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Re: [TR] Fuel starvation in my TR4 - Report back

To: dmericas@austin.rr.com
Subject: Re: [TR] Fuel starvation in my TR4 - Report back
From: Ben Zwissler <bjzwissler@gmail.com>
Date: Mon, 20 Sep 2010 17:36:17 -0400
Running out of ideas....

"It recovers immediately if I back off the throttle."  That sounds 
absolutely like fuel starvation, except about everything that would 
cause that has been suggested and you've checked.  I'd check and recheck 
anything that could cause low fuel delivery to the carbs.  Also check 
the carbs themselves, are the dashpots free to move all the way through 
their travel?  Are they Strombergs or SUs?

I second the motion on trying an electric (Facet) fuel pump if all else 
fails.  Maybe clean/replace the float bowl valves.  Remove and clean the 
main jets themselves, maybe some dirt blocking them.  If SUs maybe the 
flexible line to the jet is kinked or blocked?

Ben.....


Ben Zwissler
bjzwissler@gmail.com
Columbus, IN
1966 Triumph TR4A
1973 MG Midget
1980 Triumph TR8
2007 Mazda RX8
2002 Yamaha FZ1
2003 Honda ST1300


On 9/20/2010 9:09 AM, dmericas@austin.rr.com wrote:
> Thanks for the suggestions Ben.
>
> Regarding #1, the fuel pump is pretty low on the TR4 block, and I believe the 
>level of the inlet is almost always below the fuel level in the tank.  I've 
>had problems with a nearly full tank.  I would expect to see some fuel leakage 
>if there was a cracked rubber hose, but I'll try putting in all new hoses when 
>I drain the system.
>
> Regarding #2, I swapped out the pump with a good spare that I had on the 
>shelf, with no effect whatsoever.
>
> Regarding recovery time, a few moments is probably more accurate.  It 
>recovers immediately if I back off the throttle. It takes longer if I the push 
>on, for example to continue up the hill.
>
> Dean
>
> ---- Ben Zwissler<bjzwissler@gmail.com>  wrote:
>    
>> OK, two more suggestions.  Both based on the fact you get this problem
>> only going uphill.
>>
>> Suggestion 1.  Going back to 1979, there's a parking lot outside our
>> dorm that has a slight grade (nose up).  Roommate's car won't start when
>> parked in that position.  Starts and runs fine anywhere else.  Plymouth
>> coupe with tank mounted under trunk.  With nose up fuel level is below
>> fuel pump inlet.  There's a crack in the rubber hose at the fuel pump
>> inlet.  When fuel level is below pump inlet, pump draws air rather than
>> fuel.   Replace hose and problem solved.
>>
>> Suggestion 2.  Similar issue, but problem is in fuel pump.  Leaking
>> one-way valve on inlet behaves like cracked fuel line. Same issue if
>> there's crack in the diaphragm.  Solution, replace or rebuild fuel pump
>> or try an in-line electric pump.  Crack in diaphragm can also cause some
>> fuel to go to crankcase so adding an electric pump when you have a
>> cracked diaphragm will push more fuel into the crankcase.  Watch for
>> rising oil levels...
>>
>> Does it really take a minute or two to recover?  That seem likes a long
>> time for a fuel supply problem, starts to sound like something else again.
>>
>> Ben......
>>
>> Ben Zwissler
>> bjzwissler@gmail.com
>> Columbus, IN
>> 1966 Triumph TR4A
>> 1973 MG Midget
>> 1980 Triumph TR8
>> 2007 Mazda RX8
>> 2002 Yamaha FZ1
>> 2003 Honda ST1300

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