1987 Chevrolet 350 tbi high idle

[AuroraGirl]

Couldn’t answer question on brand. It was just a whatever was available so I could get the truck home since it was in a different city. I assume standard motor parts or something similar. It was from oreillys and a pain to change. I do not think it has a solenoid but I couldn’t answer that without looking at it and looking for a solenoid. Off memory I believe all there is a vacuum line going to map maybe? Or somewhere similar.

GM is the correct answer - They made 3 types for different uses.

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19250342 is also 214-2294 which is a new vacuum operated PURGE VALVE for evap. if yours looks like that PN, a new one is probably wise

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does this appear like your components? this should cover 87, but Just checking with you.

Also that check valve for the manifold vac is going to be important to be working too. if your engine lowers vacuum and it doesnt check valve, thats gonna **** up your MAP reading because you have a vac reservoir, dash AC and cruise control thats not supposed to be at play here. MAP readings being off will cause you issues easy.

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this is the solenoid. gm makes two, one is for leaded gas so you dont have much to accidently mix up if that is old/needs replacing.

Finally found some great info for GM EGR identification in the book for my vacuum gun kit!

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SO WHERE WE ARE AT NOW: you should check out that solenoid for sure, but you dont know if you have the right one and sorry but those cheapie dollar store ones especially since you didnt walk in there with a part number for what exactly that truck has, you probably have something incorrect or just not working. Do you have your original? We can ID that if has numbers or by the seat.

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so asking for a friend but your comment "all there is a vacuum line going to the MAP maybe"

You have nothing else conencted to TBI vacuum ports?

and simple diagnostic on your problem at hand, vacuum port all 3 spots that vacuum isput. The TBI, the EGR, leave it connected to that solenoid, and cap the solenoid feed from the TBI. Vacuum caps are cheap. and unplug the solenoid when you do this. That will make the computer NOT ever adjust AFR around assuming its part of the system since it wont have anything to command, it wont try and do so.

 

[iamtherealJayy]

I’m sssuming a stock 350 has flat tappet cams. I don’t think there’s a problem with the rings, I think it’s valve seals. It only puffs out a cloud on startup and a little haze with first rev(blowing rest of it out?) I do have a slow leak on the front of the engine somewhere if you recall. I might have my original egr valve and a part number of new one. No I have all the vacuum lines connected everywhere. I do not remember a ball canister being part of the system anywhere. Is that ac trucks only? Mines non ac and I don’t have cruise either. There may be a solenoid tho, the egr I believe has a short line coming from it. There’s a bunch of lines I was just referring the egr valve.
Edit, Seafoam throttle body cleaner, I did run a can of that straight through the throttle body before I got the high idle fixed, that stuff isn’t flammable enough to find vacuum leaks if you recall me mentioning that.

 

[AuroraGirl]

I’m sssuming a stock 350 has flat tappet cams. I don’t think there’s a problem with the rings, I think it’s valve seals. It only puffs out a cloud on startup and a little haze with first rev(blowing rest of it out?) I do have a slow leak on the front of the engine somewhere if you recall. I might have my original egr valve and a part number of new one. No I have all the vacuum lines connected everywhere. I do not remember a ball canister being part of the system anywhere. Is that ac trucks only? Mines non ac and I don’t have cruise either. There may be a solenoid tho, the egr I believe has a short line coming from it. There’s a bunch of lines I was just referring the egr valve.
Edit, Seafoam throttle body cleaner, I did run a can of that straight through the throttle body before I got the high idle fixed, that stuff isn’t flammable enough to find vacuum leaks if you recall me mentioning that.

without AC, that Manifold vacuum is presumably not present and you just have a plug on the intake?

your engine is 1987 it has likely roller to my understandning but the phase in was... not entirely 100%. Is your engine an LO3 or LO8(I think these are the engine numbers)

Edit, Seafoam throttle body cleaner, I did run a can of that straight through the throttle body before I got the high idle fixed, that stuff isn’t flammable enough to find vacuum leaks if you recall me mentioning that.

not what im talking about. its a top end cleaner, you have to have a warm engine, its added to it in a manner, its allowed to stall, soak, and then you startup and do more. usually. its not a 2 minute process.

Find the original if you can on the EGR. Take a pic of your engine from a slightly raised but centered in the engine bay so that we can see the engine almost top down with vacuum lines and stuff all visible, take air cleaner off.

I don’t think there’s a problem with the rings, I think it’s valve seals.

this changes nothing, I dont think your issue is primarily rings its at least something getting in right away which implies leakdown or something.

But. Not 100%, variables exist.

Also, did you do a compression test on each cylinder and find you have a cylinder that doesnt have a close score(or more) and were these readings in spec, and was a leakdown test indicative of a much higher compression(not good)

 

[iamtherealJayy]

I’m not sure on the plug on manifold, I can get a photo tho. Hey now that seafoam took more than two minutes lol it was a similar process of pouring some in letting truck smoke pouring until almost empty then stalling engine and letting it heat soak. Negative I have not done a compression test but I assume the valve seals are worn and after sitting for a couple days the oil in the heads leaks past the seals and down the valves into the cylinder and burns off at startup. The block for my truck is from a carbureted engine if that matters, dad blew the original and took the block from a dirt track race engine build(that was never ran to our knowledge) I’m not sure if he swapped the cam or anything or if he used just the block by swapping cam I mean the one in the block when he bought the engine or swapped in the tbi cam. To my understanding all he used was the block pistons etc and oil pan. Swapped over the heads and intake up.

 

[iamtherealJayy]

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Can cornfirm the egr solenoid. Tried to include everything I could in 5 pics.

