Friday night I'm out in the Camaro and everything seems fine. All of a sudden I hear a "clang", and she starts running like crap. Acceleration in the llow rpm's is next to nothing, and not so great in the high. Instead of the normal hum of the exhaust, it sounds more like a fast put-put-put-put, like a machine gun. Also, for a while the gas mileage has been horrible.

Car has gotten full tune-up, mods are in the sig. Oh, there was a small exhaust leak where the y-pipe meets the cat. Could this leak have gotten worse, ,robbing the car of necessary back pressure?

 

I don't think the exhaust would cause what your describing, sounds like intake back fire.

Check vaccum lines, and timing. Other then that I do not know.

 

Well my father and I checked the car out this morning, ,looks like I got a screwed up injector thats pushing out too much fuel. The car acts like its running rich, and my father said he could smell gas. This conclusion sound right?

 

U gotta be able to tell us to help ya.
Sounds like a good clue, tho

 

What was everything that you did/replaced as part of the tuneup?

Mechanics can do injector testing; it involves a "black box" that connects to each injector, and a fuel pressure gauge. The box activates each injector for a certain time period, during which, the mechanic watches the fuel pressure gauge. The gauge should drop to the same pressure after each injector fires, within a certain percentage.

Think about pulling a set of injectors from a junkyard car, and send 'em off to Rich Jensen at http://www.cruizinperformance.com - I had that done, and the improvement was amazing! The turnaround time was impressive, too; I had the injectors back the same week that I sent 'em out, and I'm in NJ, he's in Michigan. (Or somewhere in the central US)

But I don't know if I'd aim for the injectors just yet. How'd the oil smell? If it has gas in it, you could have a leaky injector, or a busted ecm. (Dad's old 2.8 car had a fried ECM, it was locking the injectors open, the crankcase was FULL of gas.)

 

Tune up consisted of:

plugs gapped at .05
wires 8.0mm MSD
cap
rotor
coil (i know, not part of a tune up, but it was replaced)
air filters, K&N
pcv valve
fuel filter (remember my battle with that?)
oil and filter
lube job
bottle of STP fuel treatment in a full tank of 89 octane Amoco gas

I still have the service manual for my 87 Grand Am. Ya think I could use the flow chart in that manual to find my problem? Funny thing is one time on that car th ECM was shot and the injector was pouring fuel in, so bad she wouldn't keep running, and it seriously thinned out the oil. I didn't think to smell the oil on the Camaro. I'll check that tonight.

BTW, doesn't Accel make injectors for us? Are they worth it?

 

The Grand Am flow chart is TOTALLY different.
Accel injctors?
Clean other set of injectors for $10/each!
You're doing good, keep searching.
Be careful of wiring and the plastic hoses & such. Try not to add to your problems by breaking them
They are brittle.

 

Yeah I read a few posts about sending out the injectors for a cleaning. I asked about using the GA flow chart because I figured the fuel delivery system consisted of similar components: ECM, TPS, injector... except that the GA only had 1 injector (TBI iron duke), and the Camaro has six. I figured this could tell me if the ecm was at fault, much easier to get to than the injectors.

BTW, how different is our 2.8 from the 3.0 used in the GA in 87, in terms of my area of concern.

 

could it be that your timing chain sliped?, just a thought

 

Thought of that, and I hope thats not it.

Anyway, sniffed the oil when I got home from work, and yep, there's a gas smell there. Looks like its running too rich.

Ok so I would think if it was an injector problem the car would run lean, so it must be an electrrcal problem causing the injectors to put out too much fuel. Anyone got a diagnostic flow chart I can use to find the problem? I suppose I'm looking at a bad sensor and/or ecm?

 

Could be the Ignition Module (in the distributer) showing signs of failure. This will cause it to run erratic and backfire sometimes. Just something else to check. The computer is suppose to show a code for this but hardly ever does.

