FAIL. Need NB help
 

Im at a loss at this point. We just put a 94 block in and my rebuilt MSM head back into my car. We've done the timing belt twice and both times it was fine. The problem Im having is that my idle is low around 950 to 800 and it bounces to a light degree. I now have 800cc injectors that arent really dialed in yet but this is the kicker; my HG's are at 10, but my afrs are normal around 14.7-15.2 at idle. I have no vacuum leaks that I can find. I sprayed carb cleaner all around the motor trying to find a leak and nothing. I figure at 10hg, that has to be one hell of an obvious leak.

The motor isnt smoking at all and it drives just fine actually. ITs the idle thats completely jacked up. Ive asked Jeremy from FM to help with the fuel settings for the injectors so hopefully he gets back with me today. Im using a Hydra BTW.

Any suggestions cause between Phil, Neogenesis, The Brain, and myself we couldnt figure it out lastnight

i asked what kPa you were idling at yet you continue to give me ~hg.

i dont know much about your build mate but i have seen this sort of problem so many time before and so many times when people take engines out and stuff they put the back in forgetting to reconnect all earth or have sprayed over the metal so earths are not good enough. im sure u already know but an earth is more important than a live. caught me out twice i know that, first time was a low idle and the second time it was hunting(idle control valve was a point of earth contact and it had been sprayed)

Also, we cant adjust the idle through the throttle body screw. no matter how much we turn it, the idle wont budge.

The grounds are fine. Ill check em again though later on this afternoon. Thanks.

does it otherwise perfom ok or is there problem through out the rev range

are you using a fuel presuure regulator. i have plumbed that backwards before and it would start but could only just idle.

It drives damn near perfect through the revs, with proper tuning it would be perfect. All the problems we're having are at idle.
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Ah another thing, and this is important, we checked the timing on the crank and the two marks were bouncing around. I still think its a timing issue but im not for sure.

No.
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i am basing my help on another make and type of engine but do you have idle control valves on 5's

Your timing was bouncing between 8-12 degrees, but that might just be because your revs were hunting.
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NB should never be bouncing. fix the timing belt and youll get your vacuum back.

ok

this suggests a hefty vacuum leak post tb

there really isnt much that can leak post throttle body
http://i94.photobucket.com/albums/l1...photo-2347.jpg

a leak post TB would increase the rpms significantly...even more so if you opened up the bypass valve.

http://ft.trillian.im/levnubhin/1279680366713660.jpg

http://ft.trillian.im/levnubhin/1279680288543519.jpg

http://ft.trillian.im/levnubhin/1279680247559037.jpg
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What about the timing mark on the crank? I know they LOVE to slip a tooth or two when your sliding the t-belt over that last idler pulley. When I did mine, I actually had to turn the crank about 1 mark clockwise so that when I put tension on the belt to slide it over the idler, it would align the marks properly. Just a suggestion though.


What's your vacuum on decel?

Does the sound of the exhaust at idle change from a lump to a purr to a lump as if the car were 'cammin' hard? Does it stall if you decel and push the clutch in or free rev it and let the RPMs drop?

ok I give up lol

Is this what you all see?

http://i32.tinypic.com/315j3fl.jpg
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i think its timing but im no expert on timing belt changes so i cant be sure

isn't supposed to be 19 teeth?

yup

I agree, there are definitely not enough timing belt teeth between the marks.

Fixed the timing. Problem is still there. Going to change out the intake mani gasket

Take a picture of the cam gears again so that we can also see the position of the front two lobes on each cam with the gears and belt in the right position.

Does the Hydra require a crank angle sensor and did you put one on the 94 block?

Does the 99 intake manifold have the vacuum tube that is capped on the rear of the manifold? I know we had similar problems on a friends NA when we forgot to put the cap back on after working on his car.

There is one underneath as well, on the #3 or #4 runner.

What version Hydra are you running?

When I was trying to set base timing with my hydra I was having a shit of a time. I saw the same high vacuum and bouncy timing mark.

