86 hunting idle
Team Owner
Joined: Jul 2004
Posts: 28,459
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From: Hartford WI
Please clarify if I am doing the FP test correctly. When I do it I attach the fuel pressure gauge to the rail and have all vacuum lines and fuel lines hooked up as would be normally. Not sure which hose in/out you're asking about.
Also what rubber thing in the tank? If you mean what I called the "sock" that would be the in tank cloth filter at the bottom of the assembly that sits in the slosh valley.
Thanks
Also what rubber thing in the tank? If you mean what I called the "sock" that would be the in tank cloth filter at the bottom of the assembly that sits in the slosh valley.
Thanks
When you replaced the pump, there was something in the lines above the pump. About 2 inches long. It would dampen the fuel pressure. It could leak. http://www.corvettefever.com/techart.../photo_18.html
See the black or sometimes white thing above the pump straps? I took that out completely so there could be no pressure leak. A hose straight to the metal hose
Thread Starter
Intermediate
Joined: Jan 2009
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From: Fredericksburg Virginia
All lines EXCEPT the one going to the FPR. That way, it simulates a WOT condition.
When you replaced the pump, there was something in the lines above the pump. About 2 inches long. It would dampen the fuel pressure. It could leak. http://www.corvettefever.com/techart.../photo_18.html
See the black or sometimes white thing above the pump straps? I took that out completely so there could be no pressure leak. A hose straight to the metal hose
When you replaced the pump, there was something in the lines above the pump. About 2 inches long. It would dampen the fuel pressure. It could leak. http://www.corvettefever.com/techart.../photo_18.html
See the black or sometimes white thing above the pump straps? I took that out completely so there could be no pressure leak. A hose straight to the metal hose
Under both scenarios FP is 45 at Ignition on, with FPR connected and engine running = 35psi, with FPR disconnected and engine running = 45 psi.
I did eliminate the "dampener" connected to the fuel pump and clamped in a 2" piece of injector hose when I replaced the pump yesterday.
Does my WOT FP look about right?
Team Owner
Joined: Jul 2004
Posts: 28,459
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From: Hartford WI
OK, just checked with FPR vac line connected AND disconnected.
Under both scenarios FP is 45 at Ignition on, with FPR connected and engine running = 35psi, with FPR disconnected and engine running = 45 psi.
I did eliminate the "dampener" connected to the fuel pump and clamped in a 2" piece of injector hose when I replaced the pump yesterday.
Does my WOT FP look about right?
Under both scenarios FP is 45 at Ignition on, with FPR connected and engine running = 35psi, with FPR disconnected and engine running = 45 psi.
I did eliminate the "dampener" connected to the fuel pump and clamped in a 2" piece of injector hose when I replaced the pump yesterday.
Does my WOT FP look about right?
Now, as to whether the fuel is being atomized well or not, IDK. Call Clark Kent aka Superman. He has X-ray vision. Still he won't know how to measure volume without a measuring cylinder that I know of.
THIS is how they test injectors.
Thread Starter
Intermediate
Joined: Jan 2009
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From: Fredericksburg Virginia
Some scan data
Sounds about right. After all, IIRC, they measure fuel pressure at 43.5 for injector tests. You don't want it too high because it can cause the injectors to lock up if they are Multecs.
Now, as to whether the fuel is being atomized well or not, IDK. Call Clark Kent aka Superman. He has X-ray vision. Still he won't know how to measure volume without a measuring cylinder that I know of.
THIS is how they test injectors.
Now, as to whether the fuel is being atomized well or not, IDK. Call Clark Kent aka Superman. He has X-ray vision. Still he won't know how to measure volume without a measuring cylinder that I know of.
THIS is how they test injectors.
BLM -- 147 closed loop at idle
TPS .6
Exhaust O2 - switching back and forth between lean and rich
IAC position: at idle - 0, at 1K rpm - 9, at 2K rpm - 27
O2 crosscounts -- varied from 1-9
MAF airflow: 5g at idle, 9g at 1K rpm, 27g at 2K rpm
Spark advance: at idle 14-19, at 1K rpm 22, at 2K rpm 32
Prom ID# 9721
Looking around the boards the BLM looks high.
