Running lean?

[George W.]

Re: Running lean?

Okay,
New dilema.
engine cold and on fast idle--cold enrichment 1st stage
lever leaves power stop to soon.
I've checked and the enrichment valve in the choke housing and it is still closed. So it (the enrichment diaphragm is not getting any "extra" vacuum signal).

so why is the lever moving towards the economy stop to soon?

I do not have any way to check the signal "boost" valve.

I've tried setting the choke both 1 1/2 notches rich and lean, and neutral with no noticeable effect.

????

thanks,
g

[Jim L.]

Re: Running lean?

Okay,
New dilema.
engine cold and on fast idle--cold enrichment 1st stage
lever leaves power stop to soon.

What do you mean by "too soon"?

FWIW, on my '60 which has a 7320 unit, like yours, I've got the first stage of cold enrichment disabled (fast idle still functions, though). This means the ratio lever will transition to the economy stop as soon as the engine starts.

I've found through measurement and experimentation, that even for 40F cold-engine starts, the engine will reliably see an air/fuel ratio less than 15:1 within 60 seconds of starting. That's rich enough for the car to be driven.

Worst case on a really cold morning, I might have to start the engine two or three times for it to want to remain running. Not a big deal to me. The alternative is, in my opinion, worse. As designed and manufactured, the cold enrichment mechanism will keep providing a rich mixture to the engine for several minutes after it really, really doesn't want it.

So, given the other matters you are addressing, my suggestion is to forget about the cold enrichment mechanism. If you plan to have your car judged someday, you can eventually work on getting it dialed in. Just not now. It's not that important.

You've noted that the FI unit was recently rebuilt. Have you thought about asking the rebuilder for his help? Since he knows the unit better than anyone, he probably has some suggestions.

Jim

[George J.]

Re: Running lean?

George, I think you've eliminated the ignition system. If you've only got a trickle when cranking, something is wrong with the unit. Like Jim said, I'd call the rebuilder.

George

[George W.]

Re: Running lean?

Morning Jim,
Up till now the lever stayed on the power stop while in first stage enrichment.
i was going by the information in the ST-12 service guide that states such.
if it's not a problem, I'll move on.
Thanks for the info.
I sent you a PM
G

[George W.]

Re: Running lean?

Okay,
now have engine starting when hot or cold.
now engine will not idle when hot?
???

[John D.]

Re: Running lean?

George, Your original post months ago was because of a repro fuel filter that contaminated the FI unit. So you disassembled the unit to clean out all the dirt/epoxy etc.
I have not been following all these posts but did read one of yours that said you have to "sneak" up on the acceleration or reving.
If your unit has a thumbtack style spill valve then I am going to guess that the thumbtack is dislodged from the nail and that's the cause of poor acceleration.
Look in the ST-12 manual for an illustration (poor at that) of the thumbtack style spill valves.

The '097 cam you have appears to be questionable. Some might use the word suspicious. My 63 FI car has a Speed Pro 097 cam. Puts out 19" at 900 RPM.

Appears your may have dirty nozzles also., That may account for the radical heat readings.
Notice how nice the 100LL is for hot starting. Puts the ethanol to shame.
Since you have had the FI unit apart several times I suspect it has some issues going on. Now I am not saying that to be detrimental to you George. Just guesing there is something going on that should not be.
Ignore the info in the shop manuals about adjusting the choke covers by the notches like in the old days. Remove the felt filter in the choke housing. When the car is ice cold adjust the cold enrichment cover by turning it clockwise so that the power boost pin (big pin closest to the fender) is about 1/4 depressed. Then using a good batter charger that puts out at least 12 Volts (not all do) test the choke assembly independent of the car to rest assure the lever inside the housing is rotation counter clockwise and depressing the small pin (enrichment pin) Then put the felt filter on.
QT: I have a flat screen TV monitor. I blew up your pic 400% and see that the windshield washer fitting has a rubber hose on it. Hopefully you have that rubber hose plugged up. Other wise a huge vacuum leak.
Put the one piece base gasket on instead of the individual leg gaskets (no good for judging). JD

I see my pal Lockwood has other advise for the cold enrichment cover. Since old JD gets involved with so many NCRS restorations that have to go thru ops and maybe PV the "choke" has to work or you fail PV.
Race cars in the old days didn't have the choke cover on. They had a crude affair that held the enrichment pin in all the way. When they started up they have to be started numerous times to keep the engine running. Today a lot of those restored race cars aren't actually race so when I work on one I hook the choke back up.
But the choke isn't your problem anyhow. JD

[George W.]

