Rx7supra

My 87 tII has lost all power, rev slow, backfires through exhaust and my pipes all the way down wear coal red...
Could my afm be too rich? how would i lean it out? what else could be the problem.. underneith my dash is a yellow wire that appeared at the same time, it looks spliced from a black wire with a white stripe.
I think i read on fc3s.org that a yellow wire into the ecu was the air flow/pressure signal output...

NZConvertible

Just taking a stab in the dark, check that your leading plugs are firing. When I forgot to plug my leading coil pack back in, the engine was still smooth but lost half its power, took ages to rev up, and with all that raw fuel burning in the hot exhaust I'm sure it would've heated up the pipes nicely (didn't look).
The AFM wiring will be in the engine looms, I doubt it could just appear from under the dash.

Rx7supra

we will try that and get back to you in a few.

Rx7supra

any other ideas... we got fire....

Felix Wankel

Your catalytic converters are probably shot.

Rx7supra

OK heres the night ending results. The leading spark plugs had a gas smell to them. (so i think to much fuel right?) We tested spark and sometime they would fire and sometimes not... So i'm gonna get new spark plugs to fix that. on the trailing coil a sparkwas jumping in diff places (from the coil "box" to diff pipes and other metal parts.) this isnt right.. if my memory servs me trailing isnt as important as leading??? but still this isnt good. The trailing spark plugs got decent fire, the leading have trouble they were very Dirty, we cleaned them and same result (little or no fire)... Any ideas on the yellow wire, tested it and its hot...) When driving i had to take off by dumping the clutch at 4Grand.. the trailing plugs matter the most about this time dont they??? I checked out the airflow meter and it looks like it has been taken aprt before.. My main converter was all torn up inside (i assume from Miss fire) (when i got the car it sputtered sometimes)

Rx7supra

feel free to corect me i'm new to my rx7... its like a bitchy girl that you cant resist, but i'll just show her some tlc and make her a lady that everyone envys =)

Silkworm

I agree, cat is probably the problem.

Too rich wouldn't cause the cherry red, too lean would.

But if the exhaust isn't getting past the cat, you'll definitely lose power, and it will heat up the manifold.

PaulC

Rx7supra

but, igot poor fire, could it be that it just isnt burning the fuel? the whole pipe was bright red even the mufflers if the cat wasnt working wouldnt it not let the end get hot? and the leading plugs smelled like gas...

Maybe i should just take it to a mazda dealer ; )

Rx7supra

BTW i cannot beleive i forgot this, Earlier today, i replaced the main cat, It was bright red, the mufflers were not after i replaced it everything got hot.. does that make a difference in your assumptions????

Rx7supra

goddamnit i am just not having a good day and i'm confused for about a half hour... To rich = to much gas, to lean = to much air ?? or is it the other way around???

Silkworm

Nope, you've got it exactly right. Too rich, too much gas, burns COOLER. That's why Turbo guys don't like to run lean, the hotter the mixture, the better the chance for little bits of carbon that remain hot to ignite the mixture, and thus, detotation.

But wait, the ENTIRE exhaust is red hot?

Um.. Then too lean. But that doesn't mesh with your plugs smelling of gas (unless you're mistaking a normal smell for overly rich, keep in mind, they do sit in a chamber that fills with gas all the time.)

Poor ignition would not do this IMHO

Could be timing, I forget which it is, but running too far advanced or retarded could do this as well. I think it's advanced, someone else chime in here who knows this stuff.

And relax, the world didn't end man. We'll get this sorted for you.

PaulC

Rx7supra

ok good at least i'm not getting to old for my age =), Yeah the entire exhaust system.. if it were to rich would that give it poor performance.. It seems like when i drive the only power i have is from the turbo (more air right) i did happen to grab my timing light but never got around to it. the power loss was all the sudden i was driving and pulled in some place and BAM no power.. Should i check my fuel pressure? The guy i bought it from had an electronic switch for the fuel pump, the only reason i wasnt to set on it being to rich was because when that switch turned off so did the car.. other then that i guess my injectors could be bad... would that be why i had to dump the clutch at 4grand? dont the secondary injectors kick in about this time?

