03CL55AMG Posted January 8 Report Share Posted January 8 so the other day I was out driving my conquest. Was running good, even boosted it up one time. A little second gear pull. Ran good, got on the interstate and was cruising charging up the battery. in fifth gear just gave it a little bit of throttle, where it would, make about 4 or 5 pounds of boost. Started hiccuping just a little, and got worse and then started missing and by the time I got home, it was seemed like it was running only on three cylinders. I will say that I had noticed when I first started it before my little road trip, that I noticed a lifter was ticking more than normal. Sometimes those lifters will tick a little bit and quiet up. so, I pulled the lifters out and the cam tower, cleaned everything in the cam tower and cleaned out the lifters and used transmission fluid and bled them. Got all the air out put everything back together ran OK, but then started missing within just a mile from the house. Still have the lifter noise. Ran a compression check after I warmed it up a bit, all cylinders were 133 to 138. So does it sound like a bad lifter. Link to comment Share on other sites More sharing options...
Fuze Posted January 8 Report Share Posted January 8 (edited) Your problem is likely related to a bad Vacuum Advance module on the distributor. When you make boost, it retards the timing. When they fail, the car hiccups when you start to make boost. To test it, pull it off and push the plunger in and hold your thumb over the nipple. If the plunger moves out, it's bad. As for lifters, I switched to mechanical lifters when I still ran the G54Bt as they're just more reliable, however they do work best with the mechanical cam. good luck Edited January 8 by Fuze Link to comment Share on other sites More sharing options...
03CL55AMG Posted January 9 Author Report Share Posted January 9 Thanks fuse…. funny thing is, I have a locked out distributor. So I don’t even remember if I have a vacuum advance. But I will look appreciate the advice. Link to comment Share on other sites More sharing options...
03CL55AMG Posted January 9 Author Report Share Posted January 9 Well….. I should’ve known that, but I did check this morning, and I don’t have a vacuum advance. Almost wish I did, so that that would be probably an easy fix. Any other ideas from anybody would be appreciated. Link to comment Share on other sites More sharing options...
Fuze Posted January 9 Report Share Posted January 9 Wait, what engine is in this car? All G54B's have the vac advance unless it was removed for standalone ignition, or something like that... Link to comment Share on other sites More sharing options...
03CL55AMG Posted January 9 Author Report Share Posted January 9 Hey Fuze…it is a G54B, I have a Holly EFI standalone. So ,no vacuum advance. When I first pulled the plugs just to see what they look like they looked really good. But the other day I was having a little bit of a problem starting it …so it may be something I’d have to get my tuner to look at. Although I don’t know how anything would’ve changed in the tune. I definitely looked at vacuum mines because I was positive the day it happened, that I had blown a vacuum line off. But I couldn’t find any vacuum lines that were off. Link to comment Share on other sites More sharing options...
03CL55AMG Posted January 10 Author Report Share Posted January 10 Hey Fuze…it is a G54B, I have a Holly EFI standalone. So ,no vacuum advance. When I first pulled the plugs just to see what they look like they looked really good. But the other day I was having a little bit of a problem starting it …so it may be something I’d have to get my tuner to look at. Although I don’t know how anything would’ve changed in the tune. I definitely looked at vacuum mines because I was positive the day it happened, that I had blown a vacuum line off. But I couldn’t find any vacuum lines that were off. Link to comment Share on other sites More sharing options...
03CL55AMG Posted January 10 Author Report Share Posted January 10 So, let me ask this question in regards to lifters. Is it possible for me to have a failing lifter that under even a light load or moderate load causes the engine to miss, but when I do a compression, check compression checks out good. Because that seems to be, what might be going on. Didn’t know if that was a possibility or not. Link to comment Share on other sites More sharing options...
BKB94 Posted January 10 Report Share Posted January 10 A picture of the plugs would be helpful. What is your plug gap and part#. Leak down test is a lot more helpful than a compression test. Link to comment Share on other sites More sharing options...
03CL55AMG Posted January 11 Author Report Share Posted January 11 Well, I will tell you when I pulled the plugs a week ago when all this started, they were just a light tan color. The gap 26. But since I had trouble starting it a few days ago, the plugs are a little fouled now with gas. The plugs I’m using are NGK-BUR7EA11. what is the leak down Test going to tell me. Link to comment Share on other sites More sharing options...
BKB94 Posted January 11 Report Share Posted January 11 (edited) Compression test has way to many variables, cranking RPM, TB open or closed, Warm / Cold, leaks. Leak down test will give you a true health of the engine. You will also know what's causing the issue by the sound either rings - crank case noise intake or exhaust vale. Is this MPFI, what are you using for a crank sensor, what is your holley telling you? You should have full data logging abilities to troubleshoot this easily. I know little about the G54 but other engines will run and not have a miss with a collapsed lifter unless you wipe a lobe or something goes horrible wrong. If it was that bad you would have had one cylinder that took many more cranks to reach compression. This is a stock low compression build 7 or 8 to 1? Edited January 11 by BKB94 Link to comment Share on other sites More sharing options...
Tim_C. Posted January 19 Report Share Posted January 19 I think the comp test is good enough to rule out a lifter. I agree it provides more information. I just don't think it is needed to find a miss when it has 130+ PSI. Most stock cam and head setups are light on the lifter preload. Like .015" when it should be .035". They can tick with light oil or just a little dirt in there to cause the lifter to not extend out. I still don't see that as the miss issue. Not sure about the Holley EFI, but the stock TBI required very clean injector clip electrical pins on both the clip and the injector. If the advance isn't retarding then that is still the most likely suspect. Either that, or I'm missing something about the Holley set up. I'm not familiar with it. Link to comment Share on other sites More sharing options...
03CL55AMG Posted January 26 Author Report Share Posted January 26 Well, I found out what the culprit was, and should’ve known better by not checking this first. As it’s one of my own rules, always go to the simplest things first. But I think the noisy lifter through my focus off. It was indeed a plug wire that was almost out of the, cap, and some corrosion developed in the cap. That was the miss. thanks for everybody chiming in. I replaced plugs. Wires, cap and rotor. Running very well now. Thanks. Link to comment Share on other sites More sharing options...
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