Mage

hey,

I'm having some problems don't know if they are related or not but here goes.

Car:
1987 GXL STOCK
156K on the od with stock engine.
only thing that have been replaced (that I know of)
Coils & plug wires brake master cel.

things I know need relpaced:
spark plugs are black and light brown
airfilter is yellow and black.

problems:

1. 1K idle on start up and for about 15Min of driveing 800K rest of the time some time (if redlining all gears) 1.4K.

2. the temp gage reads 2/3rds to 5/6ths hot. all the time (2/3rds at idle and driveing shifting at 3-5K 5/6 redlining)

3. redline 1st gear car only goes 25mph no matter what.

4.no power from 3-4k and 5-6k lot of hesatation throout the bandwith.

that's all I can rember off the top of my head (sorry at work)

I was going to do carb cleaner some time soon (as per instrctions on anther thead) but could not find the vac ling they talking about.

any help will be great!

thanks.
MAGE

kiker14

iTrader: (1)

ok... the 2/3rds to 5/6 hot = NOT GOOD. My car is running hot too, but most people say that the na's should NEVER even be at half even after hard driving... (I'm just over 1/2 most of the time) You could have lots of problems... the no power thing could have to do with your secondaries... have you done a compression test? give us more info

Mage

the dealership I bought it from (good friends of fam) did a comp test and they said it was good. I have not done one my self since I dont have the stuff and the mec is not in that does it. never tested the 2nds. I'll look in to that. (can some one give me a link to how to on comp test with piston engine tester? dont have one for rotory here.)

thanks for the reply

kiker14

iTrader: (1)

you can actually kinda do what we call a ghetto compression test w/out a tester. basicly you need a friend to rev the engine w/two of the plugs out and you feel for pulses (I'm not sure the exact process, search the forum, it's mentioned all the time) You also should think about doing a tune up w/new fluids, and replace any hoses that need to be replaced and stuff like that. Also, our cars are known for having pretty bad wiring, and now that they are 15+ years old, that doesn't help the situation. Read the "grounding" thread at the top of the forum, a bad ground can cause the secondaries to not fire. (and change the plugs and air filter a.s.a.p.) bad plugs can really screw w/our cars, and the air filter may be part of the cause of your overheating. But again, rotaries do NOT like to run hot, you will detonate your engine very quickly that way, so be very cautious, and when you are testing your fixes, don't drive it too hard or too long to prevent overheating

SureShot

You can use a standard compression tester.
Just hold the bleed valve open while cranking & watch the pulses.
Look for exactly even needle bounces ~100psi.

Here is the deal on grounds:
Your primary ground from the battery to the starter is probably good, but not perfect.
The firewall to bell housing ground uses a cheesy clip that may not be shinny bright metal to metal contact.
So, the ECU sensor voltages start to vary with alternator load & spark noise, the ECU tries to compensate & goes nuts.
Then the engine runs erratically or goes into "limp home" mode.

My 87 used to consistently run 2/3 scale on the temp gage.
As long as you never are boiling or expelling coolant into the overflow, that may be gage error.
Also, check this thread: https://www.rx7club.com/forum/showth...hreadid=206619

Mage

thanks for the info, no one here to at the shop to help me test the comp so I'll have to do it on monday.

I'll check out the groundings and the link


MAGE

Mage

bump

ok New airfilter helped but,

1. car in nutral runs like crap above 3K

2. still no power above 3k

going up hill at 100+ in 5th gear at the top of the hill I'm at 3rd gear 60mph (this flooring it the whole time)

I think I'm overheating becuse I have to floor it to get the rpms to move at all (floored in 1st to get to 3K sucks)
new rad cap helped too new thermo going in tommorow + comp test( I hope I did not blow the engine Father will kill me seeing as my other car is died and the only reason I got my 7 is becuse of that. hehe)

check both fuel filter beside some black spots (like 5-6) they look new.

I think the 5th and 6th's are sticking. anything else?

Thanks for the help I'll post again tommorow after comp test and thermo is in.

Mage

ilike2eatricers

Just in case you didnt know but get an OEM mazda thermostat. I would recommend that you go easy on the car until you figure out what's wrong with it. Redlining and possibly overheating a car that is not in the good shape already can prove detrimental to your engine.

Mage

thanks, yes I'm not driving it. It's in the shop right now, and I am getting the oem thermo.

Mage

bump,

just did the carb cleaner and the car runs lot better now (Still can't go above 6K and has problems with WOT and hills)

does anyone think it could be the cat's? also the 5ths and 6ths did not open when I reved to 4.5K (had some one look at them when I did it) could this be part of the problem of having problem at all revs about 3K?

the car is smooth to 6K and just stops reving at full gas in nutal and in gear.


thanks for the help

Mage

SureShot

The air filter is yellow & black?

Clogged cats are a possibility, but that should make the aux ports open early unless they are stuck.

The aux ports need revs with load to make enough back pressure to open.
I put a tee in the hose and using a pressure gage & a mityvac hand pump checked at what pressure they opened.
Then I extended the hose inside the cab with the gage on the end & went for a ride to see when they opened.

Mage

yes the air filter WAS black and yellow untell day before yesterday when I put a new one in.

then I belive there stuck. I'll try the vac/gage next time I drive it (dont want to blow the engine if I can avoid it.)

if the aux port are stuck how much would it cost to fix and would I need to pull the engine? (I would go to aaroncake's site but that blue and red it's hard to read!)

if the cat's a cloged I'm just going to do a stright pipe to the stock catback would this hurt it at all?


again thanks for the help more help would be great.

Mage

Mage

YAY! ok found my problem.

replaced the thermo helped some on the heat problem.

the aux ports were not opening.

and the cat was cloged, So like all good people with no money I took a crow bar and shoved it down in to the cat! thus guting the cat now WOW the power and the aux ports are opening!

thanks to everyone that help me out.

Mage

ilike2eatricers

the mazda OEM thermostat owns all!!

Mage

a thos things own but 19.00! almost 4X more than the one at advanced ah well it's worth it. now just need to get a short air ram or cai and a racing beat catback with stright pipes


Mage

ilike2eatricers

you are paying for piece of mind and dealer market thats all haha