Zigroid

well my LE3 383 isn't running as good as it should, or at least as good as it should without a dyno tune.
here are the symptoms:
- way down on power, obviously
- "searching" idle even with ion's tune. when I start the car cold the idle will drop to 500 rpm and not go up. I have to hold it at a higher rpm. sometimes it will hold steady at 950 rpm when its warm. other times it will drop to 700ish and go up and down between 600-1000. not rapid, slowly.
- terrible gas mileage. babying it 90% of the time I got about 10 mpg. normally its 7-8 mpg.
- It has very low vacuum. 5 inches at idle, NEVER climbed above 17 during driving.
- specs at no load are 5" at 1000, 10" at 1500, 13" at 2000, 14" at 2500 and 16" at 3000
- At no time under deceleration does the vacuum approach 20"
- something else that was kind of strange is if you are just sitting there and take the engine to 3000 and do not move the pedal the rpms will drop slowly to appx 2500 rpm's and remain steady. you must increase the throttle to get back to 3000.
- Its throwing codes, but I can't find someone with a scanner... yet.
- It seems to drive fine, the driving characteristics not the power, then it'll change instantly. we drove over a mountain without any hard acceleration, it ran smooth. we went down the other side of the mountain (a fairly decent grade). under decel at appx 2-3000 rpms we had appx 17 inches of vacuum. we then turned around to come back up this grade. we left it idle for approx 15 seconds to let traffic past. when we pulled back out it was like driving a completely different car. it backfired loudly through the pipes and bucked on acceleration. it did this under light and heavy acceleration. the backfire was similar to an engine with to much timing. the only thing that changed between running smoothly and backfiring was it idled briefly....less than 30 seconds.

assembling the engine:
- degreed cam, was fine
- when we adjusted the valves we did not spin the pushrod. we watched for contact at the lifter plunger and then took it a half a wrench flat further which would be 1/12th of a turn. we were very careful doing this and the lifter plunger travelled ever so slightly down its bore.
- after the engine was fully assembled we spun it over checking the compression. all was good.
during this weekend trying to figure out whats wrong:
- fuel pressure is above 40 psi throughout idle to 6000 rpm. didn't take it above 6000 because it was running pretty bad.
- sprayed starting fluid around the intake manifold to check for vacuum leaks. none. also checked brake booster.
- pushed the EGR valve open while engine was idling and it didn't phase the engine at all. dumping exhaust into an idling engine doesn't do anything? we removed the EGR valve and blew in it. It seems to be sealing. We made a block off plate and installed it. the idle vacuum went from 5 inches to 6 inches and seemed to run slightly better.
- checked the cam using the flywheel while the engine was in the car tonight, it checked out fine.
- pulled the plugs out, drivers side bank seems to be rich, passenger side bank seems to be normal. HERE is a picture. this is after 800 miles.
- did a compression test on all 8 cylinders. all are around 175.

so we had the problems narrowed down a bit more. heres what we came up with so far:
- a valve is sticking due to a faulty/improperly tightened lifter.
- the drivers side O2 sensor is messed causing that whole bank to run rich.
- theres a HUGE vacuum leak somewhere and we can't find it.


I'll get the engine back together tomorrow night then try to get it scanned on wednesday or thursday.
Any help would be GREATLY appreciated!

NVetro

I say change driver side o2, and lets see where we stand. Anyone else wanna back me up?

turbo_Z

Try adjusting the lifters again with the motor running. If they are Comp Rs then go 1/16 turn after the zero lash and 1/4 turn with OEM style. Also, the R series lifters are having quality control issues so it may be better for you to go back to OEM lifters because even if they are not the problem now.. theres a good chance will be in the future.

Getting a scan will definitely help diagnose your problem.

With a new motor there are too many variables to go guessing the solution without A LOT more data or being there in person.

NJLT1SS

I would say find the vacuum leak first and foremost, thats whats killing it for you. I had a friend with a 5.0 Mustang that had a fresh 332 built for it, and stripped 2 of the upper intake bolts, and decided the hell with them and left them out. Well, until he took the upper plenum off, drilled and tapped the bolt holes, his car ran just like you described yours to run. It was absolutely miserable, ate gas, wouldnt idle ect... Find the vacuum leak, and that will solve that problem, which can be a major one. Get that squared away, as there might be other problems, but you have to start with the obvious and go through a process of elimination. I hope that helps, good luck and keep us posted on your progress.



