Harder to get to redline

[jrwilson]

One characteristic of my car has been that it's almost too easy to hit redline on it in first gear if I really get on it - I have to be very careful because it shoots right up almost instantly.

However today, I noticed that I was having a lot of difficulty getting it past 5,000 compared to the usual. Power seems okay.

I thought it might be the alternator load from the A/C so I tried it with the A/C off and it was the same.

Any ideas what it might be? 1978 3.0 CIS motor, running fine otherwise. It was pretty hot and muggy today and air quality is really bad due to forest fires north of the city, could that be it?

[Nditiz1]

Could it be that you are not able to get to WOT? Maybe something in the pedal cluster? You think you are mashing to the floor stop, but not able to get it there? The only way I can think to rule that out is manually open the throttle vs using the pedal. See if you can achieve the same with both.

[Fixer]

Is your air cleaner clogged?

Matt

[David Inc.]

Originally Posted by Nditiz1

Could it be that you are not able to get to WOT? Maybe something in the pedal cluster? You think you are mashing to the floor stop, but not able to get it there? The only way I can think to rule that out is manually open the throttle vs using the pedal. See if you can achieve the same with both.

Yep. Almost certainly somewhere along the line the bushings are toast and you're not getting full activation at the throttle even with your foot to the floor. You still get enough air to make full power in the mid-range but at higher rpm the throttle becomes a restriction.

Lots of good resources here if you search for throttle linkage bushings.

[snbush67]

Toronto’s barometric pressure is normal at 29.84 and has been quite steady recently. That shouldn’t have any noticeable impact on performance.

[jrwilson]

Originally Posted by Nditiz1

Could it be that you are not able to get to WOT? Maybe something in the pedal cluster?

I rebuilt my cluster this past winter. This was a change pretty much overnight.

Originally Posted by Fixer

Is your air cleaner clogged?

It has about 2,000 miles on it but I'll take a look.

Originally Posted by David Inc.

bushings are toast and you're not getting full activation at the throttle even with your foot to the floor.

I did the pedal cluster but not anything past that. I'll take a look and see if there's any play.

[prschmn]

Don't know how many miles are on it but a possibility is a broken valve spring. I'tll be strong enough
at lower rpms but valve float will happen up high.

[jrwilson]

Originally Posted by prschmn

Don't know how many miles are on it but a possibility is a broken valve spring. I'tll be strong enough at lower rpms but valve float will happen up high.

Hmm, the motor is a fresh rebuild with about 2,000 miles on it now. Any way to tell if a spring is broken without dropping the engine?

[pmax]

Oil's no good.

[Fixer]

Originally Posted by jrwilson

Hmm, the motor is a fresh rebuild with about 2,000 miles on it now. Any way to tell if a spring is broken without dropping the engine?

Okay well I'd check all valve clearances then.. if you haven't already.

Didn't know it was a fresh motor. Valves will seat after the heads are reconditioned.

[Schulisco]

1. Mixture too lean or too rich (CIS troubleshooting on all aspects)
2. Ignition timing wrong
3. Throttle plate does not fully opens as it should
4. Fuel pressure too low
5. WUR control pressure not correct (see point #1)
6. Vacuum leaks after overhaul (sufficiently testable with a smoke generator only!)
7. Does the tachometer still works correctly? Crosscheck the rpm with an ignition timing gun with rpm display

Thomas

[prschmn]

There's other good suggestions here but regarding the springs-if you check valve adjustment you can try pushing to see if any valves open more easily than others.
Seat pressure is only around 65 pounds.

[prschmn]

There's other good suggestions here but regarding the springs-if you check valve adjustment you can try pushing to see if any valves open more easily than others.
Seat pressure is only around 65 pounds.

[jrwilson]

I've been having hard cold start issues so I figure I'll get that done and talk to the mechanic about the issue. I thought I'd finally whipped most of the CIS issues but who knows.

I took it out for some errands and once it was warmed up I tried again and it was a bit better, but it's probably due for a valve clearance check anyway.

Thanks for the suggestions!

[Fixer]

Originally Posted by jrwilson

I've been having hard cold start issues so I figure I'll get that done and talk to the mechanic about the issue. I thought I'd finally whipped most of the CIS issues but who knows.

I took it out for some errands and once it was warmed up I tried again and it was a bit better, but it's probably due for a valve clearance check anyway.

Thanks for the suggestions!

Yeah I bet it's your valve clearances. I'm due to check mine again too.

Good luck

[pmax]

Originally Posted by jrwilson

I've been having hard cold start issues so I figure I'll get that done and talk to the mechanic about the issue. I thought I'd finally whipped most of the CIS issues but who knows.

I took it out for some errands and once it was warmed up I tried again and it was a bit better, but it's probably due for a valve clearance check anyway.

Thanks for the suggestions!

Keep us posted as to what the mechanic says.

[jrwilson]

So, a followup from my visit to the mechanic.

It turns out a previous mechanic had left an allen key in the enrichment adjustment hole on the top of the fuel distributor, and it had migrated down and jammed itself in against the metering flap, literally preventing it from moving properly. Once it was removed the car was totally fine and it's back to pulling hard to 6500.

Wish I had checked that myself!

[PeteKz]

Thanks for the resolution. Good to hear it was something simple. Sorry to hear it was something avoidable.

[boyt911sc]

Originally Posted by jrwilson

So, a followup from my visit to the mechanic.

It turns out a previous mechanic had left an allen key in the enrichment adjustment hole on the top of the fuel distributor, and it had migrated down and jammed itself in against the metering flap, literally preventing it from moving properly. Once it was removed the car was totally fine and it's back to pulling hard to 6500.

Wish I had checked that myself!

Jeremy,

You drove your car from Toronto to Pennsylvania and visited me in late April and it was running very well. So when did the mechanic work on your car? Before or after Carlisle Swap Meet? BTW, whatever happened to the WUR I shipped to you? Thanks.

Tony

[pmax]

Good thing it wasn't a banana or equivalent in the tail pipe !