[TheSilverBuick]

Overhauled the fuel system yesterday and today. This should put an end to the fuel starvation issue for sure. I pulled the tank, and it is clean inside. I'm sure it's been replaced at some point in the car's past and the sending unit is certainly an aftermarket unit. The sock was black but relatively clean, but I removed it entirely anyways like I did on my Skylark. I moved the lift pump to the same level as the bottom of the gas tank (from the middle) and if that doesn't solve the issue, then it's the pump itself.

Made some pretty big changes by moving the pressure pump and surge tank to the rear of the car as well as all new fuel line on the driver's side (opposite side of the exhaust system and side the fuel rail is on). Despite not having a return line from the fuel rail it fires up quickly and so far runs pretty good. For reference, I've never had a return line from the fuel rail on this car. On to the pictures.

For all the dozen and a half connections in the lines, I only have one small weeper, so over all I'm quite happy. I tried tightening the union up but it won't seal. So tomorrow I'll pop it off, remake the ~12" pipe and ends and hopefully will solve that. Might switch to a flared fitting if the hardware store has them.

Here is the panel I made with all the fueling stuff on it. The lift pump on the bottom to the first filter, into the surge tank, then from the surge tank to the high pressure pump, through an EFI fuel filter, to the fuel pressure regulator then out to the front of the car or returned to the surge tank.


Mounted in the car. I utilized the lip on the gas tank as a support then two bolts through the trunk floor to secure it in place.


It's angled in place.


From the rear of the car. This union is my weeper. Just the top half, and it's the pipe that connects to the fuel pressure regulator. So I'll re-do the top half tomorrow.


Just following the brake line.


Along the outside of the subframe. Like OE, but on the driver's side.


Up into the engine bay. Ahead of the flywheel plane and a short piece of nylon fuel line to account for vibration.

[TheSilverBuick]

Replaced the union first thing Sunday morning and no more weeping. So all appears tight and good. I drove the car to work yesterday and will for the remainder of the week and if nothing serious crops up I'll drive it CA. The dirt parking lot and road coming to work should provide an excellent way to tell if I have any fuel seeps anywhere as the dust should stick to it.

I am having an electrical issue with the smog/vacuum pump popping the fuse. It seems to be drawing far more amps than it should, which I hope isn't indication it's going south. It sounds healthy, like a fan/blower motor should. There are a few examples out there of folks saying they've had continuous duty durability issues with them, but all state it quits working, nothing about popping the fuse.

So I checked the amp draw on one of my spare air pumps and it pulled between 10-12 amps running, and the one on the car is pulling about 18 amps, but it also had a ton of heat soak. So I put it on it's own circuit with a 20 amp fuse. I had two other things on the same fuse, so between the three they were popping the 25amp fuse. I'll prep the spare one for use and maybe install it on Wednesday as driving to work this morning it popped the 20 amp fuse, so it's probably ready for total failure. When I'm in CA I'll hit the junkyards and see about grabbing an electric air pump from a mid-90's Taurus as they are reportedly more robust than the LT1 one I am using.

The damn fuel problem cropped up again driving home from work yesterday. It has to be the lift pump. So I installed the Thunderbird's old TBI pump and threw the other one in the trash. Plus it moves a lot more volume too.

Time to drive it some more.

[TheSilverBuick]

Changed the oil, loaded up the trunk, and ready to head out of town tomorrow after work.

Also added some decals to please me.

[goatwgn]

Very nice work. Sounded good in video.

[TheSilverBuick]

Thanks!

Still running into fuel problems #%&*!!! I tried to leave town Thursday afternoon and it quit on me about 30 minutes out, but I found that if I pinched the return line to the gas tank the pressure would come back, so I put a clamp on it and started on my way again. It went as long as around 80 miles without a hiccup, but eventually hiccupped again and again and again. So I turned it around about 155 miles from home and went home, at which point it ran the whole 155 miles home without a hiccup, aarrrggghhh!

