Greetings,

I guess the admins (MFWIC) disabled my account due to lack of use?
Anyway im back, originally joined May 2008.
Bought car with 2500 orig miles.

1983 VDP 4,500 original miles/ looks like new.
Problem to work on because everything under the hood looks new!

Last year changed water pump and all belts/ related hoses.
It was a PITA.

Checked distributor timing and advance curve, everything was clean and
not sticking.
Also checked the air-valve door for non-stick movement.
Did this at the time because I felt the power seemed lacking.

Latest problem seems fuel related.
Starts fine, stumbles if you try to accelerate other then a crawl until it is up to temp for a while.
If you attempt to full throttle you get a light pop in the exhaust.
This (lean pop) lessens as car gets hot but never goes away completely if you go to full throttle.

I don't remember having this problem during the cooler months but I obviously do not put many miles on this car.
It is very sluggish and faster with less throttle rather them more.
Seems like problem may be fuel related.
I took the car on the highway to attempt to blow out any cobwebs but it
did not seem to help.
If it was a carburetor- I would say the accelerator pump is faulty!
I just replaced the fuel filter in the trunk - it was not clogged.

Is a fuel pressure test the next step?
Is most informative/ easy access port at one of the injectors using a length of hose and a "T" fitting?
What fuel pressure (PSI) should I expect after the regulator at the fuel rail?
If I pull the vacuum hose to the fuel regulator what PSI should the pressure increase to?

In addition problem occurs regardless of which fuel tank is selected.
I topped off both tanks, but tanks may still contain a bit of Winter gas left over.
Exhaust at idle is like a newer car with almost no odor.
If you put you hand over the exhaust pipe it is clean warm with no residue.
This seems a bit too clean/ lean.

Thanks for any advise.
(Doug are you still out there?)

Sincerely,
Ben (OB1)

 

If it feels lean during cold running and warm-up phase then the coolant temp sensor is the most likely culprit....as it's the major player in cold running enrichment.

Replace for $20-$25 or check with an ohm meter first. I can get the specs for you

Cheers
DD

 

Greetings Doug,

This VDP is lean under all temperature conditions.
If you have the data I can rule out the temp sensor.
I will also measure the voltage and range of the Air Valve Flap.

Do you think it may be fuel pressure/ fuel regulator/ injector related?

Is there an easy way to get the O2 reading to see if I am out of band?

Thanks,
OB1 (Ben)

 

CTS and O2 sensor tests

Testing the Coolant Temp Sensor
O2 Sensor Test Information & Resetting the Light

Low fuel pressure is a definite possibility. Fuel pressure should be 36.25psi when cranking. Disconnect the supply hose to the cold start injector from the fuel rail and use that nipple for your fuel pressure gauge

Cheers
DD