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73-87 Chevy _ GMC Trucks => Fuel Systems and Drivability => Topic started by: Jon87V20 on August 18, 2019, 07:37:27 pm
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I have a '87 Suburban V20 with a 350/TH400. I just replaced the engine and swapped the factory intake manifold for a Edelbrock TBI Performer.
During the course of the engine replacement, I rebuild the TBI unit replacing all the gaskets, o-rings, fuel pressure regulator diaphragm, and the screens that go on the injectors.
The first time I did the rebuild, I screwed up and put the injectors back in the pods 90 degrees off what they should have been.
I noticed the o-rings and screens were damaged and replaced them again.
With everything reassembled, the engine is running fine and there's no performance issues regarding the fuel injection. However, I'm hearing a loud ticking from the injectors. I know this is somewhat normal as I used to be able to hear them a bit with the air cleaner off. But this is very loud and I can hear them from inside the cab of the truck. Like I said, it doesn't seem to be causing any issues, but I'd like to know what's going on with it.
Thanks.
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Anyone?
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Sorry man, I got nothin, never had a model like that...
If it's running fine, maybe turn up the music? ;)
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"Loud" is a subjective word. You should hear a pronounced rush of air flowing past the throttle plates at idle to mid-RPM, especially when the engine is cold and, to a lesser extent, the pulsing of fuel from the injectors. But a "loud tick" emanating from the injectors is not how I would describe the sound. Can you link a sound clip?
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Here’s the sound from inside the cab.
I didn’t get a clip of it from outside because the fans were on and it makes it harder to hear. I’ll try to get a clip of it from outside when it’s cold.
This is definitely coming from the TBI.
https://drive.google.com/file/d/1_YzttNhgX6Yx5nTQJyl9gY_RFjsUGJv6/view?usp=drivesdk
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Update: Here's the sound from the engine compartment:
https://drive.google.com/open?id=1aVPwFrFEzwzkxs4BaNH3_1MEwOJ9669s (https://drive.google.com/open?id=1aVPwFrFEzwzkxs4BaNH3_1MEwOJ9669s)
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Clip a timing light to the ignition coil high tension wire, start the engine and watch the injector spray patterns. Do both appear cone shaped, uniform and of similar size/volume? Use a ~3' length of 3/4" heater hose as a listening tube to see whether you can differentiate the source of the ticking between the two injectors. Unplug the injector connectors and use an ohmmeter to measure the solenoid resistances. Are they similar? What is the measured fuel pressure?
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Great video, you sure slammed the doubters like me that something could be so loud!!!
You could just wrap a towel around the whole... never mind.
I'm going to go lay down by my bowl
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bd,
I tried looking at the injectors with the timing light as suggested. It's hard to see but the driver side injector seems to be cone-shaped and consistent with the spray. The passenger side injector almost looks like it's a slightly different shape that's angled a bit toward the outside on the bore.
Also, I'm not sure if this is normal or not, but I saw on both sides, a slight showering of fuel spray getting on the edges of the bores. Just a light sprinkling but I thought that may be unusual.
I haven't tried the other stuff yet, but will try tomorrow.
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Are you sure you fully seated the injectors during the rebuild? Can you post a video clip?
Blot the injector tips dry with a rag. Slip a piece of clean paper under the injectors on top of the throttle plates. Without cranking the engine, cycle the ignition ON for three seconds to build fuel pressure and then back OFF. After about a twenty-second delay repeat the process without cranking the engine. Inspect the papers slipped under the injectors. Is either paper wet with fuel? Do the tips of the injectors feel dry?
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Sorry this took forever to update.
When putting paper under the injectors and performing the procedure as directed, there is no gasoline present on the paper.
Also, here are two videos of the injectors while the engine is running. First video is idling, the second shows a few revs.
https://drive.google.com/file/d/1rfM7paDBvECuB6dD8IuE3nRg_KXhnVz_/view?usp=drivesdk
https://drive.google.com/file/d/10dfle9wpMuEezPBs4AZXoZPWruRKE2Hi/view?usp=sharing
Thanks!