off topic - need gasser help in a bad way

[Cowracer]

Guys!

My sons car is a 1990 Olds cutlass ciera with the 3300 V6. It is my ride to work until I get my engine redone in the dually.

Anyway, this thing is driving me nuts. It stalls just about anytime you give it more than half throttle. Sometimes when it stalls it will catch itself when you let off the gas. Sometime you have to restart it. And every now and then it will restart and run clean for a second or two and die.

My boy was stranded last night when it would not stay running for more than a couple of seconds. This problem started out with a hiccup one time while getting up an on-ramp a couple of weeks ago, and has gotten worse and better and then worse again.

It seems to me like its having a fuel supply issue. Dipping into my diesel knowledge, I chaged fuel filters, and I made sure the fuel pump is working. I am leaning towards the fuel pressure regulator, but they are nearly $100 and I don't want to start tossing c-notes at this thing willy-nilly.

Anyone got any ideas, 'cause I am stumped!

Tim

P.S. if nothing eles, at least I know that its not FSD related! :D

[BobND]

The fuel pressure regulator works by opening at the set fuel pressure, and returning excess flow to the tank, so at idle it will bypass the most fuel, and at full load it will bypass the least fuel. With your symptoms, I'd say 90% chance AGAINST a bad fuel pressure regulator.

The fuel pump, however, at idle needs to pump just enough fuel to feed the engine. However, when you "step on it", fuel demand goes up, and the pump needs to keep up, or the engine will fall flat on it's face. With your symptoms, I'd say 90% chance of a weak fuel pump or clogged filter "sock" on the fuel pump.

The test would be to hook up a fuel pressure gauge and monitor fuel pressure, and look for a sudden drop-off when the car stumbles. You'll have to find out the correct fuel pressure for your car PERHAPS about 50 PSI.

[Dvldog 8793]

Howdy
I had similar problems with a FeiroGT that once had and it turned out to be a plugged cat. Does the car ever throw a code? Does it matter how much fuel is in the tank? Has there been decrease in fuel MPG? If you rev it with no load does the same problem happen? Another car that I worked on had a transmission module out that would cause it to die at idle in drive. Maybe something in the trans will do the same under load?
Maybe someone filled it with gas instead of Diesel? try a bottle of Mr Supers Diesel yummies and fresh #2.... wait-a-sec I think i'm confused???? tongue.gif
Hope this helps...
L8r
Conley

[Cowracer]

Originally posted by BobND:
The fuel pressure regulator works by opening at the set fuel pressure, and returning excess flow to the tank, so at idle it will bypass the most fuel, and at full load it will bypass the least fuel. With your symptoms, I'd say 90% chance AGAINST a bad fuel pressure regulator.

But what if the regulator defective and its stuck dumping fuel back to the tank? That would allow idle and cause it to lean out and die on throttle, wouldn't it?

I will check the fuel flow and pressure into the injector rail tonight.


Originally posted by Dvldog 8793:
I had similar problems with a FeiroGT that once had and it turned out to be a plugged cat. Does the car ever throw a code? Does it matter how much fuel is in the tank? Has there been decrease in fuel MPG? If you rev it with no load does the same problem happen? Another car that I worked on had a transmission module out that would cause it to die at idle in drive. Maybe something in the trans will do the same under load?
The cat is BSN (brand spanking new). I bought the wreched old sled for $500 and had to replace the exhaust to pass inspection.

I'm gonna say fuel mileage is steady, although I usually dont drive it enough to have a good feel for it. The SES light is good, and there is no codes at all. I dont think its a sensor.

It will do the same reving it up under no load, but not nearly as bad.

It's weird becase some days its fine, then will die and wont restart for a while and then finally restart and run at small throttle, and then bam! be fine again. All in the same day, so its not like fuel level affects it.

It reminds me of a buddys truck that had the engine-mounted fuel pump. The rubber fuel line from the tank rotted, and allow it to suck air. Under load, it would sputter on heavy throttle. But it was way worse with a empty tank than a full one.

I know thats not the problem here, as the pump is tank mounted. I guess that a fuel pressure gauge will tell the whole story.

Tim

[DmaxMaverick]

I also have a 1990 Ciera, but it's a Quad-4. They are pretty much the same otherwise. I have also experienced exactly the same as you, several times (car has 300K on it), and have delt with the problem each time successfully.

Try this. With the engine idling (if it will), hood up, have someone in the car stand on the brakes, put it in D and slowly roll on the throttle. You should see the engine torque roll the engine slightly to the rear. Watch the front engine mount. If there is any movement of the mount, and the engine stumbles with it, that will be your problem. The engine ignition breaks ground (or something--we just replaced the mounts and moved on) when this happens, for some reason. On my car, it'll do this every time when the mounts are bad. They usually only last about 75K. I've also seen ~1990 Buicks (same chassis) do this with the V-6. These Buicks were dealer loaners, and I had to show them what their problem was.

