Off idle BOG at WOT

[MonteLS_84]

I did not specifically include the TH350 w/the third gear lockup because it works a little differently than the two that I mentioned. In the 350 variant, only third gear locks up and there are just two wires attached to the plug that fits into the socket located on the driver's side of the case. It still uses the double terminal switch that sits on the bracket above the brake pedal but there was no VOES (Vacuum over Electric Switch) as part of that circuit. My 700R4 does have that switch, however.

Unlike the 4 spds, the 350 does not depend on internal pressure in the case for a signal to shift. The 350, even the E version and its variants, all depend on vacuum. While there are ports on the carb that do offer full time vacuum, I personally found it better to use the vacuum port on the intake, located just ahead of the timer. In the stock iteration, there is a shaped length of tubing that is attached to the vacuum module located down and just ahead of the tailshaft housing on the passenger's side of the case by a short length of rubber hose. Up at the top at the vacuum port, another short nipple of tube makes that connection.

The stock vacuum module as it comes from the factory cannot be adjusted for shift timing. There are supposedly aftermarket versions that have that ability.



Nick

Right. So, the ALDL connector on the passenger side...jumping pins F and A will activate lock up. I have a switch between F and A to toggle on lock up, and once on, I have a vacuum switch from Superior Transmission Parts that activates the lockup based on vacuum. I also have an indicator light that tells me when the vacuum switch is engaging. The amount of vacuum is adjustable. Don't quote me but I believe I currently have it set to kick on at 10, and cut off at 12 (something like that). Seems I have it wired up pretty nifty. My only concern is that I don't "know" if lockup is actually working. I don't feel or notice rpm changes. Going back to the ALDL connector, which I have unplugged, my wiring is on the black side, as opposed to the white side. I'm not good with electrical, so I'm still trying to figure out if I'm on the right side. I'm also not sure if the lockup is thus getting activated in all gears, and even when in Park. 🤷‍♂️ I should also note that when I had the connector connected, I didn't notice any changes either. Some say you won't really notice but will see a slight rpm drop...which I haven't.

My other concern is the brake switch that you mentioned. I don't recall seeing anything but will look tomorrow. I'd like to make sure that aspect works as well.

 

[CopperNick]

If it helps, in the next batch of progress shots I take, i can rig up an example and take a few pics using a spare bracket and pedal along with that switch; think I have a spare of that somewhere.........................

Just like this. These three shots show, First, the switch to which I referred, Second, the switch used when no lockup is present, aka the regular switch, and Third, how it wouid look if you were on your hands and knees and trying to look up and under the dash to check out the brake pedal.

For everybody else, the double pedal assembly shown as the prop for the switch was the first one I could lay my hands on easily. In an automatic application, just mentally block out or erase the clutch pedal and what remains is what you are looking at.

FYI, this switch is not a permanent fixture. It actually screws into position on the bracket, there is a sheet metal insert w/threads that accepts it. To set the correct distance the switch has to be located at to correctly be triggered by the depression of the pedal, you just unplug the harnesses and turn the switch body towards or away from the pedal.



Nick

 

[MonteLS_84]

If it helps, in the next batch of progress shots I take, i can rig up an example and take a few pics using a spare bracket and pedal along with that switch; think I have a spare of that somewhere.........................



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Just like this. These three shots show, First, the switch to which I referred, Second, the switch used when no lockup is present, aka the regular switch, and Third, how it wouid look if you were on your hands and knees and trying to look up and under the dash to check out the brake pedal.

For everybody else, the double pedal assembly shown as the prop for the switch was the first one I could lay my hands on easily. In an automatic application, just mentally block out or erase the clutch pedal and what remains is what you are looking at.

FYI, this switch is not a permanent fixture. It actually screws into position on the bracket, there is a sheet metal insert w/threads that accepts it. To set the correct distance the switch has to be located at to correctly be triggered by the depression of the pedal, you just unplug the harnesses and turn the switch body towards or away from the pedal.



Nick

Thanks for that Nick! Appreciated. It has been raining here for the past 2 days, and I do not have a garage...so I haven't gotten a chance to check for the brake switch. By the way, if or when I do find this switch, how can I wire it or make sure it works woth my non-CCC set up? Assuming you know. 😅😬

 

[MonteLS_84]

Update:

As mentioned previously, I went 2 stages bigger for the secondary jets. I verified float levels. I went back to stock jetting for the primaries. I installed a brand new accelerator pump. Test drove.

No difference. Seems slightly worse with the bigger jets. However, I did notice that it is and has been hit and miss. Not as in working...but I've confirmed that when mashing the pedal, the car will either bog right down (or stall), or it will try to go. Really random...and the bog is more frequent than not.

What I mean by "try to go" is not so much a hesitation...but no bog, rather a very slow.."go". I'm going to have to take a video.