Nick

Zigroid

turbo_Z, well heres how we figured out the lifters:
the lifters need .002-.006 preload. thats .002 inches to .004 inches tightened after zero lash

we have 7/16ths studs with a thread pitch of 20 (I believe it was 20.) that means 20 threads per inch. 1/20 = .05. we tightened 1/12th of a turn past zero lash. so it would be 1/20 x 1/12 or 1/240. 1/240 = .004" of preload. is this not the general area of where the lifter must be set?

plus im afraid of adjusting them on the car

NJLT1SS, I guess I'll test for vacuum leaks again. still not sure what we could have missed? just about everything that could cause a vacuum leak comes out of the manifold, right?

turbo_Z

I really dont know the preload... just the process.

1. start car with vc off.
2. losen a rocker till it clacks.
3. slowing tighten the nut till the noise stops.. you have reached 0 lash
4. go another 1/16 or 1/4 turn depending on the lifters.
5. repeat.

I almost wonder if there a problem with the TB.. is it stock or aftermarket?

Zigroid

tb is stock, 58mm tb is on its way though.

the lifters are comp r, comp site says .002 to .004 preload.

WS Sick

I would check the torque on the intake, check all vacume lines for cracks and check the bellows between the MAF and the T/B, and crack or small rip where air can get in will screw things all up.

Z95m6

You said you checked the cam with the flywheel, i don't know what that means. I would think your cam is off one tooth if i had to guess. Its not that hard to rip the front timing cover off. Especially if you have a new motor because the front hub should come right off.

WS Sick

My thoughts are that if the cam were off ,the popping and stuff would be there on a regular basis. Do you have a scanner where you can look at all sensor input? like the PCMs temp sender etc.

TQdrivenws6

I would look into the IAC counts and BLMs. Also, get the codes read, because its probably trying to tell you something. When I was running the 52mm ported stock tb I had to open the blades up a fair amount to get it to idle smooth and not die at stop signs, but then we had to slot the TPS because that was way off. Basically for that engine combo you will NEED datamaster at a minimum so you can get it to idle right to start. Then you can monitor vacuum, MAP, MAF, BLMs etc in order to diagnose what really is happening.

NVetro

hmmmm Perhaps he has a VERY loose header bolts? Maybe intake manifold isn't sitting right? All I know is that is ALOT of vacume to be loosing, and its should be obvious. So its running rich on the driver side and their is a huge vacume leak, do we have that estabilished?

Zigroid

we popped the torque converter/flywheel cover off and used the flywheel as a degree wheel. we checked the cam before and it was fine so we did this just for piece of mind.

no I am starting to believe I will need one though.

unless any bolt loosened by itself, each bolt was tested multiple times with a torque wrench when installed. we were VERY careful when doing everything. I have a gut feeling its not a mechanical problem. ALL the header bolts were tightenened and had locks installed so they can be ruled out. if there was an exhaust leak I would hear it.

what can I get for scanning the car and where can I get it? Ive heard of scanmasters but know very little about them.

WS Sick

If you have a laptop or a freind with one, buy a cable from AKM cables (or find a freind with one) And download the Free Datamaster TTS or Freescan.
Both will give you what you need, but Datamaster is much easier to read.

Scanmasters are nice, but you have a limited screen.

Zigroid

well, we got it all back together. adjusted the valves too. mechanically there shouldnt be any problems.
on the road the car is the same. it just spits and sputters all through the midrange. at WOT it cleans itself up but still doesnt have nearly as much power as it should have. I guess this would rule out the opti as being a problem. it just seems as if the a/f mixture is way off and/or the pcm is out of whack. something isnt communicating right.
the slip tube on my drivers side mac header is leaking. we rotated the clamp several different ways but can not get it to seal at all. this could be why the drivers side spark plugs were so black. I'm seriously thinking about ditching the macs and buying pacesetters.
gotta get her scanned i guess.

I got a laptop and it seems I can buy a cable/tts datamaster from www.akmcable.com.