Hard start, back fire, low power..ummm????

[TVST*R]

This seems to be carburetor related.
Symptoms:
Hard start ie, slow turnover and must pump it about 10 times when cold or hot.
Won't idle.
When running it sounds like a severe miss AND can hear the carb sucking at an unusual frequency...like not pleasant but sort of harsh. Someone actually asked me if it was a Diesel.
Also, very low power, such that it almost won't pull a small incline.
I have driven it daily like this and it does not seem to be getting any worse.
Thoughts?
'77
Tom

[vandor]

Possibly a large vacuum leak. Are the carb hold down nuts tight? Possible crack in the booster hose or other vacuum hoses? Try to spray carb cleaner around the suspect points and listen for an RPM change. Keep a fire extinguisher handy - carb cleaner is very flammable.

[76was124]

Did the problem just start after running well, or was there work done before the problem started? Dare I ask if the plug wires are on the right cylinders? Is the timing right? All cylinder firing? Compression check?

[TVST*R]

Did the problem just start after running well, or was there work done before the problem started? Dare I ask if the plug wires are on the right cylinders? Is the timing right? All cylinder firing? Compression check?

Plug wire..funny cause that is exactly how it seems to be running. I'll check those. How do i check to see if all cyl are firing? I have electronic ign.
Thanks!!

[TVST*R]

Possibly a large vacuum leak. Are the carb hold down nuts tight? Possible crack in the booster hose or other vacuum hoses? Try to spray carb cleaner around the suspect points and listen for an RPM change. Keep a fire extinguisher handy - carb cleaner is very flammable.

I'll check my nuts. Where or what is the booster hose? Thanks!!

[TVST*R]

Immediately before this poor running behavior, my smog pump came loose (bottom bracket was missing, and top screw almost all the way out)...as a result the smog pump belt was bound up on the wrong pulley on the engine and so I just cut the belt off (the smog pump was already "bypassed" only there to satisfy visually heh heh).

[johndemar]

The brake booster hose runs from the bottom of the intake manifold to the brake booster.

When the pump belt got tangled I suppose it could have caused the timing belt to jump a tooth on the exhaust cam.

Check the timing marks on the back of the cam wheels to see if the line up visually.

[vandor]

>How do i check to see if all cyl are firing?

With the engine running pull the plug wires off the distributor cap one at a time. If you pull a wire off and there is not change in engine speed/roughness, than that cylinder is not firing.
Obviously plug wires carry a lot of current, so wear leather gloves, do ot touch the body of the car, and be very careful when you do this. You could get shocked by the spark even if you are careful. Might be a good idea to make sure the wires are not stuck to the distributor while the engine is off.

[So Cal Mark]

that car has a DIS ignition, don't remove the plug wires with it running!

[TVST*R]

that car has a DIS ignition, don't remove the plug wires with it running!

Right.

[toplessexpat]

Recommend one of these for testing spark, sensible use of <$10.

http://www.toolplanet.com/product/Neiko ... MgodhB8AuQ

[TVST*R]

The brake booster hose runs from the bottom of the intake manifold to the brake booster.

When the pump belt got tangled I suppose it could have caused the timing belt to jump a tooth on the exhaust cam.

Check the timing marks on the back of the cam wheels to see if the line up visually.

Soo..checked the timing marks...they do NOT line up. they are off by a 90 degrees...is that it?
How hard is that to adjust?

[azruss]

make sure you are looking at your timing marks and cam marks correctly. If you are off 90 degrees, the car wouldnt run at all.
If you want to check each plug wire. pull it off the plug and use a spare plug with the treads touching the cam tower cover bolt. Again, use well insulated gloves, rubber soled shoes, and do not touch the body with any part of your body. This is not ideal as it requires turning off the car and restarting it with each test. The timing hole in each cam pulley should be visible from the back, unless you have a sheetmetal cover on the back and should line up with the casting mark on each cam tower. If the timing is truly off 90 degrees then you may have bent a valve or two.

[TVST*R]

make sure you are looking at your timing marks and cam marks correctly. If you are off 90 degrees, the car wouldnt run at all.
If you want to check each plug wire. pull it off the plug and use a spare plug with the treads touching the cam tower cover bolt. Again, use well insulated gloves, rubber soled shoes, and do not touch the body with any part of your body. This is not ideal as it requires turning off the car and restarting it with each test. The timing hole in each cam pulley should be visible from the back, unless you have a sheetmetal cover on the back and should line up with the casting mark on each cam tower. If the timing is truly off 90 degrees then you may have bent a valve or two.

I only noticed the little "+" marks on the back of each cam wheel were not in the same location ie one was at 12 o'clock and the other at 2.

[76was124]

Take a look at the following posts showing the timing marks if you have the timing cover off. If it's not off look at the cam towers, you should see a cast in line on each tower that should line up with the hole on each corresponding cam with the crank aligned at its TDC mark

http://fiatspider.com/f08/viewtopic.php ... ng#p219926


http://fiatspider.com/f08/viewtopic.php ... ng#p207044