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Engine Help on dead cylinder

  • Thread starter Thread starter luisjluis1
  • Start date Start date Dec 4, 2020
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HemiRick

I'd be looking at jacking under the house
Jun 28, 2020
723
272
73
Memphis TN
Dec 4, 2020
#21
  • Dec 4, 2020
  • #21
1 side of your carb is clogged up.
 

jrichker

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Mar 10, 2000
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Dublin GA
Dec 4, 2020
#22
  • Dec 4, 2020
  • #22
I have a LOT of unkind and unpleasant things to say about people who convert an EFI car to carb. However, I will skip them and simply tell you that you made a terrible error in judgement when you converted an EFI car to carb.

The EFI system has diagnostics built into it that with just a simple jumper wire you can find almost all the things that aren't working properly. When the codes dump out, you post the codes here on Stangnet I have 5.0 Foxbody code definitions that tell you where to look and what you need to do to fix the problems.

Since it is a carb car, it is time to beg, borrow or buy a vacuum gauge to troubleshoot the problem. Most auto parts stores will rent or load one if you have a credit card.

Vacuum Gauge readings
 
Last edited: Dec 4, 2020
Reactions: Monkeybutt2000

General karthief

wonder how much it would cost to ship you a pair
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Dec 5, 2020
#23
  • Dec 5, 2020
  • #23
HemiRick said:
Yes if one side of the carb is clogged up it will only run on 4 cyl......
Click to expand...
Never encountered this scenario.
 

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
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#24
  • Dec 5, 2020
  • #24
Those plugs are toast. They don't cost that much and unless you have some tulane (I doubt you have) they are hard to clean, you can try but really just get some copper plugs, no need for those plutonium coated gold plated wizbang fancy sparkers unless you have a Mr. Fusion adapted to it.
Give us a pick of the engine compartment aka 'doghouse' please
Do you know what your fuel pressure is?
New carb, new distributor?
 
B

BigFatRoss

Member
Oct 18, 2020
12
4
13
Chicago land
Dec 5, 2020
#25
  • Dec 5, 2020
  • #25
jrichker said:
I have a LOT of unkind and unpleasant things to say about people who convert an EFI car to carb. However, I will skip them and simply tell you that you made a terrible error in judgement when you converted an EFI car to carb.

The EFI system has diagnostics built into it that with just a simple jumper wire you can find almost all the things that aren't working properly. When the codes dump out, you post the codes here on Stangnet I have 5.0 Foxbody code definitions that tell you where to look and what you need to do to fix the problems.

Since it is a carb car, it is time to beg, borrow or buy a vacuum gauge to troubleshoot the problem. Most auto parts stores will rent or load one if you have a credit card.

Vacuum Gauge readings
Click to expand...
Hello

jrichker, Thanks for posting chart, VERY HELPFULL!​

I have a question. Now that his car is running a carb, should the vacuum gauge be connected to manifold vacuum, OR ported vacuum, I’m assuming (ported vacuum). In addition if you could clear the “FOG FACTOR” for me, ……

Depending on the carb, I’m assuming you know when you are on PORTED vacuum when the gage reads 0 (at idle) and will see gauge move when the idle is increased?

And when you are connected to MANIFOLD vacuum, the gauge will be giving you a constant reading (at idle and or increased idle)?
Thank you in advance for your help.
 
9

92mustang74

Member
Apr 26, 2020
10
3
13
virginia
Dec 5, 2020
#26
  • Dec 5, 2020
  • #26
Just a thought that is easy to do, turn the carb around, if you can, then if 3 4 5 & 7 are not firing, it is your carb for sure.
 
Reactions: luisjluis1

luisjluis1

Member
Dec 4, 2020
33
4
18
Columbia, Mo
Dec 5, 2020
#27
  • Dec 5, 2020
  • #27
HemiRick said:
1 side of your carb is clogged up.
Click to expand...
Pulling the carb right now. if I find nothing wrong I'm going to flip it like 92mustang74 said to see if the problem flips to the other cylinders. What should I be looking for if a side is clogged? I'll also go get some nicer plugs today. Thanks.
 
M

Monkeybutt2000

Mustang Master
Aug 11, 2019
1,387
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Lafayette,IN
Dec 5, 2020
#28
  • Dec 5, 2020
  • #28
luisjluis1 said:
Pulling the carb right now. if I find nothing wrong I'm going to flip it like 92mustang74 said to see if the problem flips to the other cylinders. What should I be looking for if a side is clogged? I'll also go get some nicer plugs today. Thanks.
Click to expand...
Is this a new carb? Can you not see fuel squirt when you work the throttle linkage?
 

