Cylinder dead?
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Cylinder dead?
Left work the other day, started the truck and it felt like one cylinder wasn't firing. Feels worst from idle to about 1700 rpm. Was running fine when I got to work that morning. Did a tune up today... plugs, cap, rotor and air filter (plugs were well worn, I drive a thousand miles a week). Still have the miss. Plug wires look ok (they're a year old). Checked the coil with an ohmmeter... tests ok. I was thinking maybe an injector has failed or become clogged... what's the easiest way to check them? Any suggestions? What else should I be looking at?
1994 Bronco
5.0
325,000 miles
1994 Bronco
5.0
325,000 miles
Elder User
Joined: Oct 2006
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From: Redmond, WA
This miss could be a poor plug wire. Just because they visually checked out ok, doesn't mean that they haven't lost their suppression properties. If it were my truck, I'd like to remove the possibility of a poor plug wire and replace them as well. The fact that your plugs were well worn leads me to believe at least one of your wires could be in the same shape. Are your plug wires routed correctly??
http://www.supermotors.net/vehicles/...media/470416_1
This may or may not fix your problem, but will eliminate potential suspects nonetheless. Try running the truck late at night (remove your hood light) and watch for spark arcing through the powerband.
At 300,000+, a thorough compression check might be a good idea...
Good Luck
Mike
http://www.supermotors.net/vehicles/...media/470416_1
This may or may not fix your problem, but will eliminate potential suspects nonetheless. Try running the truck late at night (remove your hood light) and watch for spark arcing through the powerband.
At 300,000+, a thorough compression check might be a good idea...
Good Luck
Mike
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I ran it in the dark but didn't see any arcing from the wires and they are routed according to the diagram under the hood. When I was checking out the coil I noticed that the coil wire was loose on the coil tower and figured that might be the cause but pushing it back on didn't make any difference (I did pull it off and check it for arc marks first). We had steady rain here for 3 1/2 days and I was thinking that something might have gotten moisture into it but who knows. I was thinking of doing a compression test.
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From: sunny fla sometimes windy
put your vom meter on your wires they should be 5000 ohms per foot. Put a stethoscope or screwdriver on each injector and listen you should here them open and close if you think it's a injector! Have you ever run gas line dryer? might be time! I always recommend this nowadays with gas prices so high everyone is running around on half a tank of fuel or less (damn big bronco tanks) so condensation builds up overtime and causes all kinds of havoc!
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Tested compression... I think she's good
#1- 155, #2- 160, #3- 155.... #4- 165 - 170, #5- 155, #6- 165 - 170, #7- 165, #8- 155.
I did pull each wire off one at a time and was able to pull at least a half inch spark out of each one. I'm going to check each one with an ohmmeter. The wires are Accel Extreme 9000 Ultra High temp, only a year old. Coil is an MSD Blaster.
Never have run gas line dryer just fuel injector cleaner, maybe I'll give that a shot, we had 3 - 5 inches of rain last week just before this started happening.
#1- 155, #2- 160, #3- 155.... #4- 165 - 170, #5- 155, #6- 165 - 170, #7- 165, #8- 155.
I did pull each wire off one at a time and was able to pull at least a half inch spark out of each one. I'm going to check each one with an ohmmeter. The wires are Accel Extreme 9000 Ultra High temp, only a year old. Coil is an MSD Blaster.
Never have run gas line dryer just fuel injector cleaner, maybe I'll give that a shot, we had 3 - 5 inches of rain last week just before this started happening.
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From: Ontario
7 and 8 fire one after the other.
So if the wires are too close or touching 7 will fire 8 and 8 will fire 7.
It's a common problem with the 5.0 engine the wires have to be at least 2 inches apart from each other.
It first happened to me on my 1990 f150 about a year after I did the tune up,
it drove me nuts.
As soon as I put the space between the 7 and 8 wires the problem disappeared.
See if it helps.
Rick.
It's a common problem with the 5.0 engine the wires have to be at least 2 inches apart from each other.
It first happened to me on my 1990 f150 about a year after I did the tune up,
it drove me nuts.
As soon as I put the space between the 7 and 8 wires the problem disappeared.
See if it helps.
Rick.
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From: Redmond, WA
Looking good for 300,000. Impressive work keeping that old 5.0 running. Try running seafoam and/or some injector cleaner with a 1/4 tank of gas. Run that through and see what happens.
It's a shot in the dark!
Your truck has a different firing order (1-5-4..) then his 94 with the HO/351 firing order. The HO version has issues with 1 and 3 and 5 and 6 routing. They will cause a similar misfire if routed improperly.
It's a shot in the dark!
Originally Posted by Red Ford Truck
So if the wires are too close or touching 7 will fire 8 and 8 will fire 7.
It's a common problem with the 5.0 engine the wires have to be at least 2 inches apart from each other.
It first happened to me on my 1990 f150 about a year after I did the tune up,
it drove me nuts.
As soon as I put the space between the 7 and 8 wires the problem disappeared.
It's a common problem with the 5.0 engine the wires have to be at least 2 inches apart from each other.
It first happened to me on my 1990 f150 about a year after I did the tune up,
it drove me nuts.
As soon as I put the space between the 7 and 8 wires the problem disappeared.
Last edited by Mr. M; Aug 26, 2007 at 10:30 AM.
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From: Ontario
So you're saying the HO 5.0 litre has 351 firing order?
Originally Posted by Mr. M
Looking good for 300,000. Impressive work keeping that old 5.0 running. Try running seafoam and/or some injector cleaner with a 1/4 tank of gas. Run that through and see what happens.
It's a shot in the dark!
Your truck has a different firing order (1-5-4..) then his 94 with the HO/351 firing order. The HO version has issues with 1 and 3 and 5 and 6 routing. They will cause a similar misfire if routed improperly.
It's a shot in the dark!
Your truck has a different firing order (1-5-4..) then his 94 with the HO/351 firing order. The HO version has issues with 1 and 3 and 5 and 6 routing. They will cause a similar misfire if routed improperly.
Because he said he has a 5.0 litre I don't recall reading anything about a 351 HO.
Rick.
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From: Redmond, WA
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From: Corpus Christi
yes, there are two firing orders for the 5.0. I think 94 was the year it changed from what I have found. Yes, the second firing order is the same one that's in 5.0 mustangs (which are HO 5.0) and 351's.
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Havent had much time to mess with it during the week with work and all that good stuff. I did dump a can of Seafoam in the tank and ran it through then a can of fuel injector cleaner but to no avail. I drive 1,000 miles a week so I go through lots of gas. I had a couple of spare plug wires around so I tried swapping them one by one... didn't make any difference. I'm going to change the fuel filter and check the fuel pressure. All the plug wires are routed according to the diagram under the hood so I'm good there. Going to pull the plugs out and look at them closely and see if one plug looks different from all the rest, that would at least let me know which cylinder has the problem. Apart from the miss the engine is running pretty well and doesn't seem to be lacking in more than a small amount of power... the miss is annoying as hell though!
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You say you pulled each wire to look for spark. Did you pull the wire completly off to see if it idled differnt. If one wire can be pulled off and no change, thats the culprit. It may be the wire, plug, injector or whatever. But at least you know where to look.
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Pulled the plugs today, all except No. 1 look nice and clean. No. 1 is black. Poked around with a stethoscope and it seems like the injector for No. 1 isn't working... all the others are making a nice sharp click click click click... no sound coming from No. 1. Next I'm going to check for voltage to the injector and go from there. At least I know now which cylinder isn't working.