My next plan of action is to eliminate 1 of 2 fuel filters, and see if that has any effect. Then probably go back to stock jets for the secondaries. I was going to swap wheels to note any changes but I recalled that I was running the 15" wheels prior to getting the 20", and had the bog then.

I ordered a set of edelbrock squirters, as recommended in some other forums but they're on back order. I may drill out the stock ones if I get to inpatient.

I'm not sure what else to try at this point.

 

[CopperNick]

Somewhere back in the back pages of the Non- G-body forum, if you go digging or run a search string for "Non G-Body G-Body", it may return a series of threads on my G-10 van from back when I did the swap from a 350E to a 700R4. One the correspondents at that time was kind enough to attach a schematic of the lockup circuit for that t-box. For your purposes, the physical wiring from your source of power to the switch is not different. From the switch to the plug in on the t-mission is a factory pre-made socket assembly. Turned out when I pulled the E that the wiring was there but had never been hooked up from back when the E itself was a shop done exchange due to having blown the guts out of the original box on the fueling deck of a local gas station. ATF all over the place.

You need to go back at least two years. I may happen to have the schematic saved to the master file for Tales of my G-10 Van; can maybe take a quick peek after I log out from here. The plug in socket might be available from a specialty t-mission shop or they might know where you could score it.

As for testing it, it is a spring loaded plunger switch. you can test it for continuity using a probe llight tester like the ones in the attached picture. Just use a jumper to bring power to the switch, clip the probe to the other terminal, ground the stinger, and then depress the plunger. The light will either go out or come on, depending on how the internal circuit for the switch is designed.

Nick

 

[MonteLS_84]

stew86MCSS396 pagrunt CopperNick 78Delta88 MrSony Wageslave

Here is a video. I stop at a stop sign, pull off, punch it. Goes no where. Punch it again...stalls.

Oddly, the tach shows 1000-ish rpm when the engine almost stalls (the first time). 🤔

I got rid of my 2nd fuel filter today (prior to video). Still bogging.

I'm at a loss here. Currently 2 stages rich on secondaries (going to go back to stock, since these made no difference), already back to stock primary jets and rods, middle accelerator pump hole (tried all 3), timing is at about 14 and 36, medium springs in MSD distributor (removed heavy, and tried light but got pinging), running new manual Edelbrock performer rpm fuel pump, 1 fuel filter.

Can trans or tv cable effect take off?? Here's the link:

 

[CopperNick]

Unlike the 4 speed auto-boxes, your 350 does not have a TV cable. What you have attached to the throttle lever in the bottom position is the demand downshift cable, aka the passing cable. At cruising speed, should you go WOT, the action of the throttle plates coming wide open also causes this cable to manually downshift the transmission, dropping the transmission one gear lower to get better acceleration. Under any other circumstances, it is the vacuum generated by the engine that gets delivered to the shift module that I mentioned that determines when the t-box shifts from 1st, to 2nd, to 3rd.

Did watch your video and what I mostly noted was that the display on the Tach was going absolutely nuts. Even at its most sensitive, the tach display should not be bouncing around that much. It's almost like power to the engine from the hot side of the battery is being interfered with and the tach, being as sensitive as it is, is reflecting that fact.

Okay then, taking that as a premise, I think what may have to happen next is that you go hunting for a dead short or grounded wire in your primary electrical harness. That is the one that sends power from the battery down to the big terminal on the starter solenoid and to which those three large terminal ends with their attached fusible links are connected. I particularly suspect one of the fusible links or the wires adjacent to it may have corroded internally. What you would be getting in that case could be an intermittent connection that works fine under normal voltage crop conditions but fails under a heavy load such as that imposed by the engine under hard acceleration.

Do be aware that this is only a Scientific Wild A**ed Guess (SWAG) on my part. However, Occam's Razor suggests that when you have eliminated every other possible culprit, whatever is left, no matter how improbable, is your issue. Your factory wiring harness is 40 years old. In that time it has endured countless operational cycles, heat, oil, gas, internal corrosion, U-V degradation, and invasion by well meaning "electricians" looking to add accessories such as a world class sound system. In addition, your harness is a hybrid, copper based in the engine bay, and mostly aluminum in the run from the firewall back to the tail lights. Just lookinig okay is not a 100%guarantee of electrical continuity. This is going to be a twist the connection, tug on the wire, look for hidden cracks in the insulation and missing grounds/wired grounding where they have no business doing so exercise in hunt and see detection..............



Nick

 

[MonteLS_84]

Unlike the 4 speed auto-boxes, your 350 does not have a TV cable. What you have attached to the throttle lever in the bottom position is the demand downshift cable, aka the passing cable. At cruising speed, should you go WOT, the action of the throttle plates coming wide open also causes this cable to manually downshift the transmission, dropping the transmission one gear lower to get better acceleration. Under any other circumstances, it is the vacuum generated by the engine that gets delivered to the shift module that I mentioned that determines when the t-box shifts from 1st, to 2nd, to 3rd.

