When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Guy, don't get too excited yet....I believe this is a terminal issue, so, just park it, and write it off as a total loss, and as a favor to you, I will come and haul it away for you so you will no longer have to look at it! Sorry buddy....
Ok, ok, can't blame me for trying.....
Hoi is right....drive it...I bet it will build back up and be just fine!
I love the positive outlook I think you are right. Perhaps the cylinder was running lean and the rings never fully seated. Gonna take it out again tomorrow
Originally Posted by kiwiokie
Hopefully it just needs an Italian tune-up.
And I am just the Italian to do that ! The first time I went north of 5k rpm i felt a little like i was pushing my luck but it does it so effortlessly!
Here's a question: Does your alternator charge at idle, or does it sit at 12V until you get some revs going? I had a low speed misfire on my '79 that had to do with the alternator not doing anything until the motor go well off idle. This, combined with some old wiring was dropping the voltage to the fuel pump enough that the fuel pressure would come down at low revs. You cannot look at system pressure with the car running, but if you plumb your gauge between the fuel lines and the FD you can monitor pump pressure while running/driving. I fixed this issue on my car with a relay that supplies the pump with battery voltage directly while the pump is switched on, but I am not sure it is 100% fix. I think the ignition system may also be suffering a bit in the non-charging condition. Need to get of the root of the alternator issue, I think.
Here's a question: Does your alternator charge at idle, or does it sit at 12V until you get some revs going? I had a low speed misfire on my '79 that had to do with the alternator not doing anything until the motor go well off idle. This, combined with some old wiring was dropping the voltage to the fuel pump enough that the fuel pressure would come down at low revs. You cannot look at system pressure with the car running, but if you plumb your gauge between the fuel lines and the FD you can monitor pump pressure while running/driving. I fixed this issue on my car with a relay that supplies the pump with battery voltage directly while the pump is switched on, but I am not sure it is 100% fix. I think the ignition system may also be suffering a bit in the non-charging condition. Need to get of the root of the alternator issue, I think.
This is interesting, Karl. My alternator charges enough to turn off the charge light but the gauge rarely reads about 12. Of course the gauge could be inaccurate. Will double check this. Thanks
Checked voltage at low idle at the hot post and it shows 13.8 at low idle. My gauge reads just a hair over 12. Looks like I am charging fine. Will check voltage at pump next
Logged about 100 miles on it over the past week. Running good but still missing a little at idle. Really doesn't like extremely light throttle while in neutral. Bogs down and stumbles. Throttle it normally and it's fine. This is a totally new issue that didn't exist last week. This car definitely keeps me chasing my tail.
Otherwise it run and drives great.
My current mileage is 73011. Going to smoke test for vacuum leaks and check fuel injectors and pressure yet again.
Consensus is that my 120 compression in #1 would not be severe enough to cause any issues by itself. So I could be looking for a very minor issue that is compounded by the lower compression.
So I tried my Colortune in cylinder one to see how the mixture looked in that cylinder. Got a nice shade of blue but something odd happened once the idle lowered. The Colortune plugged fired intermittently and seemingly without pattern. In other words the glass viewing area went dark. No spark being delivered every now and again. Couldn't reproduce this issue in any of the other cylinders.
Switched out the cap, wire and rotor but still got the same results.
I did notice this minor issue. Injector was pushed out slightly. Didn't cause a vac leak but clearly it's not optimal. I reinstalled properly
Reproduced this test again and did note that spark was constant but the actually combustion was the issue. Pulled the injector, line and fittings and checked for blockage. Reinstalled, same issue.
Replaced injector, same issue.
Then I richened the mixture substantially until cylinder one no longer went dark. Apparently that cylinder was running very lean. Engine smooth now and for the time being, the misfire is gone.
Maybe a minor blockage in the FD? Does yours still have the filters at the FD ports?
Thanks kiwiokie. I don't believe its a blockage although its a possibility. I have good flow with the banjo bolt removed from that port on the FD. Filters are long gone and the FD has been rebuilt.
The richer mixture seems to help a lot! I ran the car for 15 miles today and it was very smooth.
Misfire gone? Pretty much. I still hear a little oddity in the exhaust note at idle but its intermittent. Going to run it a lot this week and see how it behaves.
This would be a good time to use so fuel system cleaner.
CIS can be pretty crotchety with fuel quality and deposits.
Did you bench-test the FI system? I did that recently and found the flow rates to be hard to balance especially after mixing up the springs and shims. If the FD is opened right-side up the little bits will disorganize themselves.
This would be a good time to use so fuel system cleaner.
CIS can be pretty crotchety with fuel quality and deposits.
Did you bench-test the FI system? I did that recently and found the flow rates to be hard to balance especially after mixing up the springs and shims. If the FD is opened right-side up the little bits will disorganize themselves.
thanks Glen. Been using techron each tank and yes, a bench test may be in my future.
I replaced an injector seal today on that popped injector. These seals were new 500 miles ago but it's amazing how poorly this one lasted.
I also used a smoke machine that I picked up on eBay. This thing is amazing and the best 60 dollars I have ever spent.
Found a large leak right where the EGR pipe entered the plenum. Snugged the hardware and problem solved. It was so bad of a leak that once I restarted it, it was idling amazingly low. Needed to crank out the idle bypass screw and lean out the mixture.
Running like a bat outta he11 now. Who knows if this is permanent but one by one I am finding and fixing issues.
For those hunting vacuum leaks, get a smoke machine. This last leak did not show up with propane or starting fluid.
Smoke machine. Cant be beat!!
07-03-2017, 05:02 PM
I think you are right. Perhaps the cylinder was running lean and the rings never fully seated. Gonna take it out again tomorrow 