Thoughts?
Team Owner
Joined: Jul 2004
Posts: 28,459
Likes: 3,288
From: Hartford WI
This is an issue to me. Your O2 should be going rich to lean and back to rich, etc, etc. At idle, if the IAC is 0, it means that it is getting too much air. So, if it needs less air, it cannot close the pintle and therefore cannot adjust via the IAC. It will have to find a less smooth way to do it.
Is there a command idle somewhere or desired idle? Just curious.
What needs to be done is to close the TB butterfly valve. ASSUMING your timing is set at 6, I would close it, rev the motor, close it, rev again till I get about 20 IAC counts. More than 20 counts, say 50 counts means the IAC is having to open up because there is not enough air. As such, you open the butterfly via the adjustment screw on the driver side of the car. Hopefully you already tried adjusting it and removed the cover plate.
Screw in, open. Screw out, close.
After that, adjust TPS.
High BLM makes me wonder if there is a leak somewhere. Did you propane test the TB? Maybe around the throttle shaft?
Another item is that maybe the injectors are not delivering as much fuel as the ECM thinks that it is doing? Refresh my memory. Injector status?
Is there a command idle somewhere or desired idle? Just curious.
What needs to be done is to close the TB butterfly valve. ASSUMING your timing is set at 6, I would close it, rev the motor, close it, rev again till I get about 20 IAC counts. More than 20 counts, say 50 counts means the IAC is having to open up because there is not enough air. As such, you open the butterfly via the adjustment screw on the driver side of the car. Hopefully you already tried adjusting it and removed the cover plate.
Screw in, open. Screw out, close.
After that, adjust TPS.
High BLM makes me wonder if there is a leak somewhere. Did you propane test the TB? Maybe around the throttle shaft?
Another item is that maybe the injectors are not delivering as much fuel as the ECM thinks that it is doing? Refresh my memory. Injector status?
Last edited by aklim; Apr 12, 2011 at 05:56 PM.
Thread Starter
Intermediate
Joined: Jan 2009
Posts: 46
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From: Fredericksburg Virginia
This is an issue to me. Your O2 should be going rich to lean and back to rich, etc, etc. At idle, if the IAC is 0, it means that it is getting too much air. So, if it needs less air, it cannot close the pintle and therefore cannot adjust via the IAC. It will have to find a less smooth way to do it.
Is there a command idle somewhere or desired idle? Just curious.
What needs to be done is to close the TB butterfly valve. ASSUMING your timing is set at 6, I would close it, rev the motor, close it, rev again till I get about 20 IAC counts. More than 20 counts, say 50 counts means the IAC is having to open up because there is not enough air. As such, you open the butterfly via the adjustment screw on the driver side of the car. Hopefully you already tried adjusting it and removed the cover plate.
Screw in, open. Screw out, close.
After that, adjust TPS.
High BLM makes me wonder if there is a leak somewhere. Did you propane test the TB? Maybe around the throttle shaft?
Another item is that maybe the injectors are not delivering as much fuel as the ECM thinks that it is doing? Refresh my memory. Injector status?
Is there a command idle somewhere or desired idle? Just curious.
What needs to be done is to close the TB butterfly valve. ASSUMING your timing is set at 6, I would close it, rev the motor, close it, rev again till I get about 20 IAC counts. More than 20 counts, say 50 counts means the IAC is having to open up because there is not enough air. As such, you open the butterfly via the adjustment screw on the driver side of the car. Hopefully you already tried adjusting it and removed the cover plate.
Screw in, open. Screw out, close.
After that, adjust TPS.
High BLM makes me wonder if there is a leak somewhere. Did you propane test the TB? Maybe around the throttle shaft?
Another item is that maybe the injectors are not delivering as much fuel as the ECM thinks that it is doing? Refresh my memory. Injector status?
Desired idle was 550 on the scanner
Timing is set at 6.
