[Aaron65]

Hi all, I just bought a quite original '74 Esprit with a 350 and all its emissions and rotted hoses intact.

I live in Michigan, and we have absolutely zero emissions requirements. What can I safely remove from this car to enhance driveability/eliminate potentially faulty valves, etc? My newest old car (other than this) is a '65, so emissions stuff is pretty new to me. Originality is less important than driveability.

Thanks to anybody who can help...I just picked this car up today and I already love it...it's my first Pontiac.

[Squidward]

A few that come to mind are egr (present in 74?), evap system, catalytic converter, and (unlikely - u r in MI) AIR system. I also think there is a TCS that alters timing, but I'm not familiar so much with that.

I'm from MI originally. I miss "anything goes" with emissions gear. I guess it's a consolation prize for all the salt on the roads.

Having emissions testing here in AZ made me have to learn some tuning. We have collector vehicle exemptions now.

Welcome!

[Will]

If you have no emissions testing then you can remove everything emission control related.

That said, you should leave the evap (charcoal) canister and PCV valve as those are actually beneficial. I'd take everything else off. '74 shouldn't have a catalytic converter so there should be no AIR pump on it, I think.

The biggest detriment to performance on a '74 is the EGR valve and as long as it's not stuck open the easiest way to disable it is simply remove the vacuum hose from it as it's normally closed.

If the car has A/C then you only need 4 vacuum hoses

1 to the vac modulator on the trans
1 to the power brakes
1 to the distributor
1 to the A/C vent controller.

If you want to keep the stock aircleaner then leaving the hot air ducting and the vacuum hoses associated with that is probably a good idea too as the car will run better in cold weather on startup and it won't hurt performance once the car is warmed up.

[Overkillphil]

The emission stuff is minimal up through 74 as the real "emission" stuff was in the leaned out carb and stingy ignition timing. Recalibrate the carb and dist., power time it and add a free flowing exhaust (if not already done) and it'll feel a whole lot different.

[Aaron65]

Sounds good...It has no A/C, but it does have EGR and what looks like a coolant temp controlled vacuum bypass, perhaps for the vacuum advance. I think I'll cap that off and run a hose between the carb and distributor. I have an Innovate MTX-L that I switch from car to car, so I'll hook that up and check out the carb tune once I get this thing going. Thanks!

[Aaron65]

Oh yeah, the air inlet hose on the air cleaner is totally rotten. Anyone know where I can get one of those?

[jackbox]

Originally Posted by Aaron65

Oh yeah, the air inlet hose on the air cleaner is totally rotten. Anyone know where I can get one of those?

Ames our host sells them in their catalog at a reasonable price

[KJL]

In the late 70's and early 80's I worked with an ex GM engineer. He sold a kit for $1 to defeat the emissions and get the engine to run properly. The kit consisted of a one page instructions, a ball bearing, and springs for the mechanical distributor advance. From memory it goes like this.

1. replace the springs on the distributor mechanical advance with the ones in the kit.
2. remove the vacuum hose from the EGR valve and insert the ball bearing and plug back into the EGR valve.
3. remove the AIR pump belt, remove the lines going from the pump to the exhaust manifolds/heads, and plug the holes on the exhaust manifold/head.
4. remove the vacuum advance and file the open slot restricting the advance tab to the dimension shown.
5. advance the distributor timing in 2 degree increments and do full throttle runs. Do this until you get spark knock and back down 2 degrees.

Did this on my '74 Monte Carlo with a 350 2 barrel. It definitely ran better. The biggest surprise was the gas mileage went from 10/10 city/highway to 14/18.

[dadsformula]

The TCS switch on the Trans, and the EGR are the biggest issues. Disable
both. EGR is easy, just pull or plug the vacume line. You can disable all the
stuff by pulling the plug out of the firewall relay. That yellow wire is the Power
for all that stuff. Remember that the TCS controls advance in the Distributor,
so once the TCS is disabled, be sure to insure proper operation of the Distributor
and a re-curve may be in Order depending on the desired setup. Carb may also
be a little lean, so that should also be on your future list. In General an easy
Car to do this on as it's the last year without the Converter although smog pumps
were present of Califirnia Cars.

