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Discussion Starter #1 (Edited)
Haven't sorted out my overheating issue yet, but wanted to see if anyone has any ideas, know something I don't, or can notice something that I'm missing. Here's what I've got:

'94 Fleetwood
Meziere HD electric water pump
Gary's Innovative water pump harness
AIR pump itself deleted
160° (the good one that's recommended in the Qalo's SS handbook, new a year or so ago)
Torqhead 24x conversion (running with 0411 LS1 PCM)

Initially I had the car running very well after finishing the Torqhead install. Got the system refilled with coolant and began the process of bleeding the air out. First test drive I overheated badly. I discovered I had blown the little 20amp fuse for the AIR circuit, thus the pump was not running. No where in the instructions does it say that you should replace that with a higher amperage, but I swear I've seen that mentioned on the forum before, so I put in a 30amp (it's what I had handy). So far it has not blown again.

I can't tell if I've blown the large fuse on Gary's harness because he ships it with a style of maxi fuse I haven't seen before, it's enclosed and you can't visually tell if it's blown. I've temporarily replaced it with a normal one that you can see through. To date I have not blown that one. I've unplugged and probed the harness and I do have voltage when the car is running. Everytime I try to drive the car though it quickly overheats like coolant isn't flowing.

I've never had an issue with the cooling system prior to this. I have flushed the heater core a couple times while I've owned it. Due to the Torqhead conversion you do have to change the knock sensors, so those were out for the first time while I've owned the car (and curiously when I pulled those nothing but pure water poured out). It's quite obvious that it's overheating before I even see the temp light come one, because it will stop blowing hot air from the heater. It will turn noticeably colder.

Here's the kicker, on one test drive I actually got it to hold a steady temp (around 195°) for quite awhile before anything weird happened, and blew piping hot air from the heater the whole time. It's been a head scratcher for sure. When it overheats, it's absolutely boiling over like crazy in the expansion tank, steam coming from it like something is on fire, and a solid dribble of coolant somewhere underneath it, (maybe the hose on the bottom of the tank, but it doesn't appear to leak a drop until it overheats). I've only seen the car overheat this bad once before, in the dead of winter when it was really, really sub-zero. I suspect that it was so cold and with my apparently high water to coolant ratio that it froze somewhere and had to thaw.

Do I need to have the AIR pump plugged into the circuit? I don't recall that being a requirement for this setup. Although Paul has said emissions equipment on his PCM isn't yet supported (including the AIR system), I do get voltage at the harness right before the pump, at least when I check it right after starting the car. Do I still have enough air trapped in the system that it's going to take multiple heating, bleeding and cooling cycles to work it out? Do I have a blockage somewhere? Did I get a bad pump that just isn't working consistently? Other?

Also, before it overheats I've tried opening the bleeder valve while the car is running, and so far every time I've done that a solid stream of coolant comes out of it, so I assume the pump is running, but I suppose if there's enough pressure from heat it could just be getting pushed out. I should try that test when the motor is dead cold to be sure I suppose. So that's where I'm at and it's definitely frustrating because I can't come up with a definitive, "ah ha!, that's the problem," whenever I mess around with it. So let's see what you guys can come up with. And, go.
 

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Just throwing this out there since I didn't notice it mentioned.....did you replace the coolant cap on the reservoir? If not, I would and see what that does
 

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....so far every time I've done that a solid stream of coolant comes out of it, so I assume the pump is running, but I suppose if there's enough pressure from heat it could just be getting pushed out......

Fair conclusion. Based on this and what else I read, I haven't caught (caughten?) where the pump has been proven to be running.
 

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Check for collapsed hoses. Sometimes they do not deform until the temp goes up to a certain point. Possibly coolant between the layers.

If it overheats, you can stop and check the water pump for operation at that time.

One of the infrared remote thermometers could give you an idea where the blockage occurs. By checking the hoses from end to end, and anywhere else you might have concerns about, it should be hot on one side of the area in question, and cooler on the other.
 

