Hello,

I have a 1983 Firebird TransAm that now has a new engine. It will start up, run for 3 minutes, then appears to loose ignition and decels. It will spit back at the throttle bodies, dies and wont immediately crank back. The distributer and spark system is new and just trying to get break in.

I don't know where to go to find out why it starts but wont run longer than the 3 minutes. Any assistance is greatly appreciated!

Melissa

 

Sounds more like a fuel problem.

Also sounds like it's CFI... what's the fuel pressure WHILE IT'S IN THE ACT OF SCREWING UP? Not, while it's sitting in the driveway, happily idling and not misbehaving; WHILE IT'S IN THE ACT OF SCREWING UP. As in, when you're driving down the street or whatever, and you press the gas, and it coughs back into the intake. WHILE IT'S IN THE ACT OF SCREWING UP.

Tape your FP gauge to the windshield with duct tape or something so you, or your assistant, can easily read the pressure WHILE IT'S IN THE ACT OF SCREWING UP.

Did I mention anywhere, that the fuel pressure while it's working right, doesn't matter, and that you need to get the reading WHILE IT'S IN THE ACT OF SCREWING UP? In case I forgot, let me emphasize, you need to know what the FP is WHILE IT'S IN THE ACT OF SCREWING UP. What it is at any other time is irrelevant. WHILE IT'S IN THE ACT OF SCREWING UP.

 

Ward, I think you were a little hard on the Beaver. But absolutely correct.

 

Yeah I know.

I get tired of seeing posts about "my fuel pressure is fine" when it's OBVIOUS that the car needs a fuel pump. People for some reason have a mental (is that really the right word?) block to the concept of getting a picture of the fuel pressure WHILE IT'S IN THE ACT OF SCREWING UP. They seem to think that if it's "fine" at any one given moment, that it'll be fine all the time. [insert obnoxious buzzer sound here] They need to find out what their fuel pressure is WHILE IT'S IN THE ACT OF SCREWING UP. That way they have at least a chance at a whiff of a glimpse of a prayer of a clue about whether their fuel pressure is falling on its face at the moment that fuel DELIVERY is called for.

 

I'm fairly confident the crossfires also used the pulsation damper in the fuel pump discharge line as well, adding another variable, and more credence to the potential for inconsistent fuel pressure.

Not that SK has ever been RIGHT about anything, and junk like that. (That one came from Wally.)

 

And the "band-aid" for getting the engine running enough to achieve a proper break-in might be something like this:

 

The fuel pressure is not dropping off when the car decides to die. It seems to be loosing some component other than fuel that then results in the engine stop. Coil, ignition module are new. Wondering what other problems would result in the loss of engine spark for lack of a better word.

This car has not been driven in 16 years. I have a new engine and have been running to try the initial break in to not void warranty.

Thanks,
MLF

 

Hi MLF , If your sure it's loosing spark , put a test light on the big pink wire going to the distributor (Or coil if it's mounted separate from the distributor) to see if it looses 12V power when the spark goes MIA .

Something else to consider here ; "Brand New" is not the same as "100% perfectly functional" , even brand new parts fail sometimes , seemingly more often these days as I'm not too sure what passes for "quality control" overseas .......

 

Was the white heat transfer grease (not the same as clear dielectric grease) applied under the ignition module when it was replaced?

Also - you need to have some common sense here - you could verify that is not a lack of fuel problem by using a spray bottle filled with gasoline to give a shot of fuel down the throttle bodies at the instant it begins to die. If the engine picks back up and runs longer, then you have a lack of fuel problem. If the engine continues to die, then look for lack of spark. Be smart if you try this - car OUTSIDE with a fire extinguisher at the ready.

 

She never said the "my fuel pressure is fine" on her initial post.

 

Didn't take long for that to appear though.

Which if I was the betting kind, I'd bet was NOT the result of watching a fuel pressure gauge taped to the windshield, and observing its indication, WHILE IT'S IN THE ACT OF SCREWING UP. Typical for this particular post on any number of car forums no matter what n00b posts it.

And Vader is right, I'm never right about anything.

 

Hello, again,

So I will give a few specifics now and update to the current fuel pressure issue. The manual states it should be 9-13 psi.

The fuel pressure before start is at 9 psi. At running, it maintains at 11-12psi. When it begins to behave, the pressure is still at the 12 psi but the engine dies.

There appears to be spark, and timing light was used to set timing. The EGR valve was bad also and was replaced. I have checked all the vacuum lines and they appear to be in working order.

The spray pattern is good at the beginning, but after it dies and I try to restart, it is no longer a nice cone pattern, but a heavy droplet like a bad shower. Engine code states bad MAP sensor.

Let me know what you think....

Melissa

 

A bad MAP sensor code (33, MAP high) can be caused by an engine that is struggling to run. Not sure which ECM a '83 f-body uses, but the '82 ECMs are dying left and right. They are not only dying, but can't be found for a direct replacement.

RBob.

 

Hello, again,

So I will give a few specifics now and update to the current fuel pressure issue. The manual states it should be 9-13 psi.

The fuel pressure before start is at 9 psi. At running, it maintains at 11-12psi. When it begins to misbehave, the pressure is still at the 12 psi but the engine dies. There is NO drop in the fuel pressure.

There appears to be spark, and timing light was used to set timing. The EGR valve was bad also and was replaced. I have checked all the vacuum lines and they appear to be in working order.

The spray pattern is good at the beginning, but after it dies and I try to restart, it is no longer a nice cone pattern, but a heavy droplet like a bad shower. Engine code states bad MAP sensor.

Let me know what you think....

Melissa

 

Your best bet is to get a scan tool and start there. I also recommend investing in a factory service manual. Typical issues with start/die are fuel related. If the spray pattern changes, that strongly suggests a fuel pressure issue. Failing that, you might have an IAC problem.

 

Thank you, OrangeBird,
I have checked voltage, changed MAP sensor, and vacuum, and EGR valve. Flooding is now a problem so I'm going to have to try to tackle this issue and consider if it is a ECM issue (hope not).

Thank you!
MLF

 

I have checked the fuel pressure and it is not changing with the engine stall. It is beginning to flood and backfire. I have had the timing verified, so I'm back to checking vacuum system (replaced), replaced MAP sensor and EGR. Tested voltage at the throttle bodies and seems to be in the appropriate range. Looking into changing the throttle position sensor and then I just don't know....

Thank you!

Melissa

 

bad TPS won't cause any major trouble an a CFI-if you are flooding out,do check the CTS that screws horizontally into the front of the intake manifold(yellow and black wires) the original style is no longer made,will need to use the 1985 up style and splice in the mating plug. Also remove and reinstall all fuses to restablish good connections.Keep the updates coming -CFI is easy to deal with

 

Will do! I'm still working at it.

Thanks,
Melissa

 

My 82 FSM suggests troubleshooting charts 7 & 11