Lean Misfire or...?

[idower]

My 1988 Grand Wagoneer is not running great.
In the morning it wants to stall at idle and it'll stall out if I floor it. As it warms up it runs better but when I step on it it pops out the exhaust (possible lean misfire). It is a new 360 long block with a new Motorcraft Carb rebiult by Holley (6,000 miles on engine and carb). I covered the mouth of the carb to see if the motor would run better (symptom of vacume leak) and it didn't. There isn't any odd colored smoke either.

These symptoms tell me that the engine is running lean. I checked the choke and it is operating properly. I suppose that even though the carb was supposed to be "rebiult" it still could be the culprit.

What could my problem be?

[Veepster]

hhhmmmm...lets start with the basics..

Is the timing correct? are you SURE that all the vacuum lines are connected correctly?

the best way to check for a vacuum leak is to spray carb cleaner around the intake in the carb base and inccluding all connections around the carb, if there is a vacuum leak the idle will go up when you spray carb cleaner around the leaking culprit..

is your 360 stock? if so I doubt a lean condition, unless the guys who rebuilt the carb changed the main jets......if you want to check pull the top off the carb and remove a main jet and check the size...it should say 48 on the side of the jet.

that should get you started on diagnosing the problem



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Peace.............BartG

the Green Flash!
78 Chero
360 2v, 400 QT with low

4" skyjacker
33x12.50 BFG KO's
Thorley headers, 3" exhaust
Infiniti power leather seats
50%LuxuryCar,50%Tractor

[ClarkGriswald]

Both 2150 carbs I have for my 88 GW had 55 jets in them and I had to drill em out with a #53 wire size bit.. now it runs great

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88 Grand Wagoneer
D44's front\rear
Warn 20990 Lockouts
AMC 360
TF 727
NP 229--Soon to be replaced by an NP208 that currently inhabits my kitchen.

"I came, I saw, I typed some stuff!"

[Veepster]

oopss...let me clarify, all the 78 Jeeps(big and small) came with a 48(with a few exceptions that came with a 47 or a 49)

that is per the TSM...

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Peace.............BartG

the Green Flash!
78 Chero
360 2v, 400 QT with low

4" skyjacker
33x12.50 BFG KO's
Thorley headers, 3" exhaust
Infiniti power leather seats
50%LuxuryCar,50%Tractor

[idower]

I have already covered every possible source of a vacume leak with my propane wand. I sprayed the carb base, the intake manifold gaskets, as well as every vacume port/switch/hose on the intake. Not once did the idle increase. I then removed every unnecessary vacume line and I capped off the ports, same problem. To top it off the timing is good.

I am really lost here.

[RudyC]

With the engine OFF. climb up on the motor and look down the carb ventries. Use your hand to give some gas, just about a 1/4 throttle as see if you get a GOOD squirt of fuel from the nozzels. this keeps it from stalling when you give it gas. as for the idle problem adjust your idle mixure with a vacuume guage.

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AKA RUDY79.
1979 WAGONEER, 360, TH400, Q- TRAC. 3" ADD A LEAFS, 31" MUD T/A'S (PEP BOYS CLONES).
" Go farther, it only breaks on the street"