Couple questions to the Pro's

[Cole]

As always very appreciative of any and all advice. Chine in on any or all if you can help please.

Fuel Pump:

Putting a new autozone one in (mechanical) and getting the bolts started and the pump seated against the block got me to the point of frustration where it wasn't fun anymore last night. Should you be able to just hand fit the pump tight against the block or does it takes the bolts to pull it in? I think if I use a longer bolt to start it at the top it might help then replace with the right size. When and IF it goes in will i need to prime it? I'm guessing pour some petro down the output line????

Emergency Brake:

Is the cable tied down in only 3 places? Mine has tons of slack. Looks like if I can remember correctly it is anchored near both rear wheels and up front on the drivers side. Anyone have a pic of how the cable routes for this? Im thinking this cable should be almost square so it can pull on both rear wheels equally. Mine's looks like a triangle if you pull the slack out. LMAO

Vacuum Advance on a FMX:

I'm missing this line on the transmission side. I think I've read she will still crank and move without it so it's not a pressing issue as the other two. But what type of fitting is that on the back of the transmission and where does the other end go.

Thanks and here's to a great start of the week. I love Mondays! Send the little one off to school and get to work so I can rest.

 

[marks73]

Fuel pump- 1 hole should be slotted so you can leave the bolt in the block, compress the arm and slide it over the bolt.

Emergency brake- There is another bracket welded the the floor of the passenger front right about where your feet go. Square bracket with a hook hanging off it.

I DON"T DO TRANNYS

 

[VegasFastback]

As always very appreciative of any and all advice. Chine in on any or all if you can help please.

Fuel Pump:

Putting a new autozone one in (mechanical) and getting the bolts started and the pump seated against the block got me to the point of frustration where it wasn't fun anymore last night. Should you be able to just hand fit the pump tight against the block or does it takes the bolts to pull it in? I think if I use a longer bolt to start it at the top it might help then replace with the right size. When and IF it goes in will i need to prime it? I'm guessing pour some petro down the output line????

Emergency Brake:

Is the cable tied down in only 3 places? Mine has tons of slack. Looks like if I can remember correctly it is anchored near both rear wheels and up front on the drivers side. Anyone have a pic of how the cable routes for this? Im thinking this cable should be almost square so it can pull on both rear wheels equally. Mine's looks like a triangle if you pull the slack out. LMAO

Vacuum Advance on a FMX:

I'm missing this line on the transmission side. I think I've read she will still crank and move without it so it's not a pressing issue as the other two. But what type of fitting is that on the back of the transmission and where does the other end go.

Thanks and here's to a great start of the week. I love Mondays! Send the little one off to school and get to work so I can rest.

Fuel pump: I always let the bolts pull the pump in Its usually too hard to try to hold it flat to the block while trying to crank them in. As far as priming goes if you tank is half full the fuel should readily run to as long as your on a flat surface, from my experience. I've always just cranked the engine and they work.

E-brake: there should be a little arm that pivots on the passenger side that holds the cable so its more of a square shape. When I'm under the car beating on the tranny today I'll take a picture

FMX: That vacuum line is for the vacuum modulator that controls shifting. You're going to want that. Any parts store will have them.

 

[Cole]

Thanks guys. Would never make any progress without everyone's help.

 

[rutkak]

Cole,

Fuel Pump: Concur with all but make sure you slide it in at the proper angle. It won't go in straight. It will likely have to slide in from under the car. You should be able to get it flush without the bolts. It's a pain but probably easier if you remove the power steering pump and oil sending unit. I just replaced mine over the weekend on my 302. I recommend cleaning up the bolts, putting some lube on them and seeing if you can clean the gunk out of the holes. I left my PS pump and TSU on, but had to use a socket set with extension and handle to get the bolt screwed in while I held it in place. The gasket doesn't require sealer but it's a pain to get in place since it slides all around and blocks the bolt holes. Finger tight should get the bolts 75% of the way in though (if you can reach and don't have sausage fingers like me).

Trans: Wow. If you are missing the vac advance rubber hose you'll notice the obvious vac leak = stumbling idle and she probably won't shift out of 2nd gear. This is a big deal. Figure out where it plugs into the trans and get a rubber hose to connect it up. I'm a C4 kind of guy but I'm sure the FMX is the same.

-KR

 

[TommyK]

It can sometimes help to bump the engine over to try and get the fuel pump eccentric in a friendlier position.

The modulator is located on the passenger side of the trans. In stock form it was connected to the vacuum tree on the back of the intake manifold. Any full manifold vacuum source will do.

 

[Cole]

The modulator is located on the passenger side of the trans. In stock form it was connected to the vacuum tree on the back of the intake manifold. Any full manifold vacuum source will do.

