Blackbari

Anyone here running an external fuel pump for their TPI Camaro? This is the third time the in tank fuel pump has died on my '88 IROC. So, I'm really thinking about running an external fuel pump since it's such a pain to change the in tank pump.

CrazyHawaiian

Have you thought about doing the fuel door mod? It supposedly makes it much easier to replace those pumps, but I dunno if its a good idea for a full interior street car. I'm lucky in that none of my cars have needed a replacement yet, but when I do eventually do the job I'm gonna cut out that fuel door. Then you'll be able to change the pump without dropping the tank. But if its full interior then you'll have to pull carpet to get to that door, so I guess its still somewhat of a PITA.

One thing to watch out for, if/when you do go external pump, pay attention to the sizes of the fuel lines that it uses. I bought a nice aeromotive pump for my Z28 project, but then realized when I got it in my hands that the gastank would need to be sumped, and custom lines made to be able to reach the advertised flow rates. Kinda wish I knew about all that before I bought it.

Blackbari

A hole in the trunk floor was cut by us when it needed to be replaced the first time. We still had to drop the tank a bit, but not pull it off the car. Second time the fuel pump went out, same thing. It's still a pain even with the hole in the trunk floor.

Couldn't GM have designed this car better with service in mind? Hell no. Taking the rear suspension off, the exhaust system, heat sheilding, and maybe if you're lucky, not stretch the brake hose.

It's so ironic that cars designed with a fuel pump access door tend to have fuel pumps that last? Yet those with fuel pumps that burn out every few years make it so hard.

So, I'll try an external fuel pump. If it doesn't work, fine. I'll just do it the way I've done it 4 times before, pull the tank down and open the trunk floor. Thanks for the replies!

HI85WH1

What brand pump have you been buying...??

My friend had an issue with Carter pumps...

he bought GM the last time and has had no issues sincee...

Duck

Here's some photos of the mod, showing the location of the cut very well, done this way the pump can be completely removed without disturbing the tank. Since the fuel system is typically 40-50 psi, AN fittings on the feed and return lines is appropriate. In my mod, welded AN fittings were used on the tank side to minimize potential problem areas. FYI had I done this mod prior to driving cross-country, it would have enabled me to install a failed fuel pump in the middle of the desert as a roadside repair of spending $1,000+ to have it done in Las Vegas a thousand miles from home. Changing the in-tank pump takes 30-minutes and you're back on the road again.

Blackbari

Has anyone done the fuel line and hose clamp mod as seen in the second photo (blue trunk)? I know TPI is high pressure, but do you think this mod can be done and driven with daily?

Duck

Sure, quite a few guys have done it using FI hose, although I'd double-up on the hose clamps. In the thread below, Pasky did it exactly that way on his 383 LT1 3rdGen. I prepared a replacement in-tank unit using welded AN fittings as shown in the photos, to replace the in-tank unit on my '87 IROC which has a broken sending unit. If I was in a hurry I would have done the FI tubing option instead of the AN fittings. The external pumps are quite noisy too ... I prefer the access panel mod, especially for doing the next roadside pump replacement [couple years ago I spent about $1,500 to have the tank dropped in Vegas when the pump in the '92 took a dump in Death Valley].

https://www.thirdgen.org/techbb2/sho...=&pagenumber=1

Duck

Here's another example of a product from a commercial company making aftermarket internal fuel pump conversions for TPI in previously carbed cars. Just make sure to use high pressure FI tubing -- NOT regular fuel tubing.

Blackbari

I tried the external fuel pump. It doesn't work. Many of you already know that electric fuel pumps push fuel better than pulling it from the tank. At least I tried.

So, after reading the flame wars on this site elsewhere about cutting a hole in the trunk vs. doing the "right" way, I'll be doing it the way I did it before: through the hole we cut in the trunk floor and removing the fuel pump from the top and still having to remove most of the rear suspension.

