Rpm fluctuating ( not just at idle ) ?! (84se)
03-09-04, 02:16 AM
#1
Junior Member
Thread Starter
Join Date: Mar 2004
Location: SoCal
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Rpm fluctuating ( not just at idle ) ?! (84se)
hi guys,
this is my first post to these forums.
boy im glad i found this place !
anyway im working on my "new" 1984 SE
(after being without an rx for a few years)
just got it running tonight infact, anyway .
the RPM will not stay steady at any throttle setting ..
it will come up the the rpm that its should .. then
drop a hundred rpm or so, then right back up then
down, up, down, up, down, etc.
im not a mechanic , I really dont know where to start,
to diagnose this problem, if you guys know how to fix
this problem, or can just point me in the right direction.
i would be VERY thankful. Or to put it another way ..
"im clueless, help me PLZ !!! "
this is my first post to these forums.
boy im glad i found this place !
anyway im working on my "new" 1984 SE
(after being without an rx for a few years)
just got it running tonight infact, anyway .
the RPM will not stay steady at any throttle setting ..
it will come up the the rpm that its should .. then
drop a hundred rpm or so, then right back up then
down, up, down, up, down, etc.
im not a mechanic , I really dont know where to start,
to diagnose this problem, if you guys know how to fix
this problem, or can just point me in the right direction.
i would be VERY thankful. Or to put it another way ..
"im clueless, help me PLZ !!! "
03-09-04, 08:23 AM
#4
Senior Member
Join Date: Nov 2001
Location: Gig Harbor, WA
Posts: 566
Likes: 0
Received 0 Likes
on
0 Posts
Welcome, first rule/lesson, search search search, there is so much info in here its scary. Here is a place you should bookmark and print, it will definately get your -se back worthy.
http://www.nellump.net/peri/epi/firs...gslseIdle.html
I would say its your bac valve and it needs cleaning then clean everything else from the air filter to the dynamic chamber, run 1oz of mmo per gal fuel. Read the above post and you should be happy. Welcome again. After its all clean then we can work on the other items but we need a baseline to start with and a clean system is the key.
http://www.nellump.net/peri/epi/firs...gslseIdle.html
I would say its your bac valve and it needs cleaning then clean everything else from the air filter to the dynamic chamber, run 1oz of mmo per gal fuel. Read the above post and you should be happy. Welcome again. After its all clean then we can work on the other items but we need a baseline to start with and a clean system is the key.
Last edited by Steve Shulz; 03-09-04 at 08:25 AM.
03-09-04, 09:04 AM
#5
mazdaspeed 3 coming soon
Join Date: Jul 2001
Location: Mississauga, Ontario
Posts: 1,761
Likes: 0
Received 0 Likes
on
0 Posts
Check or get your TPS checked by someone. I'll bet money that's what it is judging by what your saying. My buddy had an SE with the same problem.
03-09-04, 05:35 PM
#7
Junior Member
Thread Starter
Join Date: Mar 2004
Location: SoCal
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by mazdaverx713b
check injectors and fuel filter for good flow.
check injectors and fuel filter for good flow.
oh btw, welcome to the club.
Trending Topics
03-09-04, 05:47 PM
#9
Junior Member
Thread Starter
Join Date: Mar 2004
Location: SoCal
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by Steve Shulz
Welcome, first rule/lesson, search search search, there is so much info in here its scary. Here is a place you should bookmark and print, it will definately get your -se back worthy.
http://www.nellump.net/peri/epi/firs...gslseIdle.html
I would say its your bac valve and it needs cleaning then clean everything else from the air filter to the dynamic chamber, run 1oz of mmo per gal fuel. Read the above post and you should be happy. Welcome again. After its all clean then we can work on the other items but we need a baseline to start with and a clean system is the key.