Did watch your video and what I mostly noted was that the display on the Tach was going absolutely nuts. Even at its most sensitive, the tach display should not be bouncing around that much. It's almost like power to the engine from the hot side of the battery is being interfered with and the tach, being as sensitive as it is, is reflecting that fact.

Okay then, taking that as a premise, I think what may have to happen next is that you go hunting for a dead short or grounded wire in your primary electrical harness. That is the one that sends power from the battery down to the big terminal on the starter solenoid and to which those three large terminal ends with their attached fusible links are connected. I particularly suspect one of the fusible links or the wires adjacent to it may have corroded internally. What you would be getting in that case could be an intermittent connection that works fine under normal voltage crop conditions but fails under a heavy load such as that imposed by the engine under hard acceleration.

Do be aware that this is only a Scientific Wild A**ed Guess (SWAG) on my part. However, Occam's Razor suggests that when you have eliminated every other possible culprit, whatever is left, no matter how improbable, is your issue. Your factory wiring harness is 40 years old. In that time it has endured countless operational cycles, heat, oil, gas, internal corrosion, U-V degradation, and invasion by well meaning "electricians" looking to add accessories such as a world class sound system. In addition, your harness is a hybrid, copper based in the engine bay, and mostly aluminum in the run from the firewall back to the tail lights. Just lookinig okay is not a 100%guarantee of electrical continuity. This is going to be a twist the connection, tug on the wire, look for hidden cracks in the insulation and missing grounds/wired grounding where they have no business doing so exercise in hunt and see detection..............



Nick

I truly hate that you may be right. The electrical aspect scares me. I have no idea where to begin or what to look for. That said, I have no choice but to try.

Myself and another guy tossed around the idea that something electrical wasn't right. But the most I did was a peekaboo, and moved on to looking at other culprits.

When I first got the car back (with all the new goodies), I noticed something strange that would occur alongside of the bog. The radio and amplifier would shut off for a split second. Sometimes just the amp. Sometimes just the radio. Literally - stomp the pedal, and one or the other would go out. At some point it quit doing that, so I never looked into it further.

One chap told me it must have something to do with my radio or amp. I re-checked all the wiring. Nothing seemed out of the ordinary. I went and installed a higher output alternator as insurance. Sometome thereafter, I noticed the problem stopped.

Would any of that information mean anything?

 

[CopperNick]

Actually, to me it may mean that whoever the installer was, they took the lazy route when they wired in the harness and instead of creating a dedicated standalone circuit for the sound system, they may have piggy backed it onto an existing harness, either by using those blue guillotine wire connectors, or by physically stripping a small section of the wire, wrapping the parasite feeder wire around it. and then just taping the whole thing to insulate it. I have even seen masking tape used as an insulator!!

Even with the stronger alternator, the circuit that was co-opted as the source of power is only as strong as what it initially fed power to. If you were getting voltus interruptus then a circuit breaker somewhere may have been added that killed the power momentarily and then reset it once the wires cooled down again. Don't count on that; it could just easily be a sloppy/loose wire marriage of the parasite power wire to the source power wire that was making and breaking itself due to vibration or interaction with an adjacent piece of infrastructure. Don't think it was the new alternator that solved the problem, although your battery may have been thankful.

The mark of a reputable and experienced sound system technician is the work and thought they put into the wiring, sizing it correctly to meet the demand, the routing needed to avoid other components, the type of connections, and generally the overall fit and finish of the system. From such an individual you would get a sub-circuit exclusively dedicated to powering your sound system, with relays and breakers to protect the components from power surge or damage, and with heavy gauge wiring--think 10 ga primary wire as the absolute minimum here, more probably to be 8, or even 6 or 4--for the power feeds from the distribution board and a battery sized power wire to feed it. Depending on the system specs, there may even be a memory wire that goes to the receiver because any cpu's that are in the system need continuous power from an outside source or they lose their "minds".

As to how to go about doing a wiring circuit witch hunt, Just start with the battery connections at the battery, and follow them. That big red wire will, eventually and one way or another, take you to every other circuit in the whole car. To do the job properly you will need that probe that I posted the picture of earlier as well as a good multi-meter, some jumper wires, and a SH*T-TON of patience. Expect to get dirty and bring along an old toothbrush as you can use it to gently brush the crap and crud off some of the connections so that you can get a better look at them. Don't be afraid to physically touch and gently wiggle things; you be surprised how much information you can get from your finger tips.

Good Luck and Good Hunting.


Nick

 

[olskool]

if there is real water in the tank, no additive will do a thing, only dumping the tank works,,,,,,,,,,,