Vapor canister was OK, and I changed the coolant temp sensor also. In fact, I
changed/replaced the coil, ignition amplifier,distributor cap, plugs & wires, and air
flow meter. No luck. When I started it today- it ran worse than last night, even
stumbling and stalling. No more restarts and it runs OK for a moment… Lots o’ black
smoke. I changed everything, then pulled a plug- totally black. I figured if I had fixed
the fouled plugs wouldn’t fire right anyhow. Changed them and it ran OK for about 2
seconds and I guess they started fouling again.Running out of ideas…
Thanks,
Mitch
1983 VDP 145,000
Doug Dwyer wrote:> Hmmmm…seems to be sudden epidemic of rich running among the listers’
Jags recently.
Yesterday Alex wisely suggested that another lister check his vapor
canister/fuel return system. If the canister fills with fuel it can be drawn
into the intake system.
Everyone knows my favorite…“check the coolant temp sensor”. If the
sensor sends a false “cold” signal the ECU will respond by increasing
injector pulse duration to richen the mixture.
Doug Dwyer
Longview, Washington USA
----- Original Message -----
From: “Mitch Rambo” <@Mitch_Rambo1>
Just as I got my heater to work a little better, I get a new problem (a
gift I never asked for). My car has always run like silk. Tonight- the
idle speed dropped and fluctuated, while idling very rough. While
driving, everything is OK- still good at high speed, etc- but idle is
horrible. Not to mention smoky exhaust- black, rich exhaust. Pulled a
hose on the fuel pressure regulator, and idle speed goes up- no fuel
present in hose. Funny thing is, when I re-start the car after sitting a
minute it idles fine- for a little while… don’t know how long this
will last. Changed oxygen sensor- no help there. Can running very rich
like this screw up the catalytic convertors? I checked connections for
engine sensors- wiggling and reconnecting did not help. First thought
(before I noticed black smoke), was the rubber tube behind AFM (get
cracked and mess with idle), and fuel filter. Now I’m not so sure. Any
ideas?
Mitch, my man, this is exactly the failure we had when I first tried using the
left tank on our SII. The return valves didn’t operate properly, so I
replaced the left one first, then tried using the right tank – blooop! The
right valve wasn’t opening enough, so the fuel pressure to the injectors rose
and flooded the engine, resulting in completely and perfectly sooted plugs –
definitely some Buckeyballs and Carbon nanotubes in there! This is the reason
some of us have toyed with a more reliable system using a two-way valve for
this function, like the selector valve in the boot.
I suggest you get under the rear fender wells and remove and test the
reclycling valves. The left one passes gas (a figure of speech) when powered
off, the right does the opposite – check both passing and blocking states.
New ones are $43 or so from folks like Coventry West, Jagbits…–
Alex
79xj6L SII
86xj6 SIII
Menlo Park, California
Mitch Rambo wrote:
Vapor canister was OK, and I changed the coolant temp sensor also. In fact, I
changed/replaced the coil, ignition amplifier,distributor cap, plugs & wires, and air
flow meter. No luck. When I started it today- it ran worse than last night, even
stumbling and stalling. No more restarts and it runs OK for a moment… Lots o’ black
smoke. I changed everything, then pulled a plug- totally black. I figured if I had fixed
the fouled plugs wouldn’t fire right anyhow. Changed them and it ran OK for about 2
seconds and I guess they started fouling again.Running out of ideas…
Thanks,
Mitch
1983 VDP 145,000
Doug Dwyer wrote:
Hmmmm…seems to be sudden epidemic of rich running among the listers’
Jags recently.
Yesterday Alex wisely suggested that another lister check his vapor
canister/fuel return system. If the canister fills with fuel it can be drawn
into the intake system.
Everyone knows my favorite…“check the coolant temp sensor”. If the
sensor sends a false “cold” signal the ECU will respond by increasing
injector pulse duration to richen the mixture.
Just as I got my heater to work a little better, I get a new problem (a
gift I never asked for). My car has always run like silk. Tonight- the
idle speed dropped and fluctuated, while idling very rough. While
driving, everything is OK- still good at high speed, etc- but idle is
horrible. Not to mention smoky exhaust- black, rich exhaust. Pulled a
hose on the fuel pressure regulator, and idle speed goes up- no fuel
present in hose. Funny thing is, when I re-start the car after sitting a
minute it idles fine- for a little while… don’t know how long this
will last. Changed oxygen sensor- no help there. Can running very rich
like this screw up the catalytic convertors? I checked connections for
engine sensors- wiggling and reconnecting did not help. First thought
(before I noticed black smoke), was the rubber tube behind AFM (get
cracked and mess with idle), and fuel filter. Now I’m not so sure. Any
ideas?
If you haven’t looked at the following you may want to check -
Grounds - @ the water rail & engine to body. Battery strong. Alt.
belt right.
Vacuum leaks - check the auxiliary air valve hoses. You need to check
the rear one from under the car. Make sure the breather assembly at
the front of the engine is
not loose. Pinch off lines one at a time and see if it helps.
Contacts - The female parts of the many connectors are pretty flimsy
and can bend
as you wrestle with a connection to get it apart. Bend 'em back to
insure good contact.
Injectors - pinch off the cold start injector. Pinch off each of the
six FI’s in turn and see if you get a uniform drop. Unpluging each is
another way to go but won’t tell you much if they are leaky.
Gas Caps - Leave 'em open and check for return fuel flow.
Test Compression.
Hope you get it figured.
Paul Spitzer---------------------------------------------------------------------------------------
Vapor canister was OK, and I changed the coolant temp sensor also. In
fact, I
changed/replaced the coil, ignition amplifier,distributor cap, plugs &
wires, and air
flow meter. No luck. When I started it today- it ran worse than last
night, even
stumbling and stalling. No more restarts and it runs OK for a moment…
Lots o’ black
smoke. I changed everything, then pulled a plug- totally black. I figured
if I had fixed
the fouled plugs wouldn’t fire right anyhow. Changed them and it ran OK
for about 2
seconds and I guess they started fouling again.Running out of ideas…