So I made and stuck a restrictor tube in the return line to keep some pressure in the surge tank, as after some discussions with some folks it sounded like my lift pump was possibly cavitating because it was designed to hold 22psi and it was running unrestricted.

My restrictor tube, a piece of 3/8 steel with a piece of barbed 1/4" fitting inside and the sides of the steel tube crushed to hold in place.



So test drive number two. It was worth driving down the CA for the day at this point, so I opted to go to Bonneville Salt Flats for a day drive. It's about 130-140 miles each way and was forecasted to be hot. Perfect testing conditions.

Made the whole trip there without an issue. Got to the end of the salt flats road, took a "victory" picture, had lunch at the Salt Flats Café, and started home, buuuut didn't even make it out of Wendover and the car stalled out on me. This time my pinching the line trick didn't work. So if it's a vapor lock issue, it vapor locked hard with the restrictor tube in place. It was around 100ºF out, so plenty warm.

So many recommendations to re-do the fuel system again and set the regulator after the fuel rail and run a return from the engine bay, but that is a lot of work and I'm not convinced that adding engine heat via the fuel rail will actually help this case. It should be getting lots of "cooling" air flow in it's current location. So I instead made a new surge tank, similar to the old one but taller for more heat sinking ability, put the regulator return line above the lift pump inlet so fuel returned will be pushed upwards back to the gas tank instead of downwards to the high pressure pump. Which should reduce re-circulation of "worked" fuel. And lastly I welded cooling fins to the backside of the surge tank that hang off the side of the panel and gas tank and should see lots of airflow.

Thursday afternoon I leave for the Car Craft Anti-Tour. It's supposed to be 111ºF in Las Vegas, so if I have a problem it should crop up no later than there. If I have a problem, I will turn around and head back home and get my Skylark for the event.

My premature victory picture. The smoke from the Washington wildfires has settled onto the salt flats making it hazy.

[TheSilverBuick]

Made more changes to the fuel system, and it let me down again 50 miles outside of town. Going to run a temporary rubber EFI line from the fuel rail and move the regulator to after the fuel rail and see if it corrects the issue. I was pretty disappointed it didn't make it to the Car Craft Anti-Tour.

[TheSilverBuick]

I need to wash the car =/ We've had a few rain storms this week. I have not made a single change to the car, but have been driving it reliably to work and around town for the last week.

[Ollie]

I talked to you a while back about your serge tank.
I like the idea of the way you have the fuel system set up.
In a forum search on MegaSquirt I found this link.
http://www.msextra.com/forums/viewto...347224#p347224
And this link I am gong to investigate further.
http://www.bcbroncos.com/store/produ...roducts_id=119

In post 101, photo #7 what compression fitting did you use at the metal line and the nylon hose.

[TheSilverBuick]

Yup, I learned of that filter/tank from a Ford guy shortly after building my Firebird's surge tank. I'm not opposed to using one, and actually may in my Skylark when I re-do the fuel system this winter.

I'm still not sure what is up with my Firebird's system. I'm considering by-passing the surge tank altogether and simply not let the tank get below 1/4 (or 1/2 if needed..) to test the "rest" of the system. Such as a pump or regulator problem. I've always had issues when the tank is only down a gallon or two from full, so I should be able to troubleshoot without the surge tank hooked up.

I'm going to be working on the car this weekend.

[TheSilverBuick]

Since the second electric LT1 smog pump has started to give me fits I figured I need a better solution. So I'm trying out an exhaust evac system. I would of liked to of welded it in at the merge between the two manifold outlets, but given the amount of oil this thing seems to pull I didn't want to risk fouling the O2 sensor, so I put it there. It definitely pulls a vacuum, but it doesn't seem like a very strong vacuum, but does "feel" similar to the electric smog pump, so it should be a break even deal at minimum for now. I may swap out the chambered Flowmaster muffler for a flow through type or glass pack.


To further pull oil out of the line, I've replaced the breather on my catch can with the evac intake.


