cshaw07

iTrader: (14)

I bought an 85 GSL off of forum member jlewis just over a month ago. It had a sterling carb on it he bought new in 8/09, but it was dirty, and a rb exhaust - the muffler (has a fart can). Since i got it I: changed gear oil, trans oil, engine oil, all hoses, all belts, thermostat, plugs, wires, cap, rotor, antifreeze, fixed coolant leak, changed fuel filter, added a fuel filter, relocated FPR, removed the rest of the AC, removed PS pump and lines, brakes, ball joints, tie rod ends, LCA bushings, etc, etc, etc.

Found a few vac leaks and fixed them all. CAR HAS NO VAC LEAK, IVE CHECKED 15 TIMES, THEN 15 MORE. LOL Car still wouldn't idle. It had a few gallons of bad gas in it that i didnt know about. The fuel gauge read empty and PO said it was empty so i believed him. Got it running and took it to the gas station and it only took a few gallons. I figured the rough idle was maybe due to the little bit of bad gas, so i drove it until it was almost empty, changed fuel filter again, and put fresh gas in it. Still wont idle.

I then pulled the carb apart and cleaned and checked everything very very closely. It was pretty dirty, but not horrible. I pulled out all the jets and air bleeds, including the 4 fuel jets in the bowls and cleaned them well. I pulled out the two check ***** and weights as well and cleaned them and their passages. This carb is spotless. I also checked the float levels and they are in spec, fuel in the sight glasses right in the middle on both bowls. Fuel pressure is set at 3 on my gauge (carter pump, holley regulator) any more and it wants to fill the bowls too much. The base timing is perfect, the coils test perfect, the ignitors are working, I'm getting spark to all plugs. What gives? It will idle at 1500 for a while then die. If i drive it and come to a stop i have to feather the gas or it will die. It drives really well and the plugs are a decent color. Running a bit rich, plugs weren't wet but were darker than ideal. I tried blocking off all of the carb spacer ports and the brake booster vac line to rule out any leaks in the booster or the vac pots on the dizzy but no dice.

Here is a video:

I didnt touch the gas, if i set the idle any lower than that it will die. It idles at 1500 for a few, but eventually will die.

Sorry for the book, but i feel like i have tried everything. The PO didnt ever touch the carb, only put it on the car. The linkage is working fine and the throttle snaps closed when you let it go like it should. The throttle and choke cables arent binding and nothing is holding the linkage up.

I am out of ideas.

cshaw07

iTrader: (14)

oh, and ive searched and searched. Seems a few people have my problem.

Example:
https://www.rx7club.com/showthread.p...ight=high+idle

but cant find answers. wonder if he fixed his ^

Kentetsu

Any chance you got the fuel jets swapped around (primary Vs. secondary)?

Gasket installed correctly (not upside down)?

When it dies, are the bowls empty? If not, are the plugs covered with soot/fouled?




.

cshaw07

iTrader: (14)

fuel jets are in proper places, gaskets are perfect, and the bowls aren't empty when it dies. The plugs aren't that nice caramel brown color a good running engine would have, but they aren't fouled and aren't wet, just a little dark.

Thanks for your reply, i know you know your stuff with the sterling.

cshaw07

iTrader: (14)

also, like i said, i dont really trust my fuel pressure gauge. i did have someone watch the fuel levels when i reved the car (in neutral, no load) and all the way up to 7krpm the fuel levels both stayed at exactly half. I dont think my pressure is too high, the reg is almost all the way out.

The car runs and drives great. Decent low - mid, awesome power when the secondaries open up. Just this idle issue.

cshaw07

iTrader: (14)

Also, (trying to give all i can here!) the car will start up in the morning with out the fast idle rod or me needing to do anything other than get in and turn the key. Takes maybe 2 seconds of cranking (usually) and she fires right up, just wont stay running unless i give it some gas until its warm.

chris_g

iTrader: (29)

I wish you luck Curtis! It sounds just like the issues I was having. Amazing throttle response, power, everything, when running. Then, just like you, I couldnt get it to idle and it would just die after a little while.

You already know what I did though...replaced it with a stock -emissions Nikki :/

If you get it figured out, please post up. Id like to figure it out, too!

In my thread, Jeff (I think) said he had to change metering blocks in his to get it to work. I guess my terminology is poor as I didn't know ours had them? Also, I was told to try a 79 intake manifold to see if that helped.

Is your intake completely stripped?

j9fd3s

iTrader: (3)

i had a friend (zyrano) drop off his car with 1.5 sterlings (#1 had a bent throttle shaft, #2 looked fine)

i put #2 on an it ran, but no idle. i could spray a little brakeclean in the carb, and it would run, so it was lean. i pulled the top off, and checked all the passages and stuff, and they were all clear.

so step 2 was to pull #1 apart, and swap its metering block (the carb has the iron base, with the throttles, the top which is the top, and the metering block which holds all the jets and stuff), and put that into #2, and this fixed it.

at the time it fixed it and that was fine, but i really didn't know WHY it fixed it. i thought about it and i have a couple of ideas. since the idle passage goes from the metering block to the throttle block, the seal between the two of them matters. idea #1, the gasket was bad/incorrect/upside down. or the metering block wasn't flat where it needed to be flat.

chris_g

iTrader: (29)

I see what you're saying now! The main body?

