So it's been a few weeks since my last post, but I have been working on the car a fair bit. Two weekends ago I discovered that my oil seal on my distributor was leaking. When I blew into the crankcase emissions hose to check for vacuum leaks this was the result:

Since I didn't have the parts to rebuilt the distributor, that had to wait till next weekend. In the meantime I thought I would swap out the timing belt, timing belt bearing, v-belt and water pump since I had new ones sitting around. A couple of issues came up, first the aux shaft that drives the oil pump had been aligned incorrectly relative to the crankshaft... which was a little scary since apparently they won't clear each other at all alignments and a collision often results in damage to the block. Since the engine seems to be operating, and a problem usually results in catastrophic damage (from what I've read) hopefully I'm in the clear.

                                         (Old belt about to come off)

My other problem occurred late Sunday night as I was rushing to get everything assembled so I could park the car in my garage for the week and forget about it. As I was refilling the car with coolant I noticed that most of the coolant was ending up on the street! I couldn't figure out exactly were it was leaking from then, it was late and I was tired so I drove it into the garage without coolant. Last Saturday I got it patched up. It was leaking from the gasket between the metal hose to the heater core and the water pump. I had to use two gaskets to get it to stop leaking. I think the surface of the heater hose is no longer flat... but it seems well sealed now.

Last week I also pulled my fuel injectors and tried to clean them in my lab...

which proved a little more difficult than I realized... but I was able to run a few cups of alcohol through them backwards and forwards as well as let them sit in the ultrasonic cleaner for a half hour or so. I wasn't getting a very good spray pattern from them, but I was only running 15psi alcohol through them and the car operates at 35-40psi so maybe my pressure was just too low to get good atomization. I also have concerns about the injectors themselves, injectors 2 and 3 appear to be replacements... hopefully their flow rate is similar to 1 and 4? I think it might be worth having them sent out to be professionally cleaned and flow matched at some point. On top of that the cold start injector seems to fire inconsistently (probably do to my over zealousness with the vice-grips during its removal), this also makes me a little concerned that it may be leaking? In any case I can still start the car while cold... although it does seem a little more stubborn than before.

After reinstalling the injectors the car was running very poorly and roughly... my initial suspicion was that it was running on 3 cylinders (it was), but when I first pulled plug wires to see which ones made a difference somehow I missed that cylinder 3 was not firing (this was very clear to me the second time I pulled plug wires.) I took a break at this point to rebuild the distributor, replacing all of the seals, o-rings, and bearings as well as the cap and rotor. After re-install the car was still running rough obviously as cylinder 3 wasn't firing, but the idle speed did seem more constant than before. I had no idea at the time why the car was so rough... so I took it for a 30 mile ride to see if the problem would work itself out... It didn't. Shortly after returning I recheck the cylinders and discovered it was #3 that was not firing... well the injector was not firing but the plug was. So I checked and low and behold the connector on the Fuel Injection harness was badly messed up for #3... so I temporarily fixed it with some alligator clips and the car seems to be running pretty good.

I also discovered around this point (a rattle was developing) that they exhaust had rusted and broken off right behind the resonator (center muffler). So I'll need to fix that before I take it back in for inspection/smog. In any case the car seems to be running better and stronger than it ever has although I still have some concerns regarding mixture and the cold start injector. Also, it does seem to still miss at idle once every 2-3 seconds or so (better than before but still annoying).

This weekend I was trying to get the air fuel mixture right in the car, but I couldn't figure it out... I'm not sure why but turning the air bypass screw on the air flow meter doesn't seem to adjust the mixture much at all. I tried using the voltage from the O2 sensor (this is hard because the voltage jumps all over the place even if I get the sensor hot first by revving the engine for awhile.) I then tried using the colortune (clear spark plug that I ordered.) It's pretty cool to see in the cylinder while the engine is running, but it was hard to set the idle mixture using this. I had intended to make a video of this, but blanked... What I noticed is that the engine is stumbling somehow usually combustion appears blue with a hint of orange... which is about what you want (I think). However,  I can tell through the colortune that the engine is stumbling at idle, I'm not sure if it's missing or what but occasionally I get a drop in rev and a bright orange mixture for a single explosion or two. All of this was seen through cylinder 1. I am planning on looking through the other cylinders for comparison, but I had a mixture setting 'fuck it' moment and moved on to other things.

I discovered several small exhaust leaks coming from the exhaust manifold while replacing the O2 sensor, I think they are from cracks and they must be small because they are extremely difficult to locate and disappear almost completely after the engine gets hot. From what I've read I doubt these are the root cause of any of my problems so I'm going to ignore them for the moment.

I checked the temp sensor at low and high temp, seems okay. Checked voltage on the cold start injector, on for 5 seconds then off (seems okay). Used the supposedly unreliable resistance method to check my AFM, and it checked out okay. I fixed my throttle position sensor (TPS) which was not set well and needed to be rotated. This fixed the light puffing backfires on deceleration which I found charming but according to the internet are not an indication of good running.

I also swapped the spark plugs and checked compression. Fortunately the compression tested great between 115 and 120psi in all cylinders. The owner had told me his plugs were recently changed... but he was lying or his mechanic lied to him....

From cylinders 4 to 1 in order left to right. All 4 are different plugs apparently replaced at different times??? Why you wouldn't just replace them all I have no idea, a set of 4 new ones was ~10 bucks. They are all charred black to varying degrees which (I think???) is an indication of rich running, something that my emissions report already indicated. In any case I haven't been able to discern any improvement in the cars running with the new plugs.

I also rechecked the timing (seems okay at idle), and checked that the vacuum advance was working by sucking on it at idle (it is).

I would really like to fix the stumble at idle before I take it back to get my emissions tested again. I think it either has to be a problem with one of the injectors, the distributor or a really friggin sneaky vacuum leak.

I worked on her some this weekend and appear to have fixed some things and introduced a few new problems. I replaced all of the vacuum hoses and discovered a few things in the process. There was a crack in the elbow that connects the crankcase emissions to the oil vapor filter, and the oil vapor filter was completely full of sludge. So I cleaned it out and replaced the elbow. Also either the previous owner or a mechanic that he used had plugged the vacuum advance hose with a screw (???), it must have been done intentionally for some reason. I checked the diaphragm on the distributor's vacuum advance and it seems to be good (holding vacuum with my tongue) although I don't know whether or not it's actually advancing the timing as it should.

After making these changes I noticed a few things. It starts up great, in fact the idle is smoothest within the first minute or two of turning it on. It drives fine at higher RPM although it does seem to have lost some power. The funny smell I noticed before is gone (yay!). The idle now seems a little rough after the engine has warmed up. By rough idle I mean the idle rpm seems to wander a little, the digital tach on my timing light reveals that this variation is ~80-100rpm. I'm not sure if this is normal?

I checked the timing and it appears to be set properly at 10 degrees advance. I was a little busy this weekend so I didn't manage to get much else done (other than cleaning up some grounds... my blinker finally blinks at a normal speed!).

Another problem that is starting to concern me is the temp gauge. Every time I hit the accelerator hard it drops to 0 (even at a stand still). Then if I let it sit for a minute it wanders back up to 190. Perhaps some more rigorous testing with the multimeter is in order. On the plus side the fan does seem to be going on and off with some regularity still.