bad studder upon acceleration; with codes

Reply Subscribe

Thread Tools

Search this Thread

Jan 3, 2011 | 02:36 AM

branj70

Thread Starter

Staging Lane

Joined: Oct 2010

Posts: 64

Likes: 1

bad studder upon acceleration; with codes

When i hit the gas, even 1/4 throttle the motor misfires like crazy and won't go anywhere. But if its in park, it'll rev almost 100% normal. I gave it to my mechanic and it broke down on him during a test drive. It actually wouldn't start at all, even with a jump on it. You could smell the fuel building up from trying to crank it over, so i don't think its fuel related.

He had it towed back to his shop and managed to get it running and up on his lift where we shot down all the wiring with a little bit of water and turned the lights out... no sparks, arking, or anything. Got a code reader on it and we got this..

DTCs - 27, 26, 16, 11, 77

27 is EGR vacuum control solenoid

26 is the EVAP canister purge solenoid (the TB to EVAP solenoid hose is broken off at the TB, so theres a leak)

16 is the Distributor ignition system (low resolution pulse)

11 is the SES

77 for the manual cooling fan toggle switch installed.

Is 16 a complete give away to the opti??

Jan 3, 2011 | 08:33 AM

VinR1

TECH Fanatic

iTrader: (17)

Joined: Nov 2005

Posts: 1,933

Likes: 4

From: Central Texas

start cheap - plug the EVAP hose asap. May as well delete the EGR/AIR while there too since you have that code. It may not seem like it but a bad EGR will make you want to rip your entire ignition system out trying to find that misfire. Those two may clear up a big part of what you're experiencing. Also, before you go replacing the opti, have a parts store check your ICM first... I believe a bad one could throw the same code (correct me if I'm wrong)

Jan 3, 2011 | 01:23 PM

Gojira94

TECH Fanatic

iTrader: (4)

Joined: Dec 2009

Posts: 1,194

Likes: 36

From: Clayton, NC

Code 16: Check the opti harness connector where it plugs into the opti and at the other end under the EVAP purge solenoid. You may have corroded contacts or weak connection. Low res code without a code 36 is odd. If the opti was on the way out, you'd be more likely to see trash, bits of crud affecting the hi res part of the encoder wheel/ encoder unit. There are only 8 apertures in the inner diameter of the encoder wheel, and 360 in the outer diameter. Make sense?

Jan 3, 2011 | 01:57 PM

branj70

Thread Starter

Staging Lane

Joined: Oct 2010

Posts: 64

Likes: 1

We checked the contact at the top of the opti and it was clean. As well as the top one by the EVAP.

And i have to get through emissions, so i don't think i can delete the EGR/AIR. And i just replaced the TB to EVAP hose

Funny thing is, the guy i bought my car from told me that he had replaced the Opti last year. Now, i have no idea if he replaced just the cap and rotor, the whole unit, or was just completely full of crap. Isn't 16 more of an optical problem and 36 is cap and rotor?

I forgot to mention, a week before it started doing this, i flushed the radiator and changed a thermostat. All that day it misfired, then the next day it was completely fine and ran like a champ. Then the next it took a dump and this is where i'm at.

Last edited by branj70; Jan 3, 2011 at 02:24 PM.

Jan 3, 2011 | 03:09 PM

rich5368

TECH Regular

iTrader: (2)

Joined: Apr 2010

Posts: 442

Likes: 0

From: Cheyenne, WY

When you did the cooling system work, did you make sure to tuck rags around the opti to keep it dry? If it got all coolant soaked during your work there could inlie your problem.

Jan 3, 2011 | 08:08 PM

Gojira94

TECH Fanatic

iTrader: (4)

Joined: Dec 2009

Posts: 1,194

Likes: 36

From: Clayton, NC

Quote:

Originally Posted by branj70

Isn't 16 more of an optical problem and 36 is cap and rotor?

36 by itself would be classic opti failure due to either age & heat cooking the Mitsubishi J924 encoder to where it fails when warm, -or- like two I've replaced, the shaft bearing disintegrated and filled the groove between the encoder and wheel with crud/ shards of bearing. Worn out cap & rotor problems usually show up as random misfire codes. Code 16 alone is uncommon. Both sets of apertures on the wheel pass through the same encoder.

X2 on the coolant contamination. If this isn't your daily driver, it's worth a look inside the opti. You may find it's easy to clean, or you may find they guy just did a cap and rotor. Worth the experience so you don't ever have to fear the opti monster.

Jan 3, 2011 | 08:59 PM

TurboBob

Staging Lane

iTrader: (1)

Joined: Dec 2001

Posts: 92

Likes: 0

From: Detroit MI

The code 16 is "no lo-res pulses received after 720 hi-res pulses". So it indicates the lo-res pulses are not functional. It could be the opti harness, or the opti.

BigBird quit on me when I was picking my daughter up at school. It refused to start, so I had it towed home. I reset my ECM to clear any stray codes, and then cranked it over and it set a code 16.

I tried to get to the opti end of the opti harness but its really buried in there.

So I replaced my opti with a Chandler unit, along with a rebuilt water pump from waterpumpman.com and a new opti harness. Nice parts, the install went well.

The car runs great now.

But, a code 16 is pretty much a hard failure of the opti signal. In my case it was most likely the opti. But could have been the harness.

Like another poster said, you could take it apart and see if its an easy fix. I wish I had the luxury of time for that. The opti's are not complicated, just a pain to work on.

Good luck.

Bob