tmking66

Basic problem is that my 82 gsl auto dies when I press the accel. or put it in gear.

I have looked at the accel. pump and it seems to be delivering an adaquate amout of fuel when the throttle is opened. I have also looked for vac. leaks and found none.

Here is exatly what I see and hear when I open the throttle. If I sloooooowly open the throttle I can take the car from idle all the way to redline and after I get up to 2k rpms I can floor it and the car revs smoothly. Below 2k if I open the throttle too quickly I hear a hissing/sucking sound from the carb. and it dies. Same thing happens when I put it in gear.

Now, if I hold the carb. shutter valve above the primaries closed I can open the trottle quickly without the hissing/sucking sound and the engine does not die. When that shutter is open and I open the throttle it hisses and dies. All of this of course is done after I have the car warmed up. Also, all emissions equip. is intact. The car is totally stock except that the air pipe that goes to the main cat is missing.

I think I have a problem with the shutter valve. According to the Haynes man. there should not be any vacuum on the hose that comes up from the shutter valve to the air cleaner except on rapid decceleration. I have some sucktion on that hose and the amount of sucktion does not change if I get the car up to around 4000 rpms and let off the accelerator. Could a shutter valve proble cause the symptoms I have described. If so, what is the fix. The shutter valve is open. I had to replace the intake manifold gasket last week (this problem already existed) and while I had the carb. off I noticed the shutter valve was stuck closed. I removed it and cleaned it up and reinstalled and it seemed to be working correctly. I did notice that before I removed the intake that there was a lot of vaccume on the shutter valve hose. Now, there is not nearly as much vacuum there but there definately is some.

I am running out of things to check here. I need some help on this one.

Things I have already checked. Timing, compression, shuttervalve solenoid, accelerator pump; all seem to be working/set correctly, etc.

redrum3005

http://www.mazdatrix.com/FAQ/SHUTTER.HTM

bliffle

Heheheh. I had this on the 83 and I cured it with a CORK! In fact, while pearl-diving at the pick n pull I found a custom neoprene cork in the aircleaner of a 7 which fits tight and has a hat to keep it from going down the tube! I forget which air hole it is when you remove the aircleaner cover and filter, but you can figure it out by using your thumb. Been running 3 years with no problems since I plugged it. Now I look in every 7 at the PnP when I'm there in case I have the problem with the 85. A guy could probably make that cork with some cheapo Silicon caulk from home depot and plastic bag sheet as a mold down that hole, etc.

B

tmking66

Ok, plugging the shutter valve hose does not work. Engine still does the same thing.

New discovery today. With the engine running, if I cover the primary carb. barrels with my hand thus restricting the amount of air going into the carb. I can rev. the engine without killing it. With my hand over the carb. it revs. smoothly from idle on up. So, it seems that the engine is getting too much air when the throttle is opened. Or, it is not getting enought fuel for the amount of air going in. This kind of leads me back to the accelerator pump. It looks like it is delivering an adequate amount of fuel but maybe not. I guess I will tear down the carb. and rebuild it. Was hoping to avoid that.

Any other ideas out there?

Zyrano

isn't that more of a vacuum leak??

tmking66

When I had the air cleaner on I have sprayed half a can of carb. cleaner over the whole engine and can't detect any signs of a vacuum leak. Believe me that was the first thing I thought of.

Kentetsu

Maybe your jets are just so full of crap that you can't get enough fuel into the throats to handle the increase in airflow with the opening of the throttle. But, when covering the throats, you put enough vacuum on the system to suck more gas through. I don't know, sounds carby to me though.

Kentetsu

Also, I've never had any success spraying stuff around to find a vacuum leak. I hear that all the time, but even when spraying a known leak, the engine runs the same. I either listen through a rubber hose (like a stethoscope) or physically inspect each hose to make sure.

tmking66

Yeah, I guess I will bite the bullet and pull the carb. and rebuild it even though I am not convinced that is the problem.

I have found vac. leaks using carb. cleaner before. However, if this is a vac. leak it apparently only happens when the throttle is initially opened because the car runs fine all the rest of the time. I have pulled every vac. hose off and looked it over and found nothing.

I also think that I will get the emissions (rats nest) removed and see if that cures the problem or not. If it does then I am in good shape and won't mess with the carb. if it does not then I guess that I have narrowed the problem down to the carb.

Still looking for ideas here so don't be shy with any thoughts.