HELP!!! Stage 1 Mod Car runs now but has some issues

[kilgorq]

I did a stage 1 mod for the vac. line removal. Cool it will idle now but it does not run well...

87 Accord LX 155K miles 5 Speed

When I start it from Cold ( Sitting for several hours ) I have 2 pump 3 times and it will start right up. It idles at about 600 RPM and will not go into high speed idle. After about 5 Minutes (When the choke opens up) it will not idle unless I open it up enough to run at 2000 rpm. This is a midpoint behavior. Once the engine warms up all the way the the idle will drop down to 1000 rpm and will die if I touch the brakes. This pattern is very consistant. Also drivability is real bad... when I rev it out of gear it revs good but if I try to punch it while going down the road it jerks. and at a steady rpm it lunges. And dies every time I come to a stop. Where do I look now...

I have replaced spark plugs, fuel pump, fuel filters, rebuilt carb, Sprayed carb cleaner at vac connection looing for vac leaks. and adjusted float level to a little above center on that site glass.

[shepherd79]

which how to did you follow?
some people had issues with keeping the choke.
can you take some pictures of the carb from every angle on the car.

[A20A1]

You problems sounds like a vacuum leak... but is the choke open or closed when the car is warm?

For your idle problems:
You may need to readjust the idle diaphragm screw on the front left side of the motor when the car is fully warm. Set the idle to 800 rpm or to 1,000 if you feel that is better.
After that is set turn up the throttle stop screw at the back of the carb. use this to set the idle speed to 750 or the best lowest idle speed...
Make sure you unscrew the idle diaphragm screw to let the idle drop... this will make sure that the throttle stop screw is what is controlling the idle and holding it steady and not the idle diaphragm.

Then let the throttle screw stay where it is and raise the idle from 750 or the best lowest idle and with the idle diaphragm set the idle to 800 - 1,000 rpm
This should keep your idle from falling off.
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As for the fast idle problems:
It seems like there is vacuum going to the fast idle unloader and keeping it from holding fast idle. This shouldn't be the case if the thermovalve is doing it's job. Or I've draw the diagram wrong.


As for the car jerking and lunging, and partly idle related problems:
With the car fully warm, make sure vacuum line #2 is hooked up to the correct port and that it advances the timing to the correct mark on the flywheel. #25 should not be hooked up for this test.
If all your problems are mainly in cold weather you may want to hook #25 back up the the thermovalve it was originally connected to at the back of the intake manifold... This will be a vacuum line from manifold vacuum to the thermovalve port and from the other thermovalve port to the vacuum advance diaphragm.

Other posslible jerking related problms:
If the float bowl vent was disconnected you could see if removing the vent valve inside helps any, but usually the vent tubes are enough on their own.

Check to make sure that the booster venturies have not loosened.

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[kilgorq]

You problems sounds like a vacuum leak... but is the choke open or closed when the car is warm?

For your idle problems:
You may need to readjust the idle diaphragm screw on the front left side of the motor when the car is fully warm. Set the idle to 800 rpm or to 1,000 if you feel that is better.
After that is set turn up the throttle stop screw at the back of the carb. use this to set the idle speed to 750 or the best lowest idle speed...
Make sure you unscrew the idle diaphragm screw to let the idle drop... this will make sure that the throttle stop screw is what is controlling the idle and holding it steady and not the idle diaphragm.

Then let the throttle screw stay where it is and raise the idle from 750 or the best lowest idle and with the idle diaphragm set the idle to 800 - 1,000 rpm
This should keep your idle from falling off.
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As for the fast idle problems:
It seems like there is vacuum going to the fast idle unloader and keeping it from holding fast idle. This shouldn't be the case if the thermovalve is doing it's job. Or I've draw the diagram wrong.


As for the car jerking and lunging, and partly idle related problems:
With the car fully warm, make sure vacuum line #2 is hooked up to the correct port and that it advances the timing to the correct mark on the flywheel. #25 should not be hooked up for this test.
If all your problems are mainly in cold weather you may want to hook #25 back up the the thermovalve it was originally connected to at the back of the intake manifold... This will be a vacuum line from manifold vacuum to the thermovalve port and from the other thermovalve port to the vacuum advance diaphragm.

