85 TR dead bank 1-6 ( maybe) and tapping noise

As soon as I fix one issue another one comes up almost right away. This one is kicking my a**. I have a ticking noise emanating from the 1-6 bank area after the car warms up. It sounds like valve train noise or maybe an exhaust/intake leak. It will sometimes come ago but remains 95 percent of the time and usually starts a few minutes after I fire the car up. I have a US 85 TR. The car has 79,xxx miles on it. Here what I have looked into so far.

1. Exhaust leak- I checked for leaks near the exhaust manifold and all 4 CATS by spraying soapy water at the manifold gaskets and donut joints that connect the Cats and muffler. I then shoved a shop vac hose in one of the exhaust pipes (cover the other 3 holes) and then push air in the exhaust( Note- I have aftermarket CATS). The exhaust manifold gaskets are tight no leaks in that area at all but all of the other connections at the donut exhaust gaskets bubbled up right away. I tightened them all but can’t seem to seal them completely.

This is an issue that I will eventually have to address but for now I just want to fix/identify the tapping noise and possible dead bank issue. Being so far away from the exhaust manifold gaskets could this cause the tapping noise?

2. 1-6 dead bank issue maybe (spark check)? - I have spark in that bank. I can see the light sparking on and off through the ignition cap inspection hole. The inspection hole provides a direct sight to the main ignition coil inside the cap. It blinks on and off (one would think it would just stay lit) I will make a video of it so everyone can see. When I unplug 1 or 2 coils from any of the cylinders in 1-6 there is no noticeable difference in the engine rpm. When I unplug even one of the wires in 7-12 the engine responds and stumbles slightly (misfires). There is spark going to the cylinders in 1-6 because I “felt” it when I pulled 2 of them out. I have all brand new ignition caps, wires, plugs, and rotors. The ignition coils and modules are potentially original. I swapped the ignition cap and wires on 1-6 with known good ones and the noise/issue persisted. The AC compressor has been removed from the car and the alternator is mounted tightly.

3. Fuel issue/check: with the car running if I pull the RH fuel pump relay (which powers bank 7-12) the idle drops a little bit but the car remains on. When I pull the LH fuel pump relay t(which powers 1-6) the car immediately shuts off. This is confusing and indicates that the fuel is flowing for 1-6 (suspected bad bank). Your thoughts..?

4. Fuse board check: I have a rebuilt or aftermarket market fuse board. I pulled the 4 white connectors on it and there are no burn marks it is perfect. The car always turns on alright it sometimes takes a few seconds to fire up.

5. Valve issue? I recently completed a major on this car and the noise issue started about a week after the engine went back into the car. The Car sounded and drove well during that week. I did not adjust the valves (should have but didn’t) while the engine was out.

6. Next steps: I will check the fuel pressure at each fuel distributor. Potentially replace both ignition coils and modules… maybe replace both fuel pumps since they also look original.

I have been readings many threads on here to see if I can find the answer but the issue persists. Any guidance would be greatly appreciated.

 

I meant spark plug wires not coils sorry. I have not checked to see if the vacuum is equal on both sides. I will have to look into seeing how can do that. I have smoked both intakes looking for leaks. I also recall making small adjustments to the large hex nut with springs on each throttle body to smooth out the idle. Would that possibly cause it to make that tapping noise?

 

I pulled the air filter out with the housing. It appears that one of the fuel distributor butterfly valves is a lot lower than the other one. The picture is with the car running. When I press on the 1-6 bank butterfly the engine speed increases. But… when I press down on the other butterfly valve 7-12 absolutely nothing happens even if I press down a few inches. This is the same bank that does not respond when I pull the fuel pump relay off the relay board it continues to run with only a slight hesitation. When I pull the 1-6 relay it dies right away maybe a fuel issue? Image Unavailable, Please Login



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It started a week after I put the engine back in and swapped exhaust systems. The previous exhaust system on the car was a Borla exhaust with mufflers and no CATS. I now have aftermarket’s CATS all four and the original muffler back on. I couldn’t stand the smell of the Borla free exhaust.

Fuel: The relay for 7-12 was loose (I disconnected it for testing) once I plugged it back in the airflow sensors on both banks had resistance when I slightly pushed them down. I also disconnected the the fuel filters on each side and confirmed that I am indeed getting fuel to both banks (at least to the fuel filter). There was very heavy corrosion on the 1-6 fuel pump on the positive terminal I cleaned it up (still same issue) I am surprised that the pump was still working with that bad connection.

Compression: I will do a compression check tomorrow on all cylinders. I will also do another vacuum leak test with my smoker. I will also see if the plugs are wet or dry.

Ignition: I will check the spark frequency of all 12 cylinders tomorrow with my timing gun.

Guys thanks for all the help I will report back this weekend and upload a video of the sound it is making.


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Carlos 007, I do have a CO2 analyzer that I used while working on my 1979 Volkswagen Beetle some years ago. I will dust that off and see what it tells me after I confirm/verify some of the issues rifle driver mentioned.

Turbojoe, the alternator issue you mentioned is very interesting, especially considering that the alternator light has been coming on intermittently ever since I put the engine back on. I lightly press an the gas pedal and it goes away. I didn’t mention it in this thread because I didn’t think the issue was related with the noise. It was something else I was going to address after I fixed the tapping noise issue. No I wondering if it is related. Did you spray the wd40 directly in the belt?

Veedub, I have been thinking about the valve clearances ever since the noise started……If all else fails this is what I will have to do. It is very possible that the noise may have been there all along but the loud Borla exhaust may have been masking it. This idea never crossed my mind until you just mentioned it now. I regret not doing it with the engine out. I just wanted to get the car on road because it was sitting for months waiting on the major while I was finishing some other projects. I will try everything else everyone has mentioned above and any future suggestions but will prepare for the worst.


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