Cuts off at Times

[SpecM]

Have an issue that has been getting worse

Car will not idle when cold. Idle will drop, CEL will come on, and will cut off if I don't crack the throttle. CEL goes right off once rpms rise. Seems to be much worse when cold, but will still happen a little once warmed up. CEL is off, except when its acting up. I stomp-tested and got 1215, AFM malfuntion. Swapped AFM with a spare, cleaned ICV and throttle, and no change.

Yes Jim, I will do a smoke test, but are there any other obvious things it may be that I'm missing?

[jlevie]

A 1215 code doesn't necessarily mean a problem in the AFM. It can also be caused by intake leaks.

[SpecM]

holy crap its leaking out of the throttle body shaft

[SpecM]

anyone have a throttle body for sale?

[SpecM]

I replaced the throttle body, valve cover and shaft plugs, and spark plugs/wires/ca/rotor. there are no further vacuum leaks (verified with smoke)

still cuts out tho. CEL will blink, engine will loose all power for about 1/2 a second. any further ideas?

[SpecM]

New code too:

1261 Fuel Pump Relay Control

try new relay?

[jlevie]

When the is being driven and an event occurs does the tachometer react by dropping significantly more than the loss of speed would require? If so the DME is losing power or ground or timing data. Those can be caused by a DME ground connection, flaky main relay, corroded main relay socket, bad fusible link, or a bad CPS.

A 1215 code means that the DME thinks that there is a problem in the fuel pump control circuit or the relay. Usually you will see the econometer drive towards zero in an event if there really is a problem with the fuel pump relay.

But you can also get that code (or one for the injectors) if the CPS is bad, the engine harness is bad and degrading the CPS signal, or if the DME is bad.

[SpecM]

the tachometer does not drop any more than the engine speed seems to. I have not noticed what the eco-meter does. the main relay is about a year old.

I'm going to try hotwireing pins 87 and 30 on the fuel pump socket and drive around and see what happens. that will isolate the the relay and relay coil circuit from the actual fuel pump and pump power circuit (and the rest of the engine managment). seems like a good idea?

I've ordered a new relay anyway, its worth $12 to try

[jlevie]

Sure, try jumpering the relay socket, or bringing power to pin 87 from the coil positive (switched ignition).

[SpecM]

OK: new relay did not fix it. jumping power to the fuel pump did not fix it

I am leaning twards a new CPS, maybe the DME is loosing timing data

BUT the tach and eco-meter do not drop any more than the engine does

[jlevie]

If the tach isn't reacting, it doesn't sound like a CPS problem. Are you still getting a 1215 code with the replacement AFM? If so I'd have smoke test run before I did anything else.

[SpecM]

I did the smoke test, repaired a few vacuum leaks (throttle body, rocker shaft plugs, evap hose) and restest. no further leaks and the 1215 code has not returned

[jlevie]

Okay, tee a pressure gauge into the supply line to the fuel rail, zip tie the gauge to a windshield wiper and see what happens in an event while driving.

[SpecM]

check, the fuel pressure does dip slightly when it cuts out

BUT! I back-probed the CPS connection at the diag connector with a lab-scope and saw a glitch (not sure if is high volts or drop-out) in the voltage averaging once every 2-3 seconds at idle

I've got a new CPS on the way from the dealer

[Gregs///M]

Be sure your TPS is adjusted properly. This switch triggers the ECM into knowing the car is at a "idle" state. If the sensor is mis-adjusted, the ECM will never know the car is at idle and give you symptoms just like this. Check that first.

You should have electrical continuity between pins A+B when at idle, and lose continuity when lifting the throttle 10%. At 70% open, the WOT switch should close giving your continuity between B+C. This adjustment and testing procedure is also in the bentley manual.