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since when is the 4.0 a diesel?


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no I'm kinda worried I'm gonna have to spend some serious $$$.

here's the situation

1. purchased a used 4.0 with 80,000

2. put new head gasket, oil pan gasket, rear main seal, and valvecover gasket. i didnt keep the pushrods in order when i took them out so i replaced them. Also pulled the distributor out but I'm pretty sure i installed that correctly (#1 cyl at tdc, point rotor at #1 cyl )

3. installed motor in the comanche

4. i am running the motor with nothing hooked up except the battery, no fan, radiator, or serpentine belt (not for long maybe a minute at a time)

5. when i turn it over the motor fires and will sometimes idle for a few seconds

6. a lot of dark black smoke comes out of header, like a diesel black and spark plugs are black too

fuel pressure is around 30 psi not sure on compression

 

has anyone seen this before?

please leave good news, but ill take the bad too :headpop:

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Remember it's a 4-stroke engine. Each cylinder hits TDC once on the compression stroke, and again on the exhaust stroke. Are you certain you had #1 on the compression stroke when you set up the distributor? If it was on exhaust, the distributor is 180 degrees out of synch.

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Yes Air would come out of the spark plug hole on the exhaust stroke, cause there is no plug to stop it from comming, on the exhaust stroke is when your exhaust valve which in most cases is your biggest valve will open to let the already spent fuel out of the cylinder . On a Otto cycle engine such as the one in your jeep, it has 4 strokes. 1) Intake 2) Compression 3) ignition 4) exhaust

It sounds like you caught the #1 on the exhaust. I would take dirty comanches advice.

 

I'm not too sure about Automotive engines, but On piston powered Aircraft there is a marking on the flywheel, that is splined to the crankshaft and a marking on the Crankcase itself, indicating TDC. Possibly there is such a marking on the jeep but yet again I don't service automotive engines. Automotive engines in comparison to Aircraft piston powered engines are much more complicated. A small example would be In a Automobile the engines are liquid cooled, aircraft are AIR cooled, by use of baffles and RAM air.

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Also maybe, I dout that this would be the problem but maybe the valve timing is incorrect, possibly recieve the incorrect rods? or lubes on the cam are very worn. Worn rings would cause the smoke to come out your exhaust not your headers, maybe you have hotspots on your piston heads that cause pre-ignition, but you would have heard that by now.

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Will be apprenticing in a while. For now I'm stuck doing the basic stuff. I'm at nothern light's 'southern' campus, so we're limited as far as actual aircraft. As in, we have none residing. But as soon as I move up to the main campus, apparently they've got a bell 206, 212, and a couple cessna's.

 

 

 

But, we've got more non-servicable engines to play with than we'll EVER know what to do with.

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Have you ever heard of Canadore College in North Bay? The best aviation course in canada, From Transport Canada you recieve 19 months towards your apprenticeship and you al get to work on:

 

2 fully operational Bell 206's

1 Hewis 500

1 Robinson R22

2 Beech Sundowners (that have the Spars cuts)

1 Cessna Cardinal

1 150

1 172

1 Piper Apache

1 A-star

 

Have these turbine engines in the hanger also:

 

JB-111

2x P&W PT6 engines

 

and there are many more also. This is where I went to school to become an AME and now I'm 2 Hangers the runway at Voyauger Airways.

 

Maybe we should create another thread to continue this.

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Is the MAP sensor hooked up to manifold vacuum? If not it will run full rich thinking you are at WOT under full load. That would foul out everything.

With your finger over the plug hole on the compression stroke it will kinda pop your finger off the hole. It won't do it on the exhaust stroke with the exhaust valve open.

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That's awesome. What I like about where I am right now is it's local for me. So, no having to move or anything, yet.

 

 

Which is a big thing, because I know as soon as I dissapear my truck will pretty much have to go.

 

 

And thread hijacking is perfectly fine! I think that as soon as he re-indexs his dist. it'll work. It's unlikely that there's anything really wrong with his 4.0, they're tanks.

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That's awesome. What I like about where I am right now is it's local for me. So, no having to move or anything, yet.

 

 

Which is a big thing, because I know as soon as I dissapear my truck will pretty much have to go.

 

 

And thread hijacking is perfectly fine! I think that as soon as he re-indexs his dist. it'll work. It's unlikely that there's anything really wrong with his 4.0, they're tanks.

:rotfl2:

:Canadaflag: s

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I'm gona steal my forum back know

when i re indexed the distributor and cranked it over it sounded like someone was playin the steal drum in my header, it actually sounded kinda good if i wanted to hear a steal drum but i wanna hear my truck start. I'm guessin that i had it on the compression stroke the first time.

where and what is the harmonic balancer?

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ok i put the little groove on the back lip of the harmonic balancer so it was centered at the top. then put the distributor pointing at #1 cyl. motor would not fire at all. spun the distributor 180 degrees and the motor started and ran good for a few seconds then started running like it did before. when i frist start to crank the motor over fuel pressure is at 30 psi as i continue cranking it drops to around 20-25psi could this sputtering possibly be caused by a bad fuel pump or pressure regulator?

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the drop in fuel pressure could be the fuel pump. and the o2 sensor will also make things studder and not run right over all, i know this from almost every ford my dad has had these needed replaced. but these problems could also be the C-101 connector if your jeep is an 87-89, the IAC, TPS, or the FPR.

 

Alex

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i don't have an o2 sensor hooked up right now but i think the motor should atleast idle without it.

 

can i still get an accurate read on fuel pressure if the motor isnt running?the pressure doesnt rise when i pull the vaccum line off the pressure reg which is why i thought that may need to be replaced. as for the fpr which i am guessing stands for fuel pump relay, how can this be tested?

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i don't have an o2 sensor hooked up right now but i think the motor should atleast idle without it.

 

can i still get an accurate read on fuel pressure if the motor isnt running?the pressure doesnt rise when i pull the vaccum line off the pressure reg which is why i thought that may need to be replaced. as for the fpr which i am guessing stands for fuel pump relay, how can this be tested?

 

if the o2 is not hooked up the enigne will run rich and act like it can't breat or is not getting fuel.

 

the engine needs to be running so that you can test pressure when it idles, when you give it some gas, and when it backs off the gas.

 

ok to test the Fuel Pressure Regulator you need to attach a fuel pressure gauge to the rail and test for correct pressure. your pressure will be around 35-40psi for a non-HO enigine and 40-50 for a HO engine. FSM can tell you the true amount for your year and model.

 

Alex

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