Now I'm going to go swap out the front shocks and sway bar end link bushings. One of the front shocks has no bushing at all left in the lower mount.

[TheSilverBuick]

Finished changing out the front shocks and sway bar end link bushings. Neither shock had any lower bushing in it.... How is that even possible unless it was cut out intentionally? Should end one of the front end klunks it had.

[Formulabruce]

Interesting thread! My 2cents on the oil. I have rebuilt a few of these in the past, and every time we went above 60psi, we had more oil consumption, and crankcase pressure. My Grandfather ( 55 years as a GM mechanic) said it "No way" needed more than 40 psi in any condition ( warmed up). He was right, put back in a stock melling pump and oil consumption dropped way off and cam stayed plenty oiled.
Older internal combustion engines NEED to run rich to run well, and cool, on todays fuel. Modern A/F ratios for performance do not always apply for optimum economy and performance on old engines.. Just my thought, Love all your engineering, Have fun!! Bruce

[TheSilverBuick]

Interesting. I have a couple different oil pressure springs I could try/modify and make a change to the oil pressure as a test. Right now it's regulated to 50-55psi and cold with 10w-30 it doesn't exceed that and sits nicely at it cruising at 2,700rpm. Its easy enough to swap the relief springs out though. It's a stock oil pump (same as an Olds Hi-volume pump from what I'm told). I'd like to get it on a dyno (preferably after getting EGT's installed on each exhaust port...) to really check the performance.

I pulled the transmission pan yesterday because I did not like the slack that had built up in the TV cable adjustment and wanted to make sure there wasn't a mechanical problem at the valve body. There wasn't, just looks like my cable adjuster was letting the cable slip by, so I put a second cable holder on it to hold it as well as make sure the adjustment is set right for WOT.

While I was under the car I installed two clear fuel filters on my set up. One on the return line to the tank and one on the feed line to the high pressure pump. Try and get a better idea of what the fuel is doing when it "hiccups". On the next road trip out of town, I'm going to carry two lengths of fuel lines, one to run the gas tanks pickup right to the high pressure pump, and one if needed to run the regulator return line right to the gas tank's return line. It will limit my ability to run down to 1/4 tank, but should at least tell me if I'm having a fuel pump/regulator issue or an actual surge tank issue.

Also, it seems the exhaust system isn't pulling enough vacuum and must pressure up while under WOT because crank case pressure built up enough to blow out the rubber plug in the oil fill tube yesterday during some WOT blasts. That had never happened with the electric pump. However with the electric pump, if extra crank case pressure occurred it just pushed the pressure through the pump, now the way it's set up, it has to go out the exhaust and at WOT if the exhaust is pressured higher than the crankcase then there is no where for the crankcase pressure to go. I'm going to do two things, one is tee in a PCV valve on the vacuum side of the catch can (in the evac hose) and the second is look for a new style of muffler or get a glass pack. Basically a non-chambered muffler. It's going to change the sound of the car, but oh well.

Next time I am in CA I'm definitely going to the junkyard to pick up some MAP sensors and plugs, hopefully from cars with the 3.8 and supercharger on it, so I can start datalogging the crankcase pressure and maybe even the exhaust back pressure.

I also have started the process of re-painting the stock rims for the car. I'm considering going back to 14" rims (and a shorter tire) for a while and the stock look. Right now they are all white, so I need to mask off the "spokes" part and give it a coat of black.

I also ordered a "short" kit for a disc brake conversion. It was $160 for a disc brake spindle, backing plate and caliper bracket. I have rotors, calipers and a master cylinder and maybe even a disc/drum porportioning valve left over from the Skylark when I upgraded it to disc/discs and 12" rotors up front. I had a $100 Amazon gift card from a survey prize to bring the cost to $60 (free shipping even!). Not sure when I'll actually do the conversion, but I'll have the parts ready to go.

