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MagmaJct · 04-11-2009, 12:37 AM

Oh my gawd, I'm a idiot. Well, sort of. I'm an idiot because I said in my original post, that the idle was correct. But I'm not an idiot about how the automatic transmission response to RPM, because I really didn't know! I'll break this post down:

See, for some reason, I remember setting the idle when I first got the truck from my uncle after he died. But I've had this problem with the the truck wanting to go since I got it.

A few days ago the truck started well, considering the choke wasn't quite adjusted correctly. After about 30 seconds, the engine stalled at idle. I tried to restart it, but it wouldn't. The engine flooded so bad it hydro-locked the engine and fuel was leaking out of the throttle shaft and pooled on the outside of the intake manifold.

Turns out one of the needle valves stuck, so I had to take the Carter AFB carb apart and solve the flooding problem. In the past, the stock carburetor was stolen, and my uncle replaced it with the AFB. Turns out the original carb had a fuel filter in its inlet, the AFB has strainers on the needle valves.

After getting the carb back together, I decided to dial it in more precisely. I found the idle it supposed to be 550 RPM in Drive. So I hooked up my tachometer, and even though it wasn't steady, it was around 1000 - 1200 RPM!

I don't know why I remember setting the idle in the past, but it wasn't set now, and I've always had this problem. Could it be it *couldn't* be set at idle because it would stall? I have made a lot of "small" repairs to this engine, so it's possible I couldn't get a stable low idle when I tried a year ago!

So I started the engine, chocked the wheels, and set the parking brake, and put the transmission into Drive. I adjusted the idle to about 550 RPM as the sticker says. As I lowered the idle, I "felt" the truck "relax" off the brake and chocks a bit, startled me. (Yes, I'm nervous setting idle with the tranny in Drive.)

I increased the RPM again, and I "felt" the truck "move" forward a bit against the brake and chocks.

I've only ever owned vehicles with manual transmissions. I understand the basics of an automatic transmissions, but I didn't realize there was a sort of "cut in" RPM.

When I took the truck on a test drive, I found that I could stop MUCH easier, and that at idle, I can relax my foot a bit and not worry about rear ending the car in front of me. Interestingly enough, the engine no longer feels as if it wants to stall.

I suspect the high idle was causing the torque converter to "kick in" putting a strain on the engine, causing it to act as if it wanted to to stall.

The engine is quieter to! (Duh!)

Thanks everyone for your help.

04-11-2009, 12:37 AM	#12
MagmaJct Registered User Join Date: May 2008 Location: Mesa, AZ Posts: 281	Re: Transmission wants to go!! Oh my gawd, I'm a idiot. Well, sort of. I'm an idiot because I said in my original post, that the idle was correct. But I'm not an idiot about how the automatic transmission response to RPM, because I really didn't know! I'll break this post down: See, for some reason, I remember setting the idle when I first got the truck from my uncle after he died. But I've had this problem with the the truck wanting to go since I got it. A few days ago the truck started well, considering the choke wasn't quite adjusted correctly. After about 30 seconds, the engine stalled at idle. I tried to restart it, but it wouldn't. The engine flooded so bad it hydro-locked the engine and fuel was leaking out of the throttle shaft and pooled on the outside of the intake manifold. Turns out one of the needle valves stuck, so I had to take the Carter AFB carb apart and solve the flooding problem. In the past, the stock carburetor was stolen, and my uncle replaced it with the AFB. Turns out the original carb had a fuel filter in its inlet, the AFB has strainers on the needle valves. After getting the carb back together, I decided to dial it in more precisely. I found the idle it supposed to be 550 RPM in Drive. So I hooked up my tachometer, and even though it wasn't steady, it was around 1000 - 1200 RPM! I don't know why I remember setting the idle in the past, but it wasn't set now, and I've always had this problem. Could it be it couldn't be set at idle because it would stall? I have made a lot of "small" repairs to this engine, so it's possible I couldn't get a stable low idle when I tried a year ago! So I started the engine, chocked the wheels, and set the parking brake, and put the transmission into Drive. I adjusted the idle to about 550 RPM as the sticker says. As I lowered the idle, I "felt" the truck "relax" off the brake and chocks a bit, startled me. (Yes, I'm nervous setting idle with the tranny in Drive.) I increased the RPM again, and I "felt" the truck "move" forward a bit against the brake and chocks. I've only ever owned vehicles with manual transmissions. I understand the basics of an automatic transmissions, but I didn't realize there was a sort of "cut in" RPM. When I took the truck on a test drive, I found that I could stop MUCH easier, and that at idle, I can relax my foot a bit and not worry about rear ending the car in front of me. Interestingly enough, the engine no longer feels as if it wants to stall. I suspect the high idle was causing the torque converter to "kick in" putting a strain on the engine, causing it to act as if it wanted to to stall. The engine is quieter to! (Duh!) Thanks everyone for your help.