2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Fuel pump mod???

Thread Tools
 
Search this Thread
 
Old Sep 25, 2002 | 09:13 PM
  #1  
Angel Guard Racing Team's Avatar
Thread Starter
Rotary Enthusiast
Tenured Member 20 Years
 
Joined: Jan 2002
Posts: 975
Likes: 5
From: Puerto Rico Land Of The Fastest Rotaries
Fuel pump mod???

CALLING ALL UNITS!!!!!!!!!!

I met this guy that said he removed the check valve from the fuel pump so that the car won't flood at startup. He said it works... I don't know... Any comments on this will help many people.
Reply
Old Sep 25, 2002 | 09:40 PM
  #2  
CrackHeadMel's Avatar
Learned alot | Alot to go
Tenured Member 20 Years
iTrader: (2)
 
Joined: Apr 2002
Posts: 4,232
Likes: 0
From: Rotaryland, New Hampshire
the check valve that goes to the charcole canister? what would that have to do with flooding, it doesnt even go the the injectors or any of that
Reply
Old Sep 25, 2002 | 09:50 PM
  #3  
Angel Guard Racing Team's Avatar
Thread Starter
Rotary Enthusiast
Tenured Member 20 Years
 
Joined: Jan 2002
Posts: 975
Likes: 5
From: Puerto Rico Land Of The Fastest Rotaries
I don't know what check valve. Does the pump have one inside? He was talking bout not having pressure at the fuel rail at the moment of startup. I know nothing about the inside of the fuel pump.
Reply
Old Sep 25, 2002 | 09:57 PM
  #4  
inboost's Avatar
Full Member
Tenured Member 15 Years
 
Joined: Jul 2002
Posts: 166
Likes: 0
From: Orange County, CA
This is a bad idea but I'm sure it works if the hot-start is due to leaky fuel injectors ONLY...

The check valve in the fuel pump keeps pressure in the fuel rail to prevent the fuel from boiling off and 'vapor-locking' the motor. If you have a leaky injector, it leaks down this maintained rail pressure and washes down the rotor. Without oil the rotor won't seal and then you have a no compression hot-start.

Removing the check valve will result in no rail pressure and subsequently no leaking of fuel into the motor. It also allows what fuel does remain to boil off and vapor-lock the rail. Now you'll have a long cranking fit to get the pressure back up.

Not much of a solution in my opinion
Reply
Old Sep 25, 2002 | 10:02 PM
  #5  
Angel Guard Racing Team's Avatar
Thread Starter
Rotary Enthusiast
Tenured Member 20 Years
 
Joined: Jan 2002
Posts: 975
Likes: 5
From: Puerto Rico Land Of The Fastest Rotaries
Where the hell is this check valve located?
Reply
Old Sep 25, 2002 | 10:08 PM
  #6  
Liquid Anarchy's Avatar
We come with the Hardcore
Tenured Member 10 Years
iTrader: (2)
 
Joined: Nov 2001
Posts: 2,456
Likes: 0
From: Springfield, MO
If I recall, Mazdaspeed 7 mentioned this. It's on the solinoid rack. After removing everything he said that he couldn't get his car to flood no matter how hard he tried. I could be wrong tho. Ask the man.
Reply
Old Sep 25, 2002 | 10:17 PM
  #7  
inboost's Avatar
Full Member
Tenured Member 15 Years
 
Joined: Jul 2002
Posts: 166
Likes: 0
From: Orange County, CA
The check valve that maintains the fuel rail pressure is inside the fuel pump.

Up on the 'rack' is a soleniod that will temporarily increase fuel rail pressure (on S5 cars at least) during cranking. It does this by disconnecting the fuel pressure regulator from the manifold and preventing the vacuum signal from the manifold from lowering the fuel rail pressure.

Perhaps this is waht you're after?
Reply
Old Sep 25, 2002 | 10:26 PM
  #8  
Angel Guard Racing Team's Avatar
Thread Starter
Rotary Enthusiast
Tenured Member 20 Years
 
Joined: Jan 2002
Posts: 975
Likes: 5
From: Puerto Rico Land Of The Fastest Rotaries
Actually he gave me the fuel pump to try. I just want to know if the check valve can be put back in. I got a dead TII pump at home.
Reply
Old Sep 25, 2002 | 10:30 PM
  #9  
inboost's Avatar
Full Member
Tenured Member 15 Years
 
Joined: Jul 2002
Posts: 166
Likes: 0
From: Orange County, CA
That I don't know...
Reply
Old Sep 25, 2002 | 10:30 PM
  #10  
Liquid Anarchy's Avatar
We come with the Hardcore
Tenured Member 10 Years
iTrader: (2)
 
