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Just trying my best to figure this out without total failure

Poppy the '82 924 Resurrection in Progress

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Trying this again since originally it posted blank

Hey guys, we are almost to the point where Poppy can go on her maiden voyage on actual roads!!!! However, I have a sneaking suspicion this car was tuned while she was full of vac leaks, had a non functional O2 sensor, and other chaos. The car ran well previously but it seems every time we fix a vac leak she gets pissy. We recently replaced the vac line that goes to the crankcase breather (honestly surprised the car ran as well as it did with as many leaks that line had) and now she is really mad under load. She idles pretty well I would say, but under load she is breaking up really bad. The rpm gauge isnt boucning like a misfire under load but the gas gauge does.
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Just trying my best to figure this out without total failure

Poppy the '82 924 Resurrection in Progress

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I'm guessing this means there is a fueling problem? I am not totally sure what to do now because I am just barely figuring out how it even runs fuel in the first place. Has anyone had a similar issue or know what could be going on?

Here's a video: https://drive.google.com/file/d/1WJH8uo9hk0o7Ah9Bx5-D8-JNsnSQzjHd/view?usp=sharing
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Just trying my best to figure this out without total failure

Poppy the '82 924 Resurrection in Progress

[924RACR]

Can't see a video, check the link? I just see the same set of relay pics.

As for tuning... it's always back to first principles, check fuel pressures, settings, etc... but the misfire is curious, and if the fuel gauge is jumping around, that absolutely sounds like you have a general ground or other wiring problem (did you already clean the grounds under the dash?) that very easily can impact the motor running.

I wouldn't worry about the O2 sensor much, that's out of the loop for anything other than idle or light throttle conditions. Certainly not used for large throttle applications.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

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[924RACR]

Yes, there's a cluster of grounds to be cleaned off behind the fusebox - more or less on the underside of the windshield tray, inside the cabin. I find TarnX metal polish works really well on the brass terminals...

Can't really tell anything of note/weird from the video, TBH... sorry.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

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[924RACR]

OK yeah I can hear that much clearer now.

I'd definitely be chasing ignition side for that. And no, definitely not right.

I'm surprised to see the idle that high; have you tried working it down lower, or does it die? If you can't get it lower with adjusting the idle screw, that would scream more vacuum leaks.

I'd be inclined to see if it's one specific cylinder that's misfiring; best way to do this is to sequentially disconnect one plug wire at a time, with the motor running, and evaluate the rpm drop. When you get to one that doesn't change the rpm, you know that cylinder isn't doing much!

Another way if you were running a header is to use an IR temp gun on each cylinder and look for the cold one... not as useful with the stock original exhaust manifold though.

Then move plug wires and plugs, see if the problem moves with those... to rule them out as a problem.

You could also, if one cylinder and doesn't move with plug wires or plugs, look at the fuel injectors, maybe one is clogged? Have you already replaced them?

Still want to clean those grounds.

Worth also inspecting the rotor and cap for contamination - I've had that, deposits on the terminals inside the cap. Or maybe wiring to coil, coil itself...
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

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Update: the spark plug wires were CRUSTYYYY on the metal boots that go around the spark plugs. Did not realize they were that bad when we changed the plugs. That probably was not helping anything. The ground strap from the chassis to the bellhousing is also holding on by a thread. I discovered this a while ago and completely forgot about it because the oem strap I ordered from Pelican looked way different so I didn't think it would work. Turns out it will, but the bolts holding the current strap in are on there with like ugga dugga strength. I tried big bertha with no success, so I soaked it down with some deep creek and will try again.

I am hoping when we start her up she is much happier under load, otherwise I think the next step is trying to figure out the k-jet I have ordered the Probst bible off amazon and as long as amazon doesn't eat this package (like they did with my terminal covers) that will arrive on thursday.

I looked in the rats nest for the ground above the fuse box, but I cant see where it is with the rats nest as they are pretty well formed into place from being a rats nest over the years. Any chance someone has a picture? I believe I cleaned all my grounds besides that guy, behind both headlights, behind glovebox, in the trunk between the taillights, and the actual battery ground connection. Am I missing any?
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Just trying my best to figure this out without total failure

Poppy the '82 924 Resurrection in Progress

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MASSIVE UPDATE: WE WENT FOR A MAIDEN VOYAGE TONIGHT!!!!!!!!!!!

Got the new ground strap installed and fixed a blue/yellow wire at the back of the block.

She is still pissed under load and seems to fall flat on her face. It also seems the warmer she gets the worse it gets. The gas gauge is also still bouncing all over the place. However, the fans do kick on and the temp gauge works. Here is a folder from todays adventures: https://drive.google.com/drive/folders/1mysRYF2pDRUvO0YGsUJrV0ezKMnYENLs?usp=sharing
_________________
Just trying my best to figure this out without total failure

Poppy the '82 924 Resurrection in Progress