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Discussion Starter #5
I had someone else PM about whether I'd tried wiring the pump direct to confirm it's running. This is the second LT1/4 I've put the Meziere pump on, the first one I wired myself, this one I used Gary's wiring kit. The first one I can clearly hear it running, but on my car I can't tell if it is or not just from sound. But each car is louder than stock and make noises unique to each other so I don't consider that concrete evidence that it isn't running. Even so, I have the harness that came with the pump and I plan to wire it direct to the battery to see what happens.

Haven't tried a new reservoir cap, but never had an issue with the old one. They're cheap though, so I will try that as well. I don't know though, can those go bad? To be fair, the car did sit unused for a solid 3 months or more while I was doing all the upgrades.

Upper and lower radiator hoses are brand new Gates hoses. The car still has/had all its original hoses on it, and I figured as long as I had the system drained I'd at least replace those. I should replace the rest of the hoses as well, but I did so much to the car this go around that I was getting tired of delays caused by (among other things) constantly ordering more parts and pieces. I did find though that rockauto has the entire heater hose, restrictor setup from acdelco for about $70. That would at least eliminate the hose under the expansion tank as a culprit, but I'll have to order that and wait. If I suspect blockage though, I'll be opening the system back up anyways so then I'll swap the rest of the hoses for sure.

I appreciate all the responses so far. If anyone has anything else, let me know, and I'll update as I try out these various suggestions so far.
 

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you could pressure test the reservoir, and hose going to it, with one of those "loan a tool" testers. If you have a cracked tank or bad hose you will leak fluid and air will enter system

The cap is a "wear" item....

On the meziere there is a small rubber cap center on front of pump. Just pry it off and you can see it turn when on

and never put in a higher amp fuse when the one spec for the load blows.

IDK where Gary has you getting the power source from but his stuff is always made very well. Confirm your install is solid
 

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Discussion Starter #7
Didn't realize that cap on the pump popped off. Just tried it and confirmed that the pump is running. I picked up a new reservoir cap this afternoon, haven't tried it yet. It's been about 25° outside all day and I haven't had much interest in being out there working on anything. Gary's harness uses the AIR relay in the underhood distribution center to act as a signal to the relay on his own harness. When car starts up, air pump is turned on, which subsequently turns on the water pump. I still don't know why that fuse popped in the first place, I've had the air pump deleted since I bought the car and it never had an issue.

There's a small possibility that I did it when wiring in the OBD2 port. I had a brain fart moment and forgot to disconnect the battery before depinning the old port and adding in the new one. As I pulled a presumably hot wire (I think it was the white w/black stripe), I bumped the terminal on grounded metal near where I was working and got a little spark. I couldn't figure out why that would pop the fuse for the air pump, but it's the only thing I could think of. I haven't found any other blown fuses and everything else was working fine. After I installed the port I took the car for the first test drive and that's when I first overheated and subsequently found the blown fuse. Knowing the pump is running now, I could try putting the lower one back in.
 

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I did my EWP 18 years ago so before I knew about Innovative and not sure Gary was even doing kits back then.

I thought the AIR circuit was only on for a few minutes after start up. Whatever Garys instructions say though should be right. After a few minutes of running you could check to see if pump is still running

Your over heating issue started after you installed EWP, right?
 

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Discussion Starter #9
Yes, it started after that. I did so many other upgrades at the same time though, I couldn't be sure. I wasn't aware that the AIR system shuts off after a few minutes, but that could be an issue I suppose. To be fair though I don't know exactly how Gary's kit is wired up. In my own experiences in fooling around with relays, I've managed to inadvertently wire things up in such a way that once you trigger the relay, it will stay on even after the trigger is turned off. Not saying that's what he's doing, but I know it can be done. I'll have to try running it longer though to be sure. I had another thought occur to me and I'm hoping I'm wrong, but with multiple overheating incidents recently and the fact that the engine itself suddenly and mysteriously started running very poorly, I'm wondering if I didn't blow a head gasket. That's the last thing I need, especially this late in the year.
 

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The AIR pump only runs for a few minutes after start up. IDK if "air pump disable" process involves killing the +12v to it. I believe it just re-programs the PCM not to look for it

Anyway Gary knows his stuff and if that's where he says tap into #86 than that should be fine as I assume that wire stays hot with Key on Engine On

"your" installation could be suspect if power is being interrupted if it is.