For those who say doing it the "right" way "isn't so bad, 'took only three hours,' 'don't do a half okole job'" must either:

Have a lot of help and doesn't mind taking off so many things just to change a pump. Any of you who have or had a small block Chevy with a carburetor and mechanical fuel pump know changing the mechanical fuel pump is really easy.

Have a twin post lift to raise the car over your head and changes fuel pumps often on cars at a repair shop (I only have a floor jack that can only go as high as a typical 3.5 ton jack can lift)

Or is just a purist and desires to leave the car as if GM designed these cars as superior and frowns on anyone cutting up the body (many Japanese cars have fuel pump access doors to make this job much easier). And GM wonders why somtimes people don't want to buy their cars? Repair bills that are astronomical just for one job can be a reason.

Now that I have said that, I'd like to do the improvements that Duck has shown on this thread. I'm not a welder, but I'd sure like to put fittings on the fuel line to make changing the fuel pump easier. If any of you have done this, where have you gone to have it done?

Hydra-Air Pacific?

Or is there a kit of fittings to make brake hose, high pressure fuel hoses without welding?

Thanks for reading.

Duck

Doing the mod is easy enough to do in a carport, especially if you opt to do it like in the photo of the blue car and use FI tubing and a small tubing cutter. There is no need to jack-up the car or remove suspension/exhaust components. Yeah, I ran around town to find the AN fittings and had them installed at Hydra-Air. They were idiots and screwed it up the first time by using compression fittings which would have leaked and caused a fire, so I had them redo the job by welding female fittings on the engine side and flaring the tubing for female fittings on the tank side.

Next time I do it, I'll just cut the tubing and use the FI tubing.

3rdGenBlackBird

Someone else can speak up if I'm wrong, but Hydra-Air seems like the 'radio shack' of hydraulic supplies. I wouldn't use them for anything that they could screw up, because some of them don't know jack. Can't speak for every employee there, though.

Scott

acescarrsRS

i agree. they use to be alot better in the past.....don't know what happened haha!

Blackbari

Thank you for the help Duck. However, I got my IROC running Friday night. The high pressure fuel lines from a V6 1992 Firebird does fit V8 TPI cars. I got the fuel lines from that junkyard behind the old Pearl City Tavern. That F-body car was the only one in the yard. The engine was intact if anyone needed stuff from it.

I used a compression fitting from Hydra-Air Pacific for the fuel feed. The other three, I just used regular fuel hose and hose clamps. No leaks to report. Car runs just like before. The next time (I hope not soon) the fuel pump goes out, I'll spend a lot less time changing it. Those who feel doing it the "right" way by taking off the exhaust, rear suspension, dropping the gas tank, etc., are just in for a long repair.

Duck

Glad to hear it's running again. If the pump dies in the middle of Death Valley, it'll take about 30 minutes to pop in a replacement and be on your way instead of being towed to Las Vegas for a 3-day fix. There's a certain smugness in knowing this...

acescarrsRS

I still cringe hearing that story from you Ed..I can only imagine how that whole experience was!

Duck

The untold part of the story is that we were on a time deadline to enroll my son in college in Arizona, lateness would mean not being able to keep his dorm reservation. The car repair in Vegas was finished on the third day at 6 p.m. and we had to race across two states ... we beat the admissions office deadline of 12 midnight by 15 minutes.

It could have been a lot worse, as the GM dealer put our repair at the first in line, instead of making us wait two weeks. I sent the dealership a nice thankyou letter.

You never know when the pump will fail. Not a big deal here on Oahu, but it sure is on the mainland.

3rdGenBlackBird

Hydra-Air recommends compression fittings for everthing, dont they?...

