1987 Chevrolet 350 tbi high idle

[iamtherealJayy]

I can work on doing that. Do I just unplug it and start engine and twist it CC until it runs better? Like twist a little check rpm twist a little check rpm until it stops going down? Then I assume shut down engine and plug wire back in? I’m sorry for being a pain but I like really need things put in a step by step tutorial to make sure I 100% understand. I read the idle speed check test atleast 6 times the other day and still had to have it on my phone the entire time as I read it again step by step.

 

[gmbellew]

I am pretty sure the timing set procedure is in the driveability manual. it goes step by step. you will need to borrow or buy a timing light and hope that nobody has moved the reference plate with the timing marks when the truck was wrecked.

 

[iamtherealJayy]

I’ve got two timing lights, just never knew how to use them but I watched the guy that told me it was at 8° btdc. The harmonic balancer has the timing marks on it, he wrote on the 0° mark with a blue paint pen so it was more visible. Also just looked for that tan/black wire and I don’t see it? Is it plugged into the harness? There’s a black block just to the left of the air cleaner that has a maybe 8-10 wire plug coming off of it and down the wire loom a little bit is a reddish wire coming out with a plug on it. Am I missing something? Should somethiny be plugged into that? Will be sending pictures momentarily.

 

[iamtherealJayy]

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[iamtherealJayy]

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Here are photos from the latest photoshoot.

 

[gmbellew]

the timing wire should be a single wire that comes out of the harness behind the brake master cylinder somewhere. it has a little weather pak type connection

 

[gmbellew]

the engine needs to be warmed up to check timing.

run engine to warm. unplug EST and check timing. if it is off, loosen distributor hold down bolt and adjust to 0 BTDC. tighten bolt. make sure timing still at 0. turn off truck. reconnect EST. start truck.

 

[Bextreme04]

Yep, those are the two things everyone has told you to check(Idle set procedure and timing set procedure).... you CAN NOT set timing on a TBI engine without disconnecting the EST wire. It MUST be set to 0 BTDC with a few degrees in either direction variation. The TBI ECU will adjust the spark timing from that point. If the distributor is set too far outside that range because someone was trying to set timing like you would on an old carbureted engine... you probably found your high idle and overheating problem.

 

[iamtherealJayy]

So I need to advance the timing by 8°? While warm the truck was at 8° btdc, so I need to bring it to temp and adjust to 0? Correct? Should I unplug it while engine is running or while engine is off? I will go get the timing light and get to work.

 

[gmbellew]

the timing needs to be at 0 with the EST unplugged. you can unplug the wire with the truck running or off. but it may be hard to start with it unplugged. DO NOT plug it in with the truck running.

 

[iamtherealJayy]

Okay this may sound dumb, but is 8° btdc retarded by 8° or advanced? I’ve never done anything with timing other than set initial timing to get a carbureted truck running(the k10 bonanza) and you’d twist it counter clockwise to advance? And clockwise to retard?

 

[gmbellew]

btdc is advanced

 

[iamtherealJayy]

So I need to rotate it clockwise to 0°.

 

[gmbellew]

make a small change and see which way it needs to go. for some reason I think clockwise is advanced....but I can't remember

 

[iamtherealJayy]

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I couldn’t either that’s why I asked, I try and picture it in my head and I would think counter clockwise would advance because it is getting to contact sooner? Also, I just found a “super pro dual decoder” in my toolbox. I assume it’s just the same as the paper clip tho, it’s got 4 pins