Welcome, first rule/lesson, search search search, there is so much info in here its scary. Here is a place you should bookmark and print, it will definately get your -se back worthy.
http://www.nellump.net/peri/epi/firs...gslseIdle.html
I would say its your bac valve and it needs cleaning then clean everything else from the air filter to the dynamic chamber, run 1oz of mmo per gal fuel. Read the above post and you should be happy. Welcome again. After its all clean then we can work on the other items but we need a baseline to start with and a clean system is the key.
im looking thru the link that you posted, looks like some good info..thanks, as for the bac valve, i will check it as soon as i find it ;-)
03-09-04, 05:48 PM
#10
Yea, I'm working on it...
Join Date: Dec 2003
Location: Click click fucking click, Africa
Posts: 1,220
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by Rotary13B1
You might want to check ALL of your vacuum lines to make sure there's no leak.
You might want to check ALL of your vacuum lines to make sure there's no leak.
Then have a PB&J
03-09-04, 05:55 PM
#11
Junior Member
Thread Starter
Join Date: Mar 2004
Location: SoCal
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by hondah8er
Check or get your TPS checked by someone. I'll bet money that's what it is judging by what your saying. My buddy had an SE with the same problem.
Check or get your TPS checked by someone. I'll bet money that's what it is judging by what your saying. My buddy had an SE with the same problem.
it seems to be functioning atleased in some respect
if i open the throttle then pull back the plunger (on the
tps ) the engine begins to shake and the rpms drop..
like fuel starvation. releasing it returns the rpm to the previous problem..
03-09-04, 06:13 PM
#12
Junior Member
Thread Starter
Join Date: Mar 2004
Location: SoCal
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
UPDATE:
i just started it again and ran it for awhile before i start pulling it apart...
the Rpm is still fluctuating. however, I noticed
that at the bottom of each rpm drop there is a soft
backfire . (can only be heard directly behind the tailpipe)
also after reading the posted link above i found the
air/fuel resistor it set to full rich . and the air adjustment
screw is (almost) all the way out. hoever with all of that
the idle is no more then around 600-650 rpm
note also that the rpm flux seems to go away above
1000 rpm but below 200rpm... above that the
fluctuating returns.
btw, just have to say this place, and all you guys rock.. =)
i just started it again and ran it for awhile before i start pulling it apart...
the Rpm is still fluctuating. however, I noticed
that at the bottom of each rpm drop there is a soft
backfire . (can only be heard directly behind the tailpipe)
also after reading the posted link above i found the
air/fuel resistor it set to full rich . and the air adjustment
screw is (almost) all the way out. hoever with all of that
the idle is no more then around 600-650 rpm
note also that the rpm flux seems to go away above
1000 rpm but below 200rpm... above that the
fluctuating returns.
btw, just have to say this place, and all you guys rock.. =)
Last edited by invi[tus; 03-09-04 at 06:18 PM.
03-10-04, 04:30 PM
#16
84SE-EGI helpy-helperton
First off, welcome to the boards. As a fellow SE owner, I'll offer what assistance I can, but you're also held responsible to look through past posts to find information which may impact your ability to fix what you're working on - the SE and troubleshooting it's idle weirdness is a time-honored tradition around here that has to be earned! That said;
What you describe is commonly called 'Surging'. This is when the idle compensation system is trying to constantly adjust the intake system (Throttle Body=TB) to get the proper air/fuel mix, and something is out of whack. That 'something' is exactly the issue here - you have to find it, and it could be any of a number of things, or a combination of a number of things, or nothing, but it usually is something, so keep looking.
Some quick tips; most SE owners have tried in vain to troubleshoot a high or low idle speed, only to screw it up even further and never get it back to where it's supposed to be (800rpm, per the FSM -Factory Service Manual, get one). This is because they are complicated systems at work here, and you'll need to understand them to some degree to help pinpoint the problem. Instead of forcing you to search, here is the brief:
Air comes in the AFM (Air Flow Meter), through the TB, and into the Dynamic Effect Intake chamber (DEI). The TB controls airflow, the AFM reports how much fuel should be injected to match the air coming in. Bypass air comes through the BACV (Bypass Air Control Valve) on the driver's side of the DEI chamber, and is fed into the intake to compensate for A/C on, lights on, etc. When your BACV needs to be cleaned, it can cause 'Surging'. If your TB needs to be cleaned, it can cause 'Surging'. If your lifestyle needs to be cleaned, it can cause 'Surging' (just kidding).
