After tracking down most of my driveabilty gremlins, This one still Remains. This description is going to be fairly Long, because I don't really know what the problem is.

The Car wont idle in gear.

First, a Little background.

The car is a Lg4 Mated to 700R4, stock Stall.

Carb is a Quadrajet from the early 70's rebuilt, but not while ive had it. It seems To work Fine aside from this, but it is suspect.

Distributor is a late 70's Model, and the coil is the stock coil Out of my Car. Again, another suspect part.

plugs are new, and not likely the case, Wires are new, and again not likely the case.

The Distributor Is entirely stock aside from a recurve kit, and entirely old.

The Manifold is a performer RPM spread Bore. It has been reseated 3 times with the Same result, So I don't suspect vaccum leaks.

Timing is set now, below 10* BTDC, any more than that I get Ping. Vac advance is set on Manifold Vaccum. Pulls approx 12* total ( Vac) plus 20 ( centri ) plus the 10 Iniital, So approx 42 at WOT. probrably not enough, but another issue.

Cam is a Comp XE262H, with 262 duration (duh ) and not enough overlap to cause signifigant idle problems, Its a pretty mild cam.

Valve lash is assumedly Right, Valve timing is Correct as well.

Electric Fan, wired ON all the time. tapped directly to battery, with 30A relay controlled by the Choke Power lead ( possible problem ? )

So< here is the problem


Car has No choke, I removed it from the Carb because it was heated Air type, and I didnt have provision For it. I live in California So its not a huge deal.

Basically, I can't get the car to Idle in gear, and alot of times It dies in neutral As well.

It will crank up, run fine If I keep some foot it in, But if I let it drop down to idle, it will slowly sputter out. Once It gets warmed up, It will idle in park at approx 1500 RPM ( high ) but sometimes wont want to Go Higher than 1000. If I give it a little gas it sometimes will settle up to 1500 again, as soon as I slap it in Gear, however, It sputters out. Sometimes it Will run for a few seconds, Other times, almost immediatly.
If I turn the Idle down to something Normal In park, I cant get it to run for anything In gear. This is just a compromise I have figured out for driveabilty Untill this gets fixed.


Worse when Cold, But even at operating temp, its not a whole lot better.

This leads me to Theory One. The car is running extremely cool due to the fan being on all the time, and my running 100% water.

It runs below the first hash mark all the time, I have a 180 stat, but it dosent seem to be reaching that degree. Altho, The temp gauge could be wrong too...


What if The manifold was not reaching proper temperature to support atomization of fuel at low velocity's ? Resulting in Puddle up, and Fuel starvation ?

Bad stop and go gas Milage sorta points to this as well, On the highway its fine, but as soon as I get in traffic, its HORRIBLE.

My second theory is electrical. My voltage gauge reads seemingly low ( anywhere from apporx 10V to 13 at cruise ). One time, while Rolling down both windows (powerd) at idle the car died, That made me think.

The other day, I Disconnected the fan to warm it up Faster, and it idled allright, as soon as I switched the fan back on, it Died.

My third Theory is the Carb. This carb Is far from suited to My application, And I don't really know the condition It is in. Its from a 454 powerd truck. 74, I belive. It was the only carb I had when My E4ME went south, and it has worked since then, But this problem was always there a little, If I remember properly. It is always there now.

I would suspect a Vaccum leak someplace, But I Can't Find one. Anyone have any ideas of what to try next ?


If My explination wasnt very lucid, I apologize, its alot to try and describe, If I left out any details that may help, let me know and I will Fill in.


Thanks.




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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver
Reader's ride -&gt; My Ride

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

 

I Forgot to add an Important bit.


The Choke warning light is almost always On Now, It goes from bright at first startup, to Dimm.

If this is a Charging system warning light, like i have heard, Could this have something to Do with my problem ? I personally really suspect that I am ether having atomization problems or spark problems.

Thanks.



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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver
Reader's ride -&gt; My Ride

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

 

I'd suspect the carb. Tear it down, soak it in carb cleaner, and put it back together. That's probably all it needs.

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"So many Mustangs, so little time..."
ICON Motorsports

 

I myself would explore the electrical side of the problem, it seems as if the alternator is not putting out enough voltage to keep the ignition alive when an electrical load is put on it i.e. fan on all the time, power windows rolled down car dies. Check your spark should be nice fat and bluish white, if it is thin and yellow orange try a new alternator or rebuild yours to increase the output.
Hope it helps, good luck

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Original owner 1987 Iroc
Stock but not for long

 

The choke warning light is indeed a charging system problem. That would be caused by the diode trio in the alternator.

This is just a diode trio kind of day I guess...

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"So many Mustangs, so little time..."
ICON Motorsports

 

Hmm, thanks Guys.


I tore one of My Qjets apart today and put it back together, Going to try it out tomarrow.

I will also try tracking down the choke light related problem. Diode in the alternator You say ?

Sounds like Time for a new one, Something I can't afford

Ive had the alternator tested recently, to try and Diagnose this, and It test out okay, But I guess That is not entirely Definative.



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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver
Reader's ride -&gt; My Ride

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

 

Bort,

You might eventually wany to connect the fan relay to a temperature switch. The extra 150W of electrical load at idle can be enough to make the engine work harder and lower voltage at idle enough to affect the ignition. This may have manifested itself by the fact that the engine died when both power windows were operated at the same time.

Cleaning and adjusting the carb certainly couldn't hurt. Make sure the secondary metering well on the bottom side of the carb body is sealed (no leaks). This is a weak spot on 4MC/4MV/M4M series, and about all Quadrajets.

If you have one of the intermediate Rochesters (M4M series) you need to remember that there is an adjustable part throttle mixture control. Although tis is supposed to affect mixture at openings just above idle, it can also affect the idle mixture. You should also make certain teh throttle plates are aligned and not binding/sticking.

Just my 2¢

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Later,
Vader
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"Fear is how I fall, Confusing what is real..."
Adobe Acrobat Reader

 

And make sure the throttle plates arent loose, along with the throttle shaft. This causes strange problems, and happens to more than a few old Rottenchesters.