My buds g/f has an 84(85?) mustang(I know) I just gave a tune up to an it's still bogging at light throttle. from the looks of it this has been it's 1st ever tuneup (98k miles),, the plugs looked fine, the car has never been driven real hard,, oil is clean,, old plug were rusty on the outside but normal clean inside,,, looked like a few were burning lean (kinda whitish electrode) it has the factory holley 4bbl on it,, the accel pump squirts good looking at it. It has a kinda of bog/misfire at cruising speed anything below 1800 rpm (doesn't happen when choke is on tho) It pulls great (for a ford) light acceleration is good too. I haven't much of the foggiest about carbs,, but could this be the culprit ? I can't get the line to back out to change the fuel filter. Timing is 8deg, emission lable says it sould be 10 ,,can a motor be that sensitive to timing ? I just need to get this thing running right and sold so I can get my 'bird out of the garage (long story). Any help/ideas are greatly appreciated. Thanks in advance guys
And also,,,it's a PITA to start cold,, choke on it runs high idle,,smooth,,,but touch the gas to rev it and it dies,,let off it goes back up to high idle again. It takes a min or so of pumping the gas to get it to stop doing that. I don't know about it ever backfiring,,, cold the power valve in it be shot ? I've heard holley's are famous for that,, would this one built for ford have the same prob ?


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<A HREF="http://anzwers.org/free/gta" TARGET=_blank>87 Firebird
84 Camaro</A>

 

DB,

That's just about right for a POS Holley, regardless of what engine it's bolted on. Sorry, I know some people like them, but I miss the old ThermoQuad Carters, with the hundreds of metering rods, thousands of air bleed orifaces, three or more venturis in every hole, metering wells all over the place, bores that would suck a 454 'Vette hood right through... Ooh! OOH! - Makes me hard just thinking about it! (Guess I gotta get out more often...)

Anyway, I have no doubt that you're running way too lean. All of the symptoms indicate a low bowl level, sticking float (a Holley specialty) and/or plugged inlet filter. Somehow, you have to change the fuel filter. You might have to resort to removing a fuel bowl and cutting a line, but that should be a priority.

Most Holleys have a fuel level inspection plug on the side of the fuel bowl(s). You can remove the plug while the engine is running to monitor fuel level. The fuel should be just at the bottom of the plug opening. The float adjustment is a little tricky. The large screw on top of the adjustment nut is used to lock the adjustment in place. Loosen it slightly, then adjust the nut with an open-end wrench while holding the lock screw in place with the screwdriver. Adjust a little at a time until the fuel is at the correct level, just at the bottom of the port. Hold the wrench and lock the adjustment with the screw. The adjustment direction is logically backward as well - turning the nut counter-clockwise will lower the fuel level, if I remember correctly. Either way, it sucks.

Another hint about POS Holleys - the idle adjustments on the sides of the metering block(s) are not fuel adjustments like on a real carburetor, but are air bleed adjustments. Backing out the screws (open) admits more AIR, not fuel, so the idle mixture gets leaner. This *** -backward approach is just about right for a Ford. This should get you into a bit better operation, and the rest of the adjustments should be relatively normal.

As for the timing, the engin eshouldn't be that sensitive to a couple of degrees retard. If anything, a fairly worn 302 should accept a little more advance without problems. Set it to 10° and forget it.

Finally, when the fuel level adjustment is complete, shut off the engine. Get a large double-faced sledge hammer or splitting maul. Strike the top ot the Holley about three- to four-thousand times, or until the hammer/maul is worn out or the cylinder block is completely compressed into the pavement, whichever occurs first. Get a new hammer/maul and continue striking along the length and breadth of the car until I feel better...

(Just kidding about that last paragraph - I think...)

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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0

 

Wow,,Not only informative,,,but I like that last idea

Thank you much Vader,,,I really appreciate it

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<A HREF="http://anzwers.org/free/gta" TARGET=_blank>87 Firebird
84 Camaro</A>

 

hey, Hey, HEY !!!!!! Calm down Vader..Holleys are one of my personal favorites. I don't know where to start first, the problem or Vader's rant.
First, don't be too anxious to go after the power valve by pulling apart the float bowl & metering block, unless you have alot of free time on your hands. These carbs use unique metering block gaskets, different from other Holleys. In addition, the gaskets contain an adhesive for long term sealability. Downside is it takes forever to get the gasket material removed from the metering block & main body once you pry the carb open. The idle mixture screws are not as Vader described (gotcha) on 5.0L Motorcraft Holleys. They use conventional fuel control (CCW is richer) except you have to fracture out part of the throttle plate to access the hardened steel tamper proof plugs. The electric choke coil is extremely expensive $80 & is probably unavailble at Ford, but maybe available from NAPA. ahhhh where was I??? Oh yeah, the symptoms. Misses or bogs during cruise under 1800 rpm, but accelerates ok at WOT?? If the fuel filter has never been changed, I'll tell you it doesn't have 98K capability. The fuel line uses an inverted flare nut, same as brake lines, & the nut is probably coroded to the line. You have to use a lube penetrant & a back up wrench on the adaptor fitting in th efloat bowl. Other things to go after..meaning access their condition & replace or repair....plug wires, fuel pump, & also check out that mass of wires going from DuraSpark module to the left front of the engine. I'll give this some more thought, but I never had the problem you described...these things are flawless. (Note to self: prepare to duck). BTW Vader..are you thinking Jefferson this Sat?
Regards, FJK

 

FJK,

I'm STILL laughing at the "flawless" comment. So much so, in fact, that my wife came in the office to see what was up.

