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Discussion Starter · #1 ·
Hi Peeps!
I decided to wait a bit before posting this as I wanted to try it out first and confirm that it seems to be all better now! (I also wanted to test it at the SCCA Solo Nationals for an acid test!)

Some of you may have seen my struggles with fuel starvation recently and as I was able to get my 05 Elise going faster in the SCCA AStreet class, I started experiencing fuel starvation. I had the same problem many have experienced here, long left hand turns, with off camber making the issue even worse. The amount of fuel needed to prevent starvation seemed to correspond with my getting the car to go faster. What started at 1/4 to 1/3 full and having an occasional pause had progressed to a full 2 second stall with 2/3 full tank. I basically had to have 7/8 of a tank or more to prevent starvation!

While several solutions have been discussed on these forums, the rules for "stock/street" class effectively ruled out virtually all of them. The short version is, I could not update/backdate between years, and only factory parts are allowed and only factory TSB solutions or superseding of replacement parts is acceptable.

Well, I found/stumbled upon the answer.
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Discussion Starter · #2 ·
I perused MANY old threads and found many if not most talking about the sealant breaking up and leaving gaps ? at the baffle next to the fuel pump. What was not clear was how a miniscule gap at the baffle would require 7/8 of a tank to over come. Not sure if the sealant would block the "inlet" pipe or what. The sealant seemed to chunk off and I did not find any film, or fine powder that would block the inlet screen. And if this was the case, why would a more full tank improve the situation?

Well, prior to me replacing the tank, the only thing that appeared would help me was a few threads that said when the dealer replaced the tank with new, the problem went away. I had resigned myself to needing a new tank every few years to stay legal. There were some comments that the later tank solved the issue, but I soon found the tanks were changed in 06 and later. In addition to not being legal, it would not fit the same as the 05 tanks were different.

So I ordered a new tank, what follows is observations of the new tank (The REAL news) and it's improvements, observations on pump removal and why it's so difficult AND as the cars get older, a step by step change out procedure for those of us needing to retain original parts (and not break older, potentially hard to find plastic parts). All of this from my hopeful memory (I took several pictures intending to eventually write this). :LOL:
 
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Discussion Starter · #3 ·
So, I'll start with the "B" tank as that is the real news. I had several people say, just put the "fixed tank" in, no one will know. Also, as many more say "just run a full tank, certainly cheaper". Well, If you knew some of the money I've spent to save a few pounds of weight, the amount I'd spend to potentially save 30-40 pounds of fuel weight was a no brainer.

First off, I tried to order the original "A" tank, "A121L00.." and was told that they only had the "B" tank in stock. Don at AutoEurope confirmed with Lotus that this was a superseded part and the current replacement tank for the 05 Elises. I only knew of the exterior dimensions at that point, as did Don. I sent him pics of a "spare/used" I had just bought in a panic in case I needed to fix that in order to fix my issue.
Below are pictures of my tank and the spare, once I removed it and you can see the holes in the pump side baffle and failed sealant chunks.

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Discussion Starter · #4 ·
NOW, for the "B" tank improvements!! Lotus REALLY worked at fixing the issue and it's obvious inside and less so outside.

Notice the reduced holes and a PIPE welded to the inside of the pump area! Once the fuel goes in, it REALLY takes a long time to leave!! LOOK!

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Discussion Starter · #5 ·
Less obvious, but ultimately is quite important I think is noticeable from the outside.

Below is my original "A" tank..
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Note the SINGLE spot weld on the baffle per side...
 

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Discussion Starter · #6 · (Edited)
NOW, on the "B" tank, note the FOUR spot welds per side on the baffle!!

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My opinion is that the fuel sloshing around and the way the large expanse of thin sheet is held in the car is allowing distortion and thus breaking the sealant on the original tank. The four spot welds per side would go a long way towards preventing any distortion and allow the sealant to do a manageable job!
 
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Discussion Starter · #7 · (Edited)
The proof?
Well, although I had two local events prior to Nationals after changing the tank, neither had left hand turns of any real duration. HOWEVER, I had returned to running 1/4 of a tank, an instant 25+ pound weight reduction, likely more.
NO STARVATION and when I went to take the car off the trailer when I got it home, It was showing 1 bar and the fuel light was on!!
On the west course at Nationals, there was a decent large left to give more of a test and I was a bit paranoid, so added a wee bit of fuel, but likely was "just" at 1/4 tank and no issues! YAY!! Problem solved!! (Now if I could drive the car faster, I'd be even more happy!! But I still have things I have yet to address, getting faster each time :))

Next up, fuel pump replacement observations and tips.
 

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Discussion Starter · #8 · (Edited)
Okay, now on to pulling the pump. AFTER I pulled the pump, I WISH I had a little info that seems critical to ease of replacement!
It's hard to describe, but I drew a couple pictures of the issue to help explain the point. Several here may already know this, but I never saw it noted on most threads regarding replacement. The easiest is to just be sure you have the Toyota replacement pump housing top on hand, then pray and work slowly. (Toyota part #77024-17020)

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This is a representation of the untouched factory install. Where I think some of the problem is a link some have provided to a video where a tank is ALREADY out and shows the pump top is almost out and to pull the top ring AND what to do if it gets stuck... or try to do.
The problem I think is the first thing the video shows is them simply "lifting" the mounting ring off with a slight tilt. THIS is the beginning of the problem! IF you want reuse (or try) the top, LEAVE THE RING THERE. If you have the above replacement part in hand, you can cut the fuel line nipple to pull the ring if you want.