Do I adjust the throttle butterfly without disconnecting the IAC as I do when setting base idle?
I did the propane test all around the TB and did not get any revs in RPMs, I may try again.
Injectors are old and on my wish list, I believe standard MultiTec. Could be leaking some but plugs are dry and no smoke on start up!
The ECM thinking too much air would explain the rich smell and the carbon dust in the tail pipe becuase it's dumping more fuel.
Team Owner
Joined: Jul 2004
Posts: 28,459
Likes: 3,288
From: Hartford WI
Do I adjust the throttle butterfly without disconnecting the IAC as I do when setting base idle?
I did the propane test all around the TB and did not get any revs in RPMs, I may try again.
Injectors are old and on my wish list, I believe standard MultiTec. Could be leaking some but plugs are dry and no smoke on start up!
The ECM thinking too much air would explain the rich smell and the carbon dust in the tail pipe becuase it's dumping more fuel.
I did the propane test all around the TB and did not get any revs in RPMs, I may try again.
Injectors are old and on my wish list, I believe standard MultiTec. Could be leaking some but plugs are dry and no smoke on start up!
The ECM thinking too much air would explain the rich smell and the carbon dust in the tail pipe becuase it's dumping more fuel.
That and if you have a cold start injector, I would send the CS injector out
Thread Starter
Intermediate
Joined: Jan 2009
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From: Fredericksburg Virginia
Played with the timing by turning the distrubuter and found it really likes to be retarded, unless my aftermarket timing tab is installed incorrectly it's somewhere around 12 BTDC and smoother at idle but worse while driving.
Interestingly the idle smooths out with the brown/black wire disconnected while checking the timing. New cap, rotor, wires and plugs.
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Team Owner
Joined: Jul 2004
Posts: 28,459
Likes: 3,288
From: Hartford WI
Tried doing the idle adjust with the IAC in and no luck. Will try again next time I have a scanner (might buy one of the PC ones later today).
Played with the timing by turning the distrubuter and found it really likes to be retarded, unless my aftermarket timing tab is installed incorrectly it's somewhere around 12 BTDC and smoother at idle but worse while driving.
Interestingly the idle smooths out with the brown/black wire disconnected while checking the timing. New cap, rotor, wires and plugs.
Played with the timing by turning the distrubuter and found it really likes to be retarded, unless my aftermarket timing tab is installed incorrectly it's somewhere around 12 BTDC and smoother at idle but worse while driving.
Interestingly the idle smooths out with the brown/black wire disconnected while checking the timing. New cap, rotor, wires and plugs.
With the distributor you are making changes all over. That means it is at idle and at WOT. I suspect that the idle loves it but at WOT, it is detonating so the ECM is pulling out timing and your car runs like crap. You need to get the timing set first and not screw with it. Any timing changes should be made thru the chip. The chip doesn't know what timing you have but assumes base timing of 6 and advances from there.
Maybe because it needed more timing and you gave it the timing it wanted by advancing the distributor. However the chip doesn't know that and screws up your WOT.
You really need to get your base timing right. Do you know if the harmonic balancer is even in good condition? Fixing the problem is not simply turning the distributor. Fix it right or pay someone to fix it right.
Thread Starter
Intermediate
Joined: Jan 2009
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From: Fredericksburg Virginia
How did you try to adjust it WITHOUT a scanner?
With the distributor you are making changes all over. That means it is at idle and at WOT. I suspect that the idle loves it but at WOT, it is detonating so the ECM is pulling out timing and your car runs like crap. You need to get the timing set first and not screw with it. Any timing changes should be made thru the chip. The chip doesn't know what timing you have but assumes base timing of 6 and advances from there.
Maybe because it needed more timing and you gave it the timing it wanted by advancing the distributor. However the chip doesn't know that and screws up your WOT.
You really need to get your base timing right. Do you know if the harmonic balancer is even in good condition? Fixing the problem is not simply turning the distributor. Fix it right or pay someone to fix it right.
