Good Morning,
In Feb 2023 I started down a path of replacing injectors and fixing china wall leaks. After the reassembly there was a ticking that coincided with rpm. I lashed my brains out, doubted everything I did and eventually had to go back in. I spent 4 months diagnosing and asking the forum, lashing valves and chasing ghosts. All until one day I discovered the ticking was from the FPR and followed it down to the fuel return line. It was right there in front of me but I was not objective and chose to do the lifters just to make sure the cam was not getting eaten. I was appx 8 bolts away from the heads being unbolted from everything so I took the heads off and went to the only machine shop around. Then I promptly broke my ankle getting out of the car coming home. There was a lot of learning and a lot of asking and a lot help from a lot of people on this forum. My opinon of what happened was the ticking was there before I started the job and did not notice. Even though I replaced the lifters I believe / know it was a blocked return line fuel filter (UPDATE it was not, clicking returned) that was causing the FPR to bounce when all 8 injectors fired at once. The filter I discovered from a forum conversation by a few people talking about this filter and TSB number: 86-234. I can't name all of you and I apologize to anyone I miss, @WVZR-1 , @IHBD , @s carter , @FostersPerformance , @eutu1984 , @69427 , @Tunedport90 & @tequilaboy you both are a great help to this forum on ECM stuff, data is king and you spent many posts getting me there thank you, @ULTM8Z , and even @arbee who has kicked me in the ***** a few times, with arbee it is kind of like getting your Darlington stripe, @Kingtal0n , @1Eyed Willie , @dizwiz , @383vett , @Cruisinfanatic and Tyler at Autozone in Lake county Fl.. There are many more that helped and I did not name please forgive me. Thank you to this forum, it's owners and members and supporters. I did not want to turn the key this morning, I chased timing a little last night when I was tired and with a nights sleep hit it right on this morning. I turned the key and there was no ticking.

Thank you all.
Donny
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Hey, that's what these boards are for. The hot rodding community helping eachother out. Glad everything worked out for you.

 

I am sorry to say this but I don't want to steer anyone in the wrong direction,
I am going to have to eat crow here but the truth is more important than my ego. It appears I did not solve the clicking FPR. I have the clicking back and my car is still pulling fuel from the mix (BLM 108). To add insult to injury the valve job may not be holding. I have a slight pop now (after about 15 miles of testing) in the the exhaust at idle. Earlier it was idling perfectly. And yes, I have triple checked the plug wires and timing. Even more alarming is a single instance after driving the car, while idling in the driveway opening the garage door, I had a one second puff of blue smoke. What could possibly cause a single puff of blue smoke after a ride ??? Along with this is the smell of something burning that I can not find. The rabbit hole has just become deeper...... CRAP !!!!

 

The fact that you're getting the 108 BLM means a (if not the) problem has to at least be on the side with the O2 sensor. Have you done a leak down check?

Years ago, I was chasing an idle misfire for a very long time... going after injectors, spark plugs, plug wires, sensors, etc. It wasn't until I did a leak down check that I finally narrowed it down to what was most likely a stuck piston ring on the #7 cylinder. In a hail Mary before doing an engine tear down, I ran some oil additive (I forget which one) for about a hundred miles and the misfire went away. But I will say I was going through the same thing you are now... pulling my hair out, wanting to give up, etc. But overall, it's just a mechanical system and at some point you're going to find it.

I went back and found your original thread...

Seems like you narrowed it down to the FPR. Has anything been down to the fuel tank lately such that maybe someone forgot to reinstall the fuel pulsation dampener?

Other possibilities... are you running factory rocker arms or aftermarket? I have 1.6 roller rockers and there's a bit of a clicking sound to them as well.

 

So, I have a ticking going with my lt4 car.

I also looked for a TSB referenced above, but can’t seem to find it. I must be searching wrong.

Where to start?