I have a tree. Thanks Bro. That's a big help and I'll see if Kens can get me the line.

 

[matrixx]

There should be a vacuum modulator on the rear side of the transmission that the vacuum line attaches to. Yes it will move but probably won't shift at all. The fuel pump rides on a cam lobe at the end of the camshaft, it depends on where its positioned it will either slide right in or you will fight it. Sometimes I would just bump the engine over a tad and it will fit like a glove.

Can't give you much on the e-brake, as mine works great and have no desire to fiddle with it

 

[72HCODE]

all good on points 1, 2

the vacuum modulator basically overrides the mechanical/hydraulic gear change under load, it uses the engine vacuum to determine load on the trans and alters the shift points when you floor it and it can tell if you are shifting up hill or downhill by vacuum load.

the modulator is adjustable as well and you might have to mess with it.

with it disconnected the trans will still shift based on RPMS but it will not shift when you expect it or may want it to.. Like say you floor it up a steep hill. the rpms will drop down but the trans will not down shift until you floor it and the kick down rod forces a change.

with the vacuum modulator, it will see the vacuum start to fall off overriding the RPM mechanical sensor and kick down the trans, at half throttle without flooring it to use the kickdown bar which is only suppose to be for passing at cruise.

so you want to install the modulator to full manifold vacuum. inside the tube barb there is a tiny flat head screw, turn it clockwise to shorten shift points and counter clockwise to lengthening time between shift points.

the modulator has a rod inside the trans that goes to the diaphram the length of the rod is important and that will effect shift points as well.you don't want to mix and match rods from different transmissions.

most common issue: the vacuum line falls off the modulator this causes a huge vacuum leak.

engine carb backfire will blow out the modulator, would also damage the brake booster, could blow the vacuum line off as well.

some people find the modulator is blown and they just disconnect the vacuum line and plug it.

the issue with changing the modulator is the trans fluid will come flying out, so either you need to drop the trans pan and drain it. change the filter and seal and new fluid or be johnny on the spot, pop the old modulator if damaged, 5 pints of fluid starts flying out and you try to align the modulator rod and the modulator with a new seal and wiggle it home covered in trans fluid then lock it down and refill all the fluid that came out of the trans.

either way sucks, i've done it both ways.

the issue is if you have an old trans, disturbing the fluid may cause something to break free and clog up the valve body. or if the clutch pack was really worn when you put new fluid in the trans may start slipping leading to a rebuild.

the least invasive is pull the module and try not to loose more then 2 pints of fluid during the swap. if the entire trans goes empty and you have to refill it the chance for problems multiples.

you can test a modulator before you pull anything hook up a hose to a vacuum hand pump with a gauge. get a 15HG" vacuum on it and let it sit for a minute and watch the gauge if it doesn't lose vacuum the modulator is fine and just hook it back up to full manifold vacuum.

then go for a ride and see how it shifts. if you feel the shift is lazy then turn the screw inside the modulator 1-2 turns and retest. you can make it shift through 3 gears instantly when you floor it or let it build up slower and shift.

 

[Cole]

all good on points 1, 2

the vacuum modulator basically overrides the mechanical/hydraulic gear change under load, it uses the engine vacuum to determine load on the trans and alters the shift points when you floor it and it can tell if you are shifting up hill or downhill by vacuum load.

the modulator is adjustable as well and you might have to mess with it.

with it disconnected the trans will still shift based on RPMS but it will not shift when you expect it or may want it to.. Like say you floor it up a steep hill. the rpms will drop down but the trans will not down shift until you floor it and the kick down rod forces a change.

with the vacuum modulator, it will see the vacuum start to fall off overriding the RPM mechanical sensor and kick down the trans, at half throttle without flooring it to use the kickdown bar which is only suppose to be for passing at cruise.

so you want to install the modulator to full manifold vacuum. inside the tube barb there is a tiny flat head screw, turn it clockwise to shorten shift points and counter clockwise to lengthening time between shift points.

the modulator has a rod inside the trans that goes to the diaphram the length of the rod is important and that will effect shift points as well.you don't want to mix and match rods from different transmissions.

most common issue: the vacuum line falls off the modulator this causes a huge vacuum leak.

engine carb backfire will blow out the modulator, would also damage the brake booster, could blow the vacuum line off as well.

some people find the modulator is blown and they just disconnect the vacuum line and plug it.

the issue with changing the modulator is the trans fluid will come flying out, so either you need to drop the trans pan and drain it. change the filter and seal and new fluid or be johnny on the spot, pop the old modulator if damaged, 5 pints of fluid starts flying out and you try to align the modulator rod and the modulator with a new seal and wiggle it home covered in trans fluid then lock it down and refill all the fluid that came out of the trans.

either way sucks, i've done it both ways.

