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1980 Trans AM Just Dies When Warmed Up?

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Hi.

Hoping someone out there can help me.

I got my carb redid, transmission, and a slew of other things.

It was running OK; however, the choke relay under the dash was buzzing.

I replaced it with a new relay, and the buzzing stopped.

The choke works fine now. my problem now is when the car is warm, the car just bogs(dies).

I adjusted the base idle screw to 900 rpm.

When in drive, the RPM's are 750.

It starts really nice but dies on me when at normal running temperature.

Also, when the car is about to die, you can see gas squirting out of the primary ports.

Any idea out there.

Thanks in advance
Mike
 

Pontiac Trans Am

Smokey
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Before it shuts off, does it do anything strange like back fire or anything like that?

Thank you,
PTA Staff
 
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Hi Smokey.

It starts really well from cold.

The choke plate slowly opens up and then, when warm, stays open.

After running for a while, it then starts to run a bit rough then dies.

It will start up right away and run nicely, then just dies.

I did play around with the idle screw on the driver's side before this all started.

The green choke relay was buzzing.

I have ordered and replaced the relay.

The choke plate opens up really nice now.

I was thinking of turning in the screw all the way in, then start the car and turn out the screw until it reaches 900 RPMs.

In the park and 750 RPM's in the drive?

Do you think that may help?
 
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Pontiac Trans Am

Smokey
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It sounds like it could be a choke issue since it dies when it comes off the high idle.

Thank you,
PTA Staff
 
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Hi Smokey

To answer your earlier question, it does do a slight backfire, sometimes not really a lot.

If you think it is a choke issue, what could I do to look into this?
 
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Pontiac Trans Am

Smokey
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Hi Smokey

To answer your earlier question, it does do a slight backfire, sometimes not really a lot.

If you think it is a choke issue, what could I do to look into this?
Yes, cause it runs good until the choke comes off, which makes us think it could be the choke.

Thank you,
PTA Staff
 
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Hi Guys,

I pulled the fuel line off and turned on the engine, and had the fuel dump into a jar.

It looks like there is debris in the gas tank.

This may be plugging the carb and causing the carb to stall.

Since the tank is 40 years old, I am thinking of replacing the tank.

The guy who rebuilt the carb thinks there may be debris plugging up the carb from the gas tank, making the carb die off.
 
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Pontiac Trans Am

Smokey
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Hi Guys,

I pulled the fuel line off and turned on the engine, and had the fuel dump into a jar.

It looks like there is debris in the gas tank.

This may be plugging the carb and causing the carb to stall.

Since the tank is 40 years old, I am thinking of replacing the tank.

The guy who rebuilt the carb thinks there may be debris plugging up the carb from the gas tank, making the carb die off.
Oh yeah, you are fighting a never winning battle there.

Change the tank and check the whole fuel system.

Thank you,
PTA Staff
 
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Hi Smokey

I have gone on a few sites and found firebird central with the following:

1979 - 1981 Pontiac Firebird Fuel Gas Tank, Premium Quality

Correct Fuel Gas Tank for 79 - 81 Pontiac Firebird models.

Premium quality.

Made with corrosion-resistant O.E.M. approved Ni Terne steel.

All units are water-based leak tested after full product assembly.

Lock ring and gasket included. Order yours today! Replaces GM Part # 475497 perfectly.

This is the North American Made premium quality fuel tank your Firebird deserves!

The sending unit is as follows:

1976 - 1981 Firebird Fuel Tank Sending Unit with 3/8 Gas and 1/4 Vent Return Line

New factory correct design fuel tank sending unit for your bird. Exact fit for all 76 - 81 Firebird and Trans Am models.

Features a 3/8" main gas line with a 1/4" vent return line.

Includes mounting locking ring and rubber gasket.

The fuel line exits out on the right-hand passenger side.

PART NUMBER: FUE-2000

I assume that the tank and sending unit are OK.

Also, what is the best method to paint it black?

any help appreciated

Thanks, Mike
 
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Bob

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Any paint thinner or brake cleaner will clean the outside of the tank to get rid of the oily residue.

I would scuff it with a green Scotch Brite pad, wipe it down again and then use self etching primer and then paint.

Good luck; let us know how you make out.
 
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Hi all.

Just an update on what has been going on with my 1980 Firebird.

I bought a new gas tank and installed it and blew out the lines before installing it.

I got the carb redone again.

I stated the car and had it run for a while until it got to operating temperature and then it happened again.

It just bogged down and died.

It ran for about 15 to 20 min then just died by it self.

I took it out on the road the next day and drove it around the area.

Even to it on the highway to clean out the carb, it ran really nice until it reached normal temperature, I did notice that the temperature gauge did go a bit pass 220.

I got off highwayighw, and then the car started to bog down again and barely made it home.

Any ideas out there?
 
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Hello

The fuel pump is OK.

verified that there was fuel.

I now do not have a spark.

I believe that the ICM may be faulty.

I have ordered a GM one.

It should be in in a few weeks.

I changed the Coil and found out that my car has an ECM.

I am thinking of bypassing it once I figure out my spark.

Thanks for the follow-up

I will keep you posted.
 
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Hi CyclIOnus

Just to let you know that I installed the new ICM (AC Delco, GM). It worked.

I ran it yesterday for an hour in my driveway and then took it around the block.

It did not bog down.
 

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Hi CyclIOnus

Just to let you know that I installed the new ICM (AC Delco, GM). It worked.

I ran it yesterday for an hour in my driveway and then took it around the block.

It did not bog down.
Nice!

Precisely what is that part again for (part name and part number)?

I want to make sure just in case I start having the same issues.

I have a 75 formula 400.

i read somewhere that someone was having similar issues to yours in which, when it's cold and on a first startup, the car starts and runs fine.

However, if it has been running throughout the day and is as it average normal operating temps, the guy's car started bogging down during acceleration and would eventually die.

He said this issue started happening after he recently upgraded his headers.

He thinks the car is has been running hotter after the header swap.

He said because the headers are close to, the starter it was causing the starter "too hot".

He had to upgrade his seat to solve his issue.
 
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Nice!

Precisely what is that part again for (part name and part number)?

I want to make sure just in case I start having the same issues.

I have a 75 formula 400.

i read somewhere that someone was having similar issues to yours in which, when it's cold and on a first startup, the car starts and runs fine.

However, if it has been running throughout the day and is as it average normal operating temps, the guy's car started bogging down during acceleration and would eventually die.

He said this issue started happening after he recently upgraded his headers.

He thinks the car is has been running hotter after the header swap.

He said that because the headers are close to, the starter was causing the starter "too hot."

He had to upgrade his seat to solve his issue.
Hi

The part number is D1918 from Rock Auto.

Since I have an ECM and non-Turbo, I had to get the five-prong ICM from the Turbo column

I have had it working now for a week in the driveway and around the block.

The car has not shut down yet.

It has been raining a lot recently, and since I have a leak in my trunk at the hinges, I do not drive it in the rain.

That is my next thing to do.

I checked all my fuel lines to see if they were near my new dual exhaust.

All is good there.

I still have my original exhaust manifolds.
 
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