Remove the BACV (2x12mm+vacuum+connector), and the TB (4x12mm+throttle linkage+heater hose) and clean both out fully with Carb cleaner (yes, I know you're fuel injected...sheesh). Once done, get a light oil like 3-in-1 and lubricate the TB rods that hold the butterflies in place. These can get 'gummy' and cause the TB to not operate smoothly, which can cause 'Surging'. Clean, refit, replace, restart.
That didn't fix it? On to Step 2 (and Step 3, and Step 4, if necessary). There is an entire section of the FSM dedicated to the SE intake system, so don't get discouraged if you don't fix it right away - it's only about 10 or 15 other things that it could be, which are all easy to check. About as easy as the steps above, anyway. And, hey,... we've all done it before, so you might as well learn, too!
BTW, my RX-7 was that same beige color, stock. I repainted, obviously. Good luck, and report back,
What you describe is commonly called 'Surging'. This is when the idle compensation system is trying to constantly adjust the intake system (Throttle Body=TB) to get the proper air/fuel mix, and something is out of whack. That 'something' is exactly the issue here - you have to find it, and it could be any of a number of things, or a combination of a number of things, or nothing, but it usually is something, so keep looking.
Some quick tips; most SE owners have tried in vain to troubleshoot a high or low idle speed, only to screw it up even further and never get it back to where it's supposed to be (800rpm, per the FSM -Factory Service Manual, get one). This is because they are complicated systems at work here, and you'll need to understand them to some degree to help pinpoint the problem. Instead of forcing you to search, here is the brief:
Air comes in the AFM (Air Flow Meter), through the TB, and into the Dynamic Effect Intake chamber (DEI). The TB controls airflow, the AFM reports how much fuel should be injected to match the air coming in. Bypass air comes through the BACV (Bypass Air Control Valve) on the driver's side of the DEI chamber, and is fed into the intake to compensate for A/C on, lights on, etc. When your BACV needs to be cleaned, it can cause 'Surging'. If your TB needs to be cleaned, it can cause 'Surging'. If your lifestyle needs to be cleaned, it can cause 'Surging' (just kidding).
Remove the BACV (2x12mm+vacuum+connector), and the TB (4x12mm+throttle linkage+heater hose) and clean both out fully with Carb cleaner (yes, I know you're fuel injected...sheesh). Once done, get a light oil like 3-in-1 and lubricate the TB rods that hold the butterflies in place. These can get 'gummy' and cause the TB to not operate smoothly, which can cause 'Surging'. Clean, refit, replace, restart.
That didn't fix it? On to Step 2 (and Step 3, and Step 4, if necessary). There is an entire section of the FSM dedicated to the SE intake system, so don't get discouraged if you don't fix it right away - it's only about 10 or 15 other things that it could be, which are all easy to check. About as easy as the steps above, anyway. And, hey,... we've all done it before, so you might as well learn, too!
BTW, my RX-7 was that same beige color, stock. I repainted, obviously. Good luck, and report back,
Last edited by LongDuck; 03-10-04 at 04:33 PM.
03-10-04, 06:59 PM
#17
Junior Member
Thread Starter
Join Date: Mar 2004
Location: SoCal
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Update 2:
The Rpm fluctuation seems to now be fixed.
however creating a new problem in the process.
Steps Taken
1. Removed BAC/ASV asemmbly cleaned both sections
with carb cleaner oiled with wd-40 installed new
gaskets.
Result: (no effect)
2. Removed the air funnel from the throttle chamber
cleaned the throttle plates with carb cleaner.
Result: (Did not correct problem however throttle response seemed smoother)
3. adjusted TPS thru use of 2 digital mutilmeters
Result: Rpm fluctuation (surging) corrected.