the issue is if you have an old trans, disturbing the fluid may cause something to break free and clog up the valve body. or if the clutch pack was really worn when you put new fluid in the trans may start slipping leading to a rebuild.

the least invasive is pull the module and try not to loose more then 2 pints of fluid during the swap. if the entire trans goes empty and you have to refill it the chance for problems multiples.

you can test a modulator before you pull anything hook up a hose to a vacuum hand pump with a gauge. get a 15HG" vacuum on it and let it sit for a minute and watch the gauge if it doesn't lose vacuum the modulator is fine and just hook it back up to full manifold vacuum.

then go for a ride and see how it shifts. if you feel the shift is lazy then turn the screw inside the modulator 1-2 turns and retest. you can make it shift through 3 gears instantly when you floor it or let it build up slower and shift.

Super explanation of how this works. This site rulz in friendliness and people willing to help.

 

[72HCODE]

thanks it is kind of a simplified explanation.

the modulator can have a tremendous effect on your transmission shift points. it another area of tunablity that can get you in trouble too.

when i put my trans back together my first drive the trans was shifting so fast that i would floor it an basically be in 3rd waiting for the rpms to pick back up.

i thought it was slipping or not shifting so i would accelerate slowly and then i could feel 1st, 2nd, 3rd.... i didn't understand it until somebody told me about the modulator. I started to mess with it and got the shift points to spread out. then i went a touch too far and the shift points spread out too far and i was out of the power band again.

I messed with it a few times on different drives and eventually narrowed it down.. I still feel my shift point is a little too short sometimes but for 99% of the time its fine and nothing like before where it was like 123 and now its like 1..2..3

some people think it is like a shift kit but that is a change to the valve body. the modulator is more like a fine adjustment where the valve body spring kits are a course adjustment.

it is a good compensation for a low vacuum engine with a automatic, low vacuum will mess up the stock modulator settings and make the shift points way too long. making the car feel very lazy.

Like if you buy a car and then you want more power, so you drop a mild cam in the car your engine vacuum HG" drops from 20-22HG to 12-15 HG" and suddently the engine makes more noise but the car feels lazy.. so somebody tells you well that is cause you have a 3:1 radio swtich to a 3.5:1 to wake it back up...

Shhhhh,,, you could also turn the modulator screw in hold 1st gear longer and shorten the shift points back up compensating for lower HG output . there is a limit of course before you really should spend money on the rear end but you would be amazed what a couple of turns on that screw tells your butt in the driver's seat

 

[Bill73Ragtop]

My 73 C6 originally had a dual line vacuum moduator. Back in the mid-90's the re-builder changed it to a single vaccum line and blocked off the 2nd line. Not sure about FMX, but the shop manual might have more detailed information.

I also spent some time adjusting the modulator screw. Big pain since you have to try to get a long skinny small screwdriver through the transmission mount right next to really warm exhaust pipes. I would turn it one turn in - road test - readjust in or out depending on the change. Took about 3 - 4 test drives to dial it in.

 

[72HCODE]

ah yes the dual line modulator... basically you had one line going to the EGR or ported vacuum and the other to full manifold vacuum.

the shift points would change with exhaust temperature the idea was to save MPG with transmission shifting linked to the temperature of the motor through the EGR valve. usually the effect was softer shifting which is better for increasing MPG.

on the highway i think you gained like 1MPG or something. it was a way to boost the fleet MPG numbers and fall into CARB requirements.

usually if you had a dual modulator you had a dual vacuum advance on the distributor as well. usually this was for 74 models. so you could of grabbed a trans from a 74+ car and when you bolted it up to a 73 or less you blocked off the second vac line unless you wanted to use it on the later 73 cars with the EGR valve could of been a normal thing on a CALI car of the day also since they had stricker emissions laws back then

 

[wwhite72]

The original modulators were not adjustable. Always better to replace with the newer adjustable ones

 

[Cole]

Fuel pump went in with just a little effort. Thanks again for the tips.

New lines to the tank connected, gravel guard in the wheel well done. Got a 3/8 adapter for the fitting and bending the tube to the carb asap. Probably do that and get the battery and cables ready. Then its wheels back on and roll her in the driveway and see if she cranks. Ain't no way I'm cranking this gal in the basement.

Might be a good idea to go back over and recheck all the tightness of stuff I've done. Wow that's a couple days. U-joints, bearings front and rear, new master cylinder, new power booster, new calibers, new rotors, front brake lines rubber, both steel lines up front, new drums with all new hardware, new gas tank with sending unit and trunk seal, new gas line, new fuel pump, new battery cables to the trunk. Wow not bad for a couple months considering I'm lucky to get a few hours in the morning and maybe an hour or so at night once bay girl hits the sack. Still a long ways away but can't wait to take her riding in it!