1992 Firebird LO3 with 113000 miles.

Hey guys -
I just recently picked up the car and it has ran like a champ until this morning on my way to school. I was driving down the highway around 55mph when all of a sudden the car was extremely down on power. I hit a stop light and it seemed to idle fine, but when I gave it gas, it had ZERO power. I mean it felt like the thing had 50rwhp. It ran through the rpms fine, but just did it VERY slowly.

I know it has the original cat. Could that be the culprit?
Any other common probs that may cause this?

 

You could have a multitude of problems. A dying cat won't cause a sudden power loss like you describe. I would suspect a dying fuel pump or a bad 02 sensor. Check the feed line fuel pressure. You should be able to rent the Actron tester at autozone.

I would also trace all of your plug wires. Make sure none of them worked themselves loose or burnt through exhaust parts.

 

Check fuel pressure, spark plug wires, and the cat. I would suspect the cat...

 

check your vacuum lines

 

Plugs, wires, O2 and fuel filter are good. I did find that the car seems to rev just fine in neutral. Any idea there?

I may run by autozone tonight to see about the actron tester. Any guides on how to work these things?

 

If it is revving just fine in neutral then your cats are fine...

 

That's what I was thinking. Any idea on what would make it run like crap while in drive but not in neutral?

 

Sounds like a dying fuel pump

 

it almost sounds like timing. like the engine's not advancing under load. you might want to check out the m.a.p. sensor. and just for the record odds are it wouldnt be an o2 sensor. they dont just go bad all the time. there has to be something causeing it to go bad.

are you throwing and SES codes?

 

Nope, no codes yet.

I took it to the exhaust shop so they could check out my cat. He also said he would check the fuel pressure for free while it was in. What a nice guy. Saved for $50 on the tool.

Fuel pressure checked out fine and the cat was clogged. He changed the cat with a hi flow and the car ran better than it ever has. Then on my way home, it would barely idle and the symptoms got worse.

Any ideas now? I'm starting to lean towards an intermittent fuel pump.

Symptoms are now:

Sometimes it runs great, sometimes it has a low end stumble and then pickups in the higher rpms, sometimes it won't even start, sometimes it will start and then die when you put the car in gear and give it gas.

Cap is new, plug wires are new (plugs probably need to be changed though), O2 is fresh, new cat, and new fuel filter.

Would the MAP sensor cause that drastic of symptoms if it was bad?

 

check your vacuum lines... do this before doing a fuel pump... do the easy things first then knock them off your list and if they dont fix it then do the hard things like change the fuel pump

 

is there a way you can hook up a fuel pressure guage and maybe drive around withit suck in your whipers for a few days? that way when its acting up you can see what the fuel pressure is doing. i picked one up a while back at the autoparts store for like 40 bucks. or try and borrow one, dont know how often you work on cars but its a good investment none the less.

 

i hope that isnt a serious question because the obvious answer is no... why dont you run outside check all of your vacuum lines and at least comback and say that its good, i still think its a vacuum related issue

 

I changed the plugs this morning and checked the vacuum lines. The problem is still there.

At idle and in park, the rpms will raise and lower sporadically. I can put the car in gear and it will almost die. If I try to drive it, there is absolutely no power.

Cap, cat, plugs, wires, O2, fuel filter, and vacuum lines are good. Fuel pressure checked out "okay", but the test was done when it was more of an intermittent problem.

 

do what i said above. you dont have to stick it in ur whipers but just leave it under the hood. and when i does this look at the guage. also, when you check fuel pressure the pump is supposed to hold the pressure for so many seconds. does the car take a long time to start? like longer than 3 or 4 cranks.

another question, does your coolant temp sensor work?

 

Sometimes it starts on the first crank and sometimes it takes 3-4 cranks.

As far as I know, the sensor works.

 

Ignition module.

 

that may be the case. whats a good way to check it?