But here is the KEY, DO NOT TILT THE PUMP TOP AT ALL AS YOU LIFT OUT (See below)

Handwriting Orange Font Amber Writing


If you tilt the pump to lift the ring off (or try) you have a high potential to "catch" the edge of the opening. It is relatively thin metal, but not weak. The problem is the stamp places a rolled edge, almost an interference fit and you need to lift straight up if at all possible. It is a tall task, but some have done it.
As you can see in the above poor illustration, if you tilt the top, it starts to catch the edge of the tank opening and it is just thin enough it will roll up "with" the pump plastic, which in turn, locks it even tighter!!
With a new tank, it's obvious the tank starts flat and both my and the spare tank now have a "berm" at the opening where it "locked in" the Pump housing top.

Several threads discuss replacing the pump while in the car, I'll let others address the access to the pump, I just want to add observations I wish I had known before attempting mine!

Once tilted and "locked" all sorts of ugly things are done to try to remove...
the ugly results of mine below :sick:

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Discussion Starter · #9 ·
Next I'll describe tank R&R.... soon. Hopefully ONE person finds it useful!
 

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Excellent write up and thank you for the details that will help others in the future. I can't help but think the crap floating around in our tanks might be causing all kinds of intermittent issues that could be attributed to this.
 

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I had a hell of a time with mine. Could not believe the dissolved glue now powder. And likely why my pump (pain in the arse to remove tank, worse to get the pump module out!).
As I couldn’t afford a new tank, I used some bent rods to get around corners to clean up the remains. I dont think there was/is much left but…who knows. Hope I dont have a problem in the future. The POR has been holding 3 years and counting now. The Toyota replacement module was a fair price, though I went with a aftermarket pump.
 

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I don’t understand how so many people are having such a difficult time taking their pump assembly out of the car? If you do the modification to the aluminum the pump literally comes straight up and out and same in reverse. Am I missing something here?
 

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Discussion Starter · #13 ·
I don’t understand how so many people are having such a difficult time taking their pump assembly out of the car? If you do the modification to the aluminum the pump literally comes straight up and out and same in reverse. Am I missing something here?
That was the point of my post. There is a video out there that shows someone lifting the ring off of a pump top that is basically already out. If one thinks the ring needs to be pulled first, it will not go over the fuel line nipple, and the natural reaction is to tilt the top to try to squeeze it by. This starts the process of "locking" in the top.
My point is, there really is no threads with a now obvious warning..

"DO NOT TILT THE PUMP TOP AT ALL, YOU MUST LIFT STRAIGHT UP ONLY"

If I had not seen the video linked in a spot or two, I might have just pulled straight up, ring and all. Since there are MANY threads showing all the work they had to do to get it out, I'm just trying to help with a pointer/observation.
 

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That was the point of my post. There is a video out there that shows someone lifting the ring off of a pump top that is basically already out. If one thinks the ring needs to be pulled first, it will not go over the fuel line nipple, and the natural reaction is to tilt the top to try to squeeze it by. This starts the process of "locking" in the top.
My point is, there really is no threads with a now obvious warning..

"DO NOT TILT THE PUMP TOP AT ALL, YOU MUST LIFT STRAIGHT UP ONLY"

If I had not seen the video linked in a spot or two, I might have just pulled straight up, ring and all. Since there are MANY threads showing all the work they had to do to get it out, I'm just trying to help with a pointer/observation.
Yep. Sorry that wasn’t a post to knock anyone I was genuinely curious as I’ve seen a few people completely destroy their cars trying to take the pump out.
 

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I don’t understand how so many people are having such a difficult time taking their pump assembly out of the car? If you do the modification to the aluminum the pump literally comes straight up and out and same in reverse. Am I missing something here?
Pulling the housing from a '06+ tank is much easier than a '05. Which one do you have experience with? The 05 is a real pain!
 

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I don’t understand how so many people are having such a difficult time taking their pump assembly out of the car? If you do the modification to the aluminum the pump literally comes straight up and out and same in reverse. Am I missing something here?
I thought Lotus revised the tanks for 06' which made it slightly easier to get them out compared to the 05' tanks?

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NOW, for the "B" tank improvements!! Lotus REALLY worked at fixing the issue and it's obvious inside and less so outside....
Thanks for posting this. I did not know this tank existed! I will be spreading this good word, for sure.
 

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Pulling the housing from a '06+ tank is much easier than a '05. Which one do you have experience with? The 05 is a real pain!
That may be the case my last 2 were both 07+ with the housing behind the drivers seat. A quick modification to the car cutting out some of the aluminum made for Really easy removal of the assembly. If the 05+ are different then that is news to me and thats where the confusion lies
 

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I believe the access hole in the 2005 was slightly smaller than in later years. Generated quite a lot of swearing looking at some old threads. Hope I never have to replace my fuel filter.
 
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Discussion Starter · #20 · (Edited)
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You can see the "berm" created on tanks that saw battle as the top of the pump top catches and gets raised up as one fights to pull the top.

Not sure if the 05s had a tighter opening, but the new tank was flat and still snug when installing new pump cap.
 
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