There are multiple trim maps for timing that affect idle. In 2.7 (don't recall if it's this way in 2.6) the hydra even can add or pull timing to try to reach the RPM target.

Of course, the timing affects the vacuum you're pulling and that super bouncy shit you see with the timing light is probably caused by the hydra too.

I had to zero out all my idle and timing related trims and then set the spark map to 10 degrees all around the idle rpm in a big chunk. Only after that did the timing mark (when viewed with the timing light) stop jittering around and sit nice and steady real proper like.

Let me know if this works, and save your map before destroying it.

Did you pump 10 psi through the intake (removing filter and sealing intake hose) and listen for leaks? Before you pull the intake mani, do that. It'll hiss or whistle where the leak is if there is a leak.

whoa lots of responses. thanks guys. i know my tune needs to be worked on mainly because of the 800cc injectors but i also saw something last night that's tipping me now into the intake mani gasket being the issue. While phil was in the car with it idling, i was leaning on the intake mani looking for leaks. when i put the little body weight i have on it to get a better look, the car stalled out. that in itself is making me think that something is definitely leaking. im picking up the gasket later on and putting it on either tonight or tomorrow. If that doesnt do it, then ill be dicking with the tune some more

Dont have one now but its spot on for sure.

No it doesnt and yes there is one thats positioned at the right distance (credit card sized gap)

Its welded shut

I didnt notice one under there on the mani when it was off but ill know for sure in a bit. Thanks

2.5. If this gasket doesnt work, then ill be trying that

No I didnt. Ill try that though. Thanks

You also need to fix that HUGE exhaust leak between the turbo and manifold. You'll never get it tuned right if your O2's aren't reading correctly.
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AFRs effect vacuum.

I'll second double checking the settings in the hydra unless it displays it is running the correct timing. On a hot summer day my hydra was trying to idle the car on 6 degrees because the air temp trim was all jacked up.

Timing matched up in the hydra with the crank setting. The exhaust leak isnt as bad now phil. either way i know i need to get it fixed

It's worse now that you broke the stud Jared.
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Once you fix it let me know. I have different engine management but I get a bouncy idle as well that will stall. If I keep my A/C switched on, it wont stall but still drops then rises then drops and rises and then settles. If I dont keep A/C on it drops and stalls usually on the 2nd drop.

I also run fine at revs, have sprayed everything for Vac leaks, adjusted idle screw and got no response. I'll be following your tests/cure.

Might not be it, but bouncing timing makes me ask:

Did you check to see if the outer rim of the main pulley slips compared to the inner wheel?

Should be around 60kpa at 10 inches of vacuum.

Measure your turbo inlet, go into the plumbing section at lowes and create a cap to put over it. Then go to an autoparts store and buy a metal valve stem and drill the cap out to fit the valve stem in it. Set your compressor to 5-6psi higher then you plan to run and air your intake system up like a tire. Spray soapy water around the intake, the injectors, the brake booster line, the IC piping and anywhere else you can think of. If it makes bubbles, your leaking. With the truck, we set it at 35-40 PSI and it makes a hissing noise at all the leaks, but when testing N/A cars at 5-6psi, it doesn't make any noises. I've never tested at the 15-20psi you'll be testing at to know if it will make noise or be silent.

I just had a thought. Im using my NB crank pully on the NA motor. I know on the NA pully theres that metal disk that goes in the pully. On the NB its not there. By any chance, do you guys think that could be causing the issues at hand? LastnightI changed the intake mani gasket and it still didnt fix teh problem. Phil swears its all a tuning problem but I just dont think thats the WHOLE issue.

No

Dude your tune is way way off and it's still set for 550's while you have 800's in. Plus you have a pretty big exhaust leak causing false afr's.

Fix the obvious......
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Shit sprinkle some magic dust on that bitch and get it running already.

Ima sprinkle shit on you if you dont have something helpful to say, Lothar

+1

There you go

Don't know if they changed it later on, but my '99 has that metal disc. It's highly unlikely to be causing your problems though.

Twas just a thought.

How about your exhintake camshaft?

never put it in. enjoy temp bannage...again lol