[Formulabruce]

Sounds like you have a plan, or two!! hope it works out!
In Internal Combustion engines, and this is prominent in 6cyl. GM, the restrictions on the exhaust side in the head and valve timing, give the motor more torque. This is true of todays truck engines as well, the heads are different than the car engines and the exhaust is restricted to produce more Torque. I am wondering if the design "requires" more backpressure to run the way it was supposed to? Just something to think on.
I would get a stock oil pump, no hi volume, or pressure and see how it goes, the mechanicals are the same as stock as far as RPM, and the bearings.. Good luck!! Love your posts!, Bruce

[TheSilverBuick]

It is 100% stock, and well used, oil pump. I don't believe they make any other kind of oil pump for this engine. After years of hearing 10psi per 1,000HP, it makes me quite nervous only having 30psi of pressure with the stock regulator spring and winding the engine up =P And even more so knowing a turbo will be on it at some point.

I have a re-ground "turbo" cam with less over lap and more exhaust duration for when I go that direction.

[TheSilverBuick]

My "$60" disc brake conversion kit parts showed up this week. I dug out what I could find in five minutes of the Skylarks old brake parts. Looking up rotor spec's the Skylark hubs may be a 1/2" too deep =/ So might need new rotor's anyways. I didn't find the combination valve, but didn't look very long either. This project is slated for November so I'm going to get new bearings, seals and brake hoses in that time. As well as one caliper rebuild kit (the other is in the picture). Maybe a master cylinder rebuild kit as well (or just bench test it and I have another on the shelf...).

I'm going to assemble the spindle on the bench and get a feel for the rotor hub issue. Shame, because the rotors are over an inch thick and the min spec is under an inch so they can still be cut smooth. New rotor's on Amazon.com are $41 each...

[TheSilverBuick]

I pulled the exhaust on the Firebird tonight to change out the chambered 40-series Flowmaster for a flow through glass pack to make the exhaust evac system work better.



Now I just have to weld it together. I probably won't actually weld the glass pack on just so I don't have to worry that it's not "clocked" right on some of the bends. I'll U-clamp it, at least for now.

[TheSilverBuick]

The exhaust change didn't have much effect on the crankcase pressure, but today I figured out the problem! I had switched out the OE oil cap for a Mr. Gasket one, but found out the crimp seal didn't seal worth a crap and that was killing the ability to pull any vacuum in the crankcase. So my solution? A quick trip to the hardware store.



Which resulted in plenty of crankcase vacuum! However, it seems to now generate a seal whistle at around 8inHg vacuum. D'oh. I'll figure that out later. It still generates pressure at WOT and low rpm. I haven't tried WOT and high rpm yet. Cruising down the highway at 60mph it was pulling decent vacuum. :thumbs: I have noticed a change to the oil pressure to the lash adjusters though, so I have to give more thought on what to think about that.


As a reminder, I'm taking a reading from the crankcase at the brass fitting under the red tube.

[TheSilverBuick]

Last weekend I drove the car to California and who ever called bad fuel pump wins. Despite it being purchased new earlier this year and only having three or so thousand miles on it, it is junk.

Made it 70 miles before it quit on me. Hot wiring the pumps on and looking at the clear filters, it was obvious the feed to the pump had fuel and the low pressure pump was circulating fuel as I expected it to be. Pinching the return line to the gas tank still caused it to pressure up to 43psi, and de-pressurize when I let go. Strange. So I zip tied the known good pump from the Skylark (been on there since 2011 and has probably 25,000+ miles on it (2 Drag Weeks even at 4,000 miles round trip each), and moved the lines over and it fired up and made the next ~1,200 miles without any fueling issues.


(Oh, and always remember to put the car in park or set the parking brake! I pulled over there after coasting in neutral. I was under the car and it started to roll backwards on me! Yikes!)

