3.1 problems - Third Generation F-Body Message Boards

Hellbilly · 06-22-2009, 07:38 PM

I have a 1990 firebird with a 3.1L v6, automatic trans. I'm in a rather confusing pickle with this car. My patience and wallet are wearing thin.

Bought the car several years ago from a relative. He never transferred the title to his name so that I could properly register it in mine in the state I am in. Drove the car till the plates ran out, its been sitting awhile..little over a year exactly due to the fact that I don't have the funds to get it legal. I'd go out and start it every now and then just to keep it charged. I've fixed several problems on the vehicle before. Such as, the complete upper intake gasket replacement, the EGR, MAT sensor, 02 sensor, plugs, wires, cap and rotor.

Had the car on the battery charger over the weekend, tried to fire it. I got nothing. I maybe got it to run for 2 or 3 seconds before it died out and gave me a code 33. The MAT sensor isn't that old, I'm not too sure if this is my problem. I checked my plugs, they are gas soaked...probably from me attempting to start it over and over. The code 33 puzzles me as I thought I corrected this issue once before, and not too long ago.

Thus I am left with a car that will not start.

Before when I had little problems with it, it had a misfire issue which I thought was fixed by the new plugs. I haven't messed with the timing on the vehicle so, maybe the plugs or coil are bad. Maybe the gas that is in the tank is bad. It has been awhile since I've made a trip to the gas station in it, which is not letting it fire off. Hopefully getting a job soon, and do not wish to keep feeding the motor my paycheck. I do eventually want to fix the outside of the vehicle too

I've been chasing many problems with this car and am at wit's end this time. Any suggestions? I'm truly hoping this will be solved when I tune it up to attempt to head down to the highway patrol for state inspection.

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drdave88 · 06-22-2009, 08:00 PM

Ive got a few questions for ya...... How old is the gas in the tank? Are you sure youre getting spark, have you tested for it? Have you pulled or turned the distributor at all? Did it run and then just stop running at some point? Oh and is there a VATS system (vehicle anti theft system) on the car, does your key have the lil black chip toward the base of it or do you see an anti theft light on the dash? If you have that, the key chip may be worn out and not let it start. I dont remember what year VATS started on.

Hellbilly · 06-22-2009, 08:26 PM

The gas is probably more than 5 months old. It probably needs some stabilizer pretty bad. It's reaching the bottom of the tank (1/4 mark). The distributor was removed when doing the upper intake gasket job, however it was marked before pulling. the key chip is there and intact. The car ran just fine no more than a week ago, hell I even drove it around town at risk of being pulled over just to stretch it's legs. Testing spark is the next thing on my list. I'm hoping its just a case of bad gas.

drdave88 · 06-23-2009, 08:06 AM

the contacts for the chip can wear down either on the key or in the ignition, just being there and intact may not be enough.

pontiacguy1 · 06-23-2009, 05:01 PM

If it was his VATS system, then the engine wouldn't turn over at all. VATS was added to the cars in 1990 when the 3.1 replaced the 2.8 liter engine.

I would say that you might have a problem with a vacuum leak. My car is running right now, but idles terribly. It is also giving me a code 33, which is the MAP sensor-low vacuum. What I believe is causing mine is the EGR system. I believe that my EGR valve is not shutting off completely at idle and it is is causing low vacuum and a rough idle. I have also noticed that my car's RPMs do not drop nearly as quickly as they used to when I take my foot off of the pedal. That could be a vacuum leak, or a malfunctioning EGR. I have yet to find any vacuum leaks. Mine is also a 3.1 liter car.

