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Breaking up/Sputtering

Tommyd

Well-known member
Joined
Jan 18, 2013
Messages
106
Location
Fishkill, NY
So after a long few months and a move back to the east coast, 610 was up and running and running quite good. In the midst of fine tuning and adjusting all the little things, she started to sputter a bit at WOT. Then during my 5 mile drive home it got gradually worse to the point where I had to get towed home. She'll start but wont stay idling unless I'm giving her some gas. Everything is logging good, but anymore than 7-10% throttle she breaks up bad and wont stay idling. The tach fluttered a bit so i assumed CAS, but that doesnt seem to be the issue as I installed another and still having the issue. Everything is logging alright while running, no CELs. Tomorrow I was planning on checking the coil packs/plugs/wires/transistor after work, just wanted to see if anyone else had similar issues at one point. Thanks.
 

cheekychimp

Well-known member
Joined
Apr 19, 2004
Messages
7,333
Location
East Sussex, U.K.
I have had this a number of times but unfortunately there are a number of things that can cause it so you have to eliminate all of them. Things I can think of that 'might' be the culprit: -

Fuel - Fuel pump on it's way out or an obstruction. I think the obstruction is less likely personally (deterioration was too quick)!
Air - Try checking your I/C couplers. I had a rip in one. Car idled fine but as soon as I got into boost I got a leak and started sputtering.
Spark - Bad plugs and/or wires check these when you check the rest of the ignition system, coil packs, transistor etc.

I was leaning towards the I/C coupler until you said it now won't idle. Unless your coupler came progressively loose and is now pretty much off I don't really see that being it. Although ironically a completely detached I/C coupler does make the car run like crap!

Bad news is there are probably a dozen other things that could cause this but most should fall under the three main headings of fuel, air and spark. MAF also comes to mind.
 
Last edited:

b00st33d

Well-known member
Joined
Feb 6, 2006
Messages
239
Location
Central, CA
I have this problem too and pinpointed the problem to the MAF harness. I have a 2g MAF and the harness was cut and hardwired to the stock harness, which might indicate a connection issue of some sort (I am planning to fix mine next weekend). What are you using to tune?
 

strokin4dr

Well-known member
Joined
Aug 30, 2005
Messages
2,770
Location
Savannah, GA
Try a known good power transistor. I've had a couple crap out and it will give a strange tach reading while barely wanting to run. Sounded like a Subaru!
 

Tommyd

Well-known member
Joined
Jan 18, 2013
Messages
106
Location
Fishkill, NY
I have link v3 and my maf raw is giving me normal readings, which is why I didn't think of that but I Will double check. I know it's not a boost leak, but I forgot about the fuel filter I installed and I'll check the regulator too while I'm at it. I wanted to check the transistor but I don't have an analog multi meter or know anyone around that has an extra. If it's not fuel/maf it has to be spark. Just baffles me how it started slow and barely there, 4 miles later it prevented me from driving
 

Tommyd

Well-known member
Joined
Jan 18, 2013
Messages
106
Location
Fishkill, NY
Well I just snuck home between service calls(I'm a plumber) and sure as hell this time threw a Volume Air Circuit Malfunction (0012 I believe) but went off on its own almost immediately. I unplug my MAF and it actually idles perfect and I could at least move it in the drive way in limp mode. Its a 2g hacked maf wired into the stock wiring, all the connections are shrink wrapped and appear good. Probably a good time to switch to SD I guess
 

cheekychimp

Well-known member
Joined
Apr 19, 2004
Messages
7,333
Location
East Sussex, U.K.
Er ... no! But look on the bright side, this only took 5-10 posts and several days to diagnose /ubbthreads/images/graemlins/smile.gif. Plus it's not a ridiculously expensive fix.

I'd be pretty happy to be honest!
 
Last edited:

Tommyd

Well-known member
Joined
Jan 18, 2013
Messages
106
Location
Fishkill, NY
Not upset at all, SD stuff should be in tomorrow and Friday will be spent learning how to dial in the VE table. I just have never seen a MAF do that.
 
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