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Discussion Starter #1
Soooo.
Fresh rebuild on a 2.5 turbo. Got it all buttoned up and now she just won't start without hitting the gas and then won't idle at all. If I keep pressure in the fuel pedal then I can get vacuum up to 15 mg but when I let off, the iac cranks open and my vacuum drops to 10. I can hear the darn thing hissing away it's pulling so much from the orifice. No codes.

Now this is the part where I start yelling"timing" but my gosh I've checked and rechecked. The dot on the crank lines up with the line on the oil pump. The notch in the camshaft is in line with the vertical of the engine block (not the ground).

What I'm I missing. You can still yell timing if I screwed something up but I really don't think I have.
It's almost like it's got a big ol vacuum leak but at 10mg why the heck would the iac valve crank open. You'd think it would try and shut down to build up more.

Any thoughts or suggestions are greatly appreciated
 

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Discussion Starter #3
Have you tried checking the actual ignition timing with it running?
As in hooking up a timing light? Not yet as I don't have one but in the process of looking. I have switched around the distributor and moved it back and forth, doesn't allow for all that much movement
 

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Discussion Starter #4
Compression is 130 across all 4. Being a fresh rebuild I think this is all well and good.
Isolated the entire vacuum system and only ran the MAP sensor. Still had the issue.

If I hit the gas hard she dies, if I slowely increase the throttle she will try and climb. Then let off and she throws a mean pop out of the exhaust.
AFR is solid at 14.7
 

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I have had trouble with the distributor timing before and this tip is not in any repair book. The intermediate shaft will drive the oil pump, but the oil pump can be engaged to the intermediate shaft in any position! Thus, the distributor position can be wrong even if the dot on the intermediate shaft is set correctly. The fix is to line up the dots again and then pull out the oil pump and re-seat it until the distributor drive is parallel to the block. One notices that the oil pump turns as the oil pump meshes with the intermediate shaft, so one must anticipate how much it rotates. If done correctly, the distributor front will be parallel to the engine block and should run well even without the timing light. Another issue I have had after a rebuild is the valve lifters not wanting to pump up, but that is a different story.
 

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Discussion Starter #6
I have had trouble with the distributor timing before and this tip is not in any repair book. The intermediate shaft will drive the oil pump, but the oil pump can be engaged to the intermediate shaft in any position! Thus, the distributor position can be wrong even if the dot on the intermediate shaft is set correctly. The fix is to line up the dots again and then pull out the oil pump and re-seat it until the distributor drive is parallel to the block. One notices that the oil pump turns as the oil pump meshes with the intermediate shaft, so one must anticipate how much it rotates. If done correctly, the distributor front will be parallel to the engine block and should run well even without the timing light. Another issue I have had after a rebuild is the valve lifters not wanting to pump up, but that is a different story.
I e definitely done that before. Luckily didn't get to the point if engine in the vehicle but your right. It's a some trick that can save hours! Luckily that's not my problem. Turns out I had my timing spot on but my darn distributor was mounted 180 degrees from where it should have been... I feel like an idiot but it's been a long day.

I appreciate the reply and tips!
Thanks!
 

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That's a relief to know you found the problem. I was going to say that turning the intermediate shaft is easier than pulling the oil pan and all that. All that really matters is that the rotor point to #1 plug at the right time, dot or no dot. (Not really an option on the Dakota) I'm interested in your set up with the Turbo. I happen to have a '91 2.5 4 cyl. Dakota, too, but it is naturally aspirated. Question, is it true that the 2.5 in the truck application does not have the balance shafts?
 

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Discussion Starter #8
Yeah, I checked and double checked the timing. It was driving me insane! Wasn't my first time timing these engines so that was the annoying part, haha.
Yes it is true. I've had two Dakota blocks apart and both of them have not had the balance shaft installed so no oil hole to tap and plug. I've actually never seen the balance shaft that comes on the turbo cars!
 
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