Now that the "surging" has been corrected,
Ive got a whole new problem ( of course)
bringing the rpm up to 3000+ rpm then releasing
throttle causes a backfire then a small second backfire.
also the idle is being really stubborn on this car
it wants to run at 400rpm then run it at 2000+
rpm for a minute and then it wants to idle at 1000rpm
all attempts to raise the bottom number or lower the
top number seems to fail.
well im making progress anyway =)
The Rpm fluctuation seems to now be fixed.
however creating a new problem in the process.
Steps Taken
1. Removed BAC/ASV asemmbly cleaned both sections
with carb cleaner oiled with wd-40 installed new
gaskets.
Result: (no effect)
2. Removed the air funnel from the throttle chamber
cleaned the throttle plates with carb cleaner.
Result: (Did not correct problem however throttle response seemed smoother)
3. adjusted TPS thru use of 2 digital mutilmeters
Result: Rpm fluctuation (surging) corrected.
Now that the "surging" has been corrected,
Ive got a whole new problem ( of course)
bringing the rpm up to 3000+ rpm then releasing
throttle causes a backfire then a small second backfire.
also the idle is being really stubborn on this car
it wants to run at 400rpm then run it at 2000+
rpm for a minute and then it wants to idle at 1000rpm
all attempts to raise the bottom number or lower the
top number seems to fail.
well im making progress anyway =)
03-10-04, 07:42 PM
#18
84SE-EGI helpy-helperton
Idle issues; this link is your best friend... learn it, try it, love it.
http://www.nellump.net/peri/epi/fir.../gslseIdle.html
My feelings on the matter are that most SE owners attempt to adjust idle with the idle air adjust screw (an air bypass means) which is located on top of the TB. This screw comes out for more air (higher idle), etc. But if you run it out all the way, and still can't get the idle where you want it, you need to be focusing on a few other, less well-known, areas.
1) TB rod stop adjuster (right side of TB, small copper set nut, and flat-head copper adjuster - loosen set nut, turn adjuster just a tiny bit until idle comes up, tighten set nut. This sets the minimum throttle opening posiition, and sets where the throttle plates come to rest on zero throttle input.
2) Thermowax pellet and associated vacuum plumbing - the thermowax pellet is the green plastic thing coming out of the left side of the TB. Coolant from the back of the waterpump is routed here, then to the top of the block under the upper intake manifold. Hot coolant signals a warm engine, allowing the thermowax pellet to expand and open the 'choke' butterflies in the TB (on the secondaries, at the bottom (aka, by Mazda as the 'double-throttles'). When cold, the thermowax pellet is contracted which does 2 things, A) shuts off vacuum to the double-throttle diaphragm - causing choke, and B) sets the fast idle cam on the main throttle rod (primary). When cold the engine should idle at about 2500 rpm until warm, then drop down to 800rpm FSM set limit.
3) Idle Mixture Adjustment (aka, Variable Rheostat) - located at the passenger strut tower, this rheostat is a variable resistance electrical connection which tells the ECU how much fuel to inject at idle. Dealers adjusted this on arrival to destination, and then sealed the top of the adjuster screw with paste. Scrape the paste out, and you, too, can have ultimate control over idle quality, idle air/fuel mixture, and conversely, idle speed!
4) BACV - while you stated you already cleaned this out, if you have any vacuum leaks at the BACV or DEI or Rat's Nest (look it up!), then you will have idle speed variability that will drive you nuts. Most vacuum leaks are evident as poor idle quality, but stumbling idle, and backfiring are indications of a potential vacuum leak.
These are certainly some things to look into on your car, and nobody can doubt that you're learning a thing or two about this beast of a performance vehicle you call an 'SE'. Drivers earn respect as much from their ability to troubleshoot EFI systems as their driving finesse - welcome to the fold.
(Also, I don't normally write like this, it's just been a very weird week...) HTH,
http://www.nellump.net/peri/epi/fir.../gslseIdle.html
My feelings on the matter are that most SE owners attempt to adjust idle with the idle air adjust screw (an air bypass means) which is located on top of the TB. This screw comes out for more air (higher idle), etc. But if you run it out all the way, and still can't get the idle where you want it, you need to be focusing on a few other, less well-known, areas.
