Driveabilty help please

pontiac
lemans

#1

HI folks first off. Ok I have a 1989 Pontiac Lemans 1.6L, 4spd heater and a key car w/ 179K on it.
So here is what I need some help and direction to go with.
Car starts and runs perfect for about 15 minutes, then check engine light comes on. When first starting flashes 1-11 for code 12.
Then after it runs for a bit, worse when outside air temp is high, light comes on and it dies. It will start back up after maybe 4-5 key turns. When it first dies the SES light starts flashing rapily, and will either stop or start again when key is turned. After waiting maybe 10-15 seconds trying to fire it back up, the SES light will flash the code 12, then kinda fire or fires up and runs or runs then dies down.

Some times it will not die even with the light on, other times thus far 2 since this started about 1 month or so ago.

I have a simple Bosch OBD to plug into the ALDL. When it first died and I got it home I plugged it in. It gave me code’s 13 and 22, o2 sensor and throttle position sensor. Now it just stores the typical 02 sensor, 13. I am not sure if it is sensing an overly rich or lean condition. My plugs are white, not the chocolately color. I went ahead and put in a TPS, new Coolant sensor, new coil, new wires and a new fuel relay.

This thing dies like the key is turned off or just runs out of gas. When I first hit the key you can hear the fuel pump pressurize. I have looked at and tugged wires to see if any are cracked or busted, can not find any. Something else that is wierd the gas gauge does not always read right away and sometimes the tach does not move, makes no difference if car dies or not.

I have the factory service manual and so far it has been any help cause either the engine will fire or test light lights and goes to the “yes” box. I saw a flashing SES could mean either the secondary ignition has shorted to ground or ECM has lost ground. At idle it has almost 15 inches of vacum. I have watched the injector and it has a very nice and steady spray pattern. Compression is 136, 133, 134, 135. I have owned and been driving this car since 1-12-07 and it has never once let me down.

I sure hope someone might have some good advice for me. Thank you.


#2

It will start back up after maybe 4-5 key turns.

How long is each Key Turn? What if you just let it crank?


#3

Well with my 89 Riviera, it would stall after about 7 miles and start right up again. No codes though and fuel pressure was fine. I tried everything including sensors, cleaning grounds, crank sensor, and even an ignition switch. Had it to two different mechanics with no luck. Finally thought I had it solved and started driving it again but after a couple months it started again. I finally junked it and it stalled for the last time right outside the dealer where I was picking up my new car. If you’ve got codes, then that’s where to start but consider long and hard throwing many parts at a it. You might be much happier to start out with a different vehicle. Of course it could also be something like the mass air flow sensor that could be causing a rich or lean condition but you need a reader that can see the fuel settings.

Edit: Again not to be discouraging but yeah, I also swapped computers, had a new cat, IAC, spare MAF, etc.


#4

The computer is at the top of th elist of likely causes for the problems. It sounds as though the computer goes bezerk as soon as it goes into closed loop. The throttle position code should be diagnosed and all the wiring closely inspected but the computer is less than $100 from Cardone. There is a Cal-Pac that must be transferred to the new unit if you want to throw money at it.

Whever a computer throws out bogus codes or fails to give a meaningful code when the engine stalls while the CEL is flashing it has usually been a faulty computer for me.


#5

Does your FSM say what the first code you said flashed out means, the “code 12”? That’s the first place to start.

As far as what’s wrong, without a proper shop diagnosis I can only venture some guesses.

  • First off, if it is time to do it anyway, replace the spark plugs, engine air filter, and fuel filter.

  • Heat related failure items on electronic fuel injected cars are frequently the crank position sensor, the fuel pump, or the fuel pump relay.

  • Ignition system components are another heat failure item, but not as common. The coil & ignition module in particular, sometimes together called the “igniter”.

  • Idle air control (IAC) malfunctions are commonly reported on cars of this vintage. It can make the engine idle rpm too low for the driving condition, and it stalls. Likewise for this vintage, dirty throttle bodies and MAF sensors (if your engine uses an MAF.)

  • Make sure to check the fluid levels, esp oil and coolant.

  • A clogged cat could cause this, but the symptoms don’t really match what folks usually complain about for clogged cats. But it could still be that. A tech could temporarily bypass the cat to see if it helped.