 

How do you know the fuel filter is ok? How long before the engine started messing up did you buy gas? (you could have gotten some bad stuff) Maybe some jealous bastard sugared your tank. Look for residue around your gas tank filler neck. I've seen it happen before. Push the trap door in the neck open and look down the pipe with a strong flashlight, evedence will be orange crystalized substance. Other than that, low fuel pressure
(causes the engine to rev forever but seems to go nowhere) or possibly a TPS sensor going bad. You might want to check Alt. output. I had a problem with my 88 Lo3 just like yours (some times it would start first time some time not) major loss of power, and stalling. Even though I didn't get a SES light I checked for codes and there was one. Code 54 (low voltage less than 2.5V seen at fuel pump) I bought a fuel pressure tester at AZ ffor 50 bucks and it was putting out 7.5 lbs. After I replaced the pump, it was up to 13.5 and felt like a new engine. Anything less than 9 lbs is not good enough.

 

exact same symptoms when my fuel pump went out.

I am guessing fuel pump...... 90%.

 

I agree. I sill say it's the fuel pump. I also had the same symptoms before mine quit permantly

 

It really sounds like a fuel pump.

Plugg in the Electronic spark control in and look at your timing. Is it advancing if you give it gas???
If not get your timing right.

Also, make sure that ESC is connected and that all of your ignition wires are in good order (looking decent without any dents or chips).

Than check your fuel preassure!

Any codes???

Do they come on and off??

Good luck.

 

My 2 cents. It's a fuel problem. New filter could be bad or pump is on it's way out. A vacuum leak would not cause a loss of power only under load. Idle would probably be real high if the leak was that big. Ignition modules usually work or don't. Mine started breaking up around 5000rpm, then it just went dead. Could be a coil heat problem, but once again, that's usually all of nothing.

Change the filter again, it's easy and cheap. Problem still there change the pump. The pump is a little pricey and if it doesn't work having a spare is not always a bad thing. If it still does not work I would suspect a problem with the fuel pump wiring.

Steve

 

why can't you run around with a fuel pressure gauge hooked up?

 

my honda had some issues somewhat like this. ended up being the little button on the middle of the dizzy cap got stuck. spark had to jump a larger gap and then another gap going to the spark plugs.
idle was a little rough car didn't have much power and when I drove on the freeway top speed of about 67mph
pushed the button out and it worked fine again.

 

try pulling a few plugs and see how they look.
best way to do this is wait till the car starts acting up again. when it does it try to keep running running like that for a few seconds then just turn the car off (yes while driving around turn the key to off, don't stop the car then turn it off ) right after you turn the car off turn the key to on but don't start it. this way the steering wheel doesn't lock on you if you need to turn. pull off to side of road pull a few plugs out.
if they are black chances are it is either running rich or better chance of your having ignition problems.
if the plugs are a whitish color chances are your running lean. best chance is fuel pump or fuel filter.


I wouldn't think of a vacuum leak too much being it would affect idle and low load situations quite a bit but have less effect on highre load situations

 

rx7speed, white color tips on plugs in fuel injected motors are normal.

 

never noticed that. most all the cars I have seen the lpugs on they are still a light tan and that includes EFI cars.

 

THANK YOU! it may look stupid but who cares.


And to everyone else, you cant just assume something is wrong just because a problem you had showed the same symptoms. Throwing parts at a problem is NEVER GOOD! all your doing is wasting money and time. if you think somethings wrong then figure out how it works and test it.

this problem sounds fuel pressure related. if its an intermitent problem then you will need to hook up a guage and roll around with it hooked up. either under the hook or stuck in the whipers so you can see it right away. the last thing you want to do is replace a fuel pump in an fbody under asumption. cause its a PITA

 

Although I can't speak for others and their best educated guesses, I would never recommend just diving in and changing the fuel pump without knowing for sure. Your right it's a PITA!

Based on information given in these posts and without being able to physically be right at the car, all anyone here can do is give best educated guesses through personal experiences of their own. By all means the opinions that have been given should be looked into and tested if possible in order to narrow the list of "Could Be's".

 

It's the fuel pump.

The pressure dropped below 7psi today. Thanks for all the input.

 

Oh well, you got a new cat! When you get the new fuel pump it oughta run like a Cheeta!!!!

 

"Fly little pelican, fly pelican, lill pelican!pelican pelican!""
(from scarface)

 

Car's running great!