1) TB rod stop adjuster (right side of TB, small copper set nut, and flat-head copper adjuster - loosen set nut, turn adjuster just a tiny bit until idle comes up, tighten set nut. This sets the minimum throttle opening posiition, and sets where the throttle plates come to rest on zero throttle input.
2) Thermowax pellet and associated vacuum plumbing - the thermowax pellet is the green plastic thing coming out of the left side of the TB. Coolant from the back of the waterpump is routed here, then to the top of the block under the upper intake manifold. Hot coolant signals a warm engine, allowing the thermowax pellet to expand and open the 'choke' butterflies in the TB (on the secondaries, at the bottom (aka, by Mazda as the 'double-throttles'). When cold, the thermowax pellet is contracted which does 2 things, A) shuts off vacuum to the double-throttle diaphragm - causing choke, and B) sets the fast idle cam on the main throttle rod (primary). When cold the engine should idle at about 2500 rpm until warm, then drop down to 800rpm FSM set limit.
3) Idle Mixture Adjustment (aka, Variable Rheostat) - located at the passenger strut tower, this rheostat is a variable resistance electrical connection which tells the ECU how much fuel to inject at idle. Dealers adjusted this on arrival to destination, and then sealed the top of the adjuster screw with paste. Scrape the paste out, and you, too, can have ultimate control over idle quality, idle air/fuel mixture, and conversely, idle speed!
4) BACV - while you stated you already cleaned this out, if you have any vacuum leaks at the BACV or DEI or Rat's Nest (look it up!), then you will have idle speed variability that will drive you nuts. Most vacuum leaks are evident as poor idle quality, but stumbling idle, and backfiring are indications of a potential vacuum leak.
These are certainly some things to look into on your car, and nobody can doubt that you're learning a thing or two about this beast of a performance vehicle you call an 'SE'. Drivers earn respect as much from their ability to troubleshoot EFI systems as their driving finesse - welcome to the fold.
(Also, I don't normally write like this, it's just been a very weird week...) HTH,
03-10-04, 08:25 PM
#19
Ryan
bring it to me! Where are you in L.A good find where did you get it? I hope not from a guy named Will that had another one that had no motor.....
Anyways give me a call...
-Ryan
Anyways give me a call...
-Ryan
03-10-04, 08:30 PM
#20
Rotary Enthusiast
iTrader: (1)
Join Date: Aug 2003
Location: NJ
Posts: 1,171
Likes: 0
Received 0 Likes
on
0 Posts
Longduck strikes again! Damn Longduck...your explanations make me wanna take my car apart and put her back together although there's nothing wrong with my idle anymore...
I did have that problem though...and instead of fishing for the problem, I decided to replace the vacuum hoses, clean out everything from the upperintake on up...
The result is a purring kitten at a purrrfect 800rpm...or at least last i checked...
...I'm taking her out of hibernation soon...I promise...
But yeah, after putting her back together and adjusting the screws to spec I was successful in getting her running good...
BTW, your car is tight! Is that the off white or the white color like mine? I can't tell from the GLARE
I did have that problem though...and instead of fishing for the problem, I decided to replace the vacuum hoses, clean out everything from the upperintake on up...
The result is a purring kitten at a purrrfect 800rpm...or at least last i checked...
...I'm taking her out of hibernation soon...I promise...But yeah, after putting her back together and adjusting the screws to spec I was successful in getting her running good...
BTW, your car is tight! Is that the off white or the white color like mine? I can't tell from the GLARE
Last edited by bizarro; 03-10-04 at 08:33 PM.
03-10-04, 08:43 PM
#21
Junior Member
Thread Starter
Join Date: Mar 2004
Location: SoCal
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
BTW, your car is tight! Is that the off white or the white color like mine? I can't tell from the GLARE
Yes its the same color as yours..