What will happen if I just put a blockoff plate between my intake and the tube coming from the EGR valve? I am planning on doing that just to see if it is the problem. I will then either leave it or attempt to fix the EGR system.

drdave88 · 06-24-2009, 06:54 AM

I thought the VATS would allow the car to start, run for 2-3 seconds and then die. Hmmm, i stand corrected.

pontiacguy1 · 06-24-2009, 10:03 AM

Yeah, the VATS system, when activated, cuts out two things... The fuel pump relay and the starter relay. That's all that I know of that it does. It cuts the starter relay and fuel pump relay and turns on the 'security' light inside the car. The light will stay lit wheneve the key is on until the system has timed out and reset. It cuts the fuel pump to keep someone from being able to straigt jump the starter from underneath the car and then being able to drive away.

Does anyone have an opinion as to what will happen when I put a blockoff plate in between the tube from my EGR and the intake? I believe that my EGR, or at least one of the solenoids, are stuck open and it is making my car idle very rough and rich. The car has no noticeable missing or stalling at highway speeds, only when the RPMs drop down near idle.

I completely rebuilt the distributor about 4 months ago including a new module and pickup coil. The plug wires are 4 months old, and the Bosch Platinum +4 plugs are only 4 months old and each of them looked just fine when I pulled them out. The injectors were also cleaned and put back in 4 months ago. Up until about 2 weeks ago, it ran better than it has in years, then all of a sudden it idles terribly and smells rich when it is idling. Once you drive off, it smooths out fine and sounds fine too. I haven't noticed any loss of fuel economy or anything like that. The timing is set at 10 degrees BTDC. I can't find any vacuum leaks.

drdave88 · 06-25-2009, 07:12 AM

I totally removed the EGR, put a block off plate on the exhaust and intake manifolds. I removed the valve, solenoid, all vacuum lines and plugged any vacuum ports for the EGR. the only problem i have is the check engine light as soon as the car warms up....... but not for much longer hehe. But if youre going to block it off, disconnect everything related to the system.

Hellbilly · 10-01-2009, 03:53 PM

I know this is one hell of a thread bump. I'm still having issues with this car. Spitting the code 33 at me, and not starting. I checked all the vacuum lines and they appear to be fine. I have spark, the fuel is there, it's getting air. Once it does kick over, it's very rough and sometimes spews smoke (gray at times, sometimes a hint of blue.) out of the intake and dies. Had it running the other day, except it would die on idle. Now it's the other way around. Could it be my timing is off? I've done everything I could possibly think of except tossing a grenade in the engine bay.

Maverick H1L · 10-01-2009, 07:56 PM

Couple of bad things I've read in this thread:

1. VATS does NOT shut off the fuel pump relay. VATS uses a 30Hz signal to tell the ECM that the proper key is in the ignition and that it's okay to fire the injectors. The injector driver does not activate until this 30Hz signal is found. If VATS fails AFTER the engine starts, then it will still allow the engine to run but will supposedly set a code (53?).

2. Hellbilly, your engine NEEDS to be retimed, BADLY. If you're getting smoke (exhaust) out of the intake, that is known as backfiring, which means you're out of base time. Don't forget you need to unplug the 2 halves of the bypass connector (tan/blk) that is coming out of the wiring harnes by the blower fan.

Hellbilly · 10-01-2009, 09:06 PM

I'll definitely look into timing it. Just means I need to get me a timing light. I might need a refresher course on how to set base time on a non-running vehicle though.

Maverick H1L · 10-02-2009, 06:23 AM

Just unplug the connector I stated above and turn the dizzy one way or the other. My guess would be that you should turn it to the right, since it seems that you're a little too far advanced. Have you done any work in the vicinity of the dizzy lately? Something had to have knocked it out of time. It's either that, or the plug wires were disconnected and reconnected improperly. Check your firing order as well, 1-6 in order. Just as a reminder, #1 is PASS side front, not driver's side.

Hellbilly · 10-02-2009, 01:49 PM

I checked the plugs earlier, they are in the correct order. I had done a full upper intake gasket job on it a few months before. It ran great after it was done, however it sat for a bit while I was waiting for state patrol to call me back. Maybe it was fine for awhile but eventually got off track. I'm hoping the timing chain isn't causing me issues if that's the case.