  • Compressions in the 130’s are a little low, and could be related. But getting accurate compression readings isn’t that easy for a diy’er. I expect your compression is actually higher but you aren’t doing the test exactly the right way or an inaccurate gauge. You could squirt a little oil into the cylinders and see if that affected your readings.

  • Suggest to measure the intake manifold vacuum level. It should be around 17-22 inches of mercury.

  • A fuel pressure measurement might be required. At the minimum, look inside the vacuum hose connecting to the fuel pressure regulator. There should be no gasoline inside that hose.


#6

Thank you to everyone who has responded so far. Ok first I am former tech I did mainly drive lines, steering and suspension. At any rate the pressure reg on this is strange as it has no wires or vacum hose to it. The FSM does say the code 12 should be there when key is first turned and fuel pump pressureizes. Fuel pressure engine off is 6.3 lbs and running is 6.1. It is not a high pressure pump. As far as compressioin I did both the wet and dry and it only varied by a few pounds not 5+/- enough to worry and I did a leak down test and no problems.

As to how long the engine cranks I only hold the key for a few seconds and it turns maybe like 7 times or so. I have changed the air and fuel filters and none of the black gunk come out it. The computer has no idea of what the timing is and it does not have a crank or cam senor. And no this one is the 1.6L not the 2.0 so no MAF sensor.

When the engine starts cold it does not read the TPS or O2 sensor. It gets signals from the Temp sensor to tell the MAP sensor how much fuel to deliver to the injector based on temp signal. I might an idiot but from the look of plugs being white it seems like the thing is getting chocked out on fuel running extremly lean. I pulled the IAC valve and put in a new spring and gasket and checked it’s voltage and travel rate it is right in line with the FSM.

What really sucks is I have a Snap on scroll scanner, but not the chip needed for this stupid thing.


#7

Sounds like he has the brick, but not the correct “personality key”

Too bad he doesn’t live near my house. I have a current model snap on scanner, all the OBD1 adapters, and all the keys for those older vehicles


#8

Fuel injected, but only 6.1 psi fuel pressure? hmmm … I’m not familiar at all w/that engine design so pretty much guesswork here. Do you have some form of OEM throttle body injection then? It came with the new car that way, right?

Given the codes and symptoms, you may have two problems, one with the throttle body or throttle position sensor, and another with the ignition system. OBD 1 sometimes produces codes which indicate everything is ok, I presume that is what “12” means on your car. My Corolla has a code like that too, “53” I think, meaning everything is working correctly. For the life of me I can’t figure out why they thought that was a good idea. No codes logically means everything is working correctly. You don’t need a separate code for that.

You say you replaced the spark plug wires, but have you replaced the distributor cap and ignition rotor. If your engine is so-configured, that’s worth trying. Beyond that, I think what I’d do if I had this problem is try to see what exactly is going wrong when it starts to fail. I’d connect up a volt meter to the battery, with the meter on the passenger seat so I could see it, and a fuel pressure gauge positioned so I could see it while driving (not in the passenger compartment, that would be unsafe, maybe taped to the windshield). That will provide some clues anyway what’s going on. The other thing I’d try is to spray some starting fluid into the intake manifold when it wouldn’t start. If it briefly started, then died, you’d know part of it was definitely a fuel problem.

If those compression numbers are accurate, low compression is probably related. Low compression can turn what would otherwise be a minor drivability problem into a major one, and even a complete no-start.


#9

I thought an OBD1 Car , one flash, pause, two flashes was code 12. I have never heard of One flash followed by 11 flashes.


#10
Fuel pressure engine off is 6.3 lbs and running is 6.1. It is not a high pressure pump.

I’d suggest you check the spec. Although I do not know your specific car, all the GM TBI systems I have worked on in the past were closer to 12 lbs running pressure. It doesn’t explain some of the other oddities your experiencing but certainly would be a root cause for the engine running issues and feedback loop codes. I’ve had pumps go out like this before where they died a slow death…


#11

How about the ignition module in the distributor and hei coil.


#12

Thanks again to everyone and yes the fuel pump for this is strange, only takes about 15 minutes to change and is a low pressure system.

At any rate I found the damn problem. As I put in the SES light would flash fast and intermittent. This shows either short to ground in secondary ignition or ECM lost ground. Found the broken wire. The 02 sensor kept triggering as the engine temp increased. It was broke. Put back together and car runs great again. thing is with what I have done and changed, less rpm’s needed to maintain speed. Thanks again.