[jerry455]

You can leave it original looking by putting new hoses on it but plugging the ones you don't need. It would make a sleeper look.

[Aaron65]

Originally Posted by dadsformula

The TCS switch on the Trans, and the EGR are the biggest issues. Disable
both. EGR is easy, just pull or plug the vacume line. You can disable all the
stuff by pulling the plug out of the firewall relay. That yellow wire is the Power
for all that stuff. Remember that the TCS controls advance in the Distributor,
so once the TCS is disabled, be sure to insure proper operation of the Distributor
and a re-curve may be in Order depending on the desired setup. Carb may also
be a little lean, so that should also be on your future list. In General an easy
Car to do this on as it's the last year without the Converter although smog pumps
were present of Califirnia Cars.

The previous owner put in a new HEI distributor, so who knows what the curve is like now; that will be one of the myriad things I have to check out when I start messing with it. It sounds like I can just cap everything off (other than PCV) and perhaps keep the correct air cleaner for cold starts.

I've never messed with a 2-barrel Rochester before. Do they use metering rods like a Q-Jet? If so, I may end up needing a bit of guidance as far as richening it up a touch.

[dadsformula]

Yes, you do want to use the PCV as its a good thing for your motor. All I did on
my Car was to disable the emissions relay on the firewall by removing the internal
contact. This stops all power to the TCS, and any other sensors as all are powered
by the Yellow Wire. Then I pulled the Vac lines plugged them internally and replaced.
These two things will leave the system in place, but not functional.
I would also leave the EGR in place, just be sure you plug the vac line.
73 and 74 are pretty easy to bypass, and still have an original look. Later Cars
with Converters, and more elaborate emissions systems require more work.
The HEI in your Car could be original as this was available in 74. Just look for a wire
going from the trans to the Distributor (possibly through a sensor on the head as well.)
If the HEI is not getting this extra input, then your all set. regardless, just be sure to
check the Distributor for proper operation, and that it is not receiving any signals from
the Trans TCS switch.

I have a pretty old copy of Thunder Am (Old Trans Am Magazine) that actually provides
a step by step instruction for removing all of the emissions stuff from a later Cars. This
includes how to remove the pellets from the Converter, ect. Can you imagine the trouble a printed story like that would create these days. There is another story in this
mag that covers the whole History of Super Duty Pontiacs. Great reading!

[Aaron65]

I missed this response...

The original distributor is in the trunk, and it's a points distributor. It looks like someone cut a yellow wire leading to the distributor area, so I imagine that the TCS has been bypassed, although I haven't gotten into it yet. I've been replacing all of the brake hydraulics, but it's been a slow go because it's cold out! My little heaters are OK, but not great.

What do you use to internally plug your vacuum lines? Would a large ball bearing work or something?

[dadsformula]

I used copper slugs (cut from Bar stock), but a Bearing would work.

[Squidward]

I am gonna guess that yellow wire is the resistor wire bypass coming from the R terminal of your starter solenoid, and goes to the coil + terminal.

[dadsformula]

No, The yellow Wire I'm referring to is pared with a Blue Wire, and goes to a Relay
to the left of the Distributor on the Firewall. That relay is the power for all of the
emissions stuff. If you follow those, they go to the TCS Switch, and the Sensors
on the heads, that provide the temp readings when the system is active. The TCS
Switch I believe is activated by being in the correct gear or Gears for it to advance
or retard the Distributor, but my memory is a little foggy on the TCS operation.

The Yellow wire from the R terminal is not on the same circuit and is not related.
My eyes are just as old as the rest of me, so it is possible the yellow wire I am referring to for the emissions system could have a stripe I forgot about, but locate that relay
on the firewall (above the oil filter) That's the power relay for the emissions system.

[fiedlerh]

Here is a link to the 74 emissions booklet. It explains how it works.
http://pontiacpower.org/pdf/74ponticemissions.pdf