The crankcase vacuum behaved weirdly, it seemed to have a tough time pulling/maintaining vacuum below 3inHg, but as soon as it hits that 3inHg it'd pull up to 6-10inHg fairly quickly and hang onto that vacuum through a variety of driving conditions. What had confused me the most though is, it'd pull nice vacuum climbing a hill, but as soon as I start coasting down the other side the vacuum completely goes away. The intake manifold vacuum (pcv valve) is double digits and it doesn't seem to be able to pull a vacuum on the unloaded or nearly unloaded engine. Just seemed strange. It pulls plenty of crankcase vacuum at idle, yet looses vacuum cresting and going down a hill. Then a friend told me that a pcv valve only passes vaccum at mid-level vacuum, not at high or low vacuum conditions, and suddenly what I had been seeing made sense.

So I stopped by the local Home Depot and picked up a brass fitting with the same dimensions as the PCV valve and swapped it in. Now vacuum in the crankcase mimic's manifold vacuum to a tee (is there a pun in there?). I have not noticed any drivability or idle changes with the swap.

I pull the vacuum through my catch can, so any oil drawn in should drop in the catch can's copper mesh "filter" I have in there, as well as using several baffles in the crank case to try and keep most the oil down. In the mean time though, I'm going to be closely watching my oil level for any changes. In "theory", under vacuum mist should drop out of suspension in the crankcase and overall mass transfer to the catch can should drop as well. I've noticed before, the more often the crankcase stayed under vacuum conditions the less oil and such accumulated in the catch can, the more often it was at atmospheric or pressure conditions the more oil would accumulate in the catch can.

It also takes about 4 seconds after shut down for the crankcase vacuum to bleed off. I may start looking for a high flow check valve and look at possibly attempting making my own vacuum relief valve to keep vacuum below 6-8inHg. It does make me a tad nervous seeing 15+inHg in the crankcase. I keep waiting for it to suck the oil pan gasket in =P

Also the dang electrical plug on the transmission has come loose. I'm not sure what even holds it into place, but it is dripping fluid and has a ton of play in the hole. So I guess I get to drop the trans pan and inspect/replace the plug.

It made the trip like a champ since the fuel pump swap. The oil consumption driving home was even acceptably low. I didn't add any in the 475 mile drive home, which the engine was sitting at basically 3,000rpm for the whole trip.

Heading to Vegas this morning. Traffic was very light, having left my Mom's house at 5:30am.


Here are the trip stats. I averaged 19.3mpg.



The next round of changes after I fix the trans electrical plug is a small update to the exhaust evac setup and then swapping out the rear axle for a 8.5" with a true limited slip differential. For now it's parked in the garage until I have time to fix the trans leak.

[TheSilverBuick]

I also forgot to mention the trans started shifting soft about the time I noticed it started leaking (or maybe the soft shifting is why I noticed it was leaking?). It wasn't much difference initially, but the drive home and since (I haven't driven it more than 5 miles since I got home from CA) the gear engagement and shifting had gotten quite soft. So I figured when I dropped the pan to change out the plug I may drop the valvebody as well to check it out. It was suggested a check ball may have debris keeping it from sealing, etc. But as soon as I dropped the pan and saw a bolt and washer in it, I figured I probably found the culprit.

Yup, the TCC solenoid was missing one bolt and the other was fairly loose. Guess I forgot to torque them down when I last messed with the valvebody. It was probably hemorrhaging fluid and pressure there. Or at least that is what I am hoping and that by bolting it back up and tightening the bolts the shift firmness comes back. There was a fair amount of black material coating the pan, but the fluid doesn't smell burnt.


I've ordered a new plug thing to stop the leak (I broke two tabs removing it, it's crunchy) and a filter/gasket set. I think after I get it back together, if it is shifting well I'll swap out the rear axle for the 8.5" with 3.42 gears and a limited slip carrier. I'll probably be looking for a set of 4.56's for the 8.5" soon after =P

I was browsing E-bay and craigslist for a used but good 4L60e (as I was getting pessimistic about the 200-4r) and I may attempt to pick up a used one next time I leave town. We'll see.