Rough idle, NO acceleration

[Carbuilder]

Hi Guys,

I've had my car for a few months now and I've put 1,000 Kms on it, it runs and drives perfectly, and I really like it. BUT...

Today I went to start it and it started fine, but the idle was a little rougher than usual. But there was no acceleration. Pressing the gas pedal only made the idle much, much worse (shaking a lot), to the point of almost dying. Probably would have died if I kept at it. Pressing the pedal very slowly or faster didn't seem to make a difference. After a few minutes of my trying to drive back into the garage, I think it sorted itself out. I revved it a few time before shutting it off and it was OK. I started it a few hours later and the same rough idle, no acceleration was back.

I'm new to these cars but couldn't see anything obvious that had disconnected and nothing was done in the way of work on it since it was running well.

Ideas on what I should check?

Rick
Ontario, Canada
ps. it's a Canadian car if that matters.

[David T]

With the motor running, see if you can hear the frequency valve on the R/H valve cover buzzing.

[Helirich]

The warm up regulator could be acting up. If the electric heater part doesn?t work, it will warm up from the valve cover and run fine. The colder the car, the longer it takes.

[Carbuilder]

Ran it again this morning...same thing. Starts right up, lumpy idle, and won't accelerate. When pressing the gas pedal slowly the RPM will increase very slightly from around 700 to 800, running much rougher, and any more pressing and it will die.

After it warmed up for maybe 5 minutes it ran OK. Not sure if it was perfect (didn't take it for a drive, just revved it in the garage), but it would rev up and idle; idle maybe a little lower than normal.

Not sure what I am supposed to be listening for. Is this the FV, whatever is wrapped up in here:

Screenshot 2024-09-11 at 12.46.02 PM.jpg

Screenshot 2024-09-11 at 12.48.47 PM.jpg

If so, I couldn't hear anything or feel any vibration from it, before or after the engine was warmed up. My exhaust is not stock and is a bit loud, but even using a hose up to my ear I couldn't hear anything.

Rick

[mhanch]

mine did this when i had a vacuum fitting come loose. check behind the engine. those get brittle and fall off their connectors sometimes.

[Carbuilder]

Don't think a vacuum leak would fix itself every time after warming up.

Should there be voltage across these 2 connectors with the ignition on, or only with the engine running? I have no voltage with the ignition on, engine off.

Screenshot 2024-09-11 at 5.41.19 PM.jpg

I checked all of the fuses. Should I check any particular relay? If so, how?

Screenshot 2024-09-11 at 5.41.37 PM.jpg

I appreciate the help.

Rick

[FABombjoy]

Don't think a vacuum leak would fix itself every time after warming up.

It will if it's a vacuum line connected to the cold accel enrichment part of the warm-up regulator.

No enrichment will behave as described. The engine instantly leans out on throttle tip-in and stumbles.

[Bitsyncmaster]

Should there be voltage across these 2 connectors with the ignition on, or only with the engine running? I have no voltage with the ignition on, engine off.

Rick

The frequency valve only gets power with the engine running. Or cranking the starter.

[Carbuilder]

More info,

With the engine running I pulled off each of these connectors in turn and it didn't do anything. Should it with the engine cold?

Circled connectors:

Screenshot 2024-09-11 at 8.50.42 PM.jpg

The arrow points to something that doesn't look stock. A line (vacuum?) comes out of the right side of the valve, then has a filter or something, then "T's" into a line coming from the other side of the valve...with black tape holding it together. Keep in mind I haven't changed anything and the car was running fine.

Both of those lines then go off with the red one towards the front of the engine, and then down somewhere. Is there a lot wrong with this?

Screenshot 2024-09-11 at 8.50.19 PM.jpg

I'll check for voltage on the FV with the engine running tomorrow.

[Carbuilder]

Found this info on the warm up regulator. Sounds exactly like my issue.

?If the vacuum hoses are not properly connected, or if there is a fault in the vacuum circuit (failed thermal vacuum switch, cracked hose, loose hose, missing or backwards delay valve) the car will be almost undriveable (will stall on any acceleration) until the regulator warms up, and may then be just fine.?