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Engine Foxbody idle/throttle issues

  • Thread starter Thread starter red5.0fox
  • Start date Start date Mar 8, 2023
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red5.0fox

Active Member
Dec 1, 2019
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Hope Mills, North Carolina
Apr 27, 2024
#161
  • Apr 27, 2024
  • #161
General karthief said:
Is the exhaust leak before or after the 02s?
You need to set timing.
Any codes at all?
Take a vacuum reading and monitor as you drive.
Yes, go back over the checklist, you need to be methodical. Do each step one at a time in order.
Click to expand...
Exhaust leak is before O2’s. Only code is for the MAF (unplugged). I’ll take a look into doing both of those. What’s the best way to get vacuum readings while driving?
 

General karthief

wonder how much it would cost to ship you a pair
5 Year Member
Aug 25, 2016
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#162
  • Apr 27, 2024
  • #162
Vacuum tree on the firewall I believe has a port that's not used, if not use the one marked A/C
Oh, and clean up those disgusting, grimey, oily connections
 

AeroCoupe

lube between the nut and the face. I know my lubes
Founding Member
Oct 28, 2001
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Claremore, OK
Apr 27, 2024
#163
  • Apr 27, 2024
  • #163
If you have an exhaust leak between the exhaust header flange and the H-Pipe flange then it will cause inconsistent readings with the O2's. Trying to locate an intake leak with the exhaust leak up that close to the motor is pretty hard so focus on the exhaust leak. You can spray a little carb cleaner around where you think the intake leak is and if the rpm's jump up then you have a leak.

You have to set the timing or you are just throwing another variable at the EEC. It only has 12.5% +/- correction total so everything that gets out of whack starts chewing up that correction ability.

Have you cleaned the MAF sensor?
 
Reactions: General karthief

red5.0fox

Active Member
Dec 1, 2019
190
25
38
Hope Mills, North Carolina
Apr 28, 2024
#164
  • Apr 28, 2024
  • #164
AeroCoupe said:
If you have an exhaust leak between the exhaust header flange and the H-Pipe flange then it will cause inconsistent readings with the O2's. Trying to locate an intake leak with the exhaust leak up that close to the motor is pretty hard so focus on the exhaust leak. You can spray a little carb cleaner around where you think the intake leak is and if the rpm's jump up then you have a leak.

You have to set the timing or you are just throwing another variable at the EEC. It only has 12.5% +/- correction total so everything that gets out of whack starts chewing up that correction ability.

Have you cleaned the MAF sensor?
Click to expand...
I’ve been hearing the intake leak, or possible TB whistle well before I got the exhaust leaks. I’ll get them tightened up though so it’s one less problem. Getting the hardware tight on these wider chamber headers is a huge pain. I got the timing set to somewhere between 10-14°. Sorry that isn’t more accurate, the balancer goes from 10° to 20° lol. It runs much better than it did before I pulled the engine apart. It didn’t idle hardly at all before, but now it does. The falling on its own face under any throttle with the maf plugged in is still there though. I’ve also cleaned the maf sensor many times, aswell as exchanged it with another 24lb BBK sensor. A buddy of mine just gave me an OEM maf so I’m going to throw that in and see what happens. I’ll also get those vacuum readings once I fix the valve cover leaks.
 

AeroCoupe

lube between the nut and the face. I know my lubes
Founding Member
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Apr 29, 2024
#165
  • Apr 29, 2024
  • #165
What brand of balancer do you have?

So the I will go back to my original comment on the BBK MAF's in Post #7. I have heard more issues with them than good things so be aware. If you go back to a stock MAF and MAF sensor then you will need 19 lb/hr injectors.
 
Reactions: General karthief

red5.0fox

Active Member
Dec 1, 2019
190
25
38
Hope Mills, North Carolina
Apr 29, 2024
#166
  • Apr 29, 2024
  • #166
AeroCoupe said:
What brand of balancer do you have?

So the I will go back to my original comment on the BBK MAF's in Post #7. I have heard more issues with them than good things so be aware. If you go back to a stock MAF and MAF sensor then you will need 19 lb/hr injectors.
Click to expand...
It’s an orielleys “performance” balancer. It seems like it’s doing alright, timing marks are steady and very clear. I just swapped in a stock MAF just to see. No change. Maybe I do need a better MAF though. Don’t really wanna spend $300 to find out it doesn’t do anything though
 

red5.0fox

Active Member
Dec 1, 2019
190
25
38
Hope Mills, North Carolina
Apr 29, 2024
#167
  • Apr 29, 2024
  • #167
So, I got some more parts from a buddy. MSD coil, aswell as an oem MAF and MAP. Installed all 3, no noticeable difference.

