O 16581 72452 5

I rev my engine from under the hood and while it's losing rpms the engine shakes rather violently then starts idling normal again, and i have a very bad backfiring problem.

Manntis

too rich, it sounds like.

Your engine is drowning, then puking out the unburned gas which then ignites in your hot exhaust system, causing the backfires.

O 16581 72452 5

Actually my air fuel ratio gauge is showing my car running ideal to sometimes slightly lean... any other suggestions?

racermike

Which motor?? Is it a "real" backfire (though the carb or intake) or is it in the exhaust?? Coasting valve working?? (stock 12A)

O 16581 72452 5

It's fuel injected so the backfire is out the exhaust.

racermike

Well then, like Manntis said, it sounds like it is too rich.

You could have a cat problem or maybe a O2 sensor. Are you sure your gauge can be trusted? What do the plugs look like (color)? Does it have ANY other symtoms?

You may have to check ALL the intake sensors and stuff associated with computer inputs. One last question(s), how did all this come to be? all of a sudden? after any work or other incident? just getting worse over a long period time? what kind of gas milage are you getting?

I have hardly ever seen a bad motor mount, and that will have nothing to do with the exhaust explosions directly, (prob.) but if a motor or the transmision mount is broke it would lead to much more movement by the motor (violent shaking). Also, even if it is running on the right mixture, an exhaust leak may cause the "backfire". What happens is that instead of the exhaust gas coming OUT of the leak, it allows fresh air (oxygen) in and that allows it to explode.

And finally, (aren't you glad) what about doing a compression check to make sure your engine is ok on the inside......

O 16581 72452 5

I think that i might have a messed up tranny mount, when i floor it in first the stick shoots to the right and when i let off i hear a clunk... i'll check that out, as for my backfiring this might be caused by having the... acv(?) connected and no air pump. there's a cannister on the passenger side that looks to be part of my throttle with a hose coming out the back of it that is not connected... should this be connected? and where?

racermike

Check all 3 mounts, as a broken one may lead to breaking more.

If the canister is mounted on it's side (and has a cable to the throttle) it would be the cruise control. If mounted upright it would be the charcoal can. I'll have to wait until morning to check the SE for the hose. It may be the source of the problem if it allows a vacumn leak.

Sa22c_guy

I got a question for you O 16581 72452 5 how did you get those massive flames out the back, i know theres cheap ways like ripping out the cats and hooking up a spark plug with a copper wire how did u do yours?

O 16581 72452 5

I just cut out my cats and instant flames.

O 16581 72452 5

That's what i was thinking about the hose, that vacuum leak could be the source of all my problems, but i don't want to try hooking it up without checking first, i don't want to mess anything up.

racermike

Ok, I have an 84 SE out back. A quick check shows that the vacumn hose routing sticker under the hood does cover this line. If you have the sticker it should be of some help.

Starting with: Below and behind the cruse control, there is a vac line going from a switch mounted to the inside of the fender area right against the firewall, to a nipple under the intake. The vac line from the CC "T"s to this line. Just a few inches further another vac line also "T"s into this line from 1 of 2 vac switches mounted to the firewall. If the line from the CC is loose, look to see if it has a broken piece of the "T" still in the end.

So basically take the loose line from the CC and extend it toward the engine and down. You should see the line from the pair of switches on the firewall in this area and the CC loose end attaches to the same line.

I hope I didn't confuse you with the above by describing the same thing multiple times. If you have an 85 there may be some differences. Look for the routing sticker under the hood or you may have to find it in the book.

Good luck. If this doesn't get it we'll try something else.

MosesX605

I think that you are running rich based solely on the flames. Even without a cat, if your car was tuned properly, there wouldn't be a massive gout of flame from your tailpipe.

O 16581 72452 5

I've got a picture of this on my digital camera but it won't let me upload, there is also some sort of small plastic thing behind the washerfluid container with a disconnected hose coming out of it, wtf is all these disconnected hoses?

racermike

? number 1, just to make sure we are looking at the same thing, Do you have a 84? that's what I'm looking at.

""some sort of small plastic thing behind the washerfluid container with a disconnected hose coming out of it""

If it sets in the very corner of the engine bay, between the washer tank and the sub-zero fluid tank, it is:

>>Starting with: Below and behind the cruse control, there is a vac line going from a switch mounted to the inside of the fender area right against the firewall, to a nipple under the intake.<<

This is the vac line that has the 2 "T"s on it's way to the intake,,,,,the first "T" goes to the cruise control,,,and the second one:

>>Just a few inches further another vac line also "T"s into this line from 1 of 2 vac switches mounted to the firewall<<

As you are looking at this remember that if a "T" is broken, the line may look straight OR a line may look like it has a "right angle" in it, depending on which part of the "T" is broken.
I think you are looking ay exactly what I'm talking about assuming you have a 84, AND it has not been modified. The disconnected hose from the crriuse control AND the disconnected hose from the switch behind the washer tank are joined by a "T"...... the 3rd side of the "T" goes a few inches further, and connects to the vac line coming from one of the 2 vac switches mounted to the fire wall......the 3rd hose from THAT "T" continues another foot or so to the intake. (that connection is undernieth and not visible from standing outside the car.

