Surge, skipping under load

1992 Buick Park Avenue.

When accelerating, the car will surge and "skip," which basically causes the entire car to shake. If from a stop I press the accelerator anymore than a half inch, it will surge and buck and sometimes backfire (or, at least I'm assuming that's what the popping sound coming from underneath is).

I've had the coil pack go out on me in the past, causing two cylinders not to fire. The lack of power I'm experiencing now is similar to that, but it's rapidly intermittent - the car will skip and buck but sort of "catch" in between. I'm assuming it is a fuel problem - the surging is very similar to that of when the car isn't getting fuel after a sharp turn, etc.

Things I've replaced recently enough that they should not be an issue:

Spark Plug Wires
Spark Plugs (about 3 years ago, Bosch Platinums. Tonight I replaced two of them that were looking a little botched from what seems to be a little bit of oil - no dice)
Crankshaft Position Sensor
Camshaft Sensor
Ignition Module
Coil Pack
Fuel Pump
Fuel Filter

There is no error code being thrown, so I really don't know where to start. I do know that a little bit of oil is being burned and when I took out the spark plugs to check them out, a few of them had wet oil in the threads. The spark plug firing heads, however, are completely dry, albeit a little dark.

Comments and Suggestions? I would really like to troubleshoot this problem on my own and save the money from shop poke-and-play, but this problem is dragging on too long.


Edit: A good example I left out. A few times when I've had to make a right turn and kind of "get on it," as soon as I push the accelerator and demand torque going into that turn, the whole car really does surge as if I just cut off its fuel supply. Then as I let off it'll shake and, sometimes, pop a backfire. Thinking about that, it sounds like a multi-cylinder problem. When I tested the fuel pressure before replacing the fuel pump, it was 1~2 psi below the acceptable range. Clearly, replacing the fuel pump did not solve it. There is, still, the fuel pressure regulator, but I figured that a -lack- of fuel wouldn't be causing a backfire. Then again, I don't know any better.

Edit #2: Forgot to add another thing. The car has a hard start with this problem. It'll crank over multiple times and then have this sort of skipping-start. Instead of a whirr-whirr-vroom, it's more like a whirr-whirr-whirr-whirr-whirr-vr-vrr-vrr-vroom, as if even when starting up it's choking a little bit. Idling, it is smooth. I think now I haven't left anything out.

You mention changing 2 plugs, but you really should replace all of them at the same time, and I'd use delco plugs because they are made for your engine in the factory.
Are you sure there isn't a code stored in the memory that isn't popping up? Since it's a 92' you can jump the data link connector underneath the steering column (A&B together, switch the ignition to power, not starting the engine). I've had codes come up in my 92' that didn't set off the light, so maybe you'll find something out that way? Good luck!

I've checked for error codes and received only the standard "1 2" reading.

I know it's good to change out all of the spark plugs, but the other ones are pretty much in good condition. I figured that if it was such a problem, changing those two would as least show some improvement. No dice, though.

The Hayne's mentions possible vacuum leaks as one cause of backfiring. I don't really know how the Fuel Pressure Regulator works (besides, you know, regulating fuel pressure), but I understand it does have some type of vacuum system. Could my problem be linked to the Regulator?

That pressure regulator sounds like the next component to look at! A vacuum leak is a possibility, the easiest way to check for a leak without any tools is the "hissing" noise. Good thing you got a "12", at least now you know it isn't a pesky sensor!

Get the "Botch" plugs out first, they are problematic in GM cars, at best!

So I've replaced the regulator and the problem is still very much there. A couple days ago, it felt like it was running pretty good - I could really get on the accelerator and it would respond like nothing was wrong. But after a while, and yesterday and today, it's doing the same thing again.

So, to recap, within the last 2~3 years or so I've changed the ignition module, coil pack, crankshaft sensor, camshaft sensor.

And most recently, within the last month or so, I've changed the fuel filter, fuel pump, the regulator, and the spark plugs. The spark plug wires were changed about a year ago.

Symptoms still persist: rough start, sometimes a rough idle, if I ask for power while driving I'll typically get a surge or a backfire or a rough reply. There's a "trouble zone" when accelerating, meaning I can push the accelerator so far and it'll run smoothly, but when I ask for more past that amount it'll surge and kinda 'even out.' By even out, I mean it doesn't matter how much I push after that point, the acceleration is very slow and it's shuddering or backfiring.

Another note, if I'm sitting in park, sometimes it'll idle a little rough. If I rev it to about 1000 rpm or so it'll smoothen out. Of course, when I'm driving, it seems to be the reverse.

