1987 Chevrolet 350 tbi high idle

[AuroraGirl]

I’m not 100% sure on the startup fuel spray subject. But I just drove the truck home after it sat for about two and a half hour and it ran like junk at idle it was shaking and stalled first time but started right back up but sounded almost canned the way idle was dropping to around 400 and back up. I rolled to a stop sign and the truck dropped to under 100 rpm( tach bottomed out) and service engine soon light came on but then it jumped back up to 650 - 700 and light went out. Could this be the iac? If it’s cold it idles like hell but other than that runs great now. I’m having to get used to shifting again since it doesn’t shoot upto 2kwhen I press clutch

I would do the timing and IAC steps before replacing the IAC. it sounds like the computer is getting confused about the air thats coming in and jumping around trying to correct (which is what happens when its not properly set)

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

 

[iamtherealJayy]

@AuroraGirl mechanical timing is at 0, I can go through iac steps tomorrow. I’ve got a new Delphi iac I can put in I just don’t want the computer freaking out because I’ve changed so much at once

 

[AuroraGirl]

@AuroraGirl mechanical timing is at 0, I can go through iac steps tomorrow. I’ve got a new Delphi iac I can put in I just don’t want the computer freaking out because I’ve changed so much at once

is your timing the proper way for your TBI tho.. mechanical at 0 doesnt tell me that you used the connector and did the procedure so the computer is also on the same page. also can you get a mirror or something and find the pn on your distributor

 

[iamtherealJayy]

@AuroraGirl brought the truck up to temp shut the truck off unplugged the single brown/black wire plug under master cylinder, started truck and adjusted timing to 0° shut off truck and plugged back in. Yes tomorrow I can try and get a part number off my distributor

 

[AuroraGirl]

@AuroraGirl brought the truck up to temp shut the truck off unplugged the single brown/black wire plug under master cylinder, started truck and adjusted timing to 0° shut off truck and plugged back in. Yes tomorrow I can try and get a part number off my distributor

then your timing should be proper assuming your crank balancer didnt shift. you can do a procedure to verify it didnt but i would trust it for the time being.i would replace an iac and check the minimum air speed and stuff before i assume the timing mark is not proper.

 

[iamtherealJayy]

I have a new Delphi brand iac I plan on installing. But like I think it was rusty said, it may take up to 50 starts or so for everything to start learning I’m going to replace iac regardless since I’ve got one I just didn’t want to change too much at once

 

[AuroraGirl]

I have a new Delphi brand iac I plan on installing. But like I think it was rusty said, it may take up to 50 starts or so for everything to start learning I’m going to replace iac regardless since I’ve got one I just didn’t want to change too much at once

You did disconnect your battery after you changed the water pump and stuffs, right? That would take care of any learned corrections from the temperature problem times. revert to neutral. if you havent, I would just do it when you do the IAC stuff, disconnect battery to replace it. Then once running, do the procedure to set the minimum idle with the screw and the A and B ports jumped on the ALDL while its running( make sure its running, not when key on or key off. that would be for getting codes.) you can always refer to the earlier part of this thread for the procedure. I do believe the manual trans idle is 500 +/- 50, maybe 100. Its somewhere near there.

 

[Rusty Nail]

Yeah they gots a proper relearn procedure .. Up to 40 key starts pretty sure about that, mmhmm.

I was thinking Jayy, is this the right time to mention the fact that the General sells them trucks with SPRINGS in the lower radiator hose? I think it is.

 

[iamtherealJayy]

I figure a spring would help some but I’m blaming it more on the oil leak because where the hose had oil on it was super soft and crunchy at the same time

 

[Bextreme04]

I figure a spring would help some but I’m blaming it more on the oil leak because where the hose had oil on it was super soft and crunchy at the same time

Was it actually collapsing? You should have been able to see it collapsing if the lower hose was the problem. It should also have a spring in it to keep it from collapsing.

