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Discussion Starter #1
We recently put a 3.4 EFI in our 85 Jeep Cherokee. (Jeep had 2.8 carb motor). Had the Camaro wiring harness modified to just run the engine. Had the ECM cheked, all ok. Tried to start engine last week. Engine turns over then slows and kicks like it is out of time. Aslo Getting a lot of backfire from the intake. Have checked plugs, plug wires, timing marks (on gears), firing order you name it. Everything is right just acts like it won't start because timing is way off.

Any suggestions would be appreciated.
 

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Discussion Starter #3
That's what it acts like but, engine is distributor-less. EFI with a ECM. Manual said TDC is when Cylinder number 4 is TDC
 

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Driver of the beast
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Did you do any work on the cam?
If so the cam could be 180 degrees out!
Just an idea :shrug:
 

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Discussion Starter #5
No cam work. Just replaced the timing chain. TDC is when #4 cylinder is TDC on compression stroke... True ?
 

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Driver of the beast
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The timing Marks should face each other exactly when installing a new cam or just a new timing chain. According to the book How to rebuild your v-6 60 degree engine, if you are even 1 tooth off the engine will run terrible if at all!

That is all I can Think of.
 

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Discussion Starter #7
Thanks. Just picked up a timing cover gasket set. According to my Camaro shop manual TDC is when #4 is TDC on the compression stroke. True ? Thanks for your help!
 

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Driver of the beast
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That is for setting valves if I am not mistaken. Try it the way that the How To Rebuild Your 60 degree V6 book says. Match up the mark on the gears.
 

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musical engine builder
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i thought it was the marks should line up with #1 on TDC of compression.
 

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I've never really got the whole #1 vs #4 thing. Since on the 60* V6's BOTH are set to come up at the exact same time! (pull some heads on one and spin it over...)

I've assembled engines with #1 at TDC (which means #4 is also there!), then had the cam mark point straight up. Rotate the crank 360*, now it's pointing straight down.
 

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Discussion Starter #11
So, TDC is when #1 and #4 are TDC on the compression stroke ? Timing cover comes off this week. Thanks for the info..
 

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Well, they won't both be on a compression stroke at the same time - one will be, and the other will be finishing an exhaust stroke.

Of course, that's only if the heads are on, and it has a cam in it.

I guess... you could put the heads on, and no cam - then yeah, they'd both be on a compression stroke at the same time. Of course, then you'd have no intake stroke, so there'd be nothing to compress. :D
(man, I gotta eat lunch or something!)
 
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