Ideas? I'm not too keen on much of the real technical stuff, so if it's something to do with vacuums or valves, please go into detail. Thanks!

Edit: Most of the parts I've swapped over the years have been for other problems which were resolved. This problem is fairly new, happening since about the end of December.

I'll second the idea of getting rid of the botch plugs then put the car in the dark and see if the wires are any good by letting it idle and watching for leaking voltage.the next thing I would do is putting the car in gear and while holding the brake down put a load on the engine(2 seconds max),post back with results.

Ah, forgot to add that I replaced all the plugs shortly after I purchased those Bosch ones. All six spark plugs are new Delcos, the same that come factory with the car. They are also gapped to spec. When you say to put the car in the dark and look for "leaking voltage," what exactly am I looking for? Literal sparks?

I just did the brake + accelerator and got interesting results. I know that the Buick already has a limiter on it so that if the brake is depressed it will not rev past 2000 RPM, even if you floor it (don't ask me how I know that, heh). However, now when I do it, it gets up to roughly 1500, 1600 RPM and won't go any farther and I can definitely hear/feel the problem - the shaking, vibrating, struggling.

Hope that helps. I'll do the "dark" process as soon as I know exactly what I'm looking for. Another note to add: it sometimes seems to run better in really cold weather when it's been sitting for awhile (i.e., cold engine). I wouldn't say this is 100% everytime, but often enough to where I know if it's cold, I'll get a few miles out of it performing pretty well.

You could have spark scatter as described above. Also, you should investigate the timing set. I.e. cam gear & magnet, chain & crank gear. If your magnet is broken or missing, the injectors will fire out of time. You can inspect the magnet by pulling the cam sensor out and use a mirror to see what it looks like. (You may have to turn the engine over some to see it) It should look like the projectile of a 22 caliber bullet.

Also, by "leaking voltage" they did mean actual sparks escaping from the plug wires. You need to be in a pitch black area to see if the spark plug wires are leaking any spark. Don't forget to inspect the wires at every spark plug! Good luck!

Well, got the car to a really dark place. I don't have a garage so I had to drive to this little cul de sac with no street lamps anywhere. Let my eyes adjust to the darkness and idled the car. From the front three spark plug boots, I could see, barely, a little bit of blueish spark. Now, these sparks weren't arc'ing to the engine block, but they appeared to be emitting from the inside of the boot, where the spark plug head is, sorta. It was really dark so I couldn't see much more than just the spark, but the front three had a little bit of spark each. I had my roommate rev it to 2000 RPM and hold it and two of the sparks faded to invisible. The first spark plug still had a little bit of spark. I had him take it to 2500RPM and I couldn't see any spark whatsoever.

It's good to note here that while the car was idling and I could see the sparks, it was idling slightly rough. I had him put the car in drive, press the brake with all his strength (I'm in front of the dang car, after all), and rev it as high as it will go. As I expected, it only reached about 1600 RPM (instead of 2000 as it used to) and ran rough and the sparks were clearly flickering.

Interestingly enough, the spark flickering reflects the driving: when I'm idle, it's slightly rough at times. When I give it a little gas, it smoothens out. When I ask for too much, it goes back to problematic.

Could it be that my spark plug wires are already faulty after less than a year? I saw sparks at the three spark plugs I could see - even with a mirror, I really couldn't get a clear vision on the back plugs.

Another note to add: it sometimes seems to run better in really cold weather when it's been sitting for awhile (i.e., cold engine). I wouldn't say this is 100% everytime, but often enough to where I know if it's cold, I'll get a few miles out of it performing pretty well.

When the motor is cold, the mixture is richer. A leaner mixture lets some problems show up more, like bad plugs/wires.

Well, I've replaced the spark plug wires. No dice. I'm at a dead-end here. Tonight I'll take it out again to see if I see the same spark pattern when it's dark, but with new spark plug wires not fixing the problem, I really don't know what to look at next.

Help.

If you see spark scatter again (with the new wires) take off one of your new plugs and inspect it for tiny cracks. I've had a few cases of new plugs being damaged from the start. Look carefully, because cracks won't be easy to see against the white porcelain.

Disconnect the 02 sensor and see if it runs better.

I'll take the car out tonight to see if I see any sparks again. I don't really think what I saw last time is "spark scatter," but maybe I don't know exactly what that is. I never actually saw spark arcing across anywhere, I simply saw what looked like spark "light" coming from the tip of the boot or something. But maybe I was looking at actual spark arcing...