Other posslible jerking related problms:
If the float bowl vent was disconnected you could see if removing the vent valve inside helps any, but usually the vent tubes are enough on their own.

Check to make sure that the booster venturies have not loosened.

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The choke is opening correctly. The idle diaphragm screw will not reach. it is bottomed out before it is touching... It is almost like I have to have the throttle at 15% of full travel to make it run. And when adjusting the Idle with the Idle adjustment screw it hits a point where it jumps from about 600 RPM to 2000 RPM. No happy medium on it either. The fast idle cam looks like it is engaged but the throttle is opened more than the fast idle cam would lock it. I tried the carb cleaner trick looking for vac leaks and did not find any.

[kilgorq]

which how to did you follow?
some people had issues with keeping the choke.
can you take some pictures of the carb from every angle on the car.

Posted pics to carb.htm

[A20A1]

well if the screw is bottomed out then you idle diaphragm spring might be installed wrong or the spring is weak
or you are off the idle circuit cause the throttle stop screw is turned in too much or the throttle cable is too tight.
If you are off the idle circuit this is because your throttle is too high... this may be why your fast idle isn't able to reengage cause the thottle plate and linkage hasn't closed enough.

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try removing the check valve on the #6 vacuum line and connecting #6 directly from manifold vacuum to the idle diaphragm. The diaphragm uses the spring inside to push open the throttle when the idle drops and vacuum drops with it. When there is enough vacuum then the idle diaphram is pulled off the throttle.
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[A20A1]

did you plug the port on the choke opener? cause it's not plugged in the pic.

letter A hose is pinched... not that it matter that much


it does appear that the thorttle is open more then it sould be... when you are off the idle circuit your car will not idle... that is why you need to rev to keep it alive... also why the fast idle may not be engaging and why you get the jump from the idle diaphragm cause it's also adjusted to high.

your throttle cable looks tight becasue you can see the uncorroded metal exposed where the adjustment nuts used to be set at... but maybe things have changed....
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oh when refering to idle circuit.. it's an vacuum/fuel circuit not an actual electrical componenet.
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[A20A1]

dang you really mangled that egr pipe.

[A20A1]

I notticed the a/c idle boost had no hook up to it... if it is disabled casue you are removing A/C then also remove the a/c idle boost solenoid that is in the diagram


I marked the boost diaphragm

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I marked a hose I'm not sure where it is going? booster solenoid? If so connect or remove it as stated above.

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I also marked the choke opener port you should plug.



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[A20A1]

oh if you ran out of vacuum plugs/caps try removing a few from the vacuum splitter at the rear of the manifold... and for an example... remove the 2 blue caps and just loop a single vacuum line from one port to the other to plug both ports... this'll give you 2 extra caps to play around with.

[hondamanlxi]

eh, just rip it all off! Then there wont ever be that issue

[kilgorq]

oh if you ran out of vacuum plugs/caps try removing a few from the vacuum splitter at the rear of the manifold... and for an example... remove the 2 blue caps and just loop a single vacuum line from one port to the other to plug both ports... this'll give you 2 extra caps to play around with.

Ok so here is what I have done now. I have replaced the gaskets for the base of the carb. I found that the main vac port on the intake was loose so I tapped (Threaded) it and put a brass fitting in it... I re-asembled everything and I get the same behavior. But I discovered something new also. If I put my hand over the top of the carb it will rev up and I can actually adjust the rpm down to as low as 400 rpm and have it still run smooth. I think the problem is inside the carb somewhere but where do I check. I think the Idle circuit is screwy. I am not getting enough gas to run at low RPMs is my assumption. I can not get a change at all with the Idle adjusment metering screw on the back of the carb either. I also noticed that if I take the vac cap off of the power valve it will run a little better. I think I am actually getting it to run when it is out of the Low Speed Idle circuit because the low speed Idle circuit is not working properly.

