lack of power! eliminating variables...
06-21-09, 10:45 PM
#1
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lack of power! eliminating variables...
hey everyone,
i am the proud new owner of a 84 GSL. i got it from an old man who hasn't run the car for many years. it starts right up and seems to idle okay, but feels like it has about thirty horsepower while driving. it will rev up to 7k, but it takes a while and you really need to floor it. it will try to stall on very mild inclines unless revved really high and riding the clutch. i have read many FAQs and done tons of searches, and found many possible causes.
all i have done to start fixing things was fuel related. i replaced the cracked old fuel lines and fuel filter, as well as drained the old gas and put in new stuff.
it seems that one of these three things could be my problem:
-clogged exhaust, still has old cat and everything, looks pretty nasty. (can i remove cat and see how it runs? what should i do about the vaccum lines going to it?)
-carb needs rebuilding (took of air filter and looked in there, was very shiny and didnt look to bad, but am no carb expert)
-apex seal shot (will be performing wooosh wooosh wooosh self compression test tomorrow, but dont really think this is the problem)
basically just wondering if anyone has any good cheap ways to help me eliminate one or more of these variables to help me save time and money.
thanks in advance!
i am the proud new owner of a 84 GSL. i got it from an old man who hasn't run the car for many years. it starts right up and seems to idle okay, but feels like it has about thirty horsepower while driving. it will rev up to 7k, but it takes a while and you really need to floor it. it will try to stall on very mild inclines unless revved really high and riding the clutch. i have read many FAQs and done tons of searches, and found many possible causes.
all i have done to start fixing things was fuel related. i replaced the cracked old fuel lines and fuel filter, as well as drained the old gas and put in new stuff.
it seems that one of these three things could be my problem:
-clogged exhaust, still has old cat and everything, looks pretty nasty. (can i remove cat and see how it runs? what should i do about the vaccum lines going to it?)
-carb needs rebuilding (took of air filter and looked in there, was very shiny and didnt look to bad, but am no carb expert)
-apex seal shot (will be performing wooosh wooosh wooosh self compression test tomorrow, but dont really think this is the problem)
basically just wondering if anyone has any good cheap ways to help me eliminate one or more of these variables to help me save time and money.
thanks in advance!
06-21-09, 11:26 PM
#4
Blackdeath has covered one of the more common issues that contributes to a major lack of power on these models.
You have already stated another one which is a restricted exhaust system which you can remove the main catalytic converter and inspect inside to see if it has come apart. Also running the engine at that time will also confirm as the power would return if you removed a blocked converter. A lot of exhaust shops can test for this also.
You need to verify that the leading plugs are firing. If the ignitor is bad on the leading side you will have a great loss of power.
You have replace the fuel filter but don't rule out that the fuel system is ok. There could be rust in the system. Best thing to do is perform a fuel pressure/quantity test which can be found in a Haynes manual or by down loading a copy of your year FSM from the link in my signature which you can copy and paste.
Then as you stated a compression test is in order but generally if the engine starts immediately it is usually not a compression issue.
I am going to have to lean towards the suggestion of Blackdeath with the "TeeterTotter" or secondary linkage being off as my first choice. My second choice would be the leading ignition being inoperative. Then the exhaust.
But as in anything it could a multiple of issues at the same time. :-)
You have already stated another one which is a restricted exhaust system which you can remove the main catalytic converter and inspect inside to see if it has come apart. Also running the engine at that time will also confirm as the power would return if you removed a blocked converter. A lot of exhaust shops can test for this also.
You need to verify that the leading plugs are firing. If the ignitor is bad on the leading side you will have a great loss of power.
You have replace the fuel filter but don't rule out that the fuel system is ok. There could be rust in the system. Best thing to do is perform a fuel pressure/quantity test which can be found in a Haynes manual or by down loading a copy of your year FSM from the link in my signature which you can copy and paste.
Then as you stated a compression test is in order but generally if the engine starts immediately it is usually not a compression issue.
I am going to have to lean towards the suggestion of Blackdeath with the "TeeterTotter" or secondary linkage being off as my first choice. My second choice would be the leading ignition being inoperative. Then the exhaust.
But as in anything it could a multiple of issues at the same time. :-)
06-21-09, 11:45 PM
#5
I bought a gs off a lady who babied it. The secondaries hadn't pulled open in years and it was sooo carboned up too. Did the seafoam treatment, took her for a highway trip then at one point it blew out a bunch of black smoke and ripped like it should (or could), felt like I had just found about 40hp.