 

EXCACT same thing happens to my grand prix a few months back and I did the same thing, turns out i blew out a coil pack (at the distributer), my mass air sensor, a coil, and needed to replace a spark plug because the coil pack blew it 2 hell, just though id share
~Jeff

 

Just another tip... DON'T USE the "bottled fuel injector cleaner"!!! Our 2.8's use Rochester multec injectors which the cleaner actually harms them. I learned the hard way (4 bad injectors with melted tips)

 

Thaks I'll remember that.

 

Well, not quite, MDv6Man. The 2.8's ALL use the Bosch pintle-style fuel injector, NOT the Multec's. We can use fuel injector cleaner. If your Bosch injector tips melted, something else must've been wrong with your injectors. I think the 3.1's use the Multec's, but definately not the 2.8's, 85-89.

Mike, the only thing I see you missed as part of the tuneup is the ignition timing. You might want to put a gun on it. Our 86's have three marks on the harmonic balancer; you want to color in the WIDEST mark with chalk/white-out. Stock timing is 10 degrees advance, remember to unhook the EST bypass connector before starting the engine to check timing.

I'd definately check for an exhaust leak. If the "clang" was that significant, the pipes might be loose when the car's cold. I suppose the pellet bed inside your catalytic convertor might've broken up and is clogging the exhaust, especially if it's the original cat.

Did you pull the cap/rotor off to examine it for excessive carbon buildup? Did you pull any spark plugs to check the tips? They might point to a misfiring cylinder, or a gap that's opened up too far. You might also want to gap the plugs to 0.045" instead of 0.050". When I had "Just" an Accel coil and 8.5mm wires, I tried opening up the gap; supposedly, it would be better because of the higher voltage coil. I didn't notice much improvement, just a rich smell from the tailpipes, so I went back to 0.045". A wet plug might signify a stuck-open injector. A destroyed plug (like I once had) might point to overly-advanced ignition timing (like I once had), which causes detonation, which hammers on the center of the spark plug. Are you sure the plugs are the right replacement part # (heat range) for the motor? A plug that's too cold won't reach it's self cleaning temp, and could foul; and a bad enough foul might cause a misfire (and the motor to run rich). Any plug wires loosen up on the distributor cap?

 

Thank ***! MDv6man, scared me for a minute cause i put cleaner through last week in my 2.8.

Also about the timing, if you set it at like 12 or 13 degrees, will you get better preformance TomP?

 

These timing chains need to be replaced after 75K miles.
IF you haven't, bumping timing will compensate & help BUT NOT CURE OTHER PROBLEMS.
The engine management system works as a package deal. One part weak, it will show up as a problem.
These are old cars & engines.
Remember that as you try to get it back to top power output & then some.
Sometimes alot of effort (not just $peed part$!) need be put out, to get a good foundation.

 

Mike, if you smell gas and you think your running rich (take out the plugs, if there black your running rich), anyway it's proberly your fuel pressure regulator. If it goes bad or the vaccuum going to it is bad you will run rich. That can checked with a fuel pressure tester. I have one for FI cars, I'm near you if you don't have one.

 

You could get better performance; I know that people like KevinS saw a bit of extra kick when he ran at 12 advance, instead of 10. I tried 12 and didn't notice anything, but that doesn't mean it won't help. Plus, some people claim that their motors can't run at the stock spec of 10 advance. I think that might be because either (like Ked said) the timing chain stretched, OR, the isolation ring of the balancer is deteriorating, and the outer ring (with the timing mark) has slipped. But as long as you have a timing gun, it's a "free mod", so give it a shot, and let us know how it goes!

 

Thanks for the tips guys. I took tomorrow off so if the weather is good I'll be out there fixing it.

 

Well i used a gun at my schools shop and set my timing to 12, it kinda feels like i get a little more kick. I think i will leave it. most of the stuff on my 2.8L engine has 35,000km on it cause it went through a full rebuild, including a new chain. so i dont think anything is worn out, you guys might wanna try it.

 

Does it never end? Now I better add ECM, and fuel pressure regulator to my list. It just seems like something isn't right. Besides my exhaust manifold leak, i just know somethings wrong with the fuel system.