Re: Running lean?

Hi John,
Thanks for chipping in.

George, Your original post months ago was because of a repro fuel filter that contaminated the FI unit. So you disassembled the unit to clean out all the dirt/epoxy etc.
---Yes, think that is cleared up now; thanks for your advise.

I have not been following all these posts but did read one of yours that said you have to "sneak" up on the acceleration or reving.
If your unit has a thumbtack style spill valve then I am going to guess that the thumbtack is dislodged from the nail and that's the cause of poor acceleration.
Look in the ST-12 manual for an illustration (poor at that) of the thumbtack style spill valves.
--------Geese, I hope not. I just had the unit off the car this past week and checked the screen under the spill valve for debris. Wish I had looked deeper and checked out that valve. (screen was clean)

The '097 cam you have appears to be questionable. Some might use the word suspicious. My 63 FI car has a Speed Pro 097 cam. Puts out 19" at 900 RPM.
----The only thing I'm thinking that could be wrong is the valve lash settings. I set them cold when assembling the engine. Then checked them when the engine was hot, but, I did this with the engine off using the #1 and #6 TDC method as when cold (12 intake, 18 exhaust). I've since read Duke's paper on setting these and am concerned. Would a little off on the settings create such a difference in vacuum? Or is more likely that the cam grind is off?

Appears your may have dirty nozzles also., That may account for the radical heat readings.
----Did a flow test this week and all nozzles clean. Don't know what changed, but since re-assembly, heat ranges are much closer together (400-500)

Notice how nice the 100LL is for hot starting. Puts the ethanol to shame.
---Super cool stuff! As it would happen, there is an Air Park just 3 miles from me. I did not know that anyone can drive in there 24/7, put in your credit card and get Av gas($5.10 x gallon).

Since you have had the FI unit apart several times I suspect it has some issues going on. Now I am not saying that to be detrimental to you George. Just guesing there is something going on that should not be.
----The majority of my work on the unit revolved around cleaning/flushing/more cleaning. I did change out the "good Guy" spill valve, and slightly re-routed the main signal line that was rubbing both the fuel delivery line and was pushing the fuel line from the engine fuel pump into the valve cover. I don't like lines touching other lines. I did not change any settings other than on the enrichment diaphragm (found that it did not have the .004 clearance).

Ignore the info in the shop manuals about adjusting the choke covers by the notches like in the old days. Remove the felt filter in the choke housing. When the car is ice cold adjust the cold enrichment cover by turning it clockwise so that the power boost pin (big pin closest to the fender) is about 1/4 depressed. Then using a good batter charger that puts out at least 12 Volts (not all do) test the choke assembly independent of the car to rest assure the lever inside the housing is rotation counter clockwise and depressing the small pin (enrichment pin) Then put the felt filter on.
---Okay, thanks for the tip/instructions.

QT: I have a flat screen TV monitor. I blew up your pic 400% and see that the windshield washer fitting has a rubber hose on it. Hopefully you have that rubber hose plugged up. Other wise a huge vacuum leak.
---Yes, it's plugged. I did not want to go through the wiper washer canister in case there was a leak there.

Put the one piece base gasket on instead of the individual leg gaskets (no good for judging). JD
----Got it yesterday; thanks for getting it out so quickly.

I see my pal Lockwood has other advise for the cold enrichment cover. Since old JD gets involved with so many NCRS restorations that have to go thru ops and maybe PV the "choke" has to work or you fail PV.
Race cars in the old days didn't have the choke cover on. They had a crude affair that held the enrichment pin in all the way. When they started up they have to be started numerous times to keep the engine running. Today a lot of those restored race cars aren't actually race so when I work on one I hook the choke back up.
But the choke isn't your problem anyhow. JD

---Yes Jim and others have been generous with their time and helpful knowledge.

Right now I'm trying to figure out the hot idle problem. I don't know if it a lean or rich situation. Or???

Thanks again to all,
G

[George W.]

Re: Running lean?

Plugs look dark, so maybe running rich now?

Headed off for a few days of R & R.
Gonna let it rest for a week.
G

[George W.]

Re: Running lean?

Okay,
I guess I give up.
Is there anyone near San Antonio, Texas who I can hire to come out to my shop and figure out this injection unit?
Thanks for any leads,
George Wright
210 748 4693
geopar@gvtc.com