Starting problem - suddenly occured

[GothingNC]

My 82 Targa was running great yesterday but when I went to start the car this afternoon it fired right up and then stalled.

Started it again, fired right up and now idles at less then 200 RPM.

If I press the gas it just stumbles and pops; I am unable to drive it.

I checked for air leaks around the pop-off valve and it was fine.
All the screws around the airbox seam are flush and there is no movement.

I took a look at all the vacuum line connections and they were tight.


Kind of strange how it suddenly started having this problem when it was running flawless all week :-(

[Bob Kontak]

Originally Posted by GothingNC

If I press the gas it just stumbles and pops; I am unable to drive it.

Lift the front trunk lid. Is the courtesy light on?

If not that's the Lambda fuse circuit and that will mirror your symptoms.

First check fuse. Then check the cube relay under the passenger seat.

Here is a vid I made several years ago. See if it sounds about the same.

https://www.youtube.com/watch?v=5tdpCYyvqSc

[GothingNC]

My interior dome light works.

I will change the fuel filter tomorrow, might be bad gas when I refilled yesterday morning.

[T77911S]

lambda relay

[GothingNC]

I will pick up the o2 sensor at NAPA to see if that works.

Bosch part # 0-332-019-109 ?

[Bob Kontak]

Originally Posted by GothingNC

I will pick up the o2 sensor at NAPA to see if that works.

Bosch part # 0-332-019-109 ?

Come on, dude. That is the wrong part. Not the number, the part is not needed.

Lift the front hood. Look at the courtesy light in there. Not in your car, under the front hood. Check your clock and your glove compartment light. Not your dome light.

Pull that plastic cover off your fuses. Find the OXY fuse. The word is molded onto the inside. CHeck it's condition

Why are you asking for help, two dudes say the same thing is wrong and you buy a fuel filter?

[GothingNC]

The clock and glove box light work, not sure about the light in the Frunk, it never worked-I think the bulb was removed.

I will check the OXY fuse when I get home.

Thanks!

[Bob Kontak]

Originally Posted by GothingNC

The clock and glove box light work, not sure about the light in the Frunk, it never worked-I think the bulb was removed.

I will check the OXY fuse when I get home.

Thanks!

Oxy fuse ok then. All on that circuit.

Next step in chain is the relay I pulled in that video. It sends voltage to the frequency valve. If it is dead, dislodged, crusty it will create the symptoms.

One thing you can do is to just pull that relay under passenger seat. If no change in how car runs then you are getting close. If it runs worse or dies then you can assume the frequency valve is ok (as best you can assume without a multi meter).

['78 SC]

Bob, as a general lambda troubleshooting step, can't you feel the frequency valve buzzing when it is operating? Duty cycle could be wrong, but that would at least get rid of multiple (mostly electrical) suspects.

[GothingNC]

Thanks

I will pull the o2 relay with the car running later today and see if anything changes.
Does it pull straight out or is there a clip holding it?

As of now it barely idles and when I remove the oil cap it just stops.

[Flat6pac]

The relay for the lambda, if it's bad, mimics a defective WUR. This causes fuel pressure problems.
The relay is available at general auto stores,
Bruce

[GothingNC]

Thanks Bruce !

[Bob Kontak]

Originally Posted by '78 SC

Bob, as a general lambda troubleshooting step, can't you feel the frequency valve buzzing when it is operating? Duty cycle could be wrong, but that would at least get rid of multiple (mostly electrical) suspects.

You can feel the freq valve buzzing. You can also fire the freq valve without the car running if you fiddle with the diagrams and have a couple of patch wires.

I am lazy. Just unplug the relay or pull the O2 fuse. If running get worse, look elsewhere.

Several ways to skin a cat. Need to find out if this is the right cat.

Freq valve seldom fails so duty cycle will be what signal the Lambda box sends it. (separate can of worms as you know)

The 12 pin connector on the back wall (ledge) by the drivers rear shock can also interrupt the signal if the pins are corroded.

[GothingNC]

Originally Posted by Flat6pac

The relay for the lambda, if it's bad, mimics a defective WUR. This causes fuel pressure problems.
The relay is available at general auto stores,
Bruce

Bruce,

I thought only the Porsche/VW relay could be used?

[Flat6pac]

No, it's a standard relay available anywhere. If you went to VW, they don't know anything about that relay..my experience.
Bruce

[GothingNC]

Removed the 02 relay, no change.

Installed a new 02 relay, no change. I can feel the 02 relay clicking. After running it for a few minutes I can rev it but it is rough and snaps like out if sync weber carbs:-(

I will check the main connector in the engine compartment.

Then swap the fuel filter if needed.

[Bob Kontak]

Originally Posted by GothingNC

Removed the 02 relay, no change.

Installed a new 02 relay, no change. I can feel the 02 relay clicking. After running it for a few minutes I can rev it but it is rough and snaps like out if sync weber carbs:-(

I will check the main connector in the engine compartment.

Then swap the fuel filter if needed.

Getting closer.

It's the connector on the back (well, front) wall. The main connector (14 pin) is back by the driver's rear of the engine compartment. The number one terminal is one of the frequency valve feeds. They are numbered but hard to see way back in there.

I helped a guy out who would be cruising down the highway in Houston and it would crap out. When it got real hot (Houston hot) the connections would separate. Cool down then started and ran fine. Yours is consistent, though.

[Bob Kontak]

See freq valve in diagram.

Terminal one & two in 12 pin connector.

http://www.pelicanparts.com/911/911_parts/Electrical/911_electrical_82SC_Part6-2.jpg

[GothingNC]

Just7Also, the new O2 relay was a 4 pin, one on the car is a 5 pin.

Regarding hearing the FV buzzing. Does it buzz in the engine compartment or under the seat?

[GothingNC]

Photo of the connector.

I found a thread on testing the FV, with the key on and lifting the plunger the FV buzzes loud and clear.

I am going to see if i can find a 5 blade 02 Relay at the local parts store, maybe the 4 blade is not compatible.

Thanks everyone for your help !