1996 f150. Engine randomly started ticking one day across rpm ranges (sometimes it’s there sometimes it’s not really even audible). Did lifters, plugs, plug wires, distributor cap. Tried pulling cat o2 sensor to see if it cat was clogged. Was fooling around with the engine running and disconnected the IAC and it ran much better for a bit while warm, plugged IAC back in and it ran a bit worse. Replaced IAC with motorcraft one. Both TPS and IAC have been checked on multimeter and are a-okay. Innova 5210 code reader is showing my timing heavily fluctuating. I know the BTDC is 10 degrees but my reader shows 13 degrees advanced as it’s lowest all the way up to 23 DEGREES advanced timing. Typically it sits between 13 and 17 degrees advanced but I am confused on why it fluctuates. I was planning on adjusting the timing but I was hoping for another opinion. Is the timing the direct cause of the rough running or is it more likely that something unrelated to timing is telling the computer to adjust the timing erratically?

edit: I should mention that the engine ticks across all rpm ranges but sometimes the ticking is more noticeable (i.e. upon initial startup) and normally settles down when warm for a bit (still there but much less audible) and then will go back and forth between ticking and not ticking

 

Mine "ticks" on startups for a few but i have traced it down to a cracked exhaust manifold. It could be that is a possiblity for your noise as well.

You put lifters in the engine? What was the reason for that just the tick ? And did you time the engine correctly after reinstalling the intake manifold?

I don't know much about the 96 obd2 trucks and their quirks, maybe someone that knows better can help with the timing moving. But i know my 95 fluctuates at idle some so that could be normal variations in the tune as the eec aims for a steady base timing.

 

Varying timing at idle is normal with the SPOUT in. As suggested remove the SPOUT then check the base timing with a timing light. I suspect the ticking noise is a cracked exhaust manifold as well.

 

Okay I’ll look into that. Just spray around with soapy water? Time the engine after reinstalling lifters? I didn’t know I even had to do such a thing (although I should note that the ticking was present before and after the lifters were replaced. Also not sure if this is relevant but it is definitely lacking power (won’t go above about 20mph) and it will often quite down idling in park with almost no ticking but as soon as it’s put in gear it ticks again.

I originally thought it was a misfire but after pulling the plug wires with it running and no cylinder having any difference I have ruled that out. Also not sure how relevant but I have a p0385 sensor B circuit code (which I know is the misfire sensor)

 

Okay and timing should be 10 degrees BTDC, correct?

And would a cracked exhaust manifold cause a big lack of power?

 

10* BTDC is the factory setting with the SPOUT plug out. Changing the lifters would not affect the base timing. A cracked exhaust manifold is an air leak upstream of the O2 sensors. Yes it can cause a rich condition that can also cause a converter failure eventually. You could use a length of hose as a stethoscope to find the exhaust leak. I have used a shop vacuum setup in blow mode then placed a smoldering cigar in the bottom of it as a poor man's smoke machine. Slid the vacuum's hose in the tailpipe, used a few shop towels to seal it, then turned on the vacuum. Use a flashlight and your nose to find the leak, if any.

Your Code P0385 is most likely not causing your rough running problem. Start with one thing at a time. Check base timing, inspect/replace the plug wires, cap/rotor and spark plugs if not already done. Verify you have the correct firing order on the plug wires.

 

Gotcha. Ill see what I can do for that maybe I can find a smoke flare or something. I have a mechanics stethoscope so I will use that too to help find the leak. Thank you for the advice, I'll update when I have done so. Any other tips are greatly appreciated so please anyone chime in.

 

Also if it is cracked what would be the best way to go about repairing it? Ideally I can repair it still on the vehicle but I would have to assume a crack at the manifold would mean removing it completely. I have access to both a flux core and TIG welder and am proficient in both. Is there any way to fix with the manifold still on the vehicle?

 

Update: I just tested my exhaust by hooking it up to a leaf blower and I did indeed find cracks. I am going to pull and inspect both and then maybe do a pressure test after I reweld them. I’ll keep you guys posted! Thanks!

 

Also the first manifold bolt by the radiator fan and cyl 1 is blocked by a cover/shroud for the alternator, do I really need to remove the entire piece?

 

20mph max speed?! That tells me you're only running on 3 or 4 cylinders.
While the engine is idling, remove and reinstall all the spark plug leads, one at a time. They should all cause the engine to stumble a little bit. If you find one that doesn't cause your engine to change tone, that cylinder isn't making any power. Might be a bad sparkplug, or mis routed sparkplug wires, or a bad injector, or no compression.

 

Remove the alternator/smog pump and aluminum bracket. It's only being held in by 3 or 4 easy-to-access bolts and the belt. Once it's removed, everything becomes much easier to access.

 

I apologize I should have mentioned that. I have pulled plug wires one by one to check for stumble. I originally thought it to be a misfire, however they all caused it to stubmle/run poorly when removed one by one. I should also note that I have received no misfire codes.

 

Do I need to remove the bolt behind the smog pump serpentine wheel down there? It seems to be very difficult to get out. Interestingly none of my manifold bolts have been frozen thus far but this bolt holding the cover on seems frozen. I sprayed it with PB Blaster but I want to make sure I need to remove it.

 

No. Remove the hoses from the smog pump. And then unbolt the aluminum bracket from the engine block. The smog pump will come out with the aluminum bracket.