A518 46RH Converter stuck

Posted By: way2fast

A518 46RH Converter stuck - 02/20/13 08:19 PM

Hey guys, I've got a problem, wonder if anyone can help... I built a 1990 318 LA roller cam motor to put in my '78 club cab P/U, put a used A518 automatic from a '94 magnum 318. Problem was when I put it in gear it would stall in reverse or any of the forward drive gears. In trying to find the problem I've been through trying to find vacuum leaks, adjusting timing, carb settings, replaced all electronic parts etc. finally took it to a trans shop they said bad torque converter. Well not knowing the condition of the used trans I went ahead and bought a new one and a new lock up converter, got them all installed and same problem. I am using the PATC kit to control OD and Lock up. It seems to me the converter is stuck in lock up, how do I disengage it? or check that the solenoid is working?

Posted By: stumpy

Re: A518 46RH Converter stuck - 02/20/13 09:28 PM

What happens when you cut the power to the vacuum switch?

Posted By: John_Kunkel

Re: A518 46RH Converter stuck - 02/20/13 10:09 PM

The engine stalling in gear problem might not be related to the converter but might be a tune-up problem.

Try braking with your left foot and throttling up with your right foot to see if the engine will remain running with more throttle.

Posted By: way2fast

Re: A518 46RH Converter stuck - 02/21/13 04:13 AM

Stumpy..... it does the same. Stalls. The vacuum switch works like it should, I checked it with my test light and have power etc. And it switches when hitting the the gas / making vacuum drop.

Posted By: way2fast

Re: A518 46RH Converter stuck - 02/21/13 04:20 AM

Yeah but I have gone through everything trying to eliminate the problem and am still stuck at square one...new distributor, cap, rotor, coil, wires, plugs, plugs are gapped right, ignition module, ballast resistor, voltage regulator, timing chain, cam, timing. Can't find any vacuum leaks. Carb is set to specs. I'm stumped. It will run if I keep the rpms up over 12-1300.

Posted By: 1_WILD_RT

Re: A518 46RH Converter stuck - 02/21/13 04:26 AM

Unplug the three wire connector, it will eliminate lock up & O/D.. If the problem goes away you know the problem is in the control circuit...

1st, 2nd, Drive & Reverse should all work normally...

Posted By: challengermike

Re: A518 46RH Converter stuck - 02/21/13 05:55 AM

Could be a probem inside the trans also. A cross leak in the pump or valvebody.

Posted By: 1_WILD_RT

Re: A518 46RH Converter stuck - 02/21/13 06:10 AM

Quote:

Could be a probem inside the trans also. A cross leak in the pump or valvebody.

In the first post he mentions having exchanged the trans for a reman which sounds like he swapped complete assemblies with the shop... If they rebuilt his it's possible but if they knew on the way in the issue he's having they should have looked the lock up circuit over ...

Posted By: 383man

Re: A518 46RH Converter stuck - 02/21/13 06:44 AM

Quote:

Yeah but I have gone through everything trying to eliminate the problem and am still stuck at square one...new distributor, cap, rotor, coil, wires, plugs, plugs are gapped right, ignition module, ballast resistor, voltage regulator, timing chain, cam, timing. Can't find any vacuum leaks. Carb is set to specs. I'm stumped. It will run if I keep the rpms up over 12-1300.

Do you mean you have to have it about 1200 rpm or more in Park or Neutral to keep it running ? Because if you had a lock-up conveter problem it would idle fine in Park and Neutral. Ron

Posted By: 70AARcuda

Re: A518 46RH Converter stuck - 02/21/13 09:19 AM

clean out the screen where the lock up solenoid and od solenoid are bolt to the valve body...the solenoid has to be unbolted from the valve body.

if the converter went bad and dumped crap into the fluid..that screen will plug..and the converter lock up will not disengage..

dont ask how i know..but something to look at.

Posted By: way2fast

Re: A518 46RH Converter stuck - 02/21/13 03:13 PM

Do you mean you have to have it about 1200 rpm or more in Park or Neutral to keep it running ? Because if you had a lock-up conveter problem it would idle fine in Park and Neutral. Ron

No it does idle fine in park and neutral. Just dies when put in gear unless I keep my foot on the gas.

Posted By: way2fast

Re: A518 46RH Converter stuck - 02/21/13 03:15 PM

Quote:

Unplug the three wire connector, it will eliminate lock up & O/D.. If the problem goes away you know the problem is in the control circuit...

1st, 2nd, Drive & Reverse should all work normally...

I didn't disconnect it at the trans but unplugged power to the center pin to the vacuum switch. should be same effect right?