Im used to metering blocks being the spacer between the bowl and the body on Holleys, Edelbrocks, etc.

cshaw07

iTrader: (14)

i found my problem tonight. :/ vac leak at the primary throttle shaft what makes the seal there? i have a spare nikki that i pulled apart and it looks like there is a push in plastic/rubber piece in there? could be wrong though. I'd like to be able to swap throttle bodys and keep sterlings throttle shafts, but i dont know if the shaft is the problem or not (can i tell somehow?). I wont get to tear it apart until probably Wed now so its going to be killing me unitl then. im just wondering what is the best idea? im not giving up on my sterling lol

j9fd3s

iTrader: (3)

oh yeah, lol. i've no idea why i'm calling it a metering block, except that its block shaped and has all the fuel metering parts in it, its probably called something else in the FSM....

cshaw07

iTrader: (14)

7aull

iTrader: (2)

nothing to contribute, but a tip o' the hat for perseverance! well done.
Got a brand-new Sterling (seriously, brand new modded carb) sitting on my bench awaiting install, so its interesting reading here. Thanks for posting updates.

Stu Aull
80GS
Alaska

CobraStngSVT

Yes, There is a plastic insert that creates a seal on the shaft.

cshaw07

iTrader: (14)

The plastic insert is there, but not making a seal lol in my other thread they suggested a type of thick lubricant to seal the leak there. Any other ideas?

Thanks for all the help!

cshaw07

iTrader: (14)

checked plugs last night, perfect caramel color. checked compression (used piston tester guage with valve removed) front rotor 3 pulses up to about 75psi, rear rotor 3 pulses up to about 75psi warm engine. Engine is pulling about 15in vac at 1500rpm and under that the vac guage bounces around and the car dies. timing is set to stock. it almost has to be the carb i checked for vac leaks again just for giggles and there is none. why would the carb be doing this?

cshaw07

iTrader: (14)

also, the a/f mix screw doesnt do much, but if i screw it all the way in it will eventually die like it should. Im about to toss my other carb on it to test, if it works im going to tear all the sterling parts out of this sterling and put them in my other main body.

So how do the venturies come out?

cshaw07

iTrader: (14)

https://www.rx7club.com/1st-generation-specific-1979-1985-18/how-seal-nikki-carb-throttle-shaft-992415/

i went through pretty extensive things to fix all vac leaks.

cshaw07

iTrader: (14)

"Like most carburetors, the Nikki idle circuit is milled into the throttle body."
-sterling

wonder if just my idle circuit is fubar'd

cshaw07

iTrader: (14)

i could try this.



But id rather wait till last resort...


car is too nice to light on fire and laugh like i've lost my mind.



(photo cred: chris juliano photography)

inuissus_cendi

I wish I had more info to give you from when I had this problem, but I don't think I ever fixed it fully before I sold my Sterling.

After I sold it I garaged my car for over four years, but just now got a rebuilt stock Nikki put back on and all the emissions reinstalled to pass CA smog. About 60 miles down the road I ran into a similar problem, but even more pronounced. It ran pretty smooth from 1000prm up but would choke and die if it dipped any lower.
It ended up being a massive internal vacuum leak in the #2 Anti Afterburn Valve (tough to detect from the outside). I don't even remember if the Sterling has one, but I thought I'd throw it out there as a suggestion. This thread covers the problematic hose, but mine (on the stock nikki) was a collapsed valve.
https://www.rx7club.com/1st-generation-specific-1979-1985-18/hose-question-750125/

cshaw07

iTrader: (14)

thanks for your reply, i was beginning to think rx7club didn't like me anymore!

I dont have that hose or the anti afterburn valve at all. Nor any external vac leaks. Im not sure if there is a way to test for internal vac leaks or not, or what would even cause them on a bare bones sterling carb. What doesnt make sense is that "the idle circuit is milled into the throttle body" but yet another guy had this same problem and he fixed his by swapping main bodies. Ive had this carb (nikkis in general) pulled apart and looked at and cleaned so many times i could make one in my sleep! why i cant make it idle is beyond me. It's got to be the carb, everything else has been tested and working.

Jeff20B

iTrader: (13)

If the throttle body is from a different year than the main body, it will have idle problems. Sterling made these kinds of swaps (mistakes) in the early days and has since figured out the problem. So I suggest swapping throttle bodies from each year group until it idles. That'd be 81-82, 83 by itself, 84-85. So you have three choices.

Edit: I gotta say I ran into this problem on Hitachis as well. I had this one carb that just didn't idle but everything else was fine. I had swapped the throttle bodies because the original was water damaged. I left it on a 13B I sold last year. It was good enough to get it running but the new owner swapped in a Nikki (the manifold already had the Nikki stud pattern) and all is well now.

j9fd3s

iTrader: (3)

oh really? that does explain a lot... the "bad" carb i had like this was a 2009 build!

j9fd3s

iTrader: (3)

i had that happen to me too! the air pump came apart and jammed the valve.