06-22-09, 01:02 AM
#6
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The teeter totter wont rob too much power. I had mine off for awile. I figured that one out on my own just by looking at it. I was like what is this thing move for if it just holds a spring. and then I looked at the linkage put that on and it pulled way harder. But I wasn't having any real issues with power in the first place. but it makes a noticable differance. as does mech secounds. If the carbs been sitting for awhile you need a rebuild. It will just get worse and worse. I'm having carb issues at the moment.
06-22-09, 04:26 AM
#7
Huh?
The failure of the secondaries to open has a huge affect on power!
The failure of the secondaries to open has a huge affect on power!
The teeter totter wont rob too much power. I had mine off for awile. I figured that one out on my own just by looking at it. I was like what is this thing move for if it just holds a spring. and then I looked at the linkage put that on and it pulled way harder. But I wasn't having any real issues with power in the first place. but it makes a noticable differance. as does mech secounds. If the carbs been sitting for awhile you need a rebuild. It will just get worse and worse. I'm having carb issues at the moment.
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06-22-09, 07:12 AM
#8
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Maybe the TT wouldn't have much of an effect if you have mech secondaries? I don't know, he kind of contradicts himself in his post (didn't notice much difference/had way more horsepower).....
To the OP; before you dig into the carb, do some reading over at Sterling's site to prepare yourself. Also a lot of troubleshooting info there. www.sterlingmetalworks.com
To the OP; before you dig into the carb, do some reading over at Sterling's site to prepare yourself. Also a lot of troubleshooting info there. www.sterlingmetalworks.com
06-22-09, 07:30 AM
#9
The teeter totter wont rob too much power. I had mine off for awile. I figured that one out on my own just by looking at it. I was like what is this thing move for if it just holds a spring. and then I looked at the linkage put that on and it pulled way harder. But I wasn't having any real issues with power in the first place. but it makes a noticable differance. as does mech secounds. If the carbs been sitting for awhile you need a rebuild. It will just get worse and worse. I'm having carb issues at the moment.
and yes if you have Mech. secondaries the TT won't do anything, atleast on my set up it's not even on there anymore lol
list of things to check:
Teeter Totter
Fuel Delivery
Spark
and Exhaust....in that order
06-22-09, 02:46 PM
#10
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Just a bit about this whole "teeter-totter myth...
The "teeter-totter" is not related the the secondary throttle function in any way.
All of the vacuum operated extraneous components such as the auto-choke, the fast idle, the AC idle comp valve and the deceleration dashpot are designed to operate optimally at a very specific primary throttle spring rate. This rate is almost certainly different from one carburetor to the next even when brand new, let alone after years of use.
What the teeter-totter actually does is give a means to fine tune the throttle return spring rate. That's all it does. People claiming that they're secondaries didn't open when it was disconnected are absolutely mistaken. There's simply no way that it has any bearing on the secondary throttle shaft what so ever.
The secondary throttle shaft is effectively locked closed by linkage on the primary throttle shaft. Once the primary throttle shaft opens about 35-40 degrees, the secondary throttle locking linkage is unlocked, allowing the secondaries to be opened by vacuum prompting from the vacuum diaphragm box, so long as there is adequate vacuum present. The source of the vacuum signal to the secondary vacuum diaphragm box is a hole drilled into the side of the left primary venturi. The only resistance (theoretically speaking; so minus the friction of moving parts) is a fairly light spring located inside the box on the outside of the diaphragm.
The secondaries open solely as a result of air velocity through the left primary venturi, and nothing else. The vacuum secondaries on the Nikki are not even load dependent like many other 4 bbl carbs which get their vacuum signal from the manifold.
The "teeter-totter" is not related the the secondary throttle function in any way.
All of the vacuum operated extraneous components such as the auto-choke, the fast idle, the AC idle comp valve and the deceleration dashpot are designed to operate optimally at a very specific primary throttle spring rate. This rate is almost certainly different from one carburetor to the next even when brand new, let alone after years of use.
What the teeter-totter actually does is give a means to fine tune the throttle return spring rate. That's all it does. People claiming that they're secondaries didn't open when it was disconnected are absolutely mistaken. There's simply no way that it has any bearing on the secondary throttle shaft what so ever.
The secondary throttle shaft is effectively locked closed by linkage on the primary throttle shaft. Once the primary throttle shaft opens about 35-40 degrees, the secondary throttle locking linkage is unlocked, allowing the secondaries to be opened by vacuum prompting from the vacuum diaphragm box, so long as there is adequate vacuum present. The source of the vacuum signal to the secondary vacuum diaphragm box is a hole drilled into the side of the left primary venturi. The only resistance (theoretically speaking; so minus the friction of moving parts) is a fairly light spring located inside the box on the outside of the diaphragm.
