42 replies to this topic

[TexanIdiot25]

Yeah a few cans later of carb cleaner, and that's how we found the leaks in the carb base plate, and between the body of the carb and the base. The rest of the lines don't seem to leak.

I have no clue how to richen the CVCC mixture, I think I saw a thread some where.

HMMMM, I wonder if higher octane would prevent it? though, it's missing not knocking..

[Bubba]

CVCC butterfly adjustment- There is a small phillips head adjustment screw at the base of the drivers side of the carb that can accessed with a very long screwdriver angled in from over the valve cover. It simply tilts the tiny rich port butterfly more open or closed relative to the other butterfly valves. I noticed more power with it opened up farther (I believe that was clockwise), but I am a mpg nut so I like running with it closed as much as possible (this seemed to improve my mpg).

I don't know that this changes the mix, it just increases/decreases the amount of rich barrel air flow relative to the primary mix airflow.

[EuphoricBlue]

Did you change the leaking base plate gaskets? (Sorry if you mentioned this before and I missed it) There's no point in messing with the mixture if they are still leaking. You might get things better but it still won't run right. You can cut your own out of a cereal box if you don't have gasket material.

[TexanIdiot25]

Yes, all carb related gaskets that were leaking, were fixed.

I'll adjust the CVCC barrel if I can tomorrow (having a long enough screw driver). Also, just wondering, bad/dying ign coil?

[1985 CRX SI]

Also, just wondering, bad/dying ign coil?

Not my experience. Coils either work or they don't
Jeff

[EuphoricBlue]

It's possible. But I'd expect it to be more RPM depended, than load. (well, and heat but that's with almost anything)

[TexanIdiot25]

I attempted to adjust the CVCC barrel, but not sure if my screw driver could actually turn the adjustment, not quite long enough and it appeared that it wasn't turning the screw. Who knows on that regard. Just to double check, it is the screw that's on the driver's side, low down, facing the valve cover with a spring loaded collar, correct?

Only thing I've changed, to test detonation under load, I filled up from a half tank with mid grade about a day or two ago. My idea being that if it is detonating, then surely putting higher octane fuel could alleviate it. The car never made "knock" sounds under load, but I thought I'd try anyway.

The car was driven at night the next day so there's little to report then(Car is ok at night). Then last night just randomly threw in some Lucas fuel system/injector cleaner I had laying around. Funny thing, today the car was largely trouble free, even in the mid-day heat. Put 70 or so miles on it, only times it would start to miss under load was when it was just restarted. The miss would eventually disappear, and the car could be driven quite fine. I'll fill it with premium to test the theory further, but I'll be curious to see what happens.

This is while delivering pizza, so lots of stop-n-go and fairly aggressive driving (which, of course, means little in the real world, this car is so slow )

[EuphoricBlue]

Did you use any other chemicals to try to clean the carb beforehand? If not, you may have just stumbled onto another issue.

A dirty carb can do all kinds of stupid stuff. Maybe run another can of cleaner through for good measure?

[TexanIdiot25]

Did you use any other chemicals to try to clean the carb beforehand? If not, you may have just stumbled onto another issue.

A dirty carb can do all kinds of stupid stuff. Maybe run another can of cleaner through for good measure?

I used a bottle per tank on the first two tanks, including the drive back here. Just what ever I found at the gas station. I'll throw the rest of the Lucas shit in tomorrow and see how it does monday when I open again.

[Bubba]

I attempted to adjust the CVCC barrel, but not sure if my screw driver could actually turn the adjustment, not quite long enough and it appeared that it wasn't turning the screw. Who knows on that regard. Just to double check, it is the screw that's on the driver's side, low down, facing the valve cover with a spring loaded collar, correct?

There's an older post I made on page 2 where you can reference a pic of the linkage- the rich barrel adjustment screw doesn't have a collar on it. You will need at least a 16" small tipped phillips screwdriver.

http://www.redpepper...e...47380&st=15

Edit- the screw with the collar just adjusts how much the idle bumps up when the AC compressor is activated.

Edited by Bubba, 06 June 2010 - 06:51 AM.

[TexanIdiot25]

If the car falls back into it's bad habbit, I'll adjust it. At a half tank I went a head and filled it with premium for shits-n-giggles to see, and strangely enough it's running good fairly consistently now. Drove quite well today at work, but it had been raining and it wasn't terribly hot out. Only time the car would miss was on the first few miles after restarting it. I open tomorrow and will be driving it in the heat of the day, so hopefully it will keep this up. Maybe it was the carb all along?

I can't complain about being able to get into 5th at ~30 mph, and it seems FE will be better this tank, doesn't appear that it's used as much fuel by the gauge.

Edited by TexanIdiot25, 06 June 2010 - 11:49 PM.

[TexanIdiot25]

Well, I've found the only cause of this whole mess. The car simply doesn't like regular or midgrade fuel. Doesn't make sense to me either, since it's not knocking with either lower octane fues. Last fill up I stepped down to mid grade, and wouldn't you know the miss came back all today during the heat. After work, I stop and top off the half tank with premium again and with in minutes the miss was gone. Still hot outside so I'm not accounting air temp.

I can afford the extra buck or so at a fill up, and the car runs great with it as well. The average on the full tank of premium was 40.38 mpg, a large leap with no driving changes and the car's highest average.

[jsgprod]

Also, just wondering, bad/dying ign coil?

That's where I'd put my money. Especially if it's misfiring under a load and after the mention of the higher octane fuel seemingly 'fixing' it. Higher octane fuel burns slower, it's easier for the coil to ignite it. Also when you plugged the vacuum line it lessened the amount of ignition advance, it was easier for the (evidently) lessened output of the coil to fire the mixture.

I've had to replace two CRX coils over the years for similar symptoms. One was on my old 1.3l street car and it exhibited similar intermittent problems to yours. Until I barely got it home one day. The other was on the race car and it worked fine without any load on it, like sitting in the pits or free revving it. The minute it got into the mid range of the powerband and there was more than 50% throttle applied...it developed a misfire. New 18$ coil later, problem solved.

Looked on Rockauto this morning and they have some closeouts for about 21$

Jay