I followed your suggestion except eliminated the chike from the system for troublshooting reasons. I will go back and worry about fast Idle when I get the slow Idle to work. I also noticed that if I take the vac cap off of the power valve it will run a little better.

[A20A1]

Well like I said you have too high a throttle setting... if the throttle is open too much you are off the idle circuit and wont pull out any gas or not enough... thats why it isn't working... the a/f idle mixture screw at the back of the carb wont work either... since it operates on the idle circuit.

- When you removed the powervalve vacuum line you opened up the powervalve... this richened the a/f mixture... so now you are pulling out more gas.

- Putting you hand over the carb richened the mixture.

You need more gas at idle... but the 2 ways you tried above are not the right way of doing it... you'll get more gas once you Trun out the throttle stop screw and trun out the idle diaphragm screw.... and close the throttle a little more and get back on the idle circuit.

Make sure that solenoid at the back of the carb is working.

Those vacuum leaks were part of the reason your car was not working at idle... but you fixed it. Your other vacuum leak is due to your high throttle setting which affects the idle circuit.

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[kilgorq]

Well like I said you have too high a throttle setting... if the throttle is open too much you are off the idle circuit and wont pull out any gas or not enough... thats why it isn't working... the a/f idle mixture screw at the back of the carb wont work either... since it operates on the idle circuit.

- When you removed the powervalve vacuum line you opened up the powervalve... this richened the a/f mixture... so now you are pulling out more gas.

- Putting you hand over the carb richened the mixture.

You need more gas at idle... but the 2 ways you tried above are not the right way of doing it... you'll get more gas once you Trun out the throttle stop screw and trun out the idle diaphragm screw.... and close the throttle a little more and get back on the idle circuit.

Make sure that solenoid at the back of the carb is working.

Those vacuum leaks were part of the reason your car was not working at idle... but you fixed it. Your other vacuum leak is due to your high throttle setting which affects the idle circuit.

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So here is what I did

1) Loosened the throttle cable until is completly slack.
2) Backed the idle diphram screw off completly. It will not touch the arm when it is active.
3) Backed off the throttle stop screw until it was not touching the lever.
4) At this point the throttle plate should be all the way shut... I can remove the carb again and verify that.
5) Tightened the idle mixture screw till snug and then backed it off 3 full turns.
6) Will start but will not idle. Tried backing the fuel air mixture screw off by half turn increments up to 6 Turns and I get the same results.

When I rebuilt this carb it had several new parts in it (Acc pump, Gaskets, and float) . I think it was rebuilt by the owner previous to my brother ( Car never ran for my brother. Big messy deal on this one. He basically got the car because the original owner stole something from my mom. And the car is how he made restitution) . He had somehow gotten a piece of rubber stuck in one of the accelerator pump passages. So coming from this perspective am I correct in thinking that he may have installed the throttle plate incorrectly or that the passage that gives fuel to the Idle circuit may be plugged. Or is it that my method is incorrect. It has been about 12 year since I have touched a carburator and this one is really frustrating... The last one I did was a Holley and it was clean up, install kit and adjust idle mixture wa-la done...

Your help has been wonderfull.

[kilgorq]

So here is what I did

1) Loosened the throttle cable until is completly slack.
2) Backed the idle diphram screw off completly. It will not touch the arm when it is active.
3) Backed off the throttle stop screw until it was not touching the lever.
4) At this point the throttle plate should be all the way shut... I can remove the carb again and verify that.
5) Tightened the idle mixture screw till snug and then backed it off 3 full turns.
6) Will start but will not idle. Tried backing the fuel air mixture screw off by half turn increments up to 6 Turns and I get the same results.

When I rebuilt this carb it had several new parts in it (Acc pump, Gaskets, and float) . I think it was rebuilt by the owner previous to my brother ( Car never ran for my brother. Big messy deal on this one. He basically got the car because the original owner stole something from my mom. And the car is how he made restitution) . He had somehow gotten a piece of rubber stuck in one of the accelerator pump passages. So coming from this perspective am I correct in thinking that he may have installed the throttle plate incorrectly or that the passage that gives fuel to the Idle circuit may be plugged. Or is it that my method is incorrect. It has been about 12 year since I have touched a carburator and this one is really frustrating... The last one I did was a Holley and it was clean up, install kit and adjust idle mixture wa-la done...