I don't think compression fittings belong on a car, even if you carry spare ferrules. That's just my opinion though, it should work fine.

stew'86MCSS396

Doesn't make it right but suppose it's an accepted practice, if you go to Redline and look for their fuel line repair kits, that's what you'll get, 12-18" tubing with Saginaw fitting on one end and the supplied compression fitting. I guess we're not talking fighter jets with 3000 psi hydraulic systems! stew

Blackbari

This will save me time should the fuel pump go out. No leaks and it runs just fine. I don't care what people think, accepted or not, right or wrong.

3rdGenBlackBird

Yeah, don't see any problem with them on fuel systems. I don't recommend them on brakes though, but hydra air seems to.

Duck

During the weekend my pal Tony and I swapped-out the leaking fuel tank in my '87 IROC and installed the modified pump assembly with the AN fittings to facilitate access through the hatch. We put the car on a lift.

The mechanical process is simple, dropping/installing 3rdGen rears is basic, but wrestling the tank in and out is insane due to the weird angle of the neck and the tunnel it goes through. I can't imagine people doing this laying under a car on jack stands... Sure glad "big arm" Tony came along to show the tank who's Boss!

It's a good feeling to know that on the next cross-country road trip, I won't have to drop the rear to change a dead fuel pump -- just pop in the spare kept in the trunk.

Duck

Gosh oh gosh ... bad things seem to happen sometimes, sigh. After all that work Tony and I did dropping the rear and swapping the gas tank, I was driving the IROC and after filling the tank for the first time -- smelled gas.

Big smell, almost knocked me out of the car. Pulled over to the side of the road, looked under the car didn't see any fluids dripping, so pulled back the carpet and removed the pump access panel to check the fittings. Nothing loose there, but the smell of gas was overpowering, which meant the O-ring between the tank and the pump assembly wasn't sealing the joint. Rolled windows all the way down and got the car home to fix the problem.

Seems these tank seals slipping out of the groove are a common problem when pulling/replacing the fuel pump. I even put some lube on the parts to help the seating, but to no avail. I screwed up by reinstalling the OLD style seal, which looks like a big O-ring. GM part number 22515965 costs about $11 and is an upgraded AC Delco O-ring with three locating tabs and a composite with a layer of steel inside, the new design is much more stable. I should have bought this new design part first time, but I didn't know a replacement upgrade was available.

Oh BTW, changing the tank seal means removing the pump assembly. For those who haven't modified the fuel system to more efficiently access the pump, it means another lost weekend dropping the rear, dropping the tank, etc, etc, then putting it all back and starting the engine to see if the job was done right or not.

This was a good test of how valuable the access panel mod is changing a bad fuel pump on the side of the road -- using only three open end wrenches and one screwdriver enabled removing the fuel assembly, changing the tank seal, reinstalling and firing up the engine to check for leaks in 20 minutes. Hardest part was tucking the carpet back under the interior panels. Would have been faster, but I made a trip inside to put a few Steinlagers on ice and quaff a cold one.

I'm stoked about this... I'd be incredibly bummed-out if I had to pull the tank again...

Blackbari

Yes, if you have not cut a hole in the trunk floor of your car to change the fuel pump, do it. Anyone who has changed the fuel pump the "right" way knows that it takes way too much time, is difficult to do, and you have to remove far too many things. Some purists who say not to cut a hole in the trunk must love pain or only read books on how to do it. Why make things harder than it should be?

Duck

Having been at the center of a couple of flame threads in the fabrication area concerning the "do or don't" aspect of this topic, and whether or not it is a "mod" or a "hack", I can assure you the passions run high on both sides. I've come to the conclusion that it's useless to try to persuade people who have already made up their minds. That's OK -- they can do whatever they want to their stuff and I'll do whatever I want to my stuff.

micktroup

I have had to replace three fuel pumps in as many months, so this thing is going back to the dealer that put in the replacement fuel tank in the first place(as per the 1994 recall that is STILL open for 1991 cars). Particularly since it make a 'bump' sound and fails to start for no reason(pressure problems).
But why the big fight over cutting an access door in the trunk floor- sounds like a stroke of bloody genius if you ask me...
GM made 800,000+ of these things and mine cost me $2600- it's not a Ferrari! No one at Pebble Beach or Barrett/Jackson is going to mark you down because you have a fuel pump access door in your trunk!
Can someone supply a template for cutting out the correct section?

