engine is not running right after warm, movies and pictures included

[akorna]

The white smoke leads me to head gasket leak - but also think you need to test the compression of all the cylinders.

Why do you think that removal of the emissions gear would make it harder to start? Are some of the hoses/fittings not capped or plugged?

If your dizzy is more than 15 years old than the breaker plate is probably sticking and you are only getting mechanical advance. Do you have a mechanical fuel pump? Is it reading between 3-4 psi? Is the tank full of FRESH gas?

[crazyoctopus]

I'll head to the autoparts store and pick up a compression tester, meaning to get one anyway, and see how the cylinders are running.

as far as the removed emission stuff, the EGR valve, the coolant lines, anything that isnt needed to run the car is gone. all of the lines were blocked off well, but with hopefully with today's test i'll find out exactly where the leak is coming from and move on from there.

yes i have a mech fuel pump, dont have a pressure gauge, i'll see if they have one and pick that up as well, and the tank is 6 gallons full of 1 day old 91 gas.

should have something to show within the next few hours from all of the testing.

[crazyoctopus]

compression test

#1 - 125

#2 - 120

#3 - 120

#4 - 125

#5 - 115

#6 - 120

avg - 120.8

all seems to be fine on that account.

Fuel pressure is a solid 4psi.

the spark plugs when i took them out looked pretty much the same in the first couple of pictures. i'gave them a quick clean and put them back in.

I did however notice something exasperatingly stupid on my behalf, but then again I never thought to look for it until last night. Xnke on hybrdiz mentioned that i should check the brake booster, as it might be leaking internally. So before I started the car I did a visual check on the line to see how hard it was, and if there were any gaping cracks. I found this...

it was easily missed due to it looking like it was connected, but without that bolt in there it wasn't really doing anything at all. This somewhat explains why the car would do it sporadically, and even more so when it was hot. I am going to the parts store, yet again, to see if i can pick up some new lines to replace these with just in case and i'll keep you all informed.

[crazyoctopus]

that did not fix the issue.

and a new sight, i ran the carbs a bit lean to get some lean pops and see if there was any bits smoke come out of anywhere and saw that one spray came out of the rear throttle bushing. it is the first time i have seen it, but then again this was the first time that i was looking for it as well

Edited March 10, 2010 by crazyoctopus
more info

[akorna]

Others can chime in here on the numbers - but the compression seem to be pretty low, which would impact combustion - I would think you should be looking for something in the 150-170 psi range. I assume these were obtained using a "dry test" - you could follow-up with a "wet" test by squirting a few shots of engine oil into each cylinder and re-testing. If the compression goes up more than a couple PSI then your rings/pistons/cylinder walls are worn. If it does not, then you have a head gasket or valve train issue. If your static timing is off, then the valves could be opening at the wrong time and compression may be reduced.

[crazyoctopus]

yeah it was a dry/cold test, and the timing at that point was 15, I reset it to 12 and before i start the car this morning i'll try another comp test, and then once i get the engine warm i'll retest again.

[oldhemi]

My opinion - after you get the car warmed up, rev it to 2-3K for 30 seconds or better and shut it off. Take your plugs out and take a look for one that looks way different than the others. If so, that cylinder could be getting some H2O in it! Then take your compression check and see if that cylinder is lower than the others.

The reason that you want to get the revs up, is that you dont want a rich idle condition affecting your "plug chop" - reading the plugs condition. We do this on Honda 4 cyl SOHC/750's etc for main jet reading/changing when changing to different air filters, exhaust etc. I think that this technique would be applicable in this case.

[Zedyone_kenobi]

Not sure if that is an accurate test Hemi. I have read that you should look at your plugs after driving it under a load at various rpm. I am not sure if having the car in neutral simulates the same thing... I could be wrong though...

[crazyoctopus]

So the engine started, but it took a bit of time for it to actually run normally. When it did run properly it only lasted for about 45 seconds, and then the car died suddenly. It didn't sputter or choke out, it just died as if i turned it off with the key.

pictures of the plugs right after I took them out this morning, before putting them back in I cleaned them yet again with carb cleaner and a golf club brush.

plug 1

plug 2

plug 3

plug 4

plug 5

plug 6

I am going to pull the plugs shortly and see if there is any change in condition.

Here are the results of the comp test this morning.

1 - 150

2 - 149

3 - 150

4 - 150

5 - 146

6 - 150

avg - 149.2

Maybe I made a mistake when I did it yesterday, by dropping the timing to 12 deg, or because this time i removed all of the plugs before i did it; regardless, the comp on each cyl is still just about on avg.

Before I started the car I added a dollop of bearing grease, rags on hybridz's idea, around the throttle bearings hoping to stop the possible vacuum leak, but it really didn't seem to do anything at all.

while the car was actually running as it should I sprayed the crap out of everything front to back, and top and bottom listening for a change in rpm. Once I heard it in a particular spot I put on the straw and tried to localize the drop. Even with bearing grease on the throttle bushings (on both ends, and on both carbs) I was hearing a drop in RPM whenever I sprayed the side where the linkage comes into the carb body, not on the outboard side.

So does this mean that it is time to get new carbs? or should i try cleaning them again and see if the problem persists?

[mlc240z]

I'm not a great plug reader and I could definitely be wrong but.....,

Plug 1 - closest to 'normal'

Plug 2, 3, 5 and 6 - rich fuel or weak ignition

Plug 4 - wet (oil/fuel/water, not firing??)

Comp test looks ok in that all the cylinders are about the same pressure.

Maybe try pulling #4 ignition wire and seeing if engine rpm changes (dead plug or bad wire?). If no change, suspect plug/wire/dist cap for spark.

If you can afford, I highly recommend ZTherapy carbs. I had to wait about 2 years to save up, but hands down one of the best things you can spend your money on. Throttle shaft air leaks and other 'weird' conditions are totally taken out of the equation.

More knowledgeable members, please correct my errors.

Edited March 12, 2010 by mlc240z

[oldhemi]

Zedyone - I agree with you on the validity of this plug check, but I was under the impression that Crazyoct's car was not able to out on the road confidently at this point. Using this assumption, I figured that this was better than nothing. I should have been more clear!

Crazy, I have very little knowledge on these SU's, but I am agreeing that you have some leaks which could be ALL of your problems or not. Are your floats set too high? High floats will cause flooding on most carbs that I have worked on.

Since you are using a not-explosive spray to find the air leaks, you could be also loading those plugs up causing misfires leading to the plugs getting fouled -except for #1! I dont have an answer for that one!

As far as new/rebuilt carbs, I would not advise you on that. More Z - SU experienced folks would be much better than me!

[crazyoctopus]

during the most recent float setting i have noticed that the front carb requires to be a few turns richer than what it had been before i set my floats. i'll check em again maybe I wasn't putting enough pressure on then inlet tube. Also if my floats were set too high wouldnt that mean that i would have to be running leaner on the adjusting nut and not richer?

here are what the spark plugs look like right now, just pulled them not 5 minutes ago

and yeah there is no way that i can take my car out on the road i just noticed that i snapped a brake line.