Service engine light and stalling

Not good, what codes do you pull?

When you pulled codes, what codes did you get?

--scott

I should have thought of that before dropping it off, but didn't. Is it still done by turning on power 3 times?

I think by 2002, you had to use an external code reader. It's worth getting a cheap one if you're driving cars of this vintage.

The service engine light tells you that an error has been recorded, but without pulling the codes, you have no idea what error it is. It might be critical, it might be meaningless, but it will be the first clue to the problem. Without seeing the codes, you know only that the engine is misfiring.

--scott

[....]

Mechanic says the codes read "multiple random misfires." It doesn't say why. He tried replacing plugs and wires, and it made no difference. He suggested a dealer might be able to figure it out.

I would say that if you smelled gas up front then the EVAP line to the tank probably allowed fuel to dump into the intake side of the engine. Basically it's running in an almost flooded condition. Pull the vacuum lines off and blow them out, pull the EVAP line to the tank and clear it. Also probably will require you to change the EVAP canister if it got fuel dumped in it as the vacuum will pull that fuel in as well.

OH and if your "mechanic" gives up after doing the simple stuff, I'd find a real technician. There are far more than plugs/wires that cause multiple random misses.

Agree somewhat, but main point is we assume that the car was running well prior to having to pull up short, and immediately started misfiring/running rough afterwards? So look for whatever got dislodged/moved/whatever.

In the mechanic's defense, a MY2002 car may have been in need of spark plugs anyway but clearly that wasn't the cause of this problem.

nate

He says he checked vacuum lines and the EVAP line, so he said either he takes apart the intake ($700) or first I try using the superior analyzer at the dealer. So I'm going to have the dealer at least analyze it.

The past few days I got a warning that the gas cap was loose, but it was tight. I assumed it was sensed with a switch at the cap, but now I realize that would be a spark hazard.

So it is sensed by pressure in the EVAP line then right? Jesus you can't ignore the stupidest f-ing warning.

Negative pressure. If someone pulled the evap line off or left it loose, that would do it. Bypassing the canister temporarily would tell you if it's saturated, and causing the problem, as long as you don't have fouled plugs.

I can't remember what kind of car this was, but I think you said this started after an aggressive stop. Some cars have had problems with the baffles breaking loose in the tanks. If you hear something thumping in the area of the tank when you accelerate quickly and then stop quickly, it might be that.

Shouldn't need to tear the intake apart if there is good engine vacuum at the EVAP purge port. The "gas cap" code isn't really for a gas cap, (although that is the common cause for it) it means there is a failure in the EVAP system. The system is actually pretty simple in operation, but it can be a PIA to find a problem at times.

On the engine side you have a purge solenoid on the intake, It connects to a line that runs to the EVAP canister and from the canister to the gas tank. On the EVAP canister you also have another line (vent line) which is controlled by another solenoid valve. In a vented gas cap there is also a small one way valve as well.

When certain conditions are met (engine temp, fuel level, ambient air temp, and vehicle speed are the most common ones measured) the vent line solenoid will close, then the front purge solenoid opens. There is a sensor on the fuel tank which then monitors the vacuum generated inside the tank. It compares the amount of vacuum created in the tank over a set time limit. If the vacuum/time threshold is within the proper range it considers the EVAP system to be OK, and the ECM closes the front solenoid and opens the rear solenoid. While you are driving down the road it will also trigger the control open to draw off fuel vapors in the EVAP system.

Now IF the system senses a problem it will trigger the SEL/CEL light on.

P0440 is the common "gas cap" code It actually means there is a problem in the system and it cannot generate a vacuum. The catch is that any of the above parts could have failed or a line going to them is blocked/open/damaged.

Not real hard to test with a decent scan tool and a smoke machine. No smoke machines makes it a bit harder but still not that bad.

There are actually something like 38/39 codes that are EVAP specific and a few others that can be related to the EVAP system. Some are used on all vehicles with OBD II and some only on newer vehicles with more advanced ECMs.

That is probably far more than you wanted to know but it will help limit any surprises.

As to ignoring any warnings, That all depends on the vehicle, the problem, the country/state/city you live in, and what you can live with.

For instance the SEL/CEL being ON in NY is an automatic fail during inspection, doesn't matter what the reason is.

The thing is that if the car is a 2002, the good third-party analyzers should allow you to do anything the dealer system can. If it was a 2013 model, there would be a lot of GM-specific extensions that the third-party guys would not be able to deal with, but after a decade everybody has it down pretty pat.

I'd look at the intake and see if it looks gunked up. $700 seems an awful lot to take it apart and clean it, too.