With the distributor you are making changes all over. That means it is at idle and at WOT. I suspect that the idle loves it but at WOT, it is detonating so the ECM is pulling out timing and your car runs like crap. You need to get the timing set first and not screw with it. Any timing changes should be made thru the chip. The chip doesn't know what timing you have but assumes base timing of 6 and advances from there.
Maybe because it needed more timing and you gave it the timing it wanted by advancing the distributor. However the chip doesn't know that and screws up your WOT.
You really need to get your base timing right. Do you know if the harmonic balancer is even in good condition? Fixing the problem is not simply turning the distributor. Fix it right or pay someone to fix it right.
The balancer was replaced by PO about 5 years ago, timing mark holds steady at about the 1 o'clock position and there is about an inch between the balancer and timing chain cover. It's a 6 3/4 balancer. What to look for to see if it's good other than holding steady and not close to the chain cover?
I did the propane test again today and didn't find anything, unplugged a vacuum line from the plenuum and fed the propane directly in, no change in RPM's at all so the test might not be reliable or? I did verify the propane was good.
As far as paying someone, what fun is that. I've got some time on my hands (currently unemployed) so working on this puzzle is a stress reliever and a distraction.
You've been very helpful in your directions and we have fixed a few things, so thank you very much. Soon as I can scratch together enough for the scanner, I'll be back with some real data and questions.
Thanks again
Team Owner
Joined: Jul 2004
Posts: 28,459
Likes: 3,288
From: Hartford WI
I just turned the TB screw down a half turn at a time to see if anything changed, revving between steps. When it didn't I played with the timing after resetting the IAC and TPS. When I first timed the car it was very retarded as I tried today. Just wanted to confirm that it wasn't a timing issue and it was not so all is back to spec, base at 6, still stumbling.
The balancer was replaced by PO about 5 years ago, timing mark holds steady at about the 1 o'clock position and there is about an inch between the balancer and timing chain cover. It's a 6 3/4 balancer. What to look for to see if it's good other than holding steady and not close to the chain cover?
I did the propane test again today and didn't find anything, unplugged a vacuum line from the plenuum and fed the propane directly in, no change in RPM's at all so the test might not be reliable or? I did verify the propane was good.
As far as paying someone, what fun is that. I've got some time on my hands (currently unemployed) so working on this puzzle is a stress reliever and a distraction.
You've been very helpful in your directions and we have fixed a few things, so thank you very much. Soon as I can scratch together enough for the scanner, I'll be back with some real data and questions.
Thanks again
The balancer was replaced by PO about 5 years ago, timing mark holds steady at about the 1 o'clock position and there is about an inch between the balancer and timing chain cover. It's a 6 3/4 balancer. What to look for to see if it's good other than holding steady and not close to the chain cover?
I did the propane test again today and didn't find anything, unplugged a vacuum line from the plenuum and fed the propane directly in, no change in RPM's at all so the test might not be reliable or? I did verify the propane was good.
As far as paying someone, what fun is that. I've got some time on my hands (currently unemployed) so working on this puzzle is a stress reliever and a distraction.
You've been very helpful in your directions and we have fixed a few things, so thank you very much. Soon as I can scratch together enough for the scanner, I'll be back with some real data and questions.
Thanks again
Not sure. A degree is very difficult to eyeball. Assuming it hasn't separated it should be ok.
http://www.aa1car.com/library/vacleak.htm
OK. Then you are going to need a Factory Shop Manual and a couple of other tools.
Thread Starter
Intermediate
Joined: Jan 2009
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From: Fredericksburg Virginia
Not much should change if everything is within a certain window. Open the TB blades and you let more air in and the ECM will close the IAC. IOW it will compensate.
Not sure. A degree is very difficult to eyeball. Assuming it hasn't separated it should be ok.
http://www.aa1car.com/library/vacleak.htm
OK. Then you are going to need a Factory Shop Manual and a couple of other tools.
Not sure. A degree is very difficult to eyeball. Assuming it hasn't separated it should be ok.
http://www.aa1car.com/library/vacleak.htm
OK. Then you are going to need a Factory Shop Manual and a couple of other tools.