Duck

There are quite a few photos and messages with instructions for doing this modification, obtainable by searching the forums. It's so simple, just looking at the photos should eliminate any need for a formal template.

Jim Rockford

Man,you guys have got me worried now that my fuel pump is gonna go out!
I have a 1989 formula 350 with factory t-tops in addition to my second gens.
it has about 150k miles on it,and so far I havent had to change the pump.
How long do they usually go before the go out?

Can I use an in-line electric pump to avoid dropping the tank?,I'd really hate to hack up the sheet metal in my hatch if I didnt have too.
You would have thought that the engineers at GM could have thought up a better way of doing this,but they probably didnt give a damn since they want you to buy a new car anyway.

pvt num 11

Co-worker tried to stick an external in-line pump on his 1992 RS, but he left the stock pump still in the tank. Then he wondered why the in-line pump didn't deliver enough fuel - it was trying to suck through the old, dead pump he didn't remove.

Jim Rockford

Well,I guess that wont work then!

Duck

Eventually the pump will fail, it's impossible to predict when. The pump in my red '92 Z28 failed in Death Valley, CA and was replaced in Las Vegas. It now has a GM dealer lifetime parts/labor warranty that cost more than $1K.

In-line pumps don't work well with TPI setups and are really noisy. If you have a race car with open headers, you probably won't notice ... but if you like cruising on the highway without the sonic whine of a dental drill, use an internal tank pump.

Whether or not you decide to mod your car is purely a personal decision. Work done neatly using quality parts is a "mod" not a "hack". Besides, after you're done you can carry around a spare fuel pump hidden in the back, smug with the knowledge that it can be changed in less than 15 minutes with common hand tools on the side of the road.

The access hatch will be hidden under the rear carpet, no one will ever know if you don't tell them. It can be our little secret...

Jim Rockford

Hi Duck,
Thanks for the advice!,sounds like making a small **carefully done** hatch is definetly the way to go! a thousand bucks for a fuel pump replacement...OUCH!
Is it true that the factory GM replacement fuel pumps last longer than the ones bought at the local auto parts store?
In order to make a pump hatch in the trunk,the tank has to be dropped first right?
can you give me the exact dimensions that need to be cut out so I can make a template?

Aside from the fuel pump issue and the body flex with the 350 and t-tops I really love my thrid gen! Glad I found this site!

Duck

Don't know if the GM pumps last longer, but AC Delco pumps are what I have [got a couple used ones I carry around just in case...].

No, the tank stays in the car. The fuel hard lines need to be cut, then modded with removable devices. All work can be completed from the hatch area. The photos in the article show the general area to cut. Use snips, not power tools. Make sure the sheet metal screws holding the hatch cover in place are short, so they don't dig into the tank top. Oh, when replacing the fuel pump assy, install a NEW rubber O-ring in the tank seal, or it will likely not seal correctly.

Jim Rockford

Thanks again!,where can I see the article you are referring too?

Duck

Photos of hatch cutouts are in the posting dated: 11-28-2005, 06:51 PM

dirtyguido

Ok here's a twist on this discussion....

We've pulled the stock TPI setup off our our 1987 Iroc with the 350. The fuel pump isn't the greatest, as at idle it would push 45lbs, but would drop down to about 30 under engine load, and the car felt a little fuel starved. (Granted we bought this car used, as it sits, so we don't know the reliability of the gauge). The car doesn't like to idle much, (you have to keep the rpm's up using your left foot on the brake), and in general its just so much simpler without the FI on there, for now.

So we are converting this car to a holley 600cfm 4 bbl carb setup. We had it laying around anyway and just want to keep it driveable as we build the 403ci small block that will find its way into the car.