I'll get to that O2 sensor as soon as my friend's garage is open. But I always thought that a faulty O2 sensor would flip an error code, right? Still no error codes and still nothing. The car seems to be having a harder time starting now. Sometimes it doesn't seem like it'll start at all, it just keeps turning over and I'll let off the starter for a few moments because I don't to burn it out. Usually on the second go, though, it'll finally start after a few more turn overs.

It really seems like it just has a "trouble zone" it enters when a certain amount of gas is asked for. It's really peculiar how it acts when I have the brake in and I rev it up. It is literally fine until it hits about 1600 and then it just suddenly starts shaking/vibrating and won't go past 1600. It's like it simply can't.

Any other suggestions until I get to that O2 sensor?

Well I just got back from checking for spark. I still see the same light flickering pattern that I saw with the old spark plug wires. From what I can tell, it looks like the flickering is reflecting off the spark plug body where the metal thread area starts. Like, the spark plug top (that the boot clips onto) is metal, then the neck, then it gets "fat" and that fat part is metal. It seems like the flickering is actually occuring inside the boot and is reflecting off that fat body part sorta like a mirror and that's what I'm seeing. I stuck a metal knife blade down there and no current arc'd over to it or anything. A mechanic friend believes that no light whatsoever should be visible, that the electrical current travels from the clip inside the boot directly through the spark plug so I shouldn't be seeing any light. However, I see the flickering at all three front end spark plugs, although the first plug is flickering more brightly than the other two (could just be my angle).

I hope all of that made sense. Does this sound like a problem or is a little flickering from that area okay? It's pretty consistant and it's definitely not an "arc" of electricity.

Another question - what components are necessary in the startup of the engine? Fuel and air and the starter system... I know the fuel lines up to the fuel rail/injectors is okay because I've replaced all of that. The air intake should be clean and good to go, but I'm about to go check that just in case. And the spark plugs, wires, ignition module, coilpack, sensors... as I've stated, have all been replaced within the last 5 years. So what would be causing my engine to have such a prolonged start? If it wasn't getting enough power/electricity, wouldn't that throw an error code?

Etc. I talk too much. I'll wait for some responses.


Edit: I disconnected the O2 sensor, didn't help. Car wouldn't turn over. Plugged the O2 sensor back in, car still won't crank. I knew it would come to this, it's been getting harder to start. So hopefully tomorrow I can get it to crank over so I can drive to my internship... sigh.

You have replaced a lot of ignition related parts in the past 5-years, but that does not mean that the replacements are not beginning to fail. Have you got any codes? Have you checked the injector pulse with noid lights?

You said that you replaced one of the coils sometime back. Was this one out of the three, or was it the only one unit with 6 terminals? You had two types of ignition systems on the 92, one (the Delco), had three coils with two terminals, the other (Magnavox) had six terminals (three on one side and three on the other). Which one do you have? Pics on links below;

http://www.rockauto.com/ref/ACDelco/Detail.html?D552.jpg
http://www.rockauto.com/ref/ACDelco/Detail.html?D555.jpg

First picture. Thing is, the problem I'm experiencing now is nothing like the problem I had back then. And no error codes are being given. The backfiring is a problem I've never had with the car before.

You have the "Magnavox" type ignition. I would remove it and take it to AutoZone for testing. The backfire sounds like a timing issue. I.e. timing set. The symptoms you describe, all seem to be ignition-timing related. It could also be as simple as one or two plugs not firing, or misfiring under load. What kind of wires did you install? It might be a good time to invest in a spark tester! http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=4424

How about a bad CAT?

This cat is not "bad" but she is cute and the only one I got!
http://files.automotiveforums.com/gallery/watermark.php?file=/503/297374cat2.jpg (http://www.automotiveforums.com/vbulletin/%5Bimg%5Dhttp://files.automotiveforums.com/gallery/watermark.php?file=/503/297374cat2.jpg%5B/img%5D)
By the way, good thought on the cat! A clogged cat will make a car perform just like a constipated person, full of it and lazy!:rofl:
:evillol:

Well, Autozone now closes at 9:00 instead of 10:00, so I'll have to wait until tomorrow to bring the ignition module in. Yet still, I thought if the coil/ignition module started to go that an error code would be thrown. At least that's what happened when the last ignition module went out. I replaced it about a year and a half, maybe two years ago.

Would a bad CAT give the car such startup problems? Sometimes I can't even get the thing to start. It'll crank over, whirr whirr whirr, but it won't start up. Usually if I let it sit for awhile, it'll eventually crank up after a few whirrs. Blah, I'm stumped. I'll take the ignition module in tomorrow and see what the check comes back with. Let's say, though, that the module checks out to be just fine. Any ideas then?

