A Body Stalling at Idle

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pastortom1

pastortom1

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The Demon has been running great......but the other day, it started acting up at traffic lights, then got worse and wanted to stall out whenever you tried to idle with the tranny engaged.

I suspected a vacuum leak, but found nothing but some loose intake bolts.....could be the gaskets, but I was at wits end with it. I took it to an experienced mechanic..........they found a problem with the advance on my distributor, and changed it for me (good move....it was old and questionable)..........they gave it a general tuning after the installation, but the idle problem still haunted them.

They told me that they suspect the torque converter is "locking up" and wanting to stall the motor, and it needs to be changed. I have NEVER had this kind of problem before, so I'm at a loss.

I've explained that the intake was loose, and was suspect for vacuum leaks..........BUT, they still think it's the tranny.

I've driven Mopars all of my life, and dragged 904's a lot in the 70's......This seems like vacuum to me because you just have to flutter the gas a bit and you can usually keep it going............

COULD the converter act the same way? ??????

I need some input fast on this one...............................

The car runs great.......just stalls at idle when in drive.........just does NOT want to keep running.
 
Hummmm, thats not a lock up tranny though a regular trans can do the same if theres a problem. I'd hate to agree with them on this since I'm not there and have not had the same problem with a non-lock up trans.
Tranny filter was actually that cloged up on me once.
On a GM I have had this happen to me. A lock up tranny with OD. I think it was a 700r4. Gezz, been awhile.
I'm currently have the same distributor problem. Very iratic idle.
Did you inspect the carb for dirt in the passages? Need a new filter on the fuel line?
 
They blew out the carb completely, and found no dirt......put on a new filter........rebuilt distributor and new coil........checked the intake gaskets (on top only, checking for obvious leaks) and found nothing.......no other vacuum leaks.......set and reset the carb (Edelbrock 1405 I think, and new).........tried variations on the timing and idle mixtures........

The car still wants to stall at idle in drive.............

They also mentioned the idea of a "lock-up" vs non lock-up problem, as if someone may have put the wrong converter in.........BUT, that would not explain why it just started happening in the past few weeks......would it?

AAMCO just gave me an estimate of $1000. for a rebuild on the 904, including a new converter.........I almost croaked........... I thought it should be around $400. without a converter, and I can buy a good mild stall for under $200.................... Are these guys for real? Has a 904 rebuild gone up that much?????????
 
I don't know where your from, but around here, that would be a good price for a tranny replacement and torque converter.
Try and shop for a tranny here; http://www.tciauto.com/
I think MoPar has a low stall performance converter for about $200.

At the TCI page;

TCI® Street Rodder™ Transmission Packages

Perfect for a mild daily driver or a Street Rod. Equipped with a TCI® automatic valve body with a Valve Body Improver Kit, it allows you to achieve a firmer, yet not too harsh shift in the vehicle and remains fully automatic. Retains the stock shift pattern. For the system to operate properly, all throttle linkage, vacuum lines and kick-down components must be connected.

Each TCI® transmission package consists of a triple-tested TCI® transmission and precision tuned TCI® torque converter. In addition, we also include a universal transmission cooler and three gallons of premium TCI® RTF transmission fluid.



http://www.compperformancegroupstor...Screen=PROD&Store_Code=TC&Product_Code=141538
And
http://www.compperformancegroupstor...Screen=PROD&Store_Code=TC&Product_Code=111138
Though they did give a "Package" deal number without a price. The number is
"111138P1"
 
I have had a converter that was broken and was basically locked up. You would notice a difference in the way it accelerates though. If you power brake the car is it any different in what rpm that the car wants to move. I would tell you to flash it but I am asuming that you don't have a manual valve body in the tranny.
 
There seems to be absolutely NO problem with the transmission.........everything feels normal........no shaking, no jitters, no slippage, no locking up apparent when you slow down either........it does not noticeably "drag" the motor down when the rpm's slow down........

I had a GM with overdrive, and it was notorious for dragging and lurching when the lock down wasn't functioning right....this feels nothing like that.

It acts like it's a vacuum leak and won't stay running, but they can find no leaks.

Every time you put the thing in drive, it wants to stall........to keep it going, you have to give it more gas and pump the pedal to get it moving before it stalls.
 
Grab a can of carb. cleaner and use the straw so that it is a fine stream and start spraying any where on the motor that can possibly have an intake leak. If the engine changes there is a leak. Typically if there is a vaccum leak the idle would be higher in park with no load and alot of the time it will surge even with out a load on the motor.
 
The mechanic and I both have seen a change in idle speed from NOWHERE, and with no apparent reason.......this too leads me to believe it is vacuum..............

I have asked him twice now to change the intake gaskets, but to no avail..........I guess if it's something he can't see, he won't move on it.....