So how would you handle fuel for the carbed motor? Can we just use a mechanical fuel pump on the front of the motor, and disable power to the TPI pump? Will the mechanical pump suck through the in tank pump? Mind you we only need 5lbs of fuel pressure with a carb. We have a fuel pressure regulator, but in only handles 20lbs of inlet pressure, which the TPI pump exceeds. The FPR we have also does not have a provision for a return, so the tank return line would just be plugged off on this setup.

The other thing we discussed was and this may sound crazy... Building a voltage divider circuit using power resistors to slow the TPI pump down by dropping the voltage to the DC motor, and effectively spinning the motor slower, and in turn lowering the fuel pressure it delivers to a level the holley FPR can handle?

Does that sound like a viable option?

What do you guys think?

Thanks in advance,

George

Jim Rockford

Hi,according to what I've heard you should be able to install a mechanical fuel pump on the side of the engine block like it would normaly have on a non tpi car.You might have to remove the electric pump in the tank though for it to be able to suck the fuel through.
there are also smaller low pressure holley external electric fuel pumps that you can use to feed the carb if you decide to go that route.they make a little noise.but arent nearly and loud as the high pressure ones that were discussed here.
A friend of mine used one on a 50's buick and it was pretty quiet.

GaryDoug

One of the reasons some auto manufacturers stopped putting gas tank access "doors" in the trunk floor was because of all the heat they got about the ruptured gas tanks in the 70's and 80's. If the door/cover isn't strong and firmly attached , it can provide an avenue for flames and smoke in the event of a rear end collision. And it will vent directly into the passenger cabin.
Check this link: http://bestaccident-attorney.com/carcrashfires.html and many others on this subject. The best position for a rear fuel tank is ahead of the rear axle. This is the opinion of many experts in the automotive industry and government agencies. The Camaro and Firebird have the tank aft of the rear axle and ahead of the rear bumper, in the infamous "crunch zone". Make sure that whatever mod you make is as rugged as possible. Perhaps two .035" sheet metal layers, one below the deck and one above.

emeryz28

I just did mine in my 92 Z-28 (5.7TPI). It took about 20 Dremel blades to cut the panel out. I used a mini hack saw to cut the fuel lines. The two outer lines are larger than the two inner lines. I went to Autozone and bought the pump and three different lengths of fuel injection hose for less than $100. The O-ring that came with the new pump was not as thick as the original, so I reused it. It hasn't leaked so far but I just did it a few hours ago. I doubled up on the hose clamps. Sure beats dropping the rear end and exhaust. I had a full tank of gas too, so the tank would have been heavy. Never even got close to cutting the tank with the Dremel. There's about an inch between the body panel and the tank.

emeryz28

Just a follow-up on my prior post (because I don't want anyone else to have to go through this if they don't have to).

After I installed the new pump, I noticed the engine was hesitating and still hard to start. I checked the pressure on the fuel rail and it was only at 20 psi and it bled down immediately after turning the engine off. I suspected it was a bad fuel pump, so I took it back to Autozone and tried another pump. Still the same problem.

After ruling out a bad pressure regulator, the factory shop manual flow chart points to a restriction in the fuel line. So I used compressed air and blew the lines out. I was able to watch the fuel pressure gauge on the rail shoot right up to 47 psi when I blew air in from the supply line at the pump.

Then I read on this site about the fuel pulsator/damper and it dawned on me that the rubber fittings on both ends of the pulsator had expanded and caused a loose fit. To make a long story longer, the loose pulsator--a $28 part--was the cause. What was GM thinking when they designed this thing to stand behind 50 psi?

The shop manual would have you believe that the pulsator is not even installed on the 5.7L Z-28. On models that have it, they do say to dry it off, shake it and listen for fuel that might have entered into it. It says to replace it if you hear fuel inside--not a word about checking the rubber end fittings for a tight fit.

