My 92 caprice - 305 v8, non police with 230k miles :D yes!
just started dying on the road. The 2 atomizers (or w/e they are called) don't seem to be shooting the gas into the carb. Tried a shot of starting fluid and it would get her going and gas shooting in.. but still dies aparantly after the gas in the lines get used up. Changed the fuel filter. Gas was being pumped to that point, but do not have gauge to check pressure. Tune up (replaced cap and rotor, plugs, wires) few months back. The coil was checked to see if it sparked against the body and it did.

My dad seems to think it is the fuel pump. There are no codes. Only the 12.

To get it home I had to pour some gas into the carb, drive it (hauling ass :P ) until it died... made it like 2 miles each time and took 2 dies and gas shots to make it home.

I belive I can drop the tank and replace the pump, but I am definately a novice and by no means a mechanic. Was wondering (about to call now) if Autozone, etc would deliver the pump and check the pressure or troubleshoot.. when they came...?

Thanks for any advice.. I do not see how to get to a troubleshooting page for this car here (I've read at least a couple hours of posts) - if someone could link a troubleshooting spot, I would appreciate it as one post referred to a (can't remember abbreviation) - TSR, or something like that.

Thanks in advance!! :)

Fuel pump.

Two miles? Is this a carb or TBI? Two miles on a prime shot of fuel is a looooong way.

I guess TBI - it's 2 injector type things shooting gas down over the carb in to 2 bowls..

Yes, TBI.

Replaced fuel pump and strainer. Still same problem.

Won't start unless I pour gas into the Throttle Body.. then will run with my foot on the accelerator.. ran like that for 15 minutes.

As soon as I take foot off, it dies. Then will not recrank without gas added to TB.

I now have a code 23 - which is the IAT sensor (Intake Air Temp.).

Could this be the problem? And does someone know where a link on replacing that is, thanks!!

Or could the idle be too low to keep her running??

Any other suggestions.. :(

Thanks in advance!!

Found sesnor - back half of breather.

Still codes 23.

Would this even disconnected cause the problem of not running..?

Missing IAT could cause poor driveability. The computer is adjusting fuel/spark based no it. W/O it, I would assume it goes into a limp home mode.

Reconnect it, clear the codes and CHECK YOUR FUEL PRESSURE>

But it wouldn't cause it not to run at all would it?

Someone suggested replacing the throttle body or the Throttle pos. sensor..?

Don't have gauges to check the pressure...

Anything else it could be?

Can the idle be adjusted (higher) manually on this model or is that completely computer controlled..?

Was thinking if it idled a little bit higher, it wouldn't die..

and maybe I could get it to someone that knows more..

Thanks!! :D

Bump..

Still need help... :D

I know it may sound stupid, but did you put the fuel filter in backwards? I know some filters are only designed to flow in one direction.

Nopers, made sure the arrow was in the fuel flow direction..

Found sesnor - back half of breather.

Still codes 23.

Would this even disconnected cause the problem of not running..?

It makes the ECM think it's extremely cold, so it revises the fuel delivered and the fuel needed at -22 degs is not what you want at 75 deg F. So the answer is possibly YES.

See codes here:

http://www.troublecodes.net/GM/91_577_tbi.shtml

that code is also triggered when the sensor fails. Your IAT is probably bad (or a broken wire), and you might check the coolant temp sensor (CTS, screwed into the intake manifold) and clean the IAC valve (controls a stable idle speed). I think between these three things, you'll find & fix the problem.

Disconnecting the MAT/IAT will set an error code. Once this occurs, the ECM will ignore the MAT/IAT until the next start, and store the error code for the next 50 engine start/run cycles. Once the error is set, the ECM will revert to Backup Fuel and Spark Modes (a.k.a., "limp home" modes). The backup fuel tables are relatively rich, as low as 12:1, so this should NOT prevent the engine from running, albeit a bit more rich.

Actually, the MAT/IAT is used minimally for injector pulse width calculations on these older GM speed/density systems. There is a lot more relevance with the CTS.

For your other question, idle RPM is supposed to be controlled completely by the ECM via the IAC stepper motor. If the IAC passages are dirty, plugged, or the IAC is inoperative, idle could be difficult.

If you have to keep the throttles open to maintain engine RPM, there is a problem.

FWIW, if the engine continues to run after priming with external fuel, the injectors are obviously getting pulsed by the ECM. There is a chance that fuel pressure is low, and it should be checked. 11 PSIG, ± 2 PSIG is the specification. Opening the throttle more will cause the ECM to lengthen injector pulses, which may be enough to run the engine at a lower fuel pressure. Changing the filter was a good idea, but changing the pump may have been a waste of time. BTW - Did you also replace or eliminate the pulsation damper at the pump? Now, you need to start analyzing instead of parts-changing. If you have a gut feeling that the TPS is a problem, measure the voltage at the closed throttle position. You're going to have to do that anyway, especially if you change the TPS! Once you're satisfied the TPS is working, check the fuel pressure. Anything else is going to be a waste of time, and you won't know which half of the system to look toward.

Is the IAT and IAC the same, or different parts? I know where the IAC valve is.

- Did you also replace or eliminate the pulsation damper at the pump?

..no idea how to do that :(

MAT - Manifold Air Temperature (senses air temp within a manifold or plenum)
IAT - Intake Air Temperaure (essentially the same thing as MAT)
IAC - Idle Air Control stepper motor/valve

As you know, the IAC is mounted in the right side of the throttle body base. The MAT or IAT sensor will usually be mounted in the air cleaner or intake ductwork on a TBI application.

Damn, BB - wish you lived here in Pensacola, FL!!

I'll get it.. won't give up.. eventually you'll read...

SHE CRANKS NOW!!! :)


Someone's coming by tomorrow and we're gonna go over all your advice and post results. He's bringing a voltmeter. How much do those 'noid lights run?

Thx again!

.. if anyone does happen to live in P'cola.. gimme a yell!! :P

Quite a few people live in Pensacola, either temporarily or permanently. I've "visited" there myself. You live in Pensacola, and you're already working on the problem. No need to make it too crowded under the hood. You can do the real work, and the rest of us can try to help guide you through it. It's not like we're going away any time soon.

So, it's cranking and firing now?

No, still no go :(

Double post:

NEW RESULTS (8-8-6):

With volt(ohm)meter:

1. Checked the pickup coil - tested out fine.

2. Checked TPS - power continuity was OK(5v when turned power on), however, the check for the throttle closed to full (sweeping from ~.5vclosed up to ~5vfully open) gave NO readings on the meter whatsoever. This was putting the pos. terminal to the dark blue wire and the neg. terminal to the black wire.

Have I found my problem guys??

Should replacing it give me juice now?