He said he did a spray check with no results..........

Now tell me........IF the intake gaskets are the culprit, could it not be sucking air from the INSIDE with the same strange results? In such a case, it wouldn't show up with a spray test.....

....or have I taken too much Benedryl?

Seems an elementary possibility....................those gaskets are not new by a long shot, and the valve cover gaskets were baked on and leaching pretty well when I changed them...........
 
If the intake gaskets were leaking from the lifter valley, I think you would see oil burning as well, as it would suck oil from the lifter valley into the intake ports.

Here's another thought...have you checked all the vacuum hoses? Could one have developed a crack or a leak?

Can you turn down the idle to 4-500 rpm in neutral (what it would be in Drive), and does the engine stall then? If it stalls, then its not the trans. If it does, then I'd suspect a vacuum leak from somewhere.

Also, have the idle mix screws been disturbed lately?

Just my $0.02
 
It idles fine at very low rpm's unless the trans is engaged.........no evidence of oil smoke.

Idle mix has been set and reset for any variables......presently at factory specs.

When it stalls, it starts back up immediately every time....no flooding.

What do you think? Converter not right?
 
With all the things you've tried ,to fix it, and the symptoms you quote, it does kinda sound like convertor.

Just for shiggles, what kind of carb are you running?
 
pastortom1 said:
Edelbrock 1405 with an electronic choke........brand new.
Click to expand...

Ok. I was thinking if it was a Holley, you might have power valve problems.

Have you put a vacuum gauge on the engine and noted the readings idling in Neutral and in gear?
 
I'm betting it isnt outright converter failure, otherwise you would have to use more than just a little "flutter" of the gas to keep it alive, it would pull against the brakes really bad, and you would have notable "engine braking" while slowing down. In short, the car woudl drive totally different. Not bashing your shop, but it sounds like they are trying to "sell" you a new transmission. And their grasp of Torqueflites is dubious. If you had a TH700R4 I might believe the converter bit. Unless you are running a mid 80's or later transmission, there is no way anybody "accidently" installed the wrong converter. Sorry, won't fit. Wouldn't have worked fine for a while either.

I agree with 65Val's suggestion of taking vacuum readings at idle both in gear and in neutral. Here's what might be happening... With the car in gear idle speed drops and vacuum may be dropping to the point where the metering rods try to rise. This causes the primary circuit to go rich, and idle will suffer. Easy way to check this would be to pull the metering rod covers and watch what happens when you pit it in gear. If the needles try to rise, you dont have enough vacuum at idle to keep them down. But since you say it was running great before I am guessing your basic combo works and there is something minor wrong. Carbs, especially new ones don't just break.

Do you have power brakes? Replace the PCV lately? Start out by removing all vacuum load from the engine. Remove the booster line at the manifold and cap the port, same with the PCV line. Make any difference? If so one of the two is leaking. Hook one back up and try it, that should help you narrow it down. Another quick way to check the brake booster would be to set the parking brake and put it in gear and see if it still wants to die. How about if you stomp the brakes 2 or 3 times in neutral?

You suspect an intake leak, and it certainly possible that one or more ports is sucking air from the lifter valley. To check this you need to allow the crankcase to build vacuum. Cover the breather (opposite valve cover from the PCV) with the engine at idle. Use your hand so you can feel the vacuum build. If the idle speed changes at all, you have a bad intake gasket or PCV valve (but we already checked that).

Another thing that will cause the engine to die when coming up to a light would be too much timing advance, caused by a sticking mechanical advance, too much initial timing, or vacuum advance operating at idle. You said that the shop did something to your distributor. Trust but verify, in fact it sounds like they sold you a coil in trying to fix this. Coils dont cause this. If it starts, the coil ain't it. Hearing this as well as hearing that they "blew out the carb with an air hose" and "rebuilt the distributor" makes me cringe. In fact I get a real bad vibe.

I'd take a look at your base timing. Should be no more than 5-10 degrees BTDC. Make sure the vacuum advance is not getting vacuum at idle by disconnecting the hose at the distributor and verifying that there is NO vacuum. Plug with a golf tee and leave disconnected for now. Now shine the timing light on the marks again and slowly rev the engine up to 2500 rpm or so and let it drop back to idle. The timing mark will advance out of view and should return back to where it was as soon as the engine returns to idle rpm. This indicates the mechanical advance is working.

If the above checks reveal nothing, then and only then might I suspect the transmission. If possible, make these checks yourself and/or have a local forum member help you. I am guessing that you have already handed a significant amount of money to that shop and they still have no clue. Don't take it back there. Remember shops aren't in business to fix cars, they are in business to make money. Are they willing to do the transmission for free if it turns out no to be the problem?
 
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