Anyway, here's the symptoms I experienced over the past two years that I believe are directly attributable to the pulsator--not a bad fuel pump, regulator, or ignition:

Starting two years ago, under heavy acceleration, it felt like the ignition was retarding. I replaced the ignition module and related components, but no help. Now, I understand that the loose pulsator must have been bleeding fuel back into the tank under high demand and the engine was leaning out, causing the ECM to retard the timing to prevent detonation. I lived with that problem because it only happened under heavy acceleration.

Six months ago, I noticed that after I parked the car, it was gradually becoming more difficult to restart. I discovered that if I turned the ignition on and activated the 2-second fuel pump relay a few times (to pressurize the system) it would start fine. Now, I realize that the pulsator was allowing the pressure to bleed off and it didn't matter if the in-pump check valve was working or not, since the pulsator is above the pump.

I can't imagine how much time it would have taken to "do it right" and drop the tank. I had the pump out five times over the past two days.

The dealer does not carry the pulsator and they had to special order it today, so I would presume that it is not customary to change this part when they do a pump replacement at the dealer (the right way).

karl's-92'-z28

iTrader: (5)

On the hose clamps when you double up, you should have them opposite of each other, instead of the same way. So the clamping force by the screw will be kind of even, instead of one side.

emeryz28

I'll do that when I install the new pulsator and factry pump this weekend. The new O-ring on top of the tank is different than the original in that it has three locking tabs underneath. I asked the parts guy and he said that the 5.7L had the tabs but the 5.0L did not. He said that GM must have upgraded the O-ring and added the tabs. Anyone else notice this?

Duck

Yes, the new O-ring is much better than the older version. In my experience you don't need the pulsator, just replace it with a piece of FI hose. I've driven my TPI 5.7's this way for several years.

Fords88Bird

I know this post is a little old but anyone doing this should use fuel injection line and also fuel injection clamps. Later.

Duck

Actually, the post is timeless, since it goes into detail about modding Camaros to avoid dropping the fuel tank to change the fuel pump. And yes, the high pressure requires FI hose and clamps. Note that the clamps should be in pairs, set in opposite directions.

Blk84CamaroZ28

Duhhh? Are there actually different Hose clamps for Fuel Injection?

OR is that the new term for using two hose clamps in opposite directions?

P.S. I just dropped the tank the pain in the A&& way, now I stumple upon this! Dang it! I plan on adding this AWSOME access door, so when this pump fails or it's in need of up grading - I will be able to change it with a smile. But I plan on making this hole a little smaller than the previous photos I've seen, rounding the corners a little, and maybe even adding a hinge on the door?

THANKS TO ALL WHO HAVE POSTED ABOUT THIS AND ADD PHOTOS, THE PHOTOS ARE THE BEST! This experience went from dreading it to loving it. Thanks Again Yall.

HI85WH1

There is indeed a specific hose clamp used for EFI applications.

Standard hose clamps pinch the hose whereas the FI HC uses a 360 degree band...

here is a site with some info http://www.fuelfilters.biz/fuel_injection_hose_.htm

Blk84CamaroZ28

Oh I see, Thanks Again!

ASE doc

Hi guys, Just piping in on ext pumps. I run a hi G settup using a Holley blue pump at the tank with an AN 10 suction hose into the tank. It feeds a reservoir at the front of vehicle thru 1/2" fuel line. The res is maintained at 7psi using a bypass reg. An Aeromotive 1000 pump draws from the res to feed the rails. A Mallory billet reg conrtols rail press. I kind of wish I had just sumped the tank and installed the Aero 1000 direct. But my system does work well and no cut out even at 1/4 tank and 1g.

Dejan Ilic

Hi ,I am from Bosnia and Herzegovina.Just bought the Pontiac Firebird Trans am with dead fuel pump.Can U give me the mesures where to cut to reach the pump?I chose easier way. )))