87 5.9 idles high until you goose the throttle

[Bobby8008]

Hello all. I have an 87 5.9 idles high until you goose the gas pedal. Most of the time it will idle down by itself after it reaches running temp but not always. I had to smog it this year and it did not pass due to high idle. I tried to tell them to goose the peddle but he said it had to be repaired for the smog. The shop charge me to diagnose the high idle but all they did was adjust the idle down. Problem is now it idles too low when cold and runs like **** until it is fully warmed up. I'm a decent mechanic on fuel injection I just don't know anything about carbs. Any help would be greatly appreciated if for no other reason but to take the right diagnoses back to the shop and attempt to get my 150 back or at least let them know there the idiots not me. All they had to do was Rev the damn thing it always idles down.Oh yeah I'll also need to know how to readjust the idle back. Thanks in advance. Oh I'm pretty sure it's not the issue but it's in an rv with 4 6v batteries stepped up to 12v 1 12v deep cycle for the solar power but also charges from the alternator along with the car battery. The alternator did have a heavy load on it that day. I'm pretty sure the carb doesn't adjust itself to compensate but like I said I know very little about carbs so if there is a magic wireless sensor in there please correct me.

 

[18CrewDually]

Turn the idle screw back up. That has the VE pump right? Make sure the return springs are in place and functioning.

Bosch VE Fuel Injection Pump Adjustment Screws

A - Idle Screw

B - High-Idle Screw

The high-speed adjustment screw on both fuel injection pumps provides the stop for full speed. The high-speed adjusting screws are sealed. Adjustment of this screw must be performed only by an authorized fuel injection pump service center, and then resealed.

Loosen the adjusting screw locknut, (A) and adjust the idle as required.





Ooopps. The above is for 5.9 Diesel. I see now that you have a gas truck. NOT the same. Let me see what I can find for you.
But for what you described is normal behavior for a carburetor on initial startup until it warms up.

 

[Bobby8008]

I appreciate the response honestly I don't know if it has that I don't see anything that matches your pic.

 

[Bobby8008]

These are the only return springs I see seems to be stopped by the other pic

 

[Bobby8008]

I've looked all over this thing this is the only adjustment screw I see other than the idle

 

[18CrewDually]

I assumed you had a diesel so that is what I posted for so disregard. But the high idle at an initial cold start us normal because the choke/high idle is set. Once it warms up it will come down.

 

[RamDiver]

It has been quite a few years since I've had a carburated vehicle but IIRC, with many of them, the high idle would often stick, especially during colder weather.

Again IIRC, kicking them down after a warmup period was commonplace.

I vaguely remember cleaning up the choke spring mechanism to improve this kick-down performance; however, at the least, they usually required the operator to tap the accelerator pedal.

.

 

[czervika]

See if this helps at all.

Quadrajet Carburetor Choke Adjustments are the best way to get instant starting, drivability & MPG!

After a Jet and Metering rod change to get our carburetor we spend the afternoon learning, discussing operation and applying what we learned. Getting the cho...

m.youtube.com

 

[U&A]

Iv got nothing helpful so I figure Id ask what was on my mind.

What the heck did the dang goose do to you man.

Dude over here throttling gooses….. geese’en……goose’en ……

 

[Sherman Bird]

I appreciate the response honestly I don't know if it has that I don't see anything that matches your pic.

A Carter Q-jet clone of the Rochester that was so popular for very long! Doug Roe published a book on all the carbs from Rochester, including the Quadra-jet. If you can find the book, you should get it. All the pertinent information is the exact same! I have that book. I've used it many times to figure out all manner of problems over the years.

 

[turkeybird56]

A Carter Q-jet clone of the Rochester that was so popular for very long! Doug Roe published a book on all the carbs from Rochester, including the Quadra-jet. If you can find the book, you should get it. All the pertinent information is the exact same! I have that book. I've used it many times to figure out all manner of problems over the years.

Been a LONG time since I seen a quad Jet, LOL> Did they not also have the heat activated spun coil on the right side of the carb as U look at it. Mine used to stick all the time and a slight gas pedal hit disengaged the choke to slow down the idle.

All the op needed to do was hit the gas to disengage the choke to throttle down, IIRC, been a long time. Definitely not take it to get smog check till totally warmed up also, IMHO.

(California for U, lol)

 

[turkeybird56]

A Carter Q-jet clone of the Rochester that was so popular for very long! Doug Roe published a book on all the carbs from Rochester, including the Quadra-jet. If you can find the book, you should get it. All the pertinent information is the exact same! I have that book. I've used it many times to figure out all manner of problems over the years.

Had one of em piggies (not Carter made), on my 67 Supersport. Go into WOT and watch the gas gauge drop, LOL. Dat dang choke liked to always stick and I would hit the parts with WD 40 to loosen up also.

 

[Dean2]

Another one post wonder. Joined on the 25th, last seen on the 26th. Want help but never stick around to pay it back to someone else. Between that and the combative/ungrateful, attitude from so many of these new guys, I have decided to quit answering questions from new posters until they have been around a while and have posted more than "Help ME" cause I deserve it mommy.

I know, many people say I have an uncharitable attitude, others are less charitable than that in their description, but I am getting really tired of the people that expect freebies all the time.

 

[RamDiver]

View attachment 534882
Another one post wonder. Joined on the 25th, last seen on the 26th.

This could be the case but maybe, he's just still slumbering from a tryptophan OD.

I believe I heard that most of the local school boards are still on Christmas break until tomorrow, maybe, he has a hurd of kids keeping him busy this week.

After tomorrow, he's definitely a one-post wonder.

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