3800 Car Barely Idles..Won't Start w/SC Belt Off

[sr71_rgl]

Sup Fellas. I was on my way home from Home Depot and pulled up to light and the car started to sputter. I limped my car home and it had no power and what felt like a super bad misfire. The front 3 plugs looked good as did the wires. I replaced the rears even though they looked good too but replaced them anyway cuz they're a lil harder to get to. The rear wires looked good too. The car started and ran just as shitty as it did before. That's when I noticed the boost bypass was freaking out...going up and down (fluttering so to speak). I tried holding it either up or down w/my hand while it was running and it still ran like crap but didnt die (really wanted to though). So I thought removing the SC belt would remove the bypass from the equation (SC rotors spin smoothly by hand). Now the car won't even start. It cranks and I smell fuel. The only related code was P030 for random misfires. Could a fubarred boost bypass be causing all my problems? Or would it act all wierd from a vac line that broke/fell off?
thx!

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[gtphale]

sounds like a vacuum leak or a blockage of the air intake somewhere.

 

[sr71_rgl]

Originally posted by gtphale@May 21 2006, 03:05 PM
sounds like a vacuum leak or a blockage of the air intake somewhere.

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thx for the reply steve. I checked the intake and it's not sucking in coolant from a TB spacer leak. Would a bad boost bypass stick open or closed? I'd think the motor would at least start w/the SC belt off but still run shitty. Now it won't even start. I also forgot to mention I filled up w/Shell 93 not more than 20 mins before all this shit started happening? Could a bad tank of gas cause all this to happen so quick?

 

[Sinister Drag Designs]

could be both, i blow vac lines all the time and that is exactly what my car does
my bypass is removed tho
when i was SC my bypass blew a vac line off it, i was told this is rare and i was the first by what vendors tell me.

WBS will have vac rerouting kits soon i hear

 

[sr71_rgl]

Finally got around to messing with it and so far have replaced the maf, plugs, wires, ICM. I haven't done the coils yet cuz the one's I just had mail ordered were cracked/unusable. Car runs just a little better and I think that improvement was from the new maf (old 1 was sending 0 mhz). Funny thing this time was plug 2 was oily. The others were clean. I haven't even started the car in 4 days but the oil looked fresh. LS1M shows only generic P030 with cyl1 showing occassionaly as the primary misfiring cylinder. 02s seem normal, maf freq is normal, LTFTs are normal so I'm assuming FP is good too but a gauge is pretty cheap so I'll check that later. Scanner shows 22 inhg but my guage is spazing out between 11 and 15inhg. I don't hear any vac leaks and all my lines seem ok. I'm going to locate some more coil paks and swap those again but if doesn't improve things I'm thinking a comp test or a borascope is in order. I just don't see though how oil on 1 plug could make it run so bad but not show a specific cyl misfiring...

 

[Mike K]

You're replacing the wrong parts...

Bob's dead on with the vacuum leak. It sounds like one of your lower intake manifold gaskets might have ruptured. There is definetly a leak somewhere and it's rather large which explains why the car won't start without the supercharger.

Spray brake cleaner, starter fluid, or some other type of evaporating liquid (rubbing alky in a spray bottle) around the intake and see what's leaking.

The reason the boost bypass is fluctuating is because it's controlled with vacuum and there isn't enough to keep it open.

 

[sr71_rgl]

Originally posted by Mike K@Jun 26 2006, 07:58 PM
Bob's dead on with the vacuum leak.  It sounds like one of your lower intake manifold gaskets might have ruptured.  There is definetly a leak somewhere and it's rather large which explains why the car won't start without the supercharger.

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I hear what you're saying but if I do have a vac leak wouldn't my idle air counts be 0 or close to that? Right now they're around 40. Would propane also be a good option for pinpointing a leak? Just listen for the idle to change right?
thx

 

[imported_Ron Vogel]

I'm thinking ICM.

I saw similar symptoms with Lee's car. We had a steady misfire on the #4 cyl, and noticed the coil was cracked. I went back to my place to get a spare coil, and put it on. Still misfire on #4, I switched coils to see if the problem followed, and it didn't. I tested the wire, and it was fine.

I doubt out of the blue a vac leak would pop up, and if a cyl or two wasn't firing properly, it would cause the manifold vac to drop. The manifold vac would be erratic, also causing it to fluxuate the BBV.

I would swap one with a known good one to diagnose. It's pretty easy to swap them, hopefully someone will let you borrow one first to check it out before you spend more cash on it.

 

[sr71_rgl]

Originally posted by Ron Vogel@Jun 26 2006, 10:42 PM
I'm thinking ICM.

Good suggestion Ron, but I got a spare from Ed and swapped it in and the car still idles/runs like crap. I'm waiting on a replacement set of coils from Ed as we speak cuz the 1st set he sent were cracked.

I doubt out of the blue a vac leak would pop up, and if a cyl or two wasn't firing properly, it would cause the manifold vac to drop. The manifold vac would be erratic, also causing it to fluxuate the BBV.

I gotta agree. I don't know how a big vac leak would just "happen" sitting at a light. My ltft's are actually rich (negative) at idle. Doesn't a vac leak cause positive ltfts? LS1M shows cyl1 as the occassionally misfiring cylinder, but not all the time like when a had a cracked plug. Maybe the new coils will fix it.

Anybody have a borescope I can borrow if the new coils don't fix it

thx for all the suggestions everyone.

 

[CoolGTX]

O2's? what they look like? rich?

 

[Aircal]

Have you checked fuel delivery?

 

[sr71_rgl]

Originally posted by CoolGTX@Jun 28 2006, 04:34 PM
O2's? what they look like? rich?

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02s look good now .... -6 or so at idle. But I remember turning up my AFC at idle while troubleshooting this and before I turned it up I do believe they were close to 16.4 which means vac leak. I'm going to check for leaks today and see what pops up. Thx everyone for the suggestions. I'll post an update later on for all those who are curious.