If you can follow all this,,,,,,you should be able to reconnect the loose ends, and eliminate a vac leak, AND get a couple more control devices in the network. I would definately get these lines back together as it may solve ALL your problems!

MyRxBad

I have a GSL-SE w/no cats and have never shot flames. You are running way to rich air pump or not.

You have issues with the emissions crap if it's still on the car, either vacuum hoses aren't on or solenoids aren't working properly.

When you let go of the gas it's wanting to stall and then the BAC valvle compensates and bring the idle back up to normal.

O 16581 72452 5

Okay these "T"s you're talking about are those hose connectors that look like a "T"? i run these two disconnected hoses together and run a hose to my intake?

O 16581 72452 5

Okay, i checked my vacuum routing diagram, appearently my hood is off an 83 car without cruise control and carboreated... so i have no idea where to connect this hose... i've attached a picture of what i'm talking about. is the connector i baught the right thing? and where do i connect the hose from the third prog up to?

O 16581 72452 5

Picture won't upload, i give up e-mail me someone for the picture kmfdmxtort08@aol.com

racermike

Upon closer inspection,,,,,,,

If you look at the back of the intake (from the firewall) There is a LARGE vac line that comes from the power brake booster. There is a LAGE hose that goes down and back to the cat (air supply). These two LARGE hoses are only a couple inches apart,,,, and the small vac line in question is right between them!

On the 2 vac switches mounted to the firewall,,,, BOTH of them are connected to this line, not just 1. So the connector there is like a "T" with 2 bottoms. (I didn't see that before) One of the switches connects with a hose from it's top, and the other with a hose to it's bottom.

On mine, just 2 inches later,,,,the vac hose from the cruise control connects to the line with a standard "T". Then the line continues another foot or so to the vac switch mounted in the corner of the engine bay (in between the sub-zero tank and washer tank).

I would start with the connection to the intake and see if that line is there and just disconneted,,,,,or the nipple is present with no line,,,, or there is a hole because the nipple is broken off. (again, the nipple/line is right between the 2 LARGE hoses, and they are only 2 inches apart).

Then check for the TWO lines from the 2 vac switches on the firewall.

From there it only goes 2 more inches and you are at the spot where the cruise control connects,,, and the line continues to the vac switch between the tanks.

Check the ends of each unconnected vac line for a part of the "T"s inserted because it is most likely that the plastic "T"s are broken, and not just disconnected. In the area of the TWO vac switches,,,,,,several lines are zip tied together and you may not see where the "T" is connected. (which is why I thought there was 1 connection instead of 2 there)

O 16581 72452 5

Okay, i hooked that line back up, it's a line that goes into a 4 progged connecter up to two "switches?" then went out to a line that was disconnected, i hooked these two hoses up started the car, idled a little weird but didn't die, throttle responce is much better and the car jerks and bucks far less... BUT the car runs lean as all hell, my gauge is going crazy, when i'm cruising it flickers from being so lean it's off the scale to three lights into lean, if i keep on the gas until around 4k then it starts to go up into ideal and not give such crazy readings, i haven't had this kind of trouble with my car running lean before, it's always been in the dead center of ideal...

racermike

Well does that mean SOME progress?? I may not have enough experience to help with the SE over the wire. Two questions though before I give up. What was happening just before this problem came to be? Any work being done, any mods, any other problems (even if you think it's unrelated) any off-road excursions, in short, ANY thing at all??? 2nd, What do the plugs look like, color, oily, etc.,,,,,and keep them in a specific order so that you can see how the 2 leading plugs compare to each other,,,,the 2 trailing plugs to each other,,,,and the front plugs compared to the back plugs.
You may have to do some testing of individual parts, sensors, switches, etc.,,,,,,,,but let's see what the plugs can tell us.
I haven't looked at the shop manual or the "Haynes" book yet,,,,but do you have either one?? You may have a dirty or bad thottle position sensor, or O2 sensor, or any number of other devices, but lets start from the very begining of the problem, AND check the plugs for color etc.. Something may have happened that will lead us to the problem so don't discount anything as unrelated, and the condition of the plugs may tell a story.

O 16581 72452 5

Actually this hose must've been disconnected since i baught the car it's always acted a bit odd after i hooked it back up the car felt like it never has before... but this lean has to be directly related to the hose, as soon as i hooked it up my gauge started doing this but when it idles, it's in the center of ideal, i don't get it.... i just replaced my spark plugs maybe 100 miles ago so looking at them probably won't be much help... thanks for all the help by the way... download aol instant messanger if you don't have it already www.aol.com/aim i'd like to chat with you on it

O 16581 72452 5

Maybe i should just drive it around some more and see what happens, computer might need to adjust?