7.3 idi misfire?

[Fordfan90]

https://www.youtube.com/channel/UCG2XfRWKopnpkK6FoFq_S5w

1990 f250 7.3 idi non turbo misfire? Replaced injection pump. Nothing else has been done to the motor. This was ice cold with no high idle because of the plunger not being able to touch the throttle.

 

[no mufflers]

where did the IP come from?
how many miles are on the injectors?
has the engine been properly timed?
is the cold timing advance working?

it is definitely running ruff.

 

[franklin2]

While it's running you can go around and crack loose the lines on the injectors one at a time. If it runs worse you know that one is working. If there is no change, that is the cylinder that is not firing. That will at least narrow it down. If you find the one cylinder, you could swap injectors and see if the problem moves to the other cylinder by doing the crack the line test again.

 

[Fordfan90]

where did the IP come from?
how many miles are on the injectors?
has the engine been properly timed?
is the cold timing advance working?

it is definitely running ruff.

Pump is from autozone so I could get it running plan on buying a different one when I turbo it. The injectors have 150,*** miles on them and the cold timing advance won't come on at all. I cracked all the injectors and they seem to be good. Maybe something internal?

 

[no mufflers]

the injectors probably aren't any good. I wouldn't buy an AutoZone pump.

did you time it? as I asked above ^^^^^

there are two temp sensors that control the high idle and cold advance. they might be bad.

 

[Fordfan90]

Yes I had a mechanic time it but he said the misfire was getting in the way of the timing so he said he got it where he could. He told me he thought it was valves in the heads or a bad injector and can't find a bad injector.

the injectors probably aren't any good. I wouldn't buy an AutoZone pump.

did you time it? as I asked above ^^^^^

there are two temp sensors that control the high idle and cold advance. they might be bad.

 

[no mufflers]

do you know what kind of timing machine he used?

 

[Fordfan90]

do you know what kind of timing machine he used?

Nope he didn't tell me. He said he timed it at 2000rpm that's all I know on the timing part of it.

 

[no mufflers]

it wouldn't hurt to ask him. it sounds like he used a machine.

a compression test wouldn't hurt. you would find out real quick if you have a dead cylinder. that could be part of the skip it has.

 

[Fordfan90]

it wouldn't hurt to ask him. it sounds like he used a machine.

a compression test wouldn't hurt. you would find out real quick if you have a dead cylinder. that could be part of the skip it has.

Well I took an injector out and found soot built up around the whole thing and it didn't want to come out easy. The truck finally stopped shaking and puffing at the exhaust. Now I'm going to buy all new injectors for it. Thanks for all of your help guys.

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[franklin2]

You should get it timed again after you install the new injectors. Don't worry about the cold advance/fast idle thing. Mine hasn't worked for years and it runs fine and smooth, no problems. That's why I have never spent the $50 they want for a new sensor. Waste of money I think.

 

[Fordfan90]

You should get it timed again after you install the new injectors. Don't worry about the cold advance/fast idle thing. Mine hasn't worked for years and it runs fine and smooth, no problems. That's why I have never spent the $50 they want for a new sensor. Waste of money I think.

Will do thanks for the info I will definitely get it retimed after I get the new injectors put it in. So you don't really need the cold timing advance then?

 

[Macrobb]

I like the cold advance, it reduces smoke on cold startup, makes it fire off easier.
Once the engine is running for a couple of minutes, it doesn't do much.
You can always rig up a switch in the cab to drive it.

 

[franklin2]

I ran a switch on my cold advance just to test it, since I found out it wasn't working when I bought the truck. I didn't see much difference myself in the smoke level and the ease of starting. The fast idle was nice, but I don't probably need it as much since I raised my idle speed to get rid of the zf gear noise.

Then I found myself forgetting to turn the switch off a couple of times so I took it back out.

 

[IDIoit]

Don't worry about the cold advance/fast idle thing. Mine hasn't worked for years and it runs fine and smooth, no problems. That's why I have never spent the $50 they want for a new sensor. Waste of money I think.

agreed.
my temp switch decided to die, so I bought one.
it wasn't the fact that the sensor was expensive,
it was the lack of will to open up and spill fleet charge all over that has kept me from replacing it lol

its not cold here in commiefornia, except for the legislation.
no issues, starts up just fine.. I usually let her warm up past the point of it kicking off anyways before I take off.

to the OP...
while you have your sticks out, I would do a leak down test.
why go through the trouble of replacing the sticks if you have a bad valve or lifter?