Hope this helps.

[Dvldog 8793]

Howdy
Talked to Mech Friend and he said before you spend any money to crack the fuel cap and see if that makes a difference. He said maybe as simple as a bad cap.
L8r
Conley

[wfyehl]

I'm not familiar with the 3300 V6 engines, but am familiar with the 3.8 and 3800 engines. If this engine has a MAF sensor, it might be on the blink. To check, take a screw driver and tap the MAF sensor with the handle of the screw driver. If the engine stumbles, you have found, hopefully, the only problem.

I have had the MAF sensor go bad on two cars, and never set a code, just ran bad. When it finally set a code, the car would not even idle.

Good luck,
Bill

[moondoggie]

Good Day!

I have limited experience with fuel pressure regulators in 2.8/3.1 V6's; I have no idea if you car uses a similar setup.

On the 2.8/3.1's, it's REAL easy to check the fuel pressure regulator & lift, er, fuel pump.
</font> Start & idle the car. Shut it off. Pull the vacuum hose off the fuel pressure regulator. If you can detect any gas in the vacuum hose, the diaphram in the fuel pressure regulator has a pinhole or rupture. (Re-install the vacuum hose.) If this is so, stop here - you need to replace the regulator.</font> Beg, borrow, or steal a fuel pressure gauge. I bought one pretty cheap some years ago. Thread it onto the fitting on the fuel rail. Turn the key on (DON'T start the engine) for a couple seconds - the pressure should jump to ~ 40 PSI & not drop.</font> Start the engine. The pressure should be in the same 40 PSI range (I don't have exact numbers, but that's probably close enough).</font> Pull off the vacuum hose. The pressure will jump, but I don't remember if it's up or down.</font>On the other hand, the last time I has gasser trouble, I had digestive problems... :eek:

Hope that helps.

Blessings!

Brian Johnson, # 5044

[Turbo Al]

I also have this motor in my wife's car. So far the only thing to kill the motor was a very busy mouse filling up the aircleaner box with about 5 lbs of grass and paper.

[fastcat800]

The kid had a 3.8 that did the same thing as yours. It was the mass air flow sensor.

[TurboTony]

It could also be a bad crank sensor. I'm almost positive that the 3.3 uses a similar sensor as the 3.8. I've replaced dozens of 3.8 crank sensors for just the condition you describe.

Try taking a long extension or bar, approx 36" and use it to transmit a small hammer tap onto the sensor bracket. Be very carefull not to beat on it too hard or you will need a sensor for sure, lol.

The sensor is mounted behind the balancer on the front side of the motor and has three wires.

You will need to buy an updated bracket to go with the new sensor, get a delco one if you find that's the problem too.

Hope that helps. If you end up replacing the crank sensor post back first, there is a procedure to center the sensor on the vanes you need to do as well.


Tony

[patrick m.]

being in automotive service, and seeing similar vehicles and symptoms, i have to agree with turbotony.

crank sensors are common issues i see on 3.0, 3.3, and 3.8.

BUT, if the crankshaft has too much "endplay", a new sesor may do little to help.

[BobND]

Do have have any diagnostic codes? A defective MAF would likely set a code, and crank sensor MIGHT set a code, but, if I recall, a fuel pump on it's way out probably WON'T set a code.

[dkveuro]

Originally posted by Cowracer:
Guys!

My sons car is a 1990 Olds cutlass ciera with the 3300 V6. It is my ride to work until I get my engine redone in the dually.

Anyone got any ideas, 'cause I am stumped!

Tim

P.S. if nothing eles, at least I know that its not FSD related! :D My buddy next door had same issue ...was a bad DI Coil pack. Heat and vibration problem.
Like someone else said, the crank sensors do fail too due to broken loom wires...

Don.

[Cowracer]

SOLVED! :D

Turns out it was a dead short in the #4 injector. I guess it was pulling the voltage down far enough that the other injectors could not fire.

With that injector unplugged, the car would run. But as soon as I plugged it in, it would die straight away.

I actually drove it to the parts store on 5 injectors. It ran suprisingly well.

Thanks for all the help guys! You're the greatest!

Tim

[moondoggie]

Good Day!

If this engine is wired like the 2.8/3.1's, each bank of three injectors is driven by one transistor on the PCM. When you removed the shorted injector, this allowed the PCM to drive the other two with no problems.

I love my GM stuff, but for the price of four more drive transistors, I sure wish they hadn't done it this way. With this design, impedance matching of injectors is important - impedance matching wouldn't matter if each injector had its own drive transistor. I guess the $1 saved ($0.25 per transistor) times millions of vehicles made for lots of bonuses for management. :( Hey, don't flame me - I'm a capitalist to the bone, but sometimes ya gotta wonder...

Blessings!

Brian Johnson, # 5044