The secondaries open solely as a result of air velocity through the left primary venturi, and nothing else. The vacuum secondaries on the Nikki are not even load dependent like many other 4 bbl carbs which get their vacuum signal from the manifold.
06-22-09, 03:24 PM
#11
Sterling,
You have peeked my interest here and since it has been a very long time since I have owned a carbureted 7.
I do remember that when the "Teeter Totter" has been off that there was a lack of power or acceleration. Why is that so then?
You have peeked my interest here and since it has been a very long time since I have owned a carbureted 7.
I do remember that when the "Teeter Totter" has been off that there was a lack of power or acceleration. Why is that so then?
Just a bit about this whole "teeter-totter myth...
The "teeter-totter" is not related the the secondary throttle function in any way.
All of the vacuum operated extraneous components such as the auto-choke, the fast idle, the AC idle comp valve and the deceleration dashpot are designed to operate optimally at a very specific primary throttle spring rate. This rate is almost certainly different from one carburetor to the next even when brand new, let alone after years of use.
What the teeter-totter actually does is give a means to fine tune the throttle return spring rate. That's all it does. People claiming that they're secondaries didn't open when it was disconnected are absolutely mistaken. There's simply no way that it has any bearing on the secondary throttle shaft what so ever.
The secondary throttle shaft is effectively locked closed by linkage on the primary throttle shaft. Once the primary throttle shaft opens about 35-40 degrees, the secondary throttle locking linkage is unlocked, allowing the secondaries to be opened by vacuum prompting from the vacuum diaphragm box, so long as there is adequate vacuum present. The source of the vacuum signal to the secondary vacuum diaphragm box is a hole drilled into the side of the left primary venturi. The only resistance (theoretically speaking; so minus the friction of moving parts) is a fairly light spring located inside the box on the outside of the diaphragm.
The secondaries open solely as a result of air velocity through the left primary venturi, and nothing else. The vacuum secondaries on the Nikki are not even load dependent like many other 4 bbl carbs which get their vacuum signal from the manifold.
The "teeter-totter" is not related the the secondary throttle function in any way.
All of the vacuum operated extraneous components such as the auto-choke, the fast idle, the AC idle comp valve and the deceleration dashpot are designed to operate optimally at a very specific primary throttle spring rate. This rate is almost certainly different from one carburetor to the next even when brand new, let alone after years of use.
What the teeter-totter actually does is give a means to fine tune the throttle return spring rate. That's all it does. People claiming that they're secondaries didn't open when it was disconnected are absolutely mistaken. There's simply no way that it has any bearing on the secondary throttle shaft what so ever.
The secondary throttle shaft is effectively locked closed by linkage on the primary throttle shaft. Once the primary throttle shaft opens about 35-40 degrees, the secondary throttle locking linkage is unlocked, allowing the secondaries to be opened by vacuum prompting from the vacuum diaphragm box, so long as there is adequate vacuum present. The source of the vacuum signal to the secondary vacuum diaphragm box is a hole drilled into the side of the left primary venturi. The only resistance (theoretically speaking; so minus the friction of moving parts) is a fairly light spring located inside the box on the outside of the diaphragm.
The secondaries open solely as a result of air velocity through the left primary venturi, and nothing else. The vacuum secondaries on the Nikki are not even load dependent like many other 4 bbl carbs which get their vacuum signal from the manifold.
06-22-09, 04:44 PM
#12
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Dunno. I've studied the linkage very carefully several times on unmolested cores that come in, and I can't for the life of me see a corelation between the teetor-totter slipping off and the secondary throttle function. Just ain't happening, -at least not as a direct result.
However, suppose you have a functioning deceleration dashpot that you're used to driving with while the throttle return spring is lessened by the teeter-totter spring. When the teeter totter slips off, suddenly the throttle return spring is stronger, so letting up on the throttle causes that dashpot to close a little quicker. Maybe now it just feels like it's lacking "something" that it had before.
I'm just pissing in the wind here to entertain the idea of why so many seem to experience this, but like I say, I just can't find an actual cause to support these claims. A lot of people have posted, "I put the thing back on, and 'BAM', big difference". But it's really only like putting a lighter throttle spring on, and from the foot to the head, this can change the whole feel of the car. Response seems better, etc.
