wpg7

Early this spring an older gentelman who lives down the lane saw me messing with my car and stopped to ask if I could give him a hand with a few of the problems his car is having.

So I was talking to him today about the problems and he said it will not start unless he tows it to about 40 Kmh (25 Mph). Once it gets going it runs fine until you get to a stop sighn or red light then it wants to bog out and die at idle.

Here is what I know about his car.
-it is a completly stock 1983 (I do not know the trim level)
-He has recently done a tune up
-Fule filter has been replaced
-Choke works fine
-No apperent oil leaks

I am going to take a look at it for him this Saturday, any info you can give on what to look at first or most likely problem based on the symptoms would be a huge help.

Thanks
Steve

Hades12

Sounds like low compression.

Dan_s_young

iTrader: (1)

maybe a vacuum leak? The bogging you described can be caused by this... Maybe its flooding? Make sure the a/f mixture is set properly... And he said it won't start? Make sure it actually turns over and stuff, then you can rule out the possibility of the starter going bad... I assume the vehicle is just flooding if it does this and does not want to start...


I also agree with the low compression comment, maybe take it to a local mazda dealership and get it compression tested to see what hes dealing with...

wpg7

bump

13B4port

wooo hooo diagnostics 101

rememebr a car needs 4 things to run. Air, fuel, compression, and spark. find out whick one isn't there and trace it back.

first thing. take out the leading spark plugs and unpluge the plug wires off the trailing plugs. put your hands over the holes and have someone crank the motor over. 2 things that you should notice is that the pulses of air coming out should be even (one not stronger than the other) and going back and forth from hand to hand. the other thing is the sound should be a nice percky chirp. if you notice the pulsses of air go as followed: left hand, right-hand, left hand, left hand, right hand. there is a seal problem. if you notice that they are all kind of weak look into ATF treatment. while your there see how moist your hands get.(avoid smoking a cigg for the next couple mins) if your hands are soaked with a clear liquid the car is flooding. if your hands are covered in dark wet liquid then their is way to much oil. if your hands end up with nothing on them then there could be a fuel problem. if the car is flooding and you can't adjust it out, chances are the float is stuck. take a hammer and *lightly* tab the bowl. LIGHTLY people.

next check ignition. look at the plugs, if they appear dark and moist, clean them with carb clear or starter fluid, let dry before reinserting them into the engine. set the plugs with the plugs wires still plugged in along a grounded peice of metal on the car and have someone watch the plugs and make sure each one sparks. this is easier to do at night time. make sure the plug doesn't touch the grounded peice of metal(the car) but it within 1/2 an inch of it. if all that checks then move on to timing. also check the cap and rotor for moisture. if there is moisture in the caap spray it down with WD40 and wipe it out. check for carbon build up. check for proper ware on the arching pillars on the cap. if there is a big indent on them. replace the cap and rotor (always replace as a pair). if that all checks out move back to the coils. check the Ohms of resistance across the coils. a repair manual should tell you what they should read. make sure the coil is unplugged when doing this.

Next check for gasket leaks and vacum leaks. use water in a tight spray bottle and with the engine running start spraying stuff down. if it doesnt stay wet then there is a leak there. i like to use carb cleaner because when you find the leak the engine will revv a little. if you use my method use the cleaner sparyingly. if you spray a ton of it on the leak you risk destroying the motor as detonation is a bad thing.

if you're still having issues make sure the exhaust is free flowing. meaning no clogged cats. you can tell if a cat is bad a couple of ways. tapping on it and hearing stuff jingle arround inside means it's time to replace it. if it starts to smell like roting eggs, thats sulfar built up in the cat. another way to check the exhaust is when everything hooked up crimp the fuel line so that it can't start and crank the motor over, you should be able to feel the pulsing of the motors compression in the exhaust pipe. it is not going to be anywhere near as strong as the spark plug holes but should still be noticable.

if you have any more questions post away and i'll try to help

IanS

iTrader: (4)

Another thing also is if it is flooding, unplug the fuel pump fuse. Looking at the fuse box (under dash drivers side near driver door), it will be a 10 amp fuse on the right side of the box. Look at the cover if it is there. If not, know that the fuel pump fuse is away from the rest of them. It kind of "hangs out by itself" so to speak. This is better than clamping the fuel line shut, trust me on this one. Now, with fuel pump not running attemp to start the car. This should clear the carb and engine out of fuel. Next, try to restart with fuse back in. If possible, have someone look into the carb while key is on and cranking to make sure fuel isnt being dumped into the bowls.

If the car does not start with fuel pump fuse out, when it does start it will smoke alot. You just pumped a whole bunch of gas right into the exhaust. Good luck and hope that helped some.

IanS

EDIT: Also check the carb out real good and pay close attention to the linkages. One of them may be obviously bent or had fallen/broken off somehow.

13B4port

he's right about the fuse. but dont' stick your head over the carb. i've seens some nasty as buns because the car backfired.

wpg7

Thanks for all the info, I'll let you know what I find out.
If anyone has any other thoughts please feel free to add them as well.
Thanks again
Steve