My inclination would be another independent guy, but the dealer probably isn't going to hurt if you can get the one older-model expert at the dealer to look at it.

What does the warning actually say?

Yes. That indicates that there is an evap system problem somewhere. And no, you can't ignore warnings, they are there for a reason. Car manufacturers today hide so much information from the driver that what information they have left is pretty important stuff.

--scott

It was a single fuel injector stuck wide open. Almost $1000 at the dealer. The EVAP was unrelated and remains as it was, so I might still get the gas cap loose warning.

Another guy said the intake gasket was leaking. I assume that means antifreeze on the outside. So I thought they could do that at the same time and save hours, but I was told the injector manifold is only 1/4 of the way to the intake gasket. Then why is the injector so much? The other estimates for the intake gasket were $500-$700. He had the bad injector exposed so he could see the gas shooting out of it during the diagnostic.

Then they told me if I get the gasket replaced, the manifold might not be reuseable and it's $700, so it's a gamble to get that fixed, or not to get it fixed. So what do you do?

That seems a little much. How did they find it? I'm assuming it was spewing out a million "O2 sensor out of range" errors from running so rich.

The injector shouldn't be too expensive a part, and getting to it really should not be that bad on this car. Not a whole lot has to come off. The injector rail is pretty easy to get off.

If the intake gasket is leaking and you don't see any signs of a problem, I would just leave it.

I'd sell it and buy a VW bug. No injector problems, no cooling system problems. No heat and no acceleration, mind you, but still fun.

--scott

He said that he saw gas squirting out when he turned on the fuel flow, or something like that. And 40,000 misfires on that cylinder.

The independent shop wanted about $250 less, but then I'd have to pay the dealer $105 for the diagnostic, and if the diag was wrong and the work didn't fix it then I'd still have to pay for it. And I'd have had to drive it on 5 cylinders to the other shop.

The book value is $3200 and I paid $2000 so now I've just finished paying for it.

It was $190, but the dealer's labor is huge. His diagnostic is no more than average at $105 for some reason, and he exposed the thing during the diagnostic. So it's not consistent.

Can coolant get into the gas or the oil?

Isn't an EVAP problem even less serious?

I like power steering.

Tom Del Rosso wrote: (snip)

Yes. There is plenty on You Tube about changing a 3.8 upper and lower manifold gasket and the entire plastic manifold. If it leaks coolant to the outside edges then maybe you can see it. But if it leaks internally... it's a serious problem. Do a google search: "3.8, GM, leaking intake manifold"

Be aware that a badly leaking injector could destroy the CAT if not caught in time.

EVAP problem won't destroy the engine as easily as a intake manifold leak could.

Odd coincidence...

Does not sound unusual. I would ask the guy *what* is leaking. Is it running rough? Are you losing coolant? If the latter, is it leaking outside the engine, or getting into the intake runner(s), or getting into the oil? Answers to those questions determine where to go.

3800s with the plastic intake, sadly, seem to be notorious for intake manifold gasket leaks and yes, they sometimes do warp. Supposedly Fel-Pro has an improved gasket set and I believe that Dorman (I think? check my memory before buying anything) released an improved upper intake manifold as well. It's a shame that you have to do this as otherwise the 3800 is one hell of a strong engine.

I'm pretty sure that if you have a torque wrench and socket set that this is in the realm of possibility of a DIY weekend project, once you know what you need and have got the right stuff together.

nate

Forgot to add, if the dealership didn't do it for you, you should probably change the oil because I bet it's got fuel in it.

nate

How much are the injectors? It's probably a lot of part cost at OEM dealer prices for a set of new injectors. And yes, removing or disconnecting the injectors is generally speaking in the first third of things to do to replace an intake manifold gasket.

How bad is the leak? What damage is the leak doing? Are you annoyed watching it? A small weeping where the coolant goes to the ground isn't a big deal. The problem is if if the surface of the manifold or head is damaged or gets worse so a new gasket won't seal or the leak gets worse and you dont notice.. There are cheaper sources for replacement intake manifolds for the 3.8L V6. What would make it unusable is if it has a crossover or Tstat housing that could crack.

I replaced the gaskets on my mustang and shortly after noticed a hairline crack weeping on the crossover. So I replaced the manifold.

Looks like some people have the replacement down to 20mins.

(haven't watched the whole thing yet)

I haven't been following this at all, but if the coolant is leaking into the valley, it will wash the oil off of the cam lobe(s), and you could end up with a rounded cam. Then it gets real expensive. I can't remember at all, though, which years had problems with that.

Agreed, and I think the OP's engine falls in the year range that this is common for, but I don't think that he's specified exactly what "intake manifold leaking" means yet.

nate