1987 C30 Cliff Diver

[Maknwine]

I picked up this truck end of summer and drove it about 500 trouble free miles before coming back home one night and having it basically shut down. After looking for anything obvious it finally got running and I limped home with a awful running missing engine.
Wires looked great and couldn't see anything arcing under hood. Checked wires for spark, coil for spark. Pulled cap and couldn't see any issues. Cleaned all grounds around manifold and to front of truck. Did not clean ground behind pass side head but it is intact. Have removed and cleaned terminals on CTS and had a new AC Delco on hand for K5 but made no difference, so have the old one back in. Decided to go with new wires, plugs, cap, and rotor button since I didn't know how long since changed. Still the miss continued. Tried carb spray around vacuum lines and intake, no change. Checked vacuum lines visually as well. TBI is spraying conical spray as it should. Looks just like 91 K5 I have that runs well...knock on wood. So took the Ignition Control Module to Advance Auto and it tested fine. Decided to put the K5 Distributor into C30 and ran a little better. The C30 coil tested in spec on ohmmeter but decided to take K5 coil and put in C30...still ran a little better but no where near like it should. When using timing light, the light would not flicker like it should. So tried on my 87 S-10 and light flickered continually like normal. So I decided to try my K5 ECM in the C30. Well, it starts quickly and runs better but still is not right. The timing light however now flickers like it should. Before ECM change, it would light up and not light for several revolutions then light up and so on. I have the timing set at 6`BTDC with wire uplugged. I decided to go ahead and put a new coil on that I had last night and ran it around a bit but still lacks power and missing a bit. It starts easy though.

So, I'm going to check to make sure I didn't put a wire to wrong dist spot tonight. I think I'm going to swap the ECM back to see if it runs worst with original ECM. I need to do a compression check as that's probably the first thing I should have done. Will remove all plugs, pull coil wire (is that all I need to do to stop any electrical issues? ), and block the throttle open.

Well, I expect this thing to continue to kick my rear and since everything else in and around the house is breaking, blowing up, or rusting to death it should fit right in!

Tks
TJ

 

[Maknwine]

...and I will update this thread with findings/results in hopes it helps other.

 

[Maknwine]

In looking at dist cap....the wires are bassakwards from a normal setup. When I changed wires, I did one wire at a time just like I got truck. But I am going to swap wires around and put the dist around to time.

Maybe some Pics are necessary....

 

[Maknwine]

Rerouted the wires on dist cap tonight and repositioned the dist. Went to time engine but timing light was not lighting up on plug wire 1. Moved the inductor clamp to all plug wires and light will blink on all except cylinders one and two. Haven't seen that before.

I'll read up on pic posting and get an engine pic up soon

 

[da_raabi]

Damn thats funky. This is why I like my 86. Screw electronics. They make things way too complicated.

 

[Maknwine]

test upload of nasty engine pics

 

[Maknwine]

Well, I can see um. Nothing much to see here. BTW, that bolt sticking out of the tee connection at PCV fitting is a prior owner gift to me. It was there when purchased and truck ran fine with it prior to present state.

With new plugs, wires, cap, rotor....not sure why cylinders 1 and 2 don't appear to be firing. I hope I haven't ruined my ECM from the K5. Need to do compression check on all cylinders still and then probably pull valve covers to see if anything jumps out and kicks me in the balls some more.

 

[Maknwine]

Finally able to get back to the C30. Checked compression yday and got these results:

1 168
2 168
3 170
4 175
5 168
6 0
7 170
8 165


Pulled the valve cover pass side and #6 exhaust valve was way too loose. Was able to tighten it down and able to watch it move a few revolutions Not sure why it was so loose hopefully just needed tightening. Also, notice 8 was looser than probably should be. I'm pulling drivers side cover and going thru the adjust valve procedures today. Cant say I remember the valves ticking when it did run but I guess I'll know soon enough.

 

[bucket]

Did anything look out of place with cyl #6? Like bent/broken pushrods or studs pulling out of the head?

 

[Maknwine]

Looks like further troubles. #6 exhaust valve was dropped passed the keepers. I didn't see that until after I had gone thru the adjmt process for all valves and cleaned covers etc.
I stopped after seeing that and got on to other problems.
Spring, keepers, and the rest of parts were all in place....just the stem was lower than keepers. I need to look closer at keepers to see if they are worn or cracked. Also, the stop of valve stem looked ok initially but I need to look closer. The valve is still up so I'm hoping its not hit the piston. I was thinking of getting new keepers and something to compress the spring and do a compression test again on 6 and hope for the best.

 

[Maknwine]

Here's a pic of the exhaust valve on #6.

 

[Maknwine]

I think the valves an parts you see are cleaner then the pic makes them look. Almost no sludge at all.

 

[Maknwine]

I've got to get a new regulator for my air compressor and pickup a Harbor fright spring compressor.
Also, I will order a kit for seals and orings, and new keepers, I'm sure you can't get just one.

How far down is the exhaust seal located? I didn't see one at all.

 

[Maknwine]

.....tap tap tap....Is this thing on?

 

[Maknwine]

I've tried to push down on the exhaust valve but its not budging....my next thought is to put a wire around it in the groove so it doesn't fall down then try breaking it loose with some hammer work.

What does the people here say about that thought?

tks