Vacuum Hose Question

[bilbo]

I have searched but didn't find anything like what I'm experiencing. Most of what I found is the clatter/clicking type noise. This is a regular clink, clink, clink in time with the RPM of the camshaft. Is it possible one of the lobes went flat also? I wouldn't think it would make that kind of noise, though.

I only had the truck for about a month before I had to rebuild the engine, but it didn't make this noise before the rebuild.

I'm going to double check the oil and have another go at it this evening. I may also start pulling vacuum lines and plugging to see if that's the issue with the unstable idle. Would there be any harm in unplugging the mixture control solenoid on the feedback carb? Maybe that's not working correctly and leaning things out?

 

[bilbo]

Some good progress last night! I found the noise was from the camshaft pulley bolt backing out and letting things rattle around. Fixed that. Then my neighbor came over and worked his magic and it is idling fairly well now. It still has an intermittent miss while idling. He said it may be the throttle shaft play; he's seen worse but it's fairly bad. Tonight he is going to help me time it. He has some nice tools for that like a scope.

On that note, it was really cool watching him work on that engine. He is a retired mechanic of many years. People like him should be writing books. The amount of knowledge and tricks contained in his mind is awesome. During tuning we had the air cleaner off and every once in a while it would spit back through the carb. It made me jump but he never moved; ice in his veins. It took him an hour to fix what I'd been messing with for a few days.

 

[bilbo]

It's running now! I still think it's having a bit of a fuel delivery problem but it's driveable. I even drove it to work this morning! My neighbor and I hooked it into his scope last night and went to work. Couldn't get it to idle without missing, and started pulling plug wires. #4 was dead. Fearing the worst, we grabbed a compression tester and pulled the plug. Purely by chance while passing the plug across the engine bay and flipping it over, he noticed the gap was closed. The insulator had broken and would slide up and down. When the plug was upright, it would close off the gap and spark. It still fired, and showed up ok on the scope, but wouldn't ignite the fuel. That's our theory anyway. A new plug all but eliminated the miss.

Anyway, I'm going to replace the fuel filters again just to be sure it has unobstructed flow. Maybe something was stirred up from the bottom of the tank and plugged them? Then probably start looking at a reman'ed carb.

The EVTM I ordered arrived yesterday as well. It is very detailed on the electrical side and cleared up some ground location questions I had, but there is no mention of vacuum stuff really, unless I missed it. Is it the Engine/Emissions Troubleshooting manual that covers this?

 

[Mark_88]

Some good progress last night! I found the noise was from the camshaft pulley bolt backing out and letting things rattle around. Fixed that. Then my neighbor came over and worked his magic and it is idling fairly well now. It still has an intermittent miss while idling. He said it may be the throttle shaft play; he's seen worse but it's fairly bad. Tonight he is going to help me time it. He has some nice tools for that like a scope.

On that note, it was really cool watching him work on that engine. He is a retired mechanic of many years. People like him should be writing books. The amount of knowledge and tricks contained in his mind is awesome. During tuning we had the air cleaner off and every once in a while it would spit back through the carb. It made me jump but he never moved; ice in his veins. It took him an hour to fix what I'd been messing with for a few days.

Good to hear of the progress. I had the same thing happen to my 2.0 after I changed the timing belt. I also left the cam bolt too loose. Also discovered an oil leak from the front of the engine and it turned out to be another mistake I made...forgot to put thread sealer on the bolt and the oil started leaking out...fixed it but it sure had me worried and could have caused more problems.

I saw your latest post too...just wanted to comment on this before I forgot...

Good work...sounds like you are closing in on having a great running truck