Alright, here’s the deal. I have been having some issues lately. Back in Jan I had a failing fuel pump, before I could replace I was in an accident. Some of you may have seen my pics of my car vs a pig in my profile.

Anyways, after I finally get my car back from TX in mid March I finally get a chance to do my LS2 coil swap. That went okay after a couple setbacks; I finally picked up new modded fuel pump from swoope. The swap went great, after I was still getting misfires…figured out I had bad coil. I replaced it and every since I have had start up issues, I made sure to check all connections and everything is fine…hooked up a timing light to make sure I was getting spark and that checked out fine. It kinda feels like it is having fuel pressure issues...had a couple people tell me it sounds like it wasn't getting enough fuel on start up. I had the battery checked and it is in perfect condition. So, I’m at a loss with that.

Now, I have noticed the car is extremely sluggish before 4k rpm, after I get above 4k it’s full power like normal. I was thinking maybe when I swapped out the fuel pump it got some gunk in the fuel lines and was clogging the primary fuel injectors. I dunno? I have run 2 treatments of STP fuel system cleaner through and finally got a hold of some BG44K and ran that through, but still have the same issues.

I pulled the plugs also and they were in great shape, I swapped them out when I did the coil swap. I was thinking of swapping my cat back out for the midpipe, thinking the cat might be clogged. I haven’t thrown any misfire codes since I got the coil issue fixed and no other codes have popped up in a couple months. If anybody has an idea what else I could check for that would be awesome. Oh yeah, I have a low idle issue too.

Car stats:
2004 MT; 77000 miles, 40k on the rebuilt motor; regular oil changes (10w40 Syntec/50 WT Redline) depending on the season; K&N V2; LS2 coils; HKS 3” Hi Power

Nic

 

swap out the injectors or have them blueprinted, just a wag

 

Thanks Team, I am really leaning toward the injectors...just don't have that kinda cash right now.

 

What are the A/|F like...with crappy injectors it should be strange....either rich from sticking/leaking...or Lean from being partially plugged.

I can't see having low speed problems with the pump and it being normal higher up..should be the other way around

Not throwing any codes?? SSV stuck open? Dunno?

 

1) Put a pressure gauge on the fuel inlet pipe.
2) Put a timing light sequentially on the plug wires, tape it to the windshield and drive.

Probably the two most telling diagnostics I can recommend.

 

I was just listening inside the engine bay and I noticed a very distinct sound coming from the intake manifold. It sounds like a flapper type noise, and it is definitely coming from the intake and not the motor. I'm wondering if one of the SSV's is actually stuck or if one of it's vacuum lines came loose and the valve is stuck open? Wouldn't that cause an issue with throttle response at low rpm's?

 

yep- agree. That would be the best to do.
hard starting and low rpm power sounds to me it MAY be a fp issue. Swap your old pump back in and see if your low speed, cranking changes?
Still that is just playing--do what MM suggests to know for sure.
Secondary's could be stuck open?
OD

you posted before I could! Yep if secondary is stuck open then you would have a cel to that affect. those sx's could i guess be caused like that. vacuum line also. no cels?
here a sound check all the lines 1st?

 

A bad fuel injector O-ring can make some really strange, disturbing, cyclical noises.
They are surprisingly failure-prone.

 

Check the SSV..it is right behind the thermostat housing area...it should be closed at idle and open with increased RPM's.

 

yep he is going to have to go down the list.
may want to take a vacuum reading? easy to do.
OD.

 

Agree.
You can open/close the SSV valve easily by hand.

 

It's a good thing I'm not working right now...I can actually spend a little time on it this week. I'll check the SSV and go from there. I'm gonna order a FP gauge this week from Summit and get that installed too. If it end up being an injector, it's just gonna have to wait a little bit til I can get the funds together.

 

I figured out the noise, the SSV is chattering. I manually opened it and the chattering stopped...I'm gonna post up a vid soon to show what I mean. And I'll post up a vid of start up.

 

Weird. Is the valve loose? Can you pull it in and out.
Maybe the two bolts holding the valve in came loose.
Or maybe the actuator isn't holding the valve closed?

 

It's the actual plunger itself, like it isn't sealing all the way closed at idle. If I barely hold the valve open the sound stops, I've never seen or heard of it before either.

Here's the vid of start up:


And here is the sound from the engine bay:

 

Are you referring to the actuator when you say plunger?
Because the SSV valve is a cylinder and acts like a ball valve.

 

The actuator.

 

That sucks... might be a challenge replacing that inside the engine compartment.
Its only held on by one bolt, but an e-clip connects the actuator's rod to the valve.
That would be the challenge.

 

Here's the vid with me manually opening the actuator:

 

Wow.. that is crazy.
Hard to judge by the video, but is the sound coming from around the valve or the actuator?
If the bolts came loose holding the valve in, the actuator would be moving/vibrating with the sound.
But the actuator doesn't appear to move at all.
That is really strange.

 

There might be a pinhole leak in the actuator diaphram.....or the solenoid is crapping out? I would check both...

 

It's coming from the actuator...if I put my finger on it there is no sound as soon as I release it it chatters as you can hear. The actuator does not move at all...I'm at a loss on that one. I'm wondering if that could be causing my start up issues though, say the SSV isn't staying fully closed at idle? I dunno, I'm sure I still have a fuel injector problem but it may turn out to just be the valve. Who knows!?

 

That makes me wish I would have kept my extra actuator from my VFAD.

 

nick,

injectors, i am still fighting the issue to some degree. but not as bad. send me an email to my screen name at gmail.

i have a few laying around.. also i would do a compression check.. you motor is doing the same think mine does to the t..

not much power or tq till 4500 rpms. then it is fine.

btw have run ~ 5 track days like this.. i wish i had taken the time to flow some fuel through the rails before i replaced the primarys.

btw, i could see one of the primarys was very clogged.

and i have to tell you swapping them out is a bitch!


beers

 

Come on Swoope.....you should have the UIM down to about 20 minutes by now

You need a lot of crap to plug up the filter baskets on a set of injectors.....I had a set out of a 87 FC that went 200K miles...and they were clean as a whistle

If you think you got a bunch of crap in there....pull the UIM and both fuel rails..and then flush out the plumbing. Send the injectors in to be cleaned and flow tested...should only be about $20 per injector..and then you will be sure

I would fix the SSV actuation first though...it idles like crap with it open