Great article on Vacuum leaks, thanks!
As you know I've done the propane test a few times with no sucess so today I tried the compressed air test with soapy water.
With just a small amount of air feeding into the PVC hose, the only place it was coming out was around the throttle plates, I put a piece of cardboard over the face and did not find any other leakage.
Should the TB leak a little normally when the engine is off and cool, or could this be a source of my extra air intake. Plates not sealing completely shut?
I do have a local shop that will do the smoke test for $89.
TB has been cleaned thoroughly and all new gaskets. Looks to be the original.
Thanks
Team Owner
Joined: Jul 2004
Posts: 28,459
Likes: 3,288
From: Hartford WI
The TB blades will leak. Think about it. When you screw the adjustment screw in, it opens the blades.
Now, at this point, I would try to send the injectors out. ALL of them. Why? because it probably needs it anyways.
How is your 02 sensor
Now, at this point, I would try to send the injectors out. ALL of them. Why? because it probably needs it anyways.
How is your 02 sensor
Thread Starter
Intermediate
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From: Fredericksburg Virginia
I know the injectors! saving up for the Bosch III's.
O2 is a Bosch unit I replaced in the fall, single wire.
Team Owner
Joined: Jul 2004
Posts: 28,459
Likes: 3,288
From: Hartford WI
Yep. That could be your issue
I wish you were closer and I would lend you my scanner. You can see if the O2 sensor has become lazy or is dropping in and out of closed loop which can happen when you have headers.
Thread Starter
Intermediate
Joined: Jan 2009
Posts: 46
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From: Fredericksburg Virginia
Blades, at least in mine, do not make a perfect seal. In fact, mine are open slightly but mine has a higher command idle
Yep. That could be your issue
I wish you were closer and I would lend you my scanner. You can see if the O2 sensor has become lazy or is dropping in and out of closed loop which can happen when you have headers.
Yep. That could be your issue
I wish you were closer and I would lend you my scanner. You can see if the O2 sensor has become lazy or is dropping in and out of closed loop which can happen when you have headers.
Thanks!
I'll be in MI next week but flying in and out for a job interview.
No headers here, all stock.
I should try to connect with some forum members in my area or join a local club. I'm getting to the point where I'm tired of replacing parts that I "think" might be bad. Need to know before I buy that the purchase will fix or get me closer to fixing the problems.
Next purchase is definately a scanner.
Thread Starter
Intermediate
Joined: Jan 2009
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From: Fredericksburg Virginia
Got a scanner!!!
Hey guys,
Got a job and a scanner, flying around the country a lot and need to get this car running right for to and from airport transportation.
Using an old laptop with Datamaster, ran my first scan tonight.
If this link doesn't work, let me know and I can email it to you.
http://home.comcast.net/~mark-hatfie.../FIRSTSCAN.uni
Blew a fuel preassure line at the tank just after this scan so that's what I'll be doing over the weekend. Too many pinches doing fuel test I guess. Patch or replace if I can find one.
Car is running awful, idle still a mess and very rich. Bogs now on acceleration.
Hope to hear from you soon.
Mark
Got a job and a scanner, flying around the country a lot and need to get this car running right for to and from airport transportation.
Using an old laptop with Datamaster, ran my first scan tonight.
If this link doesn't work, let me know and I can email it to you.
http://home.comcast.net/~mark-hatfie.../FIRSTSCAN.uni
Blew a fuel preassure line at the tank just after this scan so that's what I'll be doing over the weekend. Too many pinches doing fuel test I guess. Patch or replace if I can find one.
Car is running awful, idle still a mess and very rich. Bogs now on acceleration.
Hope to hear from you soon.
Mark
Thread Starter
Intermediate
Joined: Jan 2009
Posts: 46
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From: Fredericksburg Virginia
Thread Starter
Intermediate
Joined: Jan 2009
Posts: 46
Likes: 0
From: Fredericksburg Virginia
If that doesn't work