Posted By: way2fast

Re: A518 46RH Converter stuck - 02/21/13 03:22 PM

Quote:

Could be a probem inside the trans also. A cross leak in the pump or valvebody.

I swapped out to a complete different trans (swapped for a rebuilt one) and ended up with same exact problem? also two different converters, swapped out used one for a re-manufactured one. And the problem didn't build up and get worse it was there from initial start up. I'm about to go buy a chevy....

Posted By: John_Kunkel

Re: A518 46RH Converter stuck - 02/21/13 10:20 PM

Quote:

It will run if I keep the rpms up over 12-1300

Then the problem isn't the converter locking....it's engine related.

Posted By: 1_WILD_RT

Re: A518 46RH Converter stuck - 02/22/13 12:41 AM

Quote:

Quote:

It will run if I keep the rpms up over 12-1300

Then the problem isn't the converter locking....it's engine related.

100%

Posted By: way2fast

Re: A518 46RH Converter stuck - 02/22/13 02:41 AM

Quote:

Quote:

Quote:

It will run if I keep the rpms up over 12-1300

Then the problem isn't the converter locking....it's engine related.

100%

.
OK where do I go now? The cam is set straight up, have good vacuum. Timing is at 10 * plugs are gapped right , have new everything....what could be causing this? If I had a vacuum leak under the manifold would a compression check reveal it?

Posted By: 383man

Re: A518 46RH Converter stuck - 02/22/13 05:38 AM

Quote:

Quote:

Quote:

Quote:

It will run if I keep the rpms up over 12-1300

Then the problem isn't the converter locking....it's engine related.

100%

.
OK where do I go now? The cam is set straight up, have good vacuum. Timing is at 10 * plugs are gapped right , have new everything....what could be causing this? If I had a vacuum leak under the manifold would a compression check reveal it?

Thats why I asked about if it ran ok in Park. If the converter was locked up then it would be just like trying to keep a stick car idleing with the trans in gear and the clutch out. You can not keep it running at a stand still in gear with a locked converter clutch. I have had it a few times myself over the years. Had a van that the lock-up relay on the firewall mounted upside down and it was filled with water and would lock the converter right up. But that year it would not lock up until it hit third gear as it had to have the lock-up valve move over to work which would only move when it shifted into third and as soon as it shifted into third the converter was locked.
I agree with John as it sounds like and eng problem. What is the eng vacum at idle and is it steady ? Ron

Posted By: roadrunninMark

Re: A518 46RH Converter stuck - 02/22/13 02:35 PM

A compression check will only show if you have a leak in the cylinder....piston/ring, valve, head gasket.

To check for a vacuum leak, try spraying some starting fluid in areas you think are problematic. If there is a leak and it is sucked into the engine, there should be a momentary RPM rise.

Posted By: way2fast

Re: A518 46RH Converter stuck - 02/22/13 05:03 PM

Quote:

A compression check will only show if you have a leak in the cylinder....piston/ring, valve, head gasket.

To check for a vacuum leak, try spraying some starting fluid in areas you think are problematic. If there is a leak and it is sucked into the engine, there should be a momentary RPM rise.

I have checked for a vacuum leak using propane and carb cleaner all around the intake and base of carb several times...can't find one. I have also replaced vacuum hoses, brake booster hose and check valve, all new block off caps for the unused ports.

It's been a few months since I had the vacuum gauge on it (I'm in Maine and it's freakin' cold out) but i think I was pulling over 18 inches of vacuum,

The only thing under the hood I have not replaced is the engine "Run" harness. If I had corroded wires to the fusable link and ballast resistor would it cause this? letting enough voltage through to run at idle with no load, but not enough voltage to coil with a load on the engine?

Posted By: roadrunninMark

Re: A518 46RH Converter stuck - 02/22/13 05:16 PM

I think it could...??? Check for loose grounds too. Do any of the wires get hot?

Did you check the color of your plugs? That can tell you also if you have an air leak or running too rich.

Posted By: PlumCrazyChris

Re: A518 46RH Converter stuck - 09/19/13 05:03 PM

I did a A500 swap on my car and having the same problem.

Did you figure out what the problem was?

After reviewing a lot of similar issues on here and other sites, I keep coming back to bad converter, or it being lock up at idle speeds.

You unplugged the center wire, which is 12v and should do it? I'm going to try that when I get home tonight.

Hope thats it.

If you figured it out, please post it on this thread.

Thanks!

Attached picture 7858170-A518wiringdiagram.jpg

Attached picture 7858170-A518wiringdiagram.jpg