Thanks for the tip on the Ford/Holley idle mix adjustment. Now that's something else I'll have to try to forget about Fords.

I agree that the filter is a priority, and removing the bowl would be a last resort. But it certainly sounds lean to me. And I don't recall saying anything about the power valve, other than possibly removing the bowl for filter access/removal.

Good point about the potential weak ignition. I assumed that was at least serviceable since the plugs were clean and lightly colored.

Yes, I'm thinking about taking the short hop up to the show Saturday. I know I won't be entering anything, just browsing for ways to spend more cash. Weather notwithstanding, I may see you there. The forecast shows a chance of rain, but that can change. I'll probably take an Impala if I decide to go - if I drive a van I'll probably come back with too much stuff.

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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0

 

HeThanks a milloing guys,,, it's nice to actually get some feedback for once about this,,, w/o too much ford bashing I don't like the car either but it has to be in a sellable (term used loosely lol) running condition due to some $ I loaned. Anyhow tho, My 1st approach was a general tune up,, it has new cap, rotor, plugs, wires & coil. (I wish my printer would work so I wouldn't have to write this down to take ouot with me,, but whatcha gonna do huh ? lol)
I'm on my way out to see how well I can make this worse (oh wait,,it's ford,,,it's already bad ),, mainly to get to that $*&% filter,,, I might have to resort to Vaders hammer idea
Hopefully this will get better

Again,,,thanks alot FJK,, Vader,,, you've been of great help so far,,, hope I don't have to post much more about this 'fine' piece (of shi..) machinery
just someone answering this was nice

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<A HREF="http://anzwers.org/free/gta" TARGET=_blank>87 Firebird
84 Camaro</A>

 

Deadbird: More on your deal...this engine's carb is really calibrated on the edge...last model year to meet emissions with a carb. So, anything goes wrong & you have a driveability problem. Other things to check
Miles of vaccum hose for leaks
Hot air ducts to air cleaner, also check the vaccum motors on the snorkels for operation &/or failure to hold vaccum
Although you say timing is 8 degrees, vac adv disconnected I presume, when connected you should be pulling ~ 30 advance at low idle.... if not, suspect a leaking vac adv diaphram.

Vader
I do have my moments. Glad you enjoyed it. I'll wander by the North entrance of the main building, high noon. Look for an F-guy.
Regards, FJK

 

FJK,,, yes,, I did plug the vaccuum line when I checked the timing. At low idle,, isn't 30* adv a little bit extreme ? I haven't had time to check that just just but I know when I disconected the line to the vac. adv. it didn't seem to have much of any suction too it (problem??) and the sound/speed of the motor didn't seem to change any.

I was able to finally change the fuel filter,,, didn't do anything but bring up the idle about 100 rpm.. I've yet to be able to check the float level just yet because of time,,,,(sigh). but that is next along with checking the advance at idle.

Since changing the filter tho it does idle a little better,,, but the miss is still there.
It has a 'lope' at idle,,, but from the feel in the shifter,,,it feels more like it's randomly misfiring a cylinder,,, could this be from that Duraspark ignition thing connected to the distributor going bad,,, or would it just be one of those things,,, it works or it doesn't ??

This is bugging me,, but I appreciate you guys doing the best you can to help w/o actually being able to look@it yourself.

Thanks alot guys,, your help means alot to me and if I can get this car sold I can get my $ back to get my dead 'bird back on the road,,, I really miss it now after driving a 5spd again

 

Deadbird:
The timing values I gave you were a liitle off. I recheck my records & found that with vac adv connected, timing was another 8 degrees advanced over base timing. I'd usually run 14 deg base & have 8 come in when I connected the vac advance @ low idle. This was a point of interest, I don't suggest you set up the timing that high unless the idle mixture can be richened up. Otherwise you'll have an erratic idle. Back to your situation. I'm gearing this advice based upon the fact that you want to get the car running reasonably well & dump it. Meaning, you don't want to spend alot of time & money. Here's one thing to do, remove the carb & tighten all the throotle body base screws. While the carbs off, replace the accelerator pump diaphram, which should be available separately from NAPA or anyplace that carries bubble-packed Holley parts. This is the same diaprhram used on all Holleys.
Relative to the DuraSpark module, they die differently than GM modules. A GM drops dead at any time & stays dead. DS modules die when hot & restart when cold. However, they don't deteriorate gradually.
Stay with it & good luck.
FJK

 

Alright guys,,, i finally got some free time today.
I was actually able to get the fuel filter changed and check the float level.
Not much changed as far as putting in the new filter except the idle came up about 100.