Joined: Nov 2001
Posts: 2,456
Likes: 0
From: Springfield, MO
... Maybe he's an idiot?
Reply
Old Sep 26, 2002 | 02:09 AM
  #11  
Angel Guard Racing Team's Avatar
Thread Starter
Rotary Enthusiast
Tenured Member 20 Years
 
Joined: Jan 2002
Posts: 975
Likes: 5
From: Puerto Rico Land Of The Fastest Rotaries
What the hell, I'll take them apart and see wat's inside. I got nothing to loose.
Reply
Old Sep 26, 2002 | 11:24 AM
  #12  
NRA T2's Avatar
Senior Member
Tenured Member 05 Years
 
Joined: Sep 2002
Posts: 420
Likes: 0
From: wa
go for it
Reply
Old Sep 26, 2002 | 02:31 PM
  #13  
jacobcartmill's Avatar
just dont care.
Tenured Member 20 Years
iTrader: (6)
 
Joined: Jul 2002
Posts: 9,387
Likes: 4
From: Nashville, TN
i removed my solenoid rack (and rats nest) and i cant get my car to flood no matter what i do. i can leave the fuel pump primed for like 1 minute and it wont even flood.
Reply
Old Sep 26, 2002 | 08:34 PM
  #14  
Angel Guard Racing Team's Avatar
Thread Starter
Rotary Enthusiast
Tenured Member 20 Years
 
Joined: Jan 2002
Posts: 975
Likes: 5
From: Puerto Rico Land Of The Fastest Rotaries
Great! I'll be doing surgery on monday so I'll let ya'll know...
Reply
Old Sep 30, 2002 | 05:03 PM
  #15  
RETed's Avatar
Lives on the Forum
Tenured Member 10 Years
 
Joined: Feb 2001
Posts: 26,664
Likes: 22
From: n
A fuel pump cut-out switch will cure almost ALL flooding problems without breaking the check valve out of the fuel pump.


-Ted
Reply
Old Sep 30, 2002 | 05:19 PM
  #16  
RestoTII's Avatar
Senior Member
Tenured Member 10 Years
 
Joined: Jul 2001
Posts: 576
Likes: 0
From: Havre de Grace, MD
I hate saying it, since the Fuel Switch is a really rigged mod that screams "I can't fix the real problem, so I'll work around it", but the switch actually does serve it's purpose VERY well. I haven't had any probs with mine after installing a switch, but it still seems like the "using a 30A fuse cause you keep blowing 20A fuses" fix.
Reply
Old Sep 30, 2002 | 05:24 PM
  #17  
RexRyder's Avatar
Rotary Freak
Tenured Member: 20 Years
iTrader: (11)
 
Joined: Dec 2001
Posts: 2,965
Likes: 6
From: Tucson
and plus if you hide the switch real well, you can use it as an anti-theft device.
Reply
Old Sep 30, 2002 | 05:30 PM
  #18  
RETed's Avatar
Lives on the Forum
Tenured Member 10 Years
 
Joined: Feb 2001
Posts: 26,664
Likes: 22
From: n
Yes, it's a band-aid, but if your engine does flood (and it will), at least you won't be caught in the rain or some similiarly bad position.

I run 4x720's and my engine will still flood on a very hot day.

At least the switch doesn't inconvenience me in any way like the other methods I used to use (pull fuses under the hood, pull fuse in the kick panel, pull relay on steering column).

A $2 switch and some connects makes it a $5 job and an hour of your time.&nbsp Very cheap considering your other options...


-Ted
Reply
Old Sep 30, 2002 | 06:35 PM
  #19  
silverrotor's Avatar
Moderator
Tenured Member: 20 Years
iTrader: (1)
 
Joined: Mar 2002
Posts: 7,592
Likes: 5
From: Toronto, Corporate Canada
Originally posted by RETed
A fuel pump cut-out switch will cure almost ALL flooding problems without breaking the check valve out of the fuel pump.