Rx7supra

ok good at least i'm not getting to old for my age =), Yeah the entire exhaust system.. if it were to rich would that give it poor performance.. It seems like when i drive the only power i have is from the turbo (more air right) i did happen to grab my timing light but never got around to it. the power loss was all the sudden i was driving and pulled in some place and BAM no power.. Should i check my fuel pressure? The guy i bought it from had an electronic switch for the fuel pump, the only reason i wasnt to set on it being to rich was because when that switch turned off so did the car.. other then that i guess my injectors could be bad... would that be why i had to dump the clutch at 4grand? dont the secondary injectors kick in about this time?

I guess you right the world didnt end but i'm moving in 10 days and i bought this car to get there... =\ thanks for the support

rx7_ragtop

It REALLY sounds like your leading coil isn't producing consistant/enough spark. Either that or the timing is WAY retarded... but the symptoms sound JUST like a bad leading coil. (I've seen this on a car where someone hooked up an MSD to the leading coil... the MSD box failed, so the leading coils wasn't firing. It would run, but really down on power, and very hot exhaust.)

Brad

ghebert

I had a similar problem with a 87 non-turbo I bought last year. Ran fine then all of a sudden I heard a little pop, loss of power, Idled like ****, vibration got so bad I thought the engine and exhaust was going to fall out. Check your compression, could have blown Apex seal. Check the 2 pronged connection for your leading coil, female connectors my need crimping for good connection, try shaking down this connection during idle. Check your Pulsating Dampner for the screw being backed out. Look in the forum search for good pic and location. My engine blew an apex seal on the aft rotor and I believe that the faulty pulsating dampner caused this. When I did blow the apex, It caused blow by and cherry red exhaust. Look for hard to start/flooding symtoms if your seal and or pulsating dampner are failing. Keep us posted. One other thing, don't drive the car until you find your problem!!!!! Gary

NZConvertible

You're talking about full power situations. Under sustained full power, it's easy to get the exhaust glowing whether rich or lean.
If barely any of the fuel is being ignited (i.e. only trailing plugs only) it'll ignite and burn in the hot exhaust instead, heating the exhaust up further.

Rx7supra

after fooling with my car more today. i got no nothing, this is the first chance i had to check the forum... after getting no furthur, i put the car togather and towed it to a guy that says he's been working on these cars for 14 years (+) he's out of town , no one will even look at a rotary in this town (v8 heads, and the import guys are basicaly dumb.) It would be nice to keep everyone posted but all my posts end up and the end of the list and i dont know how to keep it up. The ++ on the guy thats gonna look at it tomarrow is that he has a dealer code tester and compression tester. I hope i didnt blow an apex.. theres prolly no chance that this be a sticky eh? until we all find out the problem ; ). explain to me what the pulsation dampner does???? I'm no expert, i guess i'm just one of those guys with common auto knowledge...

vroom7

any replys today people see i always fall behind... =( this sucks

vroom7

this is interesting, i want to see the end result

hanman

ghebert,
exactly how did the pulsation damper break an apex seal? All it does is smooth out the pulsations in the fuel system from the fuel pump.
I don't understand how it could affect the apex seals in the engine.
Thanks,
hanman

peejay

how does the engine sound when cranking it? sound kinda different?

it sounds like a classic case of blown rotor... engine makes no power because it has no compression on one rotor, but the rotor still gets fuel, and the raw fuel just gets blown into the exhaust, where it ignites and burns, causing an extremely hot exhaust system and lots of backfiring when you've got the throttle down.

Rx7supra

backfiring happens when i let off throttle

keep replys comin!

Rx7supra

it doesnt sound any different, i dont think.. i mean nothing to catch my attention. a few times it was hard starting but little spark would do that i think??? sounds smooth at 1 grand. no clanks or scratch... what should i be looking for? i have not done a compression test. but if i didnt have any ot would be a little ruff right?

peejay

ok if it sounds smooth then it's probably not dead engine *whew* dead engine shakes a lot and feels like a lawnmower with a badly out of balance blade attached.