It may just be a bleeding issue although that is fairly simple. I have the "bleeder valve" mod I did WAY back when and it came with a plastic clear hose you just run into reservoir so you can see when air bubbles stop which for me have always been fairly quick once T stat opens. Its hero function is it is a mess free way of bleeding to not spill any coolant near Opti. Not necessary to have just to bleed the air out though

By "over heating" if you mean the temp gauge pegged all the way over and you continued driving than yeah maybe head gasket damage if you let it go that far. Otherwise not

It does help to have the nose of the car slightly up when bleeding so air migrates to that higher front point vs rear of car being higher
 

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Didn't realize that cap on the pump popped off.
yeah in the Meziere instructions it has you popping that cap off to confirm the pump is running....and in the right direction.

It is possible the connector on pump is wired backwards thus the pump would "run" backwards but would not "pump" water since rotation is backwards.

IIRC the pump rotates clockwise but check your instructions. worth checking and simple

again, your overheating issues are after EWP install, right?
 

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I would respectfully argue that jacking the nose up on a LT1 may do more harm than good.
The only way the air will come out of the heads is the bleeds that are at the back of the heads.

Raising the front will let LESS air out .

Totally agree with an extended bleed hose that you can let run and run into the tank.

Better yet , invest in a vacuum bleeder.
I work on some pretty weird engine-rad combos and would be dead without it
I don't even open the bleed on an LT1 after vacuum bleeding

As for "is the pump running"
You could jam two little wires in the plug at the pump and jury rig a little light on the windshield to test.
 

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The only way the air will come out of the heads is the bleeds that are at the back of the heads.

Raising the front will let LESS air out .

.
so the rear of the heads don't want to be lower than bleed screw on front of motor?

Guess they already are with car sitting flat as the engine angle is 4-5 degrees (rear lower) anyway
 

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I would respectfully argue that jacking the nose up on a LT1 may do more harm than good.
The only way the air will come out of the heads is the bleeds that are at the back of the heads.

Raising the front will let LESS air out .

Totally agree with an extended bleed hose that you can let run and run into the tank.

Better yet , invest in a vacuum bleeder.
I work on some pretty weird engine-rad combos and would be dead without it
I don't even open the bleed on an LT1 after vacuum bleeding

As for "is the pump running"
You could jam two little wires in the plug at the pump and jury rig a little light on the windshield to test.
This part does not make any sense. There are no bleed holes at the rear (steam tube) and they do not vent to the outside. The bleeder on the thermostat housing is specifically for bleeding air out of the coolant system. The idea is to be at the highest point in the system to allow the hose to fill with coolant, and become efficient.
 

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Didn't realize that cap on the pump popped off. Just tried it and confirmed that the pump is running. I picked up a new reservoir cap this afternoon, haven't tried it yet. It's been about 25° outside all day and I haven't had much interest in being out there working on anything. Gary's harness uses the AIR relay in the underhood distribution center to act as a signal to the relay on his own harness. When car starts up, air pump is turned on, which subsequently turns on the water pump. I still don't know why that fuse popped in the first place, I've had the air pump deleted since I bought the car and it never had an issue.

There's a small possibility that I did it when wiring in the OBD2 port. I had a brain fart moment and forgot to disconnect the battery before depinning the old port and adding in the new one. As I pulled a presumably hot wire (I think it was the white w/black stripe), I bumped the terminal on grounded metal near where I was working and got a little spark. I couldn't figure out why that would pop the fuse for the air pump, but it's the only thing I could think of. I haven't found any other blown fuses and everything else was working fine. After I installed the port I took the car for the first test drive and that's when I first overheated and subsequently found the blown fuse. Knowing the pump is running now, I could try putting the lower one back in.
Which side of the AIR pump relay are you connected to? If it is the hot in "run/bulb check/start" side, you should be OK. If you hooked it up to the power when energized side, it may turn off after the initial start up, only to come back on when the car is idling. You may want to use a different source for "on in run/bulb check/start" circuit. You need a wire that is on in run/bulb check/start.
 