Sorry about the pic took it with my cell phone
common color, rare model.
its a 2+2 with power steering =)
Yes its the same color as yours..
Sorry about the pic took it with my cell phone
common color, rare model.
its a 2+2 with power steering =)
03-10-04, 08:58 PM
#23
Rotary Enthusiast
iTrader: (1)
Join Date: Aug 2003
Location: NJ
Posts: 1,171
Likes: 0
Received 0 Likes
on
0 Posts
wow...so we both have the same color, same model and same year...
i notice your car has pinstrips...mine were removed i guess when the previous owner had the car painted...(sucky paintjob)...
when i first got my car the PS was shot...so i replaced the pump and all is smoooooth....does your car have leather? does it have lighted keylocks?
mine doesn't...but it seems to have the other options...although some people don't like the creature comforts, i do and intent to keep it in tip top shape...not racing shape...but stock shape...
i just got springs, shocks, struts, bushings, brake pads, brake master cyl, optima battery and tires...so at least this summer the ride will be restored...next summer will be the paint job...
what other work is needed on your car?
i notice your car has pinstrips...mine were removed i guess when the previous owner had the car painted...(sucky paintjob)...
when i first got my car the PS was shot...so i replaced the pump and all is smoooooth....does your car have leather? does it have lighted keylocks?
mine doesn't...but it seems to have the other options...although some people don't like the creature comforts, i do and intent to keep it in tip top shape...not racing shape...but stock shape...
i just got springs, shocks, struts, bushings, brake pads, brake master cyl, optima battery and tires...so at least this summer the ride will be restored...next summer will be the paint job...
what other work is needed on your car?
03-10-04, 09:11 PM
#24
Junior Member
Thread Starter
Join Date: Mar 2004
Location: SoCal
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by bizarro
wow...so we both have the same color, same model and same year...
i notice your car has pinstrips...mine were removed i guess when the previous owner had the car painted...(sucky paintjob)...
when i first got my car the PS was shot...so i replaced the pump and all is smoooooth....does your car have leather? does it have lighted keylocks?
mine doesn't...but it seems to have the other options...although some people don't like the creature comforts, i do and intent to keep it in tip top shape...not racing shape...but stock shape...
i just got springs, shocks, struts, bushings, brake pads, brake master cyl, optima battery and tires...so at least this summer the ride will be restored...next summer will be the paint job...
what other work is needed on your car?
wow...so we both have the same color, same model and same year...
i notice your car has pinstrips...mine were removed i guess when the previous owner had the car painted...(sucky paintjob)...
when i first got my car the PS was shot...so i replaced the pump and all is smoooooth....does your car have leather? does it have lighted keylocks?
mine doesn't...but it seems to have the other options...although some people don't like the creature comforts, i do and intent to keep it in tip top shape...not racing shape...but stock shape...
i just got springs, shocks, struts, bushings, brake pads, brake master cyl, optima battery and tires...so at least this summer the ride will be restored...next summer will be the paint job...
what other work is needed on your car?
yeah its has leather and the lighted keylocks
im still figuring out what all its going to need.
all and all thou its in good shape, completely
stock right off the floor.
other then the fact that i changed the tranny
out from a junker 83' GSL (5th and reverse were gone on the orginal trans)
cleaning the injectors are on my list aswell as
a few small things
the PS will blow all its fluid out in 10 to 15 min ...Sigh
is yours a 2+2 aswell ?
03-10-04, 09:23 PM
#25
Rotary Enthusiast
iTrader: (1)
Join Date: Aug 2003
Location: NJ
Posts: 1,171
Likes: 0
Received 0 Likes
on
0 Posts
if you mean 2 seater w/ 2 wd then yes it is...although mine doesn't have the leather interior...nor the lit keylocks...i want the keylocks...the leather i can do without since 20yo leather cracks when not taken care of...
my PS was doing the same thing...i replaced the pump with another and done...never had a problem since...
how many miles you have on yours?
my PS was doing the same thing...i replaced the pump with another and done...never had a problem since...
how many miles you have on yours?