When was the last time that the timing gear and chain were replaced? If I remember right, they are designed to last around 50k miles before being stretched beyond what the damper can compensate for.

I had a very similar situation as your car on my 86 olds 88. It had new coils, tested ICM, new vacuum hoses, new plugs, new wires, hollowed cat...no codes.

I ended up pulling off the front of my engine and lo and behold my timing chain was stretched out significantly more than the replacement getting ready to go in. This was a full day's work though...

Unfortunately, it was put in incorrectly so it runs worse now than it did before I swapped them... Oh well... spring break project for me.

Anyway, I hope you get something to cooperate with you.

Timing chain. Gee, I'm all smiles just thinking about it. Well, I'll get the ignition module tested and if it's fine and dandy, which it probably will be, then the car is going straight to a shop. I simply don't have the tools, garage, nor expertise to go removing large pieces of my engine. And now the car is having a hard enough time starting when it's hot that I'm afraid to go somewhere for fear of being stranded. So, I'll have to just cough up the cash (not that I haven't wasted enough buying parts already) and let the big boys handle it.

Question about the chain, though. Would that explain my symptoms, rough start and bucking and whatnot at certain loads? Could that explain why if it's cold enough, the engine doesn't have as hard of a time starting (chain metal cold, less stretchec, etc)?

Hey Eskareon, how many miles does your Park Ave have? I had to get my 92's chain replaced at 143,000 miles, I think it was the original timing set in there! I didn't have starting problems from it, however I did have some bucking, LOTS hesitation, and stalling. I got a camshaft sensor code when it stalled for the first time, and at such high mileage it was highly recommended that I replace the timing set. 4 days and 450 dollars later I got my car back, running smooth as silk and having way better gas mileage (timing chain affects that, too!)

My Buick has 183,000 miles on it. *grin* And I have no idea if the timing chain has ever been replaced. I'll give my father a call and find out.

50k is just the recommended mileage for a timing chain change. My 88 has 120k on it and I think the gears/chain I pulled may have been the originals.

One more thing, if you do have the gear and chain replaced, you may want to go ahead and have the shop install a new camshaft interruptor magnet and make sure that they expoxy the bugger in. That way you spend an extra ten bucks to avoid an evil code 41 in the future (involving the front of the engine being removed to replace said 10 dollar magnet).

Anyone else think the symptoms match the timing chain/gears?

50k is just the recommended mileage for a timing chain change. My 88 has 120k on it and I think the gears/chain I pulled may have been the originals.

One more thing, if you do have the gear and chain replaced, you may want to go ahead and have the shop install a new camshaft interruptor magnet and make sure that they expoxy the bugger in. That way you spend an extra ten bucks to avoid an evil code 41 in the future (involving the front of the engine being removed to replace said 10 dollar magnet).

Anyone else think the symptoms match the timing chain/gears?

Read post 9 & 20 again! If you replace the "timing set", that would consist of a new chain, cam gear with magnet (installed) and crank gear. I would also replace the tensioner! I would still not rule out the ICM-coil pack as being the culprit. If this is the second Magnavox ICM you have had, you may want to consider changing over to the Delco ICM & coils(very easy to do). You can get the complete unit from a bone yard, cheaper than the ICM from the parts store.

IT WAS THE MOTHER @#($*&@#(*& IGNITION MODULE.

Ah. That felt good. So, it was the 8-month-old ignition module. Weeeeeeeeeeeee... blah. Lesson learned: test everything you can before you start swapping parts, even if all signs point elsewhere.

I figured if the freaking brand new ignition module wasn't firing the spark plugs, an error code would surely be thrown from the computer. But somehow it slipped past the system. To think that I replaced the fuel pump and all that other stuff for nothing... oh well, they were all old parts on a Buick with 183k miles, better new anyhow. Lesson learned.

Thank you all for your help. I'm sure I'll be visiting these forums again real soon, heh. Learned a lot just from this problem. Actually, I have a question - the speaker covers over the Bose door speakers, can I just pull them off? I started to pull a bit on one but it didn't seem like it'd just snap off. I don't want to break the thing - got a loose wire or something on the driver's side speaker causing it to cut in and out.

The door panels have to be removed to get the covers off. Even if you pry them off, the door panel would still have to be removed to gain access to the speaker wiring.

Hey guy, have you thought about having your injectors cleaned? I just bought a PA Ultra, and it ran really rough, and threw belts like mad until I had a shop clean the injectors, replace the EGR tube, and swap out the crappy Bosch Platinum spark plugs for OE plugs.