Subject: [TR] TR3A running poorly when outside temp goes up

From: "Kinderlehrer" <[email-masked]>
Date: Sat, 17 Aug 2013 15:17:35 -0700

I've been having this problem for awhile but it seems to be getting worse.
On Tuesday it was the worst; I drove to Carmel,CA, about 1 1/2 hours. It was
cool out in the morning and the car ran great. I'd already replaced points,
plug, condenser, and coil and rerouted the gas line and gas filter. Coming
home, the car started right up and ran well for the first 30 mins, then I
got out of the coastal fog and into the sun and an ambient temperature in
the 90's. Then the car started backfiring, popping, cracking and losing
power. All of this at highway speeds, no lights, no stops. If I backed off
the gas for a few seconds then gave it gas, it would run ok for a few
seconds and then start backfiring again. Engine temp and oil pressure were
normal. I nursed it home this way and parked it until the next day. I pulled
the plugs and the last 2 were black and oily. The front 2 looked good, it
looked like I had been running on 2 cylinders. 

I installed a heat shield I had ordered from TRF, removed the rear float
bowl, checked the float, cleaned the bowl and valve and checked the float
level. It fired right up, I then adjusted the carbs as it seems they were
running too lean. 

This morning I drove about 15 minutes in town for breakfast then about half
an hour on the highway to club gathering and it ran really great. Maybe half
an hour later I went to move it and it didn't want to start. When it finally
did, it was coughing and sputtering. Left the bonnet up for a bit, then it
started and after coughing a bit starting running ok -  clouds had come in
and temperature was cool. 

I thought it might be a bad tank of gas, but I've had the problem in
different forms through many fill-ups. I thought it might be the corn they
put in the gas, but no one else seems to be having this issue. The only
other thing I can think of is the fuel pump. Could that be it? 

Any ideas would be greatly appreciated.

Thanks,
Bob

** [email-masked] **

Archive: http://www.team.net/archive

---

From: "Kinderlehrer" <[email-masked]>
Date: Sat, 17 Aug 2013 16:47:53 -0700

Yes, I suspected vapor lock. I did clean the filter and change the element,
it's one of those glass tube things- maybe I should change it. I didn't
remove the sediment bowl  -I will do that though I don't know why that would
be heat related. I have replaced the soft lines after the fuel pump. No
after market mods to the top half of the engine, but I can pull the valve
cover to see if anything looks strange. 

It seemed too lean because when I pushed the pin  or lifted the damper, it
would stumble and stall. Also, on compression while driving - going down
hills, downshifting for stops - there was a lot of popping, which seemed to
be alleviated this morning while it was running well.

I appreciate the ideas, thanks!
Bob 

-----Original Message-----
From: Randall [mailto:[email-masked]] 
Sent: Saturday, August 17, 2013 4:08 PM
To: [email-masked]; 'Triumphs'
Subject: RE: [TR] TR3A running poorly when outside temp goes up

> If I backed off the gas for a few seconds then gave it gas, it would 
> run
ok for a few seconds and then start backfiring again.

That sure sounds like a fuel delivery problem, though I can't explain why it
would only happen when it's hot.  Did you try changing the (aftermarket)
filter?  Check the sediment bowl & screen?  How's the tank vent?  Have the
soft fuel lines near the carbs been changed in the past 10 years or so?

> I pulled the plugs and the last 2 were black and oily.

The oily part sounds suspicious.  Do you have any modifications that would
increase oil on top of the cylinder head?  Might be worth pulling the rocker
cover, just to check that the pushrod tubes (which double as oil drains) are
open.

> I then adjusted the carbs as it seems they were running too lean.

Can you expand a bit on that?  Why did it seem too lean?

-- Randall

---

From: Jonas Payne <[email-masked]>
Date: Sun, 18 Aug 2013 08:54:11 -0700

Check your oil and make sure you didn't blow a head gasket.

Its also likely you have a vacuum leak around your new shield and it's
causing the car to run lean and therefore hot.

Jonas Payne
PBR Consulting
702-882-6711

-----Original Message-----
From: [email-masked]
[mailto:[email-masked]] On Behalf Of Kinderlehrer
Sent: Saturday, August 17, 2013 3:18 PM
To: 'Triumphs'
Subject: [TR] TR3A running poorly when outside temp goes up

Thanks,
Bob

Archive: http://www.team.net/archive
http://autox.team.net/mailman/options/triumphs/[email-masked]

---

From: "Kinderlehrer" <[email-masked]>
Date: Sun, 18 Aug 2013 10:34:29 -0700

Thanks, Jonas. Did check the oil, all is well. The problem started before I
installed the heat shield, but I'll check for vacuum leaks again. 

-----Original Message-----
From: Jonas Payne [mailto:[email-masked]] 
Sent: Sunday, August 18, 2013 8:54 AM
To: [email-masked]; 'Triumphs'
Subject: RE: [TR] TR3A running poorly when outside temp goes up

Jonas Payne
PBR Consulting
702-882-6711

-----Original Message-----

Thanks,
Bob