Bill Ball

Er, uh, you're right. I do have leakdown setup and will use that.

Bill Ball

I'd like to work on the dead hole, but now the car started surging again. Remember I thought I had a bad ground for the idle stabilizer and throttle position switch, using the manifold for ground. I put a jumper on the ground wires to a temporary ground until I could get in there and move the wires permanently. The surging stopped. Viola! So, today I moved the wires to a good ground. Idle stabilizer no longer works and surging is back. Argh!

SharkSkin

I'd say put the jumper back and see if the surge goes away. If it does, check to see if there is any voltage between the two points, then check from the jump post to each point. Also you may not want to disconnect the battery at this point because it would reset the brain... but doing so would allow you to safely put an ohmmeter between the battery - point and each of those ground points to see if there is significant resistance in either path...

bd0nalds0n

Surging is almost certainly a vacuum leak. Did you use blue loctite on the manifold bolts? They will loosen up with vibrations. Also, I think the gaskets compress over time. I have had to tighten up my manifold bolts very tight to avoid vacuum leaks. And Tony said "Tight Tight Tight" when he was chasing manifold vacuum leaks. I'd like to tell you what torque I used, except I didn't use a torque wrench , I just tightened 'em up with a regular ratchet. If I had to guess, though, I would say that I used more than 25 ft lbs.

I've also had some leaks around the copper elbow that attaches to the manifold and the hose that runs to the bypass valve.

Thanks, SharkSkin for the props. Hope the problems get resolved quickly, that's the most important thing. It can get frustrating getting everything right when all you want to do is drive drive drive.

bd0nalds0n

One more thing. When I had surging, my "easy" fix was to unplug the Idle Stabilizer Valve. Maybe the bad grounds are actually causing the ISV to NOT WORK, which eliminates the surging?

Tony

ill guess i will clarify to make certain.

Im mean "Tight" as in a tight seal....air tight seal... not neccesarily tight bolts. Use the tqs that Andy specs and beyond that, you guessed it, your on your own . You will strip threads very easily in the manifold if your not careful. While the "right stuff" is good, IMHO it is crap for trying to seal 2 surfaces like this manifold. it WILL SQUEEZE OUT, and if it isnt applied evenly it will just exagerate the problem.
This is what i did to seal the manifold...
As pointed out, mine is a "modified" set up so take all this for what its worth.
I placed and extremely thin bead along the base of the upper maniofld then bolted the two halves together. While the 2 halves were being held together via 6-8 bolts i masked the perimter around the two mating surfaces and spread a nice even bead OVER the joint. (if that makes sense) I will try and get a pic of it. It made a very nice, neat and good seal once the tape was removed. When cured i removed the 6-8 bolts clamping the halves together then lifted the entire assembley into place, then torquing it to values Andys stated. I went on to anther job and hour later went back and re TQ again. Havent touched them since. So it was sealed twice...1)along the joint between teh surfaces and 2)outside along the perimter.

Ok, im confused? There are 2 wires for the idle stabilzer when installed stock. All i did was snip those 2 and extended them to my new location? I didnt have to find a ground like you describe?
Im using a stock S4 throttle body so i cant speak for the throttle switch but the same thing should hold true i imagine? Snip the wires from stock and extend them?

Any time you change a ground point you could be inducing a ground shift in voltage. the idle stabilzer is grounded via the LH. By grounding else where you could be messing something up perhaps?
Surging could also be a rich mixture..operating at a limit of the idle system. I wish i could nail it for you as i did have the same thing at one point. Between sealing the manifold and adding the 24# injectors, my probelm is gone...
Have you tried dropping your idle fuel pressure?
just things that i have tried....

HTH




What you see below, as shipped to me, IMHO aint gonna cut it.
(yoooz'es may have been different,)

bd0nalds0n

I've never taken my manifold apart. I was talking about securing the manifold to the heads. I was unaware that anyone has ever specified a torque value. FWIW, the cork gaskets work much better than the rubber ones.

Bill Ball

Tony:

Yes, instead of cutting and extending the ground wires for the MAF and TPS, I moved the both ground wire bundles with the devices and just regrounded them on the manifold. Seemed to work fine for weeks, then the ISV and TPS became erratic. So, I jumped the ground to the body, thinking the manifold was a bad ground. That seemed to fix it. Worked great until I decided to actually move the ground from the manifold to the new ground point and get rid of the jump.

In terms of sealing, Andy now does what you describe, Tony, running a bead on the outside as well as between the plates. Also, Brian, he now uses a compressed gasket and calls for 30 lbs of torque.

Bill Ball

I intially grounded the wires to the manifold. Worked fine for weeks. The the ISV and TPR began acting up. I ran a jumper to one of the injector rail bolts and then temporarily to the crossbar bolt. Everything then worked great. I decided to move the ground bundles to a bolt on the block - a bolt that holds the water outlet at the rear of the block. It showed continuity with the block. As soon as I made the change I disconnected the battery to reset the brain and ran the Hammer idle adaptation. The engine quit before competing the adaptation and the idle surged when driving. It quit every time I ran the idle adaptation. Bad sign. So, I moved the ground to a bracket that bolts the air pump diverter valve to the block. No improvement. I removed the ground bundle and jumped it to the crossbar. Idle stabilization still fails, but it did not surge on a brief drive. It got late and I put it away for the night.

John Speake

Hi Bill,
As far as idle stabilisation is concerend - it may be that there is a problem with fuelling, preventing a sucessful idle adaptation, as Tony suggested. I would strongly recommend only grounding direct to the block.

If the idle surges, then it tells you the ISV is receiving a signal from the LH, but it can't adapt the idle, so the loop just "huints" up and down while the system trys to adapt.

It is quite likely that you had the steadier idle when the ISV wasn't properly grounded.

The idle stabiliser system has a limited range, so air leaks, and fuelling issues can prevent it from achieving stabilisation.

I assume you are running with an O2 loop ? Is so, do you get any O2 loop warning fault codes ?

Is the CO OK at idle ?

I don't have any theories on the #7 misfire, maybe the injector. The only other car I know that had a similar problem, it turned out to be cam timing. This also casued a one cylinder misfire. But in your case I assume all was well before the s/c install ?

Regards

Tony

those steps i think take care of both...securing the halves together and thus when on the engine securing the whole unit to the heads.



ok..back on topic.
Id just conenct the ISV back to the orignal wires with whatever length wire you need to make the ends meet.

Bill Ball

That's what I plan to do today. Remove the rear SC intake horn to get to the correct ground point. In the process, check the gounds and other wires for the ISV and TPR. Then swap the #7 injector and proceed through the rest of the rule-out tests for the dead hole on idle.

Appreciate the moral support and advice.

mark kibort

sure the cap has been checked on that applicable side?
just a streatch. also, check to see if the coil is shorting out from the coil wire to the side low voltage posts.
had both of these hard to nail down causes for a couple of rough running and missing issues.
MK

G Man

OK Bill. I read this thread before I went to bed last nite and I actually had a dream about helping you fix the car. It turned out to be a weak battery causing your trouble. I thought I should throw that out there to get it off my mind.

Bill Ball

Good one, Gman. I've been dreaming about this too.

Today I established a good ground, swapped the affected injector to the next hole, carefully sealed a few potential air leaks. Car started and idled well. No surging. As the car warmed up the old roughness and miss started to appear. Will see tomorrow if the dead hole moved.