so I've sprayed carb cleaner around the base of the carb before without hearing any throttle increase, ill try spraying in more places. I replaced the mechanical fuel pump a couple months ago as well.letank wrote: ↑Tue Jul 05, 2022 4:25 pm Spray carb cleaner or WD40 at the base and around the base of the carb... any vacuum leak with create a idle speed change. Look for loose vacuum lines... or questionable base carb gasket
As for the warm restart... usually it is vapor lock or a weak fuel pump, our mechanical fuel pump leaning against a warm engine is not the best set up with the reformulated gas containing ethanol...
Post edit: as said below, the vacuum gauge is the best tool... I have one install permanently inside on my dash... as for values for the 2150, my sea level is a steady 18" and 20" when the choke is on!
Yes the 2150 is the stock motorcraft carburetor.Stoney wrote: ↑Wed Jul 06, 2022 5:36 pm so I've sprayed carb cleaner around the base of the carb before without hearing any throttle increase, ill try spraying in more places. I replaced the mechanical fuel pump a couple months ago as well.
I don't know much about carbs at all, I've heard of vapor lock and have a basic understanding of it, is there any way to prevent it? though im not sure what you mean by 2150, is that the carb?
There are no stupid questions! We all... at least I have done all the mistakes!
no, im not sure at all. I don't know much about those Trannys. I'll look some stuff up, but any links would be greatly appreciated.devildog80 wrote: ↑Thu Jul 07, 2022 7:04 pm The TH400 has a vacuum Modulator.
Are you sure that vac connection is good?
Also I've noticed that if im accelerating hard, like when im coming onto the highway, the transmission sounds and feels like it goes into neutral for like, half a second, then I get power back. it'll do this a couple times until I get to speed or stop accelerating so much, could that also be from a bad transmission modulator?letank wrote: ↑Fri Jul 08, 2022 5:28 pmThere are no stupid questions! We all... at least I have done all the mistakes!
yes the trans modulator can leak a bit, it will show as a large exhaust white smog upon start up.... as the trans fluid is sucked up the carburetor by the vacuum control hose!
the stalling in reverse could be an indicator -COULD- of a lean mixture, I had that happened on a project... on cold morning it was impossible to drive in reverse... and indeed, it had main jets of 50, stock is 55 for the motorcraft 2150... so you have a Holley... you can always fiddle with the mixture screw(s) and enrich the mix by 1/4 to 1/2 turn... yes it is not the proper way... but I am the shortcut guy
check your transmission fluid level, wheel choked, on level ground, trans in neutral and at operating temperature - which is about 5 to 10 miles of driving depending on outside temp- and having shifted to all gears including reverse, and back to neutral, engine at idle speed.Stoney wrote: ↑Fri Jul 08, 2022 5:45 pm Also I've noticed that if im accelerating hard, like when im coming onto the highway, the transmission sounds and feels like it goes into neutral for like, half a second, then I get power back. it'll do this a couple times until I get to speed or stop accelerating so much, could that also be from a bad transmission modulator?
i just replaced the transmission gasket, so im 99.9% sure that the fluid level is fine, ill check again thoughletank wrote: ↑Sat Jul 09, 2022 9:06 amcheck your transmission fluid level, wheel choked, on level ground, trans in neutral and at operating temperature - which is about 5 to 10 miles of driving depending on outside temp- and having shifted to all gears including reverse, and back to neutral, engine at idle speed.Stoney wrote: ↑Fri Jul 08, 2022 5:45 pm Also I've noticed that if im accelerating hard, like when im coming onto the highway, the transmission sounds and feels like it goes into neutral for like, half a second, then I get power back. it'll do this a couple times until I get to speed or stop accelerating so much, could that also be from a bad transmission modulator?
I was considering just replacing all those hoses anyways and now that you're saying it it definitely sounds like the way to go. Do they have vacuum hose kits? or do I just buy so many feet to cover the whole truck?1978J10REDWHITE wrote: ↑Mon Jul 11, 2022 2:19 pm I would isolate everything that is connected to the intake and get it down to the carb only, and see what they produces such as smooth adjustable idle etc.
This is a lot of TS type work to verify things Like was said the TH400 Modulator , or the EGR or a poor intake gasket etc. your rig has way too much on t to do it piece by piece, SHOTGUN it~!
A healthy engine should have 14~18 Intake vacuum (Hg) around or at near idle!
The Carb air fuel mix screws and the timing will affect this both in a certain combo.
Need to First get those two things to achieve the best highest idle vacuum numbers obtainable.
Your PCV / EGR network hose-tubes connections is a "controlled "Vacuum LEAK" system so it is possible a poor seal on the vlv covers and the hoses connected somewhere will allow extra air to get into the intake making this lean High idle condition.
Definitely need to VERIFY every single hose in your entire engines connections and any intake switching port control devices, etc, they are NOT cracked leaking.
Hose clamps etc.
All three of my rigs , 76,78,79, I shotgunned ALL the rubber tubes, hoses in the entire cab then under dash, 100% Everything!
There were plenty of bad pieces and so to TS this piece by piece was a complete waste of time.
Once you get the best #'s from Carb idle screw Adj and timing, then introduce things one by one.
Including verify the small 7/32 I think is the size, metal vacuum tubes that might be on Passenger side , which branch down to the Transmission.
Those fail and get clogged too!