I pulled out the site plug while the car was running and a small amount gas trickled out, so I figured that was a good sign.

I rechecked the timing again today as well,, I was slightly off and the timing was at 6* instead of what I said before,,, so I moved it to a little over 10* this time,,, I did notice that regardless of the vaccuum line on or off,,,it didn't affect the timing. I'm assuming that's bad,,, also,,, should the advance canister work (hold vaccuum)with a hand held vac. pump,,,or is it designed to bleed off a certain amount keeping it from pulling the diaphragm in fully all the time ?

Also,, I was asking all of this to a guy at work while looking at the motor,,,he pointed out the insulation on the wires to the harness at the Duraspark box was for the most part,,,not there and looked to be touching each other. I seperated them and taped them off,, but it didn't help any. Could this have partially fried the box ?

After all the adjustments,,timing mainly,,,it starts somewhat better and seems to not want to bog taking off/accelerating from low rpm. One thing I did seem to notice is it also misfires coasting down in gear,,, the same as it does holding a steady speed,, almost like it is randomly not firing a cylinder,, at least that what it feels like in the shifter.

The guy from work says from the sounds it's something electrical,,, mainly being the Duraspark box.
Thanks again guys for racking your brains to help me out,, FJK,,, you are correct about me wanting to keep from spending alot on the car,,,but I'd feel alot better selling it knowing it's running good and isn't going to be a big heap for the next owner (karma)

The accel pump,,from watchiong it,,,seems to squirt a smooth stream to the centers of the venturies (I guess that's what they are called ?),, but I didn't think that effected holding a cruising speed ?? or am I wrong on the too?

sorry about the length

 

DB,

The accellerator pump does nothing at cruise - you are correct.

The vacuum advance should make a difference at idle, since the vacuum is full manifold. Sound like the advance unit is holed-out or the linkage id stuck/disconnected in the distributor.

A little fuel dribbling out the level plug hole is just about right, or at least the float is not excessively low and you have fuel in the bowl.

Not sure about the DuraSpark units, but if you have spark now, it's probably O.K. I believe all timing is initiated at the distributor. Still, an intermittent/weak spark could cause all your problems, and a new ignition amplifier is relatively inexpensive, as I recall.

I'm with you on not wanting to hand off a car in bad condition, unless it's getting recycled.

FJK - Sorry, I didn't make the trip. I was a little disappointed by the weather, and I've been fighing the lame-*** insurance company representing the guy who hit my parked Fiero. They want to total the car for $1,800 in repairs, and the verbal appraisal I had for it this spring was $3,500.00. I asked the claims rep to find me an equal vehicle for $1,800.00. She said she was sorry, but they are offering book value. My wife was not impressed when I informed her that I could rent a crane for $170.00/hr to "deliver" the vehicle to the top of their office as free advertisement, and I felt it might be worthwhile. She has no sense of humor regarding such things.

Pray you never have to deal with these dolts. I guess you could say I've been a "General Casualty" of their system...

As far as Jefferson, there's always next spring.

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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0

 

Deadbird
The recommendation to change the accel pimp diaphram was only a "since you were there" deal. Making sure the throttle body screws were tight was the real issue.
Yes, the diaphram should hold vaccum when pumped; otherwise it's deteriorated. I'm not sure if what you experience on decell is what you feel on accell. Decell popping out the exhaust was either an issue of the vacuum advance or the air pump, I can't remember which...I'll have to think about it. But that was personal prefrence issue, not a driveability issue. Back to your issue. The vaccum adv unit vaccum source must be metered somehow; that's why/how you get some, but not all vac adv at idle.
Relative to DS, I agree with Vader that the possibility of bare wires short would not decay the box. It works or it doesn't. However, that's why I told you originally to check out the wire bundle going to the DS.

Vader
Had a similiar situation when our 88 Bird got totaled out (Thunder not Fire). Obviously an 12 year old car, but a cherry with 32K miles. God, I like that car. I wrote a letter to the other person's insurance adjuster who challenged me on why the car was worth more than they wanted to pay. I used the argument of "the useful life of a vehicle", providing them what it would cost to purchase newer T-birds with similar mileages & comparing that to what I paid for my car, adjusted down for useful life. My figures rationalized that what I wanted for my car was still lower than what would have to be paid to find a newer car with similar miles. It worked for me. Also remember, if you're not really hurting for the cash, let the subject dwell for awhile. After a month, the insurance companys don't like to see unresolved claims linger.

Regards to all, FJK