KRUISR

10 Year Member
Apr 16, 2015
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Dec 5, 2020
#29
  • Dec 5, 2020
  • #29
When you have your carb off, check to see what cylinders are feed from what side of the carb. If all 4 you are having issue with are same side of carb. That to me is screaming as the problem.
 

luisjluis1

Member
Dec 4, 2020
33
4
18
Columbia, Mo
Dec 5, 2020
#30
  • Dec 5, 2020
  • #30
Monkeybutt2000 said:
Is this a new carb? Can you not see fuel squirt when you work the throttle linkage?
Click to expand...
Its a brand new carb and intake from summit. Ive seen fuel squirt into both primaries when I goose it. Could it not be getting enough air?
 

luisjluis1

Member
Dec 4, 2020
33
4
18
Columbia, Mo
Dec 5, 2020
#31
  • Dec 5, 2020
  • #31
luisjluis1 said:
Its a brand new carb and intake from summit. Ive seen fuel squirt into both primaries when I goose it. Could it not be getting enough air?
Click to expand...
Just pulled the carb. one side of the intake is dry while the other is wet. the dry side feeds all the bad cylinders. this is the problem. Thanks to all for your help! I will definitely find the problem with the carb here soon.
 
M

Monkeybutt2000

Mustang Master
Aug 11, 2019
1,387
849
133
Lafayette,IN
Dec 5, 2020
#32
  • Dec 5, 2020
  • #32
luisjluis1 said:
Just pulled the carb. one side of the intake is dry while the other is wet. the dry side feeds all the bad cylinders. this is the problem. Thanks to all for your help! I will definitely find the problem with the carb here soon.
Click to expand...
Strange.What brand of carb is it?
 

luisjluis1

Member
Dec 4, 2020
33
4
18
Columbia, Mo
Dec 5, 2020
#33
  • Dec 5, 2020
  • #33
Monkeybutt2000 said:
Strange.What brand of carb is it?
Click to expand...
Its a summit brand but really it's a holly. Just reversed the carb and ran it and the same cylinders weren't running. Thinking its intake.
 

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
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Dec 5, 2020
#34
  • Dec 5, 2020
  • #34
The carburetor is the least likely thing to effect individual cylinders, spark plugs, wires, cap or rotor.
 
Reactions: luisjluis1

luisjluis1

Member
Dec 4, 2020
33
4
18
Columbia, Mo
Dec 5, 2020
#35
  • Dec 5, 2020
  • #35
General karthief said:
The carburetor is the least likely thing to effect individual cylinders, spark plugs, wires, cap or rotor.
Click to expand...
Okay. Ive taken the headcovers off and watched the valves move up and down. Is there something else I can do to Check valves?
 

luisjluis1

Member
Dec 4, 2020
33
4
18
Columbia, Mo
Dec 5, 2020
#36
  • Dec 5, 2020
  • #36
luisjluis1 said:
Okay. Ive taken the headcovers off and watched the valves move up and down. Is there something else I can do to Check valves?
Click to expand...
Also just thinking about going to a separate coil and distributor setup just to rule that out.
 
M

Monkeybutt2000

Mustang Master
Aug 11, 2019
1,387
849
133
Lafayette,IN
Dec 5, 2020
#37
  • Dec 5, 2020
  • #37
luisjluis1 said:
Its a summit brand but really it's a holly. Just reversed the carb and ran it and the same cylinders weren't running. Thinking its intake.
Click to expand...
How could it be the intake? If you've verified that each spark plug has spark, and your distributor is installed correctly,it's your carb.
 

2Blue2

will be trying this sex one when I can find it
Mod Dude
Mar 5, 2019
4,430
2,893
163
Oahu
Dec 5, 2020
#38
  • Dec 5, 2020
  • #38
Monkeybutt2000 said:
How could it be the intake? If you've verified that each spark plug has spark, and your distributor is installed correctly,it's your carb.
Click to expand...
This is logical but,

Just spitballing
Could the intake have shipping material plugging it ?
I remember seeing a blower with plastic wrap still on bottom get installed.


maybe time for a compression test?
 

luisjluis1

Member
Dec 4, 2020
33
4
18
Columbia, Mo
Dec 5, 2020
#39
  • Dec 5, 2020
  • #39
2Blue2 said:
This is logical but,

Just spitballing
Could the intake have shipping material plugging it ?
I remember seeing a blower with plastic wrap still on bottom get installed.


maybe time for a compression test?
Click to expand...
We just got the good cylinders to fire with the carb off by spraying starting fluid straight into the intake. Bad ones still didn't fire. Carb is out of the question now. It has good compression (10:1) but still could be valves. The problem is definitely down to spark or valves not working correctly.
 

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
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Dec 5, 2020
#40
  • Dec 5, 2020
  • #40
Have you put copper spark plugs in it yet?
 
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