I did run codes, and according to the reader for the KOEO I have a 31O, 81O, and an 82O. I deleted my EGR, smog, and all TAB solenoids and such in the passenger area. KOER test I have a cylinder 4 misfire, 12R, and 21R. I did this test with all those parts installed. Not sure if I’ve mentioned this before, but the car is super rich.
 

red5.0fox

Active Member
Dec 1, 2019
190
25
38
Hope Mills, North Carolina
Apr 29, 2024
#168
  • Apr 29, 2024
  • #168
red5.0fox said:
So, I got some more parts from a buddy. MSD coil, aswell as an oem MAF and MAP. Installed all 3, no noticeable difference.

I did run codes, and according to the reader for the KOEO I have a 31O, 81O, and an 82O. I deleted my EGR, smog, and all TAB solenoids and such in the passenger area. KOER test I have a cylinder 4 misfire, 12R, and 21R. I did this test with all those parts installed. Not sure if I’ve mentioned this before, but the car is super rich.
Click to expand...
Also, I have replaced the coolant temp sensor, and harness a while ago. Aswell as the coolant reservoir sensor. Car still shows low coolant at all times. Temp seems accurate though.
 

red5.0fox

Active Member
Dec 1, 2019
190
25
38
Hope Mills, North Carolina
Apr 29, 2024
#169
  • Apr 29, 2024
  • #169
I fully intend on going through the whole checklist to narrow things down before spending a boatload on parts, just gotta wait for an empty day. As of now, here are my personal thoughts in no particular order.

1. Computer
2. Oem fuel pump not enough for setup
3. Maf truly is a bad brand
4. Distributor/TFI from orielleys is bad (I’ve had 1-2 go bad before)
5. To much air from 70mm throttle body
6. Intake not seating on heads correctly if the heads were machined prior to ownership (the engine looked to have been a fresh rebuild when I pulled it)

There were some other things that I don’t remember, but those are just my ideas. I don’t think any of those really correlate with my cyl 4 misfire though.
 

limp

wrap a little cheese around it and its a done
5 Year Member
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#170
  • Apr 30, 2024
  • #170
red5.0fox said:
Not sure if I’ve mentioned this before, but the car is super rich.
Click to expand...
Have you by chance installed a cooler thermostat than what is recommended new?
 

red5.0fox

Active Member
Dec 1, 2019
190
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38
Hope Mills, North Carolina
Apr 30, 2024
#171
  • Apr 30, 2024
  • #171
limp said:
Have you by chance installed a cooler thermostat than what is recommended new?
Click to expand...
I believe I did the opposite with a 180
 

limp

wrap a little cheese around it and its a done
5 Year Member
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Florida
Apr 30, 2024
#172
  • Apr 30, 2024
  • #172
red5.0fox said:
I believe I did the opposite with a 180
Click to expand...
I am guessing stock is 205? Your computer will think your car is too cold and will enrichen your mixture until it reaches what is the correct temperature in its program..... Had this happen in a ford V6 minivan years ago.... Friend did this and his mileage went to 10mpg and it never ran right until we put the " hotter correct temp stat back in it......
 

red5.0fox

Active Member
Dec 1, 2019
190
25
38
Hope Mills, North Carolina
Apr 30, 2024
#173
  • Apr 30, 2024
  • #173
limp said:
I am guessing stock is 205? Your computer will think your car is too cold and will enrichen your mixture until it reaches what is the correct temperature in its program..... Had this happen in a ford V6 minivan years ago.... Friend did this and his mileage went to 10mpg and it never ran right until we put the " hotter correct temp stat back in it......
Click to expand...
You are partially right, I didn’t realize that. Stock thermostat opens at 195, and I do believe I went to a 180. However, these problems are present no matter what temp the engine is at. Also, I believe everyone does the swap to a 180 so I can’t imagine it’s causing any issues especially since it isn’t a drastic change. Just helps it run a little cooler.
 

limp

wrap a little cheese around it and its a done
5 Year Member
Oct 4, 2020
5,463
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Florida
Apr 30, 2024
#174
  • Apr 30, 2024
  • #174
red5.0fox said:
You are partially right, I didn’t realize that. Stock thermostat opens at 195, and I do believe I went to a 180. However, these problems are present no matter what temp the engine is at. Also, I believe everyone does the swap to a 180 so I can’t imagine it’s causing any issues especially since it isn’t a drastic change. Just helps it run a little cooler.
Click to expand...
I understand wanting to run a car cooler and maybe with a lesser pressure cap too....
Just telling you what my experience was....
When we reinstalled the correct hotter thermostat the car ran like new with 20+ mpg again....
 