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This part does not make any sense. There are no bleed holes at the rear (steam tube) and they do not vent to the outside. The bleeder on the thermostat housing is specifically for bleeding air out of the coolant system. The idea is to be at the highest point in the system to allow the hose to fill with coolant, and become efficient.

Spend some time studying the LT1 cooling system.




If you leave out the head bleeds ( self bleed to tank), you will see all the water enters ( top) and leaves the block (bottom)
fairly low in relation to the heads, pump, thermostat, rad , etcetera.

The is a large slug of air that will not "leave" the system into the tank
This has nothing to do with the coolant in the engine that is higher than the ports in the front of the block.
This is handled by the two head bleeds.
In a normal situation on filling the the thermostat bleed will allow the air trapped in the system around the pump ( and rad in a 95-96 ) to bleed.
Air in the heads will bleed out to tank through the "steam" lines.

In normal use and if there is no cavitation air will not collect in the top of the pump.
Any steam bubbles that form in the heads will rise and work their way out through the head bleeds to the tank.

Now, if you jack the front of your conventional BB chev, the highest part of the system will be the front of the heads and the air will wander out the coolant crossover to the thermostat housing and up the the rad , which often the cap is .

Jack an LT1 up and every thing above the block water pump holes and the rear head bleeds will be trapped.

The more level the heads are, the more air that will migrate out of the heads.

The short answer is the LT1 has two separate high points in the system that can trap air.
The heads which self bleed,
The top of the water pump and (95-96) rad that must be done manually
 

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Discussion Starter #17
Didn't touch the car today, was busy getting some stuff for my grandmother to come home from a rehab facility tomorrow. A couple quick things, the ewp does spin (although I don't know if it stays running after a few minutes), it appears to spin clockwise, and I followed Gary's instructions almost exactly. Although there are some differences in the distribution center between the Fleetwood and the other b-bodies, I'm confident I have it connected properly. Being I used Gary's kit, it does have an extra wire for adding in an LED kit that used to be sold on here (and if I dig I think the schematics to make it yourself are on here somewhere). I could dig that wire back out of where I hid it in the harness and try that to see that it is running all the time. My driveway is at a very slight incline anyways, so I don't think I'd benefit much if any from jacking the front up to try and bleed it. I probably missed a few things, but hopefully I can tackle it some more this weekend, weather permitting. I did get my hptuner setup on the laptop last night, so hopefully I can also jack into the PCM and see if I can figure out why it's suddenly running so rough as well.
 

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Is the PCM tuned stock or have modifications to the fan/temp cut on parameters been adjusted ala re-programming?

Just saying as I haven't seen that put out there after gleaning over this.

To X2 what 4Door stated early on, yes. Replace the cap w/ a new one. Start there.
 

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Thanks for the tutorial Gerry. I am guilty of passing on 411 I, like others, have read on this forum about raising nose of car up to assist bleeding.

With that said I have had the car up on ramps when doing a WP swap or Opti as well as just having the car sit flat in garage. In either position I did not have any issue bleeding the cooling. I do have though the "easy bleeder" that you can use a tube to route the bleed coolant back into the reservoir which, for me, has always worked well.

I have always noticed after car did completely cool down over night The coolant level is about 1" low in the reservoir so I just top it off.

Would this be the air still in the lower part of motor "burping" its way out through the steam pipes over night?

Car however does not overheat between initial fill/bleed/drive prior to this though
 

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Being I used Gary's kit, it does have an extra wire for adding in an LED kit that used to be sold on here (and if I dig I think the schematics to make it yourself are on here somewhere). I could dig that wire back out of where I hid it in the harness and try that to see that it is running all the time.
You can just look at the WP without that black cap to see if the pump is still turning after the car has been running a few minutes also. Obviouslly if it is not...you found the "why" to your over heating issue

IIRC the "light mod" simply tells if electrical power is still reaching the EWP...not that the EWP works itself. In the 18 years and 90k mi I have on my EWP I have always just looked at the temp gauge....

Garys instructions and product are always very good. If you followed his instructions and your connection points are solid the wiring should be good. IDK if there are variances in your B body model vs the SS/Caprice sedan that would alter the source point for trigger power (relay) to something other than pin 86 in the under hood fuse block that Garys instructions have you tapping into
 
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