 

DAM!!! That was fast!! It took me 3 weeks just to talk my wife into buying the FP tester. He must be single!!!

 

I'm married...so I made the wife get out there and cut the hole in my hatch while I took a nap.

 

Yeah, I did the same thing to mine. It only took 2 hrs. and I didn't get any dirt in my eye's. SOME people call it a hack job but hey, it's not a T/A, Pro Am, Z, or IROC. Like it's going to ruin the value or something. I'll probably be the last owner anyway!

 

buy or rent a fuel pressure gauge, i had half the stock PSI and it felt like i had half the power... i can break traction again, its not that bad of a process.. just a little frusterating when trying to get the tank tube manuevered out

 

Exactly!!! People crack me up who say "that's not the right way to do it". How exactly is it not the "right" way to do it? The problem gets fixed, and the car is visually the same...unless you want to prop the hatch and rip up the carpet to see the nicely patched trap door. Plus, if the pump goes out again or you want to upgrade in the future, you're already setup.

Why turn a 2-3hr. job into an all day mess?

 

Mind explaining to me why that wouldn't work? Althought complex because of the needed fittings he would have to purchase running a FPG is a common thing. I ran a 2 5/8" liquid filled Autometer in the cowl of my 4" hood. It was nice being able to always tell what your fuel pressure is doing.

Since the problem is so "off and on" I wouldn't expect it to be any vacuum lines. I would look at your ignition module and your fuel pump.

 

Oops I own a pro/am!!!
Too late now! The trap door is in
All I gotta do now is put in a new pump, but its soo freakin' cold here in Denver nowdays.
Maybe sat. morning.

 

WHAT? You live in Denver, and you don't have a garage? I have 550 sq ft in mine but I don't think running a 35,000 btu kerosene
ready heater would be a good idea while messing with an open gas tank.
KABOOM!

 

Garage is a comodity I can not afford.
However, I still got ***** and I just changed my bumper today in 20sumtin degree weather. Windy as hell too!
I feel kinda sick, but hey I got an 92 bumper on my 89 and it looks cool!

 

Let me guess whats next, hmmmm, cowl induction hood? That's what I would do! That little power bulge just doesn't do it for me.
Can't get no cold air. I'm thinking about reversing a dual snorkel (I think that's how you spell it) and hooking them up to vent's cut into the firewall so they will suck air from the heater intake vents between the hood and the windshield. I've seen it done in one of the Hi-po mag's. It looked good and was very functional. Besides, a dual snorkel air cleaner is a lot cheaper than a $900.00 ram air or cowl hood BEFORE paint! You never know though, I do play the lotto!! Hey, when you put that 350 in there, how bout you send me that computer?

 

Who's computer is that you want???
You know that the 305's computer can be run with the 350 with 350 sensors??
Anyway, I am getting a new computer so if you want my old one let me know. I just can't guarantee that it will work right. I think its faulty thus causing problems with my bird!!!

Anyways, I am glad someone actually fixed their problem here!!!

 

Your's! The 88 chip is a stand alone (different than the other years) and is difficult to find with a performance set-up. You have to get an 88 reburned somewhere and that seems to involve doing without the car for a while. I can't seem to find anyone that sells them off the shelf!!

 

I have an 89 one!

 

I guess your's wouldn't do me any good then. You probably have TPI in a pro/am, unless I could get a TBI chip and put it in there. But then again, you say it may be faulty. Thanks anyway. sqzbox

 

i used to own a 88 LO3 tbi maro. The only diffrence in the 88 ecm and the 89-92 ecm besides part # is the 88 ecm has 2 drivers for the injectors and the 89-92 has 4 drivers in it. The ecm wiring is the same.


get a Alldata print out of the wiring pin-out and compare the 2.

i done the swap so i could get a chip reprogrammed for it.

but i think now tunercat has got the bin files for the 88 ecm code now.

 

Do you know what the emission laws like for us in denver xlwhellraiser? I need to know what I can get away with before I put a tbi 350 in my camaro. Some days it doen't matter if you do have a garage in the winter here, I can't feel my face after an hour working in my garage.