If you were getting a flashing check engine light when it was running bad, I'd check the codes before you reset anything. You have the ALDL reader now, so you should be able to look at codes and also see what the IAC is being commanded to. If the IAC is bad, it will be reading all out of whack.

 

[iamtherealJayy]

The lower hose didn’t have a spring, yes I’ve got an aldl cable now but I have 0 idea how to use it. I’ve downloaded several programs. I’ve been trying to use tuner pro rt and I can’t get it to connect

 

[iamtherealJayy]

Can confirm teuck ran like absolute garbage this morning. I had to start it three times and feather the gas on the third time to keep it running, it was idled too low. It “stalled” twice but didn’t completely turn off it just dropped to basically 0 rpm and the SES light came on (like any time you go to start it)and then it came back to life. Once it was warm it still took a bit to start and one time I didn’t think it was going to start, you could hear it firing a couple cylinders but it did that for a second before it finally started after cranking for probably 7/8 seconds. Dads saying the timing is too low. When I first got it started this morning it sounded good but not throttle body injection good… it sounded cammed… it eventually smoothed out, am I missing something? The first start in the morning taking a few seconds doesn’t bother me as much as sitting at a intersection and you have to keep your foot ready on the gas for when it just dips below 500 rpm and wonder if it’s gonna stall out. And what sucks more is wondering if it’s going to start back. Should I disconnect the battery for a little while and reconnect it? Check the idle speed by unplugging iac? It idles at around 600-700 most of the time and occasionally 1200 on cold start but sometimes it doesn’t jump up on cold start, that’s the days you have to start it again and push the gas a little bit.

 

[gmbellew]

just replace the darn IAC and do a quick relearn.

 

[Bextreme04]

Can confirm teuck ran like absolute garbage this morning. I had to start it three times and feather the gas on the third time to keep it running, it was idled too low. It “stalled” twice but didn’t completely turn off it just dropped to basically 0 rpm and the SES light came on (like any time you go to start it)and then it came back to life. Once it was warm it still took a bit to start and one time I didn’t think it was going to start, you could hear it firing a couple cylinders but it did that for a second before it finally started after cranking for probably 7/8 seconds. Dads saying the timing is too low. When I first got it started this morning it sounded good but not throttle body injection good… it sounded cammed… it eventually smoothed out, am I missing something? The first start in the morning taking a few seconds doesn’t bother me as much as sitting at a intersection and you have to keep your foot ready on the gas for when it just dips below 500 rpm and wonder if it’s gonna stall out. And what sucks more is wondering if it’s going to start back. Should I disconnect the battery for a little while and reconnect it? Check the idle speed by unplugging iac? It idles at around 600-700 most of the time and occasionally 1200 on cold start but sometimes it doesn’t jump up on cold start, that’s the days you have to start it again and push the gas a little bit.

I'm not sure why we are still going through this... when everyone said "now that you got the overheating fixed, check the IAC before you change it", that meant drive it around or do the checkout procedure(in the manuals we pointed you to) and if everything works well then don't worry about it. You are now several days into it not idling properly and not kicking up into high idle on cold start. Since you have an IAC valve on hand... I don't understand why you haven't done the check or just changed the valve yet?!?!

For the IAC check and idle set procedure, get the engine nice and warm and then shut it off, then you need to short Pin A to Pin B in the ALDL connector and turn the ignition on for at least 10 seconds, this will command the IAC Pintle closed. Then unplug the IAC valve and start the truck to check idle RPM. If idle RPM is less than 650, you might have a fuel problem or you need to adjust the idle set screw. If it is more than 650... you probably still have a vacuum leak or you have a bad IAC valve. Judging by the intermittent nature of the idle, I would bet you have a bad or sticky IAC valve. If the IAC pintle can't open when it is cold, you will get a pig rich and poor running truck on cold start

 

[iamtherealJayy]

I haven’t had time recently to do anything. I’m on my lunch break right now. I’m going to eat and go change it I reckon. Now that it’s a little warmer today it’s running way better. So I’m going with iac as well.