General karthief

wonder how much it would cost to ship you a pair
5 Year Member
Aug 25, 2016
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polk county florida
Apr 30, 2024
#175
  • Apr 30, 2024
  • #175
red5.0fox said:
I believe everyone does the swap to a 180 so I can’t imagine it’s causing any issues especially since it isn’t a drastic change. Just helps it run a little cooler.
Click to expand...
I did it, a few members here have done it too, most are attempts to resolve a 'running hot' condition, real or perceived, I did it because I'm old and wrote must of 'the old mechanics tails'. In the real world of EFI and Computer Controls (although our stuff is mostly dated now) they are 'programmed to do things at certain temps, the 180* thermostat just allows the coolant to flow more sooner, the engine temp is gonna be what it is which most times should be 190* to 205*.
The small temp range on the stock gauge give some owners panic attacks, I always say the stock gauge is just a guess.
 

red5.0fox

Active Member
Dec 1, 2019
190
25
38
Hope Mills, North Carolina
May 1, 2024
#176
  • May 1, 2024
  • #176
General karthief said:
I did it, a few members here have done it too, most are attempts to resolve a 'running hot' condition, real or perceived, I did it because I'm old and wrote must of 'the old mechanics tails'. In the real world of EFI and Computer Controls (although our stuff is mostly dated now) they are 'programmed to do things at certain temps, the 180* thermostat just allows the coolant to flow more sooner, the engine temp is gonna be what it is which most times should be 190* to 205*.
The small temp range on the stock gauge give some owners panic attacks, I always say the stock gauge is just a guess.
Click to expand...
I’ll keep it in for now, can’t imagine it’s causing much issue. It’s super hot outside, so I’ll wait for the weekend to run more tests, but I pulled the wire off cyl. 4 while running and I think I noticed a slight change, but maybe I’m crazy. I know if it was running properly it would be a pretty substantial change, so there’s something going on over there. I’ll check spark and fuel this weekend to see if there’s an issue there.
 

red5.0fox

Active Member
Dec 1, 2019
190
25
38
Hope Mills, North Carolina
May 1, 2024
#177
  • May 1, 2024
  • #177
red5.0fox said:
I’ll keep it in for now, can’t imagine it’s causing much issue. It’s super hot outside, so I’ll wait for the weekend to run more tests, but I pulled the wire off cyl. 4 while running and I think I noticed a slight change, but maybe I’m crazy. I know if it was running properly it would be a pretty substantial change, so there’s something going on over there. I’ll check spark and fuel this weekend to see if there’s an issue there.
Click to expand...
Sorry, actually I know spark is good because I jolted the hell out of myself doing it lol. So that tells me there’s a different issue, unless it’s not enough spark? I’m unsure
 

General karthief

wonder how much it would cost to ship you a pair
5 Year Member
Aug 25, 2016
27,868
10,542
203
polk county florida
May 1, 2024
#178
  • May 1, 2024
  • #178
The computer told you there is a problem with #4 cylinder,check plug, wire and that tower on the cap, if you can do a compression test on that cylinder.
Have you done the 'surging idle checklist '?
 

red5.0fox

Active Member
Dec 1, 2019
190
25
38
Hope Mills, North Carolina
May 1, 2024
#179
  • May 1, 2024
  • #179
General karthief said:
The computer told you there is a problem with #4 cylinder,check plug, wire and that tower on the cap, if you can do a compression test on that cylinder.
Have you done the 'surging idle checklist '?
Click to expand...
In the past, in pieces. Fully intend on doing it start to finish when I get a chance. Just haven’t had a moment to really sit down with the car. I plan on inspecting the cylinder this weekend and hopefully starting on the checklist.
 
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AeroCoupe

lube between the nut and the face. I know my lubes
Founding Member
Oct 28, 2001
5,821
3,952
183
Claremore, OK
May 1, 2024
#180
  • May 1, 2024
  • #180
Check the spark plug for cracks. Get your hands dirty and rub the body of the spark plug. This will show any cracking which could cause the issue.
 
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