Problems again...any ideas?
Thread Starter
Instructor
Joined: Sep 2018
Posts: 212
Likes: 37
From: Southeast Virginia
Problems again...any ideas?
1986 Coupe with 87 engine...everything ran great before parking the car for a few days. I decided to knock out a few projects on it.
Replaced shocks all 4 corners (I'm pretty sure this didnt cause my problems)...I did the throttle body bypass and swapped out my damaged front bumper. Went to drive it, it drove fine for about 5 min, then as it warmed it started to idle odd. Went up and then back to normal several times. I then turned around to take it back home and after I stopped and then hit the gas it felt like it wanted to die. It picked back up. I got it home and then it died right in the driveway. I tried to start it and it wouldn't start unless I gave it a lot of throttle which of course it shouldn't have to do that. No codes...i checked.
Any ideas or where to start checking? Do you think there's anything I did when doing the bypass or bumper swap?? Could I have hurt something that would cause this? Could the bypass make this happen?
IAC Sensor malfunction??
AND when I got it started again i had to give it a lot of throttle to keep it from dieing while hitting the brake to keep from going too fast.
Any help is appreciated.
Replaced shocks all 4 corners (I'm pretty sure this didnt cause my problems)...I did the throttle body bypass and swapped out my damaged front bumper. Went to drive it, it drove fine for about 5 min, then as it warmed it started to idle odd. Went up and then back to normal several times. I then turned around to take it back home and after I stopped and then hit the gas it felt like it wanted to die. It picked back up. I got it home and then it died right in the driveway. I tried to start it and it wouldn't start unless I gave it a lot of throttle which of course it shouldn't have to do that. No codes...i checked.
Any ideas or where to start checking? Do you think there's anything I did when doing the bypass or bumper swap?? Could I have hurt something that would cause this? Could the bypass make this happen?
IAC Sensor malfunction??
AND when I got it started again i had to give it a lot of throttle to keep it from dieing while hitting the brake to keep from going too fast.
Any help is appreciated.
Last edited by c B; Jul 22, 2020 at 08:07 PM.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
Problem
Did you take the hoses off of the evap canister?
it will do as described if the canister hoses are not correct.
look on the radiator cover for vacuum hose routing on the left side
it will do as described if the canister hoses are not correct.
look on the radiator cover for vacuum hose routing on the left side
Thread Starter
Instructor
Joined: Sep 2018
Posts: 212
Likes: 37
From: Southeast Virginia
No, I was able to leave the evap cannister connected to hoses but I will go back over it and the diagram to make sure everything is connected and routed properly.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
You really need a data logger for these computer controlled cars. But it reads like the work on the throttle bypass had something to do with this. Can you restore it from what changes you made?
Burning Brakes
Joined: Oct 2010
Posts: 1,037
Likes: 28
From: Montclair New Jersey
I am just guessing but; since you were messing around with the throttle body. I would start by testing the electrical connection to the IAC. If the connection is good. I would remove the IAC and clean it or buy another one. There are plenty of videos and posts explaining the removal and cleaning of the IAC. Your symptoms sound like the IAC is stuck, dirty, or not working. I don't think they are expensive new. Like I said I'm just guessing by what you are saying.
Thread Starter
Instructor
Joined: Sep 2018
Posts: 212
Likes: 37
From: Southeast Virginia
I have considered putting things back together as they were.
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Thread Starter
Instructor
Joined: Sep 2018
Posts: 212
Likes: 37
From: Southeast Virginia
I am just guessing but; since you were messing around with the throttle body. I would start by testing the electrical connection to the IAC. If the connection is good. I would remove the IAC and clean it or buy another one. There are plenty of videos and posts explaining the removal and cleaning of the IAC. Your symptoms sound like the IAC is stuck, dirty, or not working. I don't think they are expensive new. Like I said I'm just guessing by what you are saying.
Le Mans Master
Joined: May 2004
Posts: 5,866
Likes: 60
From: Hellinois
Finalist 2020 C4 of the Year - Modified
Before you start throwing parts at it. do some checking of the wiring associated with the IAC. If the IAC was okay before you did the mods then it should be okay now. I'm willing to bet you have a wire loose or even broken or a vacuum line disconnected. All this is free
Thread Starter
Instructor
Joined: Sep 2018
Posts: 212
Likes: 37
From: Southeast Virginia
Before you start throwing parts at it. do some checking of the wiring associated with the IAC. If the IAC was okay before you did the mods then it should be okay now. I'm willing to bet you have a wire loose or even broken or a vacuum line disconnected. All this is free
Thread Starter
Instructor
Joined: Sep 2018
Posts: 212
Likes: 37
From: Southeast Virginia
I put the stock setup back on for the throttle body coolant lines and everything is back to normal. Any thoughts? Why would this make a difference? Im fine with keeping the stock setup. There's no major benefit from it so...
It idles right between 600 and 700 ram but when sitting at a light it just doesn't feel right. Feels like it is just about on the edge of stumbling and or stalling.
It idles right between 600 and 700 ram but when sitting at a light it just doesn't feel right. Feels like it is just about on the edge of stumbling and or stalling.
Last edited by c B; Jul 23, 2020 at 02:15 PM.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
Stumbling
Recheck your vacuum lines.
Pull all your spark plugs and smell them for gas from a leaking injector.
i could not make my cruise control work for a year, playing with everything involved.
Finally i thought i would just change all the vacuum lines. Thats when i found it.
apparently the Vacuum check valve had fallen on the exhaust when someone before me was working on it, and they just put it back on.
the bottom of it had melted away, causing a huge vacuum leak.
everything started to work normal when i replaced it.
don’t give up, what may look or sound stupid is troubleshooting procedures, and That’s how u will find it.
things happen.
good luck
Pull all your spark plugs and smell them for gas from a leaking injector.
i could not make my cruise control work for a year, playing with everything involved.
Finally i thought i would just change all the vacuum lines. Thats when i found it.
apparently the Vacuum check valve had fallen on the exhaust when someone before me was working on it, and they just put it back on.
the bottom of it had melted away, causing a huge vacuum leak.
everything started to work normal when i replaced it.
don’t give up, what may look or sound stupid is troubleshooting procedures, and That’s how u will find it.
things happen.
good luck