16)

I let it idle for a long time with the lisle funnel on. It holds 190, and no bubbles.
I feel like I can see the water pump and thermostat working.
If it were either of those, wouldn't it overheat at idle?
I don't think the pinhole or a weak pump would hold temperature, idling for 15-20min.


The pulse feels weak out of the tail pipe. It doesn't have any flow....Or, feels weak to me.

silverTRD

iTrader: (37)

Sounds like a clogged cat to me. The secondary boost being weird sounds like the exhaust can’t get out. Also that is feels a little slow, of course that could be because it has been warmer lately as well. But the cat would be my first thing to check.

Sgtblue

iTrader: (16)

A weak lower hose partially collapsing? Sticky t-stat?

Slides

Collapsed/blocked exhaust, failing ignition or blocked/collapsing intake filter/intake hose.

gracer7-rx7

iTrader: (16)

imo
Cooling system pressure test is step 1.
Then while the car is jacked up and the cooling system is under pressure and you are under there looking for drips, drop the front of the cat and shine a light in there to check if clogged. Looks like a shower drain clogged by hair. I posted a pic of mine once upon a time.

DaleClark

iTrader: (55)

I have no idea why you were running race gas. There's a reason it says RACE GAS and not STREET GAS - most times it's leaded and will kill a catalytic converter over time. Regardless of your next steps STOP DOING THAT.

If you are worried about the cat, stop dorking around and drop the cat and take a look. It's REAL obvious if it's clogged. Take the whole thing down, it's not that hard. Look in the inlet and see what's up.

As I recommended in PM, change the thermostat. It's 3 bolts to get to it, super easy. If you haven't done it in living memory it's probably worth doing. Mazda OEM ONLY. Parts store thermostats are CRAP, period, end of story. I have known SO many people burned on the parts store thermostats to where it's ridiculous.

Also your location says "Dagobah" - while that's interesting, it doesn't help anyone to know where you live. Cooling recommendations are VERY different if you live in the Great White North where a hot day is 82 degrees, if you are in central Florida where it's 98 and 100% humidity, or in Vegas with 110 deg. and 10% humidity.

In general, if you have working fans, good coolant, good thermostat, and a good radiator and nothing is leaking the FD cools just fine especially just driving around.

Also how are you measuring water temps? Do you have stock ECU? FC thermoswitch?

Dale

Narfle

iTrader: (16)

Thanks, was mostly doing that while sorting through some boost issues for extra ping protection. Can't figure out if 76 100oct has lead in it or not. But, haven't been mixing for a while. Either way, the cats probably didn't approve, when I did.

Car has the stock precat! Don't want to break a stud. I'd drop the main cat in a heartbeat. But would rather not drop anything before the big trip.

Replaced the thermostat with one from Atkins a while back. Tried to get OEM, can't remember which box it came in.

We're in California. And, it is HOT this week.

Fans move air, ron davis radiator (basically metal tank stock rad, not much thicker), FC thermoswitch. Depends on what I'm doing but I see from 190-210F* usually.

Defi gauge tapped into the thermostat housing.



Going to get the charging situation sorted out from the other thread. Somehow they go together. Could be that my fans are not getting enough power. Or, it could be that the ign system is not burning effectively and causing overheat. Or, maybe the low power is making my defi gauge read weird. Cats are probably not clogged I guess. Nothing glowing, and I hit 10psi just fine before I ran out of battery last night. Still want to swap in my JDM OEM downpipe, just didn't need all this crazy crap right before the big road trip.

Thanks for all the help and engagement!

gracer7-rx7

iTrader: (16)

The pre cat is scary. If one of them is going to melt, that would be the one to melt first.
And, yeah, highly likely to break a stud too. Hit them with PB Blaster as far in advance as possible.
Good luck and try to make as few changes as necessary before the big drive.

DaveW

That, IMO, says to me that this is your issue. The precat is notorious for failure, clogging (itself or the main cat), and overheating the engine compartment. IMO, it should be replaced with a downpipe before any long trip, i.e., NOW.

And my car has passed every emissions test without it. However, in California, it may not pass a visual inspection without it. My precat has been stored in the rafters for the last 17 years after I installed an HKS downpipe (reputed to be one of the easiest to install).

Narfle

iTrader: (16)

OK, so. After seemingly getting the charging issue sorted out. I still feel like the car is a little slow to boost and running a little hotter than usual. Whatever is wrong is not catastropic, but I'm gonna gear up to re-do the whole exhaust.

I've got the OEM JDM downpipe. Need to order a cat-back. Hopefully the main cat is OK, or I'll find a used one. I don't feel like evading or fighting California smog. Or, else I'd go 3" straight through with a resonator. (I've got a pettit ecu in a box, and some other helpful stuff).

I might need to get one of those nut ductor heater things or rent one to see if I can not-break the stock downpipe studs. Fun fun.

DaleClark

iTrader: (55)

FYI the studs are on the cat, NOT the downpipe. They typically aren't that big of a deal to deal with unless you have a rust belt car.

Worst case if you break a stud you can just cut/drill out the studs and replace with a bolt and nut.

Again, it's not as big of a deal as you would think. Access is pretty good. Hit it with some PB Blaster and if all possible use an impact gun to remove the nuts, the hammering motion of the gun makes a big difference.

Get a floor jack under the cat, it's HEAVY and awkward.

I would probably plan on doing the pre-cat at the same time. Pro tip - remove the ABS heat shield (easy) and the Y-pipe from the twins, gives a ton more room to get down in there to the nuts/studs. May want to get a set of 4 new studs from Mazda and get some copper clad locking exhaust nuts -

https://www.clipsandfasteners.com/M1...-p/pm40781.htm

Don't use the Mazda nuts or try and re-use them, they are WAY too aggressive.

Dale

mdp

Just a note, if you have the car smog checked in Cali, On the technician’s visual check list displayed on the computer screen is “check for presence of pre-catalytic converter”. If the technician does check he probably knows what a precat looks like. Bad things are set in motion when a car is flagged with missing smog equipment. Removing the innards and replacing the empty shell is a safer way to go.

Narfle

iTrader: (16)

Well aware. And, if they break my ***** over this, then I'll start paying my income tax in another state.