Your help has been wonderfull.

Forgot to ask how do I test the valve. Is it just a selenoid with a needle on the end of it?

[A20A1]

you can test it by removing it from the back of the carb... it's held on by one 10mm or 8mm bolt. Then either ground the solenoid by laying ot against the manifold and having some one turn the ignition key or hook it up to a 12 volt source.. the pin should retract when the solenoid gets voltage.

[kilgorq]

you can test it by removing it from the back of the carb... it's held on by one 10mm or 8mm bolt. Then either ground the solenoid by laying ot against the manifold and having some one turn the ignition key or hook it up to a 12 volt source.. the pin should retract when the solenoid gets voltage.

Ok the valve checks out good. I also removed and inspected the carb again... It looked OK. SO I reinstalled everything and started over from step one... I got the exact same results. This is acting like it is not getting enough gas in the Idle mode. Is there something else that can cause this besides vac and carberation.

Or is it possible that the carb is just shot... I have never run across a non-rebuildable carb. If the fuel pump was bad wouldn't you notice the problem when accelerating and not at idle.

I also noticed on this latest try that the jerking that I was talking about when running down the road happens at 3000 to 4000 rpm.

Also another strange to me characteristic is that when it actually Idles it will rev itself up from 1200 rpm to 1800 rpm then drop back down on its own. Then do it again.

[A20A1]

So you removed the choke parts? Did you plug that port on the choke puller... it's partly fed by an vacuum line drilled in the carb.
I'd say if you removed the choke dumped the fast idle as well... and get rid of the thermovalves... that way you can rule them out as problem causing.

[kilgorq]

So you removed the choke parts? Did you plug that port on the choke puller... it's partly fed by an vacuum line drilled in the carb.
I'd say if you removed the choke dumped the fast idle as well... and get rid of the thermovalves... that way you can rule them out as problem causing.

I left the choke on the carb to take advantage of only the electric part of the choke. I removed all of the vac lines to it and the thermovalves and capped the choke puller. I presently have 2 vac lines hooked up The Idle valve and the acc pump port. I also have the ABC box hooked up. (Forgot what it is called.) I unhooked the Power brake booster and did not see a differance so I hooked it back up but other than those vac items there are no more. I diconnected every vac line except for the essentials. I sprayed around the base of the carb, every vac port and arount the intake gasket with carb cleaner and did not notice any engine performance changes.

Also if I remiove any of the vac lines it will die. I am 98% sure that it is not a vac leak.

[kilgorq]

So you removed the choke parts? Did you plug that port on the choke puller... it's partly fed by an vacuum line drilled in the carb.
I'd say if you removed the choke dumped the fast idle as well... and get rid of the thermovalves... that way you can rule them out as problem causing.

Found the problem I think... The PCV Was stuck open. But the car still desiels really bad. It will blow off the vacuum lines and caps at times. But I got it to idle down to 800 RPM decently but it still stumbles and then catches itself. It also dies if I corner hard. Is this the carb still or do I need to start looking elsware. Catalytic converted or timing belt and distributor timing. Also the muffle is broken off and I have black soot on my bumper from the exhaust. And when the secondaries kick in it wants to die. I Found another carb to try (Condition Unknown)

[A20A1]

hmm blowing off vacuum caps?
Well now things have changed... definately keep the check valve on #6.

As for a fix to your problem(s)
might be that you have serious blow-by or your timing belt is off or a valve is not set right or not sealing right... so I guess check the timing belt and the crank alignment for now. Then recheck the ignition timing.

[FyreDaug]

Whats the latest on this?

[kilgorq]

Whats the latest on this?

I ended up replacing the carb... It had a internal problem with the idle circuit. The backfiring and blowing off the vac caps. Was due to the PCV Valve and having the Idle set way high and actually being way off of the idle circuit.

[A20A1]

Thank you for the update.