-Ted
I did It with spectcular results. Never flooded after that and even still, the Fuel Pump Cut of Switch acts as a great securuty measure.
Reply
Old Sep 30, 2002 | 08:39 PM
  #20  
RexRyder's Avatar
Rotary Freak
Tenured Member: 20 Years
iTrader: (11)
 
Joined: Dec 2001
Posts: 2,965
Likes: 6
From: Tucson
Originally posted by silverrotor


the Fuel Pump Cut of Switch acts as a great securuty measure.
exactly
Reply
Old Sep 30, 2002 | 09:17 PM
  #21  
Angel Guard Racing Team's Avatar
Thread Starter
Rotary Enthusiast
Tenured Member 20 Years
 
Joined: Jan 2002
Posts: 975
Likes: 5
From: Puerto Rico Land Of The Fastest Rotaries
My car does not flood at all ever!!! I just need a TII pump and he gave me this one. I got 550 primaries and 720 secondaries on an 87 n/a turbo engine, auto tranny and ecu. I just wanted to know what was up with that check valve thing.
Reply
Old Sep 30, 2002 | 11:20 PM
  #22  
RestoTII's Avatar
Senior Member
Tenured Member 10 Years
 
Joined: Jul 2001
Posts: 576
Likes: 0
From: Havre de Grace, MD
the security measure I won't argue with, but since my car has never had any threats of theft, I'm not that worried about it. I have a Viper alarm that's only armed when I accidentally hit the button in my pocket, so it's not that great of a bonus. However, if it's used for anything other than a theft device, then it's merely a "lazier" way of pulling the fuses under hood. Not that I'm knocking it, since I use it myself but I'm just saying it's really rigged and the real problem needs to be addressed.

To Angel Guard... I don't believe the check valve will make much difference, and like was mentioned earlier, the pressure related explanations are the same reason I'd use.
Reply
Old Oct 1, 2002 | 12:19 PM
  #23  
Angel Guard Racing Team's Avatar
Thread Starter
Rotary Enthusiast
Tenured Member 20 Years
 
Joined: Jan 2002
Posts: 975
Likes: 5
From: Puerto Rico Land Of The Fastest Rotaries
the security measure I won't argue with, but since my car has never had any threats of theft, I'm not that worried about it. I have a Viper alarm that's only armed when I accidentally hit the button in my pocket, so it's not that great of a bonus. However, if it's used for anything other than a theft device, then it's merely a "lazier" way of pulling the fuses under hood. Not that I'm knocking it, since I use it myself but I'm just saying it's really rigged and the real problem needs to be addressed.

To Angel Guard... I don't believe the check valve will make much difference, and like was mentioned earlier, the pressure related explanations are the same reason I'd use.
Reason you'd use for what? My car does not flood at all. I just need a TII fuel pump and stumbled upon this one that had been modified. The guy did it when the pump was still in his car and this solved the flooding for him. Since my car does not flood I just wanted to know if it could damage the pump.
Reply
Old Oct 1, 2002 | 01:08 PM
  #24  
Kspurr's Avatar
Sometimes I miss my RX-7s
Tenured Member 05 Years
 
Joined: Mar 2002
Posts: 321
Likes: 0
From: McKinney, TX
Lol, I actually bought my first TII by selling "modified fuel pumps" when I was 17to 18. I did the mod on my first rx-7 vert, because I couldn't get it to stop flooding and I wouldn't ghetto rig a damn switch to my injectors and clear it whenever the car flooded. People said to do everything from hook up some purge thing that let pressure off the fuel system sold by Mazdatrix, to hooking up the ghetto switch. Since my dad and I had dealt with an injector leak on an old project 240Z w/a v8 by removing the pressure valve on the pump, I gave it a try. It worked great and my car never flooded again. Yes, the car will take a second longer to crank, because it has to build up to the 35 or so psi maintained by the stock fuel system. If you can tell that it takes longer to crank, you have issues. I would bet that you couldn't tell a differeence when cranking my TII Convertible with a modded FD pump and another TII.

To do it just take the pump out of the car and get some needle nose pliers. Then rip the little plastic looking basket thing out of the fuel pump opening.

You won't be able to put it back in. Really, you'll break it pulling it out.

This will save you from the embarrassment of have to clear your motor with that ghetto "theft detterent" switch, and you won't leave a big plume of white smoke when you get the car started.

Some people may not like this mod, but to all their own. I would only have a switch like that in a car that I didn't have passengers in. Both are patches instead of solutions, one just doens't require any intervention or maintenance.

PM me if you have any questions or issues.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Queppa
New Member RX-7 Technical
11
Nov 18, 2024 03:47 AM
trickster
2nd Generation Specific (1986-1992)
25
Jul 1, 2023 04:40 PM
Rotospectre
New Member RX-7 Technical
3
Mar 28, 2018 03:33 PM
Skeese
Adaptronic Engine Mgmt - AUS
65
Mar 28, 2017 03:30 PM
ChrisRX8PR
Single Turbo RX-7's
21
Oct 18, 2015 04:01 PM




All times are GMT -5. The time now is 12:30 PM.