Still having weird idle issues

[stever_sl]

In a previous topic I mentioned that my TR8 is having an erratic idle, sometimes way too fast but usually way too slow - and that it was hard to start because it wasn't choking (the car has water chokes). Got some good advice that led to me having the carbs cleaned and adjusted, and when I got the car back I was happy to see 800 rpm idle on a cold engine. Then I drove about half an hour at highway speeds, but when I pulled off to a traffic light and put in the clutch I found that the idle is 2100 (again) with a hot engine. This pattern has been repeating since then - 800 rpm cold, 1500-2100 hot. The shop mentioned something about needing a vacuum advance unit (vacuum retard?) but those seem to be as rare as hens' teeth, and I'm not sure why they think the one in the car is bad - I get great acceleration with no hesitation now.

Since cleaning and adjusting didn't help this erratic idle issue, does anyone have any thoughts about what I could try next? I really respect the huge amount of knowledge here!

- Steve Richardson
St Louis MO
76/77 TR7
80 TR8

[busheytrader]

I had an similar issue with a carb'd engine. As the engine warmed up so did the vacuum hoses which began to soften. An existing split opened up causing an air leak which bypassed the carbs - hence the higher idle.

As the engine cooled down the hoses hardened up and became airtight again.

Adam





TR7 V8 DHC Jaguar Solent Blue. 9.35cr Range Rover V8, Holley 390cfm, JWR Dual Port, 214 Cam, Lumention, Tubular Manifolds, S/S Single Pipe Exh, 3.08 Rear, 200lb Spax & PolyBushes all round, Anti- Dive, Strut-Top Roller Bearings, Capri Vented Discs & Calipers, Braided Hoses, 4 Speed Rear Cylinders, Uprated Master Cylinder & Servo, AT 5 Spokes and Cruise Lights, S/S Heater Pipes, Replacement Fuel Tank. No Door Stickers. Mine since July 1986, V8 from 1991

[Workshop Help]

A friendly reminder; underneath the fuel filler hose is the plastic vapor separator box with it's two hoses. As these hoses are hidden from view, they are usually forgotten and deteriorate to allow a vacuum leak.

These 5/16" hoses are cheap to replace. It may be worth a look behind the metal panel with it's three screws.

Mildred Hargis