 

[AuroraGirl]

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Can cornfirm the egr solenoid. Tried to include everything I could in 5 pics.

I mean.. I am assuming there is a difference related to the internals...
what you said in my opinion means we dont know jack **** about how this engine is supposed to run if its hobbled together.. what happened to other block... and youre missing spark plug wire heat shields btw

why do you have a PCV valve and a pipe directly plumbed into your TBI

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this pic is for the throttle, is your linkage retained like the one shown? your pic has a thing in way just ,making sure

 

[AuroraGirl]

Why is there a breather in your valve cover where the oil cap is supposed to be..

 

[iamtherealJayy]

The pcv is ran the same way as your photo of throttle linkage, it goes into the spacer between air filter and throttle body, can you elaborate on the throttle linkage retained? Do you think I’m missing a part or something. The breather has always been there since I’ve had it, so I don’t know why it’s that instead of a cap. I do know the truck let’s out a faint smoke if you remove the breather after shutting off the engine but while running there is no obvious blow by

 

[AuroraGirl]

can you confirm there are any grounds going to the passenger cylinder head, the one by your thermostat housing?

also i have been over this with you. thats your ECM ground and its rusted to ****.

Id also ask why you have springs installed holding your throttle closed when the springs on the shaft between the TBI and the plate are for that

 

[AuroraGirl]

The pcv is ran the same way as your photo of throttle linkage, it goes into the spacer between air filter and throttle body, can you elaborate on the throttle linkage retained? Do you think I’m missing a part or something. The breather has always been there since I’ve had it, so I don’t know why it’s that instead of a cap. I do know the truck let’s out a faint smoke if you remove the breather after shutting off the engine but while running there is no obvious blow by

You need to properly seal your engines crankcase. its a vacuum leak since its not controlling with PCV its just open to atmosphere and that means your PCV isnt working right either

You also have a spring on your throttle plate thing. Look at the pic I sent, it looks like you HAVE a throttle spring on the side you cant see much between the TBI

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your valve covers should have an opening for pcv(yours is right), the breather tube(back side, yours is there)and an oil fill cap, the place you have a vent.

How is it retained? You can pickup a gm standard cap at a store but im confused whats holding it

 

[AuroraGirl]

Whats the bullet connector on the coil doing? How much RTV/threadlocker is on that ECT? It looks like its RTV. did you not use a new sensor with preinstalled red stuff on it? Or is that just the stuff on it? How much threads are in the intake (I cant tell)

 

[iamtherealJayy]

There is a ground beside the thermostat housing on the alternator bracket area. I will clean it. I haven’t added any spring, could extra springs be the reason for the throttle being hard to press? I don’t have anything to compare to so I just figured it was a little harder to press, to make sense of it, the throttle doesn’t gradually increase you press it gently and when it gives you shoot up in rpm, that’s part of the reason the 650 idle bothered me it’s hard to just go to 1000 to take off you kinda have to rev up and let off to get to where you want to be. By bullet connector I assume you mean my female spade connector for the tachometer? And the engine coolant temp sensor has the preinstalled red locker on it. I couldn’t tell you how far in the intake it is without removing it but it’s tight. It never leaked. The throttle cable is connected to the linkage how it was when I took it apart I try to avoid changing things. So I need to find a flat cap for my drivers side valve cover instead of a breather? Comparing to your photos I assume your truck is an auto having all the other cables going to the throttle linkage, mine had a spring when I took it apart so I kept a spring on it. Without the spring what actually returns throttle to closed?

 

[iamtherealJayy]

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Original egr valve top and bottom and box of new one.

 

[AuroraGirl]

https://www.walmart.com/ip/ACDelco-GM-Original-Equipment-EGR-Valve-Kit-214-5073/826116616
i would advise getting this at your available convenience since it will be much more reliable and for sure not screw you over as much as a part store box one


I found 1 website that says it interchanges, but I cant find one that says it interchanges with the OEM number. did your new one come with washers?

 

[AuroraGirl]

was

There is a ground beside the thermostat housing on the alternator bracket area. I will clean it. I haven’t added any spring, could extra springs be the reason for the throttle being hard to press? I don’t have anything to compare to so I just figured it was a little harder to press, to make sense of it, the throttle doesn’t gradually increase you press it gently and when it gives you shoot up in rpm, that’s part of the reason the 650 idle bothered me it’s hard to just go to 1000 to take off you kinda have to rev up and let off to get to where you want to be. By bullet connector I assume you mean my female spade connector for the tachometer? And the engine coolant temp sensor has the preinstalled red locker on it. I couldn’t tell you how far in the intake it is without removing it but it’s tight. It never leaked. The throttle cable is connected to the linkage how it was when I took it apart I try to avoid changing things. So I need to find a flat cap for my drivers side valve cover instead of a breather? Comparing to your photos I assume your truck is an auto having all the other cables going to the throttle linkage, mine had a spring when I took it apart so I kept a spring on it. Without the spring what actually returns throttle to closed?

I dont have one but from what I can see in YOUR picture is that you have a spring on the shaft next to the TBI like most Modern TBs have compared to having a spring yank a pivot they do it around the shaft coiled up. take off your spring , extra one. and then just use your hand, if your throttle shuts, its fine prob

just confirm not many threads are above the intake

You need to put an oil fill cap on yes, can you show the hole without that?

Also since tachometer is an AC signal and youre having strange issues, Id recommend getting that wrapped and maybe shielded. dont touch spark plug wires at all, have them touch nothing as well.I also not sure if your year uses a filter for the tach or not but if you have a eratic reading it could be that(not big issue)

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ignore arrow for this purpose, but you see the spring i mentioned

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