 

So, I have a ticking going with my lt4 car. I also looked for a TSB referenced above, but can’t seem to find it. I must be searching wrong.
Where to start? Just know that I know nothing about LT4's. Check the fuel pressure regulator and valve covers.I would start with a mechanics stethescope, yes you can use a long tool but the stethescope is better. I do not know if the LT4 has the second filter, as per my update was not the problem. 85 thru 87's were the only ones with the second filter. After that a fix was engineered into the car.


Thanks for replying,

Has anything been down to the fuel tank lately such that maybe someone forgot to reinstall the fuel pulsation dampener? I installed a new pump appx 15 months ago and did the pulsator delete, sitting behind me is a new pulsator I purchased in anticipation the fix did not hold. I just recieved the new tank gasket yesterday for when I pull the pump assy out and reinstall the pulsator.

are you running factory rocker arms Yes stock rockers, clicking was there after new bosch DIII injectors which could also be suspect. popping exhaust was there a week after valve job. I have been in twice, first time injectors and valve stem seals, That is when I discovered the clicking and running rich. Second time springs, pushrods, lifters. The heads went to the machine shop and they did the valves, but I am not blaming them. Funny thing is I don't smell a rich exhaust except maybe on startup. Plugs are not black, no black smoke ever. Temp sensor in front of intake is new, as are plugs, wires, rotor, cap, coil, O2 sensor, throttle body cleaned, EGR new, timing is from 4° to 8°, cranks in the first second of rotating, all new filters, vacuum 21HG, FP is 41psi, vac lines new, cruise deleted, no brake booster leak, does not miss under throttle and wires are routed with holders, pulling vac line off of FPR no difference. Oil and coolant are still pristine. I intend to add the pulsator and change the ECM I have on hand. The single puff of blue smoke worries me though.

Popping seems to be more prevelant when warm.

 

Well, the thing is a BLM of 108 doesn't necessarily mean the engine is running very rich. It means the engine wasrunning rich and the ECM trimmed the fuel back to compensate.. so you may be actually pretty close to normal. 108 also means that the ECM is out of adjustment range, so you still might be running slightly rich. If you're not smelling fuel in the exhaust, there's no black smoke, or the plugs look normal, then it may be the ECM was able to trim back to normal. That's not to say there still isn't a malfunction someplace...

Any rate, that could be resulting from the Bosch-III injectors, which may require a re-tune for the voltage offsets.

The fuel pulse dampener is definitely on the list of possibilities here.

Have you also tried the "poor man's stethoscope"? If I'm trying to isolate a noise, I'll put an ear plug in one ear, then use a piece of heater hose or something in the other ear to probe around the engine. Usually can pinpoint it like that.

 

I use a mechanics stethescope and it is definitley in the FPR and the fuel return fitting at the rail. The ticking was the whole reason for lifters and head job. I just re-checked vacuum and it is 20HG stable in the green.

 

I think I found the smell, it's something I have already planned on. The 700r4 tailhousing bushing & seal, VSS oring and slip yoke. It appears Dexron is leaking past the rear seal and dripping onto the Y pipe right before the main cat. It smells bad and has a tiny amount of smoke after driving but not idling.

 

Do a leak down test just to get that out of the way. Then you can eliminate the valves and machine shop work.

 

Even better. In which case I'd be willing to bet money it's your fuel pulsation dampener.

Next time I run my Camaro, I'll see if I can detect a similar click coming from mine. I have Bosch-III injectors and don't run a fuel pulsation dampener. My 1.6 roller rockers produce a little clacking, which probably masks any noise coming from the FPR.

 

Agreed. For completeness in the investigation.... especially for the 108 BLM issue.

 

Unfortunately the garage is not user friendly to jack stands and the weather has been so bad that this 5 day dry stretch forces me to choose the tranny first. Hard to test drive it with the tranny fluid on the pipes. I did do both the dipstick tubes and the shifter shaft seals during the head gasket job.