Weird symptoms and car won't start. What's your take?

[CajunKenny]

I drove my car to my destination, turned it off, and went inside. Nothing abnormal there...

Got inside to leave and turned the key and all it does is sputter, backfire, and try to start. It turns over nicely without any problems. During this process my boost gauge hits about 25psi because of the backfire. Right...?

Now, here's the interesting part. About two weeks ago I tried to fire her up after 2+ years of being down. (The details for that are probably irrevelant.) She did EXACTLY the same thing. Just turned over and sputtered and backfired every now and then. Then I pulled the #1 plug to verify spark. Couldn't really verify it because I was alone; but, I did turn it over to clear the #1 chamber. After that, I put the plug back in and she fired right up and purred like a kitten.

She has run strong, hard, and flawlessly for the past two weeks with the exception of a bad/going bad BOV.

Tonight I pulled the #1 plug and the plug was dry; but, I could smell fuel while turning it over.

So, I have fuel, pretty sure I have spark because of the sputtering and backfiring. I think it's something intermittent; but, not sure.

What are your thoughts?

 

[zachm611]

have you checked codes.. maybe check timing..if its still got the gas from 2 years ago thats bad..big boost leak maybe, i had a really big one at the 3000 pipe to the TB and it would start sputter and die.

 

[88YotaTurbo]

Ignition Timing? Loose Cam sensor etc...? any engine error codes? Air leak after AFM wouldn't explain fuel smell though unless it is running ultra rich from detecting an air leak.

 

[CajunKenny]

Haven't been able to check for codes yet.

No bad gas. I drained out the old and have been running new/fresh for the past two weeks.

Timing...doubt it. Unless something is loose and shifting around; but, you wouldn't think so because it's been running great!

Air leak...? A bad bov wouldn't cause this much grief would it?

 

[88YotaTurbo]

A bad BOV would cause a massive air leak , if it is not sealing.
Why couldn't you check for codes? Car doesn't have to be running to do that.

 

[wildfire0310]

check codes that would be the biggest help

 

[djordan97]

can't check codes cause car is 5 miles from him.

 

[Apollonius]

check the connection to the AFM

 

[MDCmotorsports]

Check the connection to the afm...
-Check for boost leaks...
-Replace your spark plugs. Autolight 3923's are nice and cheap.....

 

[jdub]

Wiggle your CPS wiring while a helper turns it over.

 

[IwantMKIII]

Wiggle your CPS wiring while a helper turns it over.

x2, exactly what i was thinking when i read through first post, those wires get people all the time

 

[CajunKenny]

Ok guys.

I took the day off work to get this figured out. Plus, she's not sitting in the "Beverly Hills" part of town if you know what I mean...:aigo:

I'll try all above suggestions starting with checking for codes then messing with the CPS wiring. Fortunately, I have a second motor so I have a second set of plugs, wires, cps, etc... I'm bringing all those things with me.

I'm heading to the kitchen for some eggos. Then it's off to rescue my damsel in distress.:biglaugh:

Thanks for all the input everyone! I'll post my findings!

 

[CajunKenny]

Ok. Here's what I did. First I tried to fire it up; but, still the same...

Then, I popped the hood and unplugged the AFM and plugged it back in. Then I pushed down on all plug wires, coil pack connections, and wiggled the CPS wires.

Hit the key again and she fired right up. My guess is either a bad AFM or CPS wire.

So, kudos to all that guessed wiggling a wire or two.:icon_bigg

Ha...but, now I have a different problem.

While driving normally, my boost gauge indicates that it is boosting early and not showing as much vacum as normal. I can also hear the turbo spooling earlier than normal. Boost leak? Bad BOV? Could the sputtering and backfiring caused this?

 

[jdub]

It's the CPS...very common problem. The car will start and run with the AFM unplugged

Suggest you check codes...The timing signals from the CPS may not be getting to the ECU as to effect timing advance. You also could have a boost leak.

 

[CajunKenny]

I'll check the codes this evening.

Could a stored code cause early boost and/or symptoms of a boost leak?

I've been getting a fluttering type sound on decel after boosting. I'm hoping it's a bad BOV because I have a Bosch replacement sitting in the garage that I'm going to put on tonight. I hope that resolves the issue!

 

[jdub]

I was referring to the drop in vacuum, but that is a symptom of valve timing.

Check your codes and check for boost leaks.

The fluttering does sound like it's the BOV.

 

[CajunKenny]

I looked at the TSRM link for areas of possible boost leaks; but, is there a down and dirty way to check? Something easier than hooking up a gauge that I don't have?:icon_bigg

 

[jdub]

DIY Boost Leak Tester...read the entire thread closely:
http://www.supramania.com/forums/showthread.php?t=19718

Or, you can check every clamp/hose from the turbo to IC to intake manifold. Hose cracks are NOT always obvious.

Based on what you said before, I would suspect the BOV is leaking.


BTW - the search feature on this site is a wonderful thing

 

[CajunKenny]

Thanks jdub!

 

[IwantMKIII]

While driving normally, my boost gauge indicates that it is boosting early and not showing as much vacum as normal. I can also hear the turbo spooling earlier than normal. Boost leak? Bad BOV? Could the sputtering and backfiring caused this?

I was referring to the drop in vacuum, but that is a symptom of valve timing.
.

again, x2. I recently ran into this when i redid my timing, i started boosting at 1500RPM :aigo: barely stepping on the gas. I realized that later the cam gear had jumped a couple teeth....its all it takes.