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I have a 1986 f150 4x4 302/5.0 efi. I recently went to change the water pump and of course broke off a bolt. So I had to remove the timing cover to get the bolt out. While in there I changed the timing chain also. I fell pretty good that I did everything correct as far as aligning things up not to mess up the timing. After getting it all out back together it now seems to have a slight engine miss and seems to have lost some power. So would I be right to assume I need to check the timing or is there something else I should check. It cranks and runs and even drives but seems to start missing and lose power once up to temperature. Thanks for the help.
When you checked/adjusted the timing with a timing light, did you disconnect the connector ? The one with the yellow wires. Sorry, I forget what it's called. Make sure you plug it back together afterwards.
I have not checked the timing yet at all. All I’ve done is put it back together. That’s what I was asking was if I needed to check it now that I’ve got it back together. Wanted to make sure before I go buy a timing light.
It's called the SPOUT connector - SPark OUTput - the black connector in the front of that picture, it has a single yellow (possibly with black dots) wire on both sides. Disconnecting it removes computer control from the ignition timing.
So would I be right to assume I need to check the timing or is there something else I should check...
Are you talking ignition timing or camshaft timing? I think you mean ignition timing, as you mentioned getting a timing light, but I want to be sure.
But even more importantly, this is a new problem, right? It seems the truck ran well previously? You had to replace the water pump for an unspecified problem. That project turned into a can of worms (no surprise) and while you were in there, you also replaced the timing chain and sprockets. I ran into your exact scenario myself.
But now you've got a new problem. One YUGE question: Did you remove the distributor or touch the adjustment? If no, and IF (big if) the new timing chain was aligned properly, the ignition timing should have remained unchanged. check
I would still check the ignition timing as part of basic troubleshooting, but if untouched, my hunch is the problem lies elsewhere. I'd suggest reviewing all recent work performed. Check for an unseated electrical connector, loose vacuum line or plug wire, pinched fuel line, etc.
He took the timing cover off to fix the broken bolt when doing the water pump.
Being the cover was off he changed out the chain & gears.
Now being I dont the motor all that well but it sounded like he had to remove the dist. to do the job.
If that is the case the base timing would need to be set so the computer can adjust it as needed.
Just my .02
Dave ----
it sounded like he had to remove the dist. to do the job. If that is the case the base timing would need to be set so the computer can adjust it as needed.
Waiting to hear back from him if he did touch the distributor. On my 351W, when I replaced the timing chain, I left the distributor alone. That's not to say he didn't remove it for better access, but it's not necessary.
Yes I had a leaking water pump and decided to change it and that turned into a can of worms. I did not remove the distributor to do what I did. I simply aligned the dots on the timing gears then removed it and replaced with new gears and chain putting the dots on the gears back in the same spot. Someone told me the new chain being tighter can make the timing be off just a small amount. Not sure if that is true or not. Sounds like I may just need to buy a light and Check and if it’s ok start looking for other causes. This a new problem also. Truck ran great when I started this job. Did a tune up replacing plugs, wires, coil, cap, and button only 100 miles prior to this. Truck was running better than it’s ran since I had it until I did this job.
Someone told me the new chain being tighter can make the timing be off just a small amount.
This is true, but I bet the difference is so small you wouldn't be able to discern any change in performance.
The big unspoken fear is if the timing gear set was aligned improperly. I'd suggest checking the base timing as previously described. If still within a few degrees, that would imply the camshaft timing is good. Hopefully that will put that fear to rest.
I'm still leaning towards something didn't get reconnected properly. Have you checked the alternator output? The alternator would have been removed, so maybe something was left loose. Even if the starter seemed to spin at an adequate speed, the battery may be slowly running down. Low voltage to the ignition will certainly cause performance problems.
If his timing chain and gears had a lot of wear, then the timing would be changed by just putting a new chain and gears in place. We can make an assumption that the timing had been set with the worn timing setup. The timing light is looking at the crankshaft, and is fired from the distributor. So it probably does need to be tweaked with a light to get it back in at 10 BTDC with the spout connector disconnected.
Thank You! I will be checking the timing. Hopefully it’s still good. I was very careful to not mess that part up but I know things don’t always go as planned. I will recheck all connections again along with the coil connection. I didn’t have to remove the alternator to do the job, just removed the belt from it but never unplugged it. It’s just weird it will crank easily and runs good until warm then starts to miss and just seems bogged down.
If his timing chain and gears had a lot of wear, then the timing would be changed by just putting a new chain and gears in place. We can make an assumption that the timing had been set with the worn timing setup. The timing light is looking at the crankshaft, and is fired from the distributor. So it probably does need to be tweaked with a light to get it back in at 10 BTDC with the spout connector disconnected.
Thank You! It was the original timing set and did have a good amount of slack. I’ve only owned the truck a few months so not sure what the PO may have done. I feel like I need to answer the timing question and then I can look elsewhere if that doesn’t seem to be the problem.
This is true, but I bet the difference is so small you wouldn't be able to discern any change in performance.
The big unspoken fear is if the timing gear set was aligned improperly. I'd suggest checking the base timing as previously described. If still within a few degrees, that would imply the camshaft timing is good. Hopefully that will put that fear to rest.
If it's a sin to know exactly what you need to do and then not do it, I'm going to hell. I chased every possible lead down until I surrendered and tore off the timing cover again. Oops.
I agree that the new chain will change the timing but would be unnoticeable. I also agree that if the OP misaligned the gear set, a timing light would help point that out. His base timing will be off 9° for just one tooth on the cam gear.
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