However, suppose you have a functioning deceleration dashpot that you're used to driving with while the throttle return spring is lessened by the teeter-totter spring. When the teeter totter slips off, suddenly the throttle return spring is stronger, so letting up on the throttle causes that dashpot to close a little quicker. Maybe now it just feels like it's lacking "something" that it had before.
I'm just pissing in the wind here to entertain the idea of why so many seem to experience this, but like I say, I just can't find an actual cause to support these claims. A lot of people have posted, "I put the thing back on, and 'BAM', big difference". But it's really only like putting a lighter throttle spring on, and from the foot to the head, this can change the whole feel of the car. Response seems better, etc.
06-22-09, 05:04 PM
#13
wow, this is a first for me. i've never had this problem because i've had mech. secondaries since i can remember. but from lots of reading and what not it seems like this has been the solution to a lot of "lack of power" problems...i'm very intrigued now.
06-22-09, 05:15 PM
#14
From my personal experience of my only non SE owned 7 which was a GSL I had the teeter totter come off and there was a tremendous lack of power. Sometime after that in the 90's I was buying and selling and working on 7's and encountered the same issue many times. Every time I would put the teeter totter back on then power would return.
Perhaps a member with a stock carbureted 7 can remove their teeter totter and take it for a test drive and report the results. :-)
Perhaps a member with a stock carbureted 7 can remove their teeter totter and take it for a test drive and report the results. :-)
06-22-09, 06:29 PM
#15
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The book calls it a throttle sub-return bracket and refers to it as a safety system. It's a very curious thing, because I actually use the sub return rod & spring as the main primary throttle return spring on the Sterling Nikkis. Seems to me, if all it did was afford fine tuning of the throttle return spring rate, it could be used all by itself in a simpler fashion along with an adjustment nut on the rod.
-I also see from playing with one that when it flips off, the primary spring then has less tension, not more like I stated.
-I also see from playing with one that when it flips off, the primary spring then has less tension, not more like I stated.
06-22-09, 09:28 PM
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WOW!
thanks for all the responses, but i didn't mean to spark such a teeter totter debate.
i ran the car for about an hour today. still very weak, but it will rev all the way to redline... i can't imagine that a apex seal could be busted, or even that the front rotor plugs weren't operational if it can rev that high, right?
also, when i step on the gas anytime its like there is a delay before it does anything, slight, but noticeable...maybe i'm just not used to the way it drives.
thanks again!
thanks for all the responses, but i didn't mean to spark such a teeter totter debate.
i ran the car for about an hour today. still very weak, but it will rev all the way to redline... i can't imagine that a apex seal could be busted, or even that the front rotor plugs weren't operational if it can rev that high, right?
also, when i step on the gas anytime its like there is a delay before it does anything, slight, but noticeable...maybe i'm just not used to the way it drives.
thanks again!
06-23-09, 08:48 PM
#22
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Well, mice do make homes in the exhaust system when the car sits for a while. It's the perfect place, and they bring all kinds of **** in there to make their nests.
But the real trouble is when cats chase them into the exhaust and get trapped inside.
Then you have a cat clogging issue.
All kitting aside,
, I had a burned cat in my wife's Huyndai and it would rev but not go above 40 MPH on a flat, and I literally had to back down a steep hill where there was no shoulder or driveway to turn around. The car simply wouldn't make it up the hill, but of course it didn't decide that until 2 miles up!
-I was headed to the muffler shop, too!
But the real trouble is when cats chase them into the exhaust and get trapped inside.
Then you have a cat clogging issue.
All kitting aside,
, I had a burned cat in my wife's Huyndai and it would rev but not go above 40 MPH on a flat, and I literally had to back down a steep hill where there was no shoulder or driveway to turn around. The car simply wouldn't make it up the hill, but of course it didn't decide that until 2 miles up!-I was headed to the muffler shop, too!
06-24-09, 09:19 AM
#25
From my personal experience of my only non SE owned 7 which was a GSL I had the teeter totter come off and there was a tremendous lack of power. Sometime after that in the 90's I was buying and selling and working on 7's and encountered the same issue many times. Every time I would put the teeter totter back on then power would return.
Perhaps a member with a stock carbureted 7 can remove their teeter totter and take it for a test drive and report the results. :-)
Perhaps a member with a stock carbureted 7 can remove their teeter totter and take it for a test drive and report the results. :-)
I'll give this test a try the next time I have the car out for a romp; I have a fairly steep uphill approach to my house, which should work as a reasonable "ghetto dyno."
Results will still be subjective, as we're talking about perceived power rather than measured power, but I'll try my best to be objective about it.
Moe lata.
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