Weird backfire issue

***popo8*** · 09-20-2013, 09:02 AM

.50 is a BIG gap

MEMBER @ LTXtech.com

**Sahara54** · 09-20-2013, 03:37 PM

Originally Posted by popo8

.50 is a BIG gap

MEMBER @ LTXtech.com

I hope he meant 0.050. Lol

***popo8*** · 09-20-2013, 07:31 PM

Originally Posted by Sahara54

I hope he meant 0.050. Lol

lol... me too. but i still think thats alot of gap. no?

MEMBER @ LTXtech.com

**atufo1475** · 09-20-2013, 08:15 PM

Umm I definitely put .050 go look lol but that's exactly what it reads right in front of the radiator on my car.

It says "gap spark plugs to .050"

But I talked to one of my coworkers, an ASE master certified technician and he said if a plug wire was burnt or broken you'd be able to feel it more than just at redline.

He test drove it and seems to think it's my redline but I'm not totally convinced, it was also raining so he didn't want to slam on the gas to much.

But he used his crazy nice code reader, Snap-On of course...

And came up with these codes...

This one was from the engine scanning section..

(84) 3-2 Downshift Feedback Fault

(27) EGR Electrical Fault (QDM)

(43) ESC Module or Sensor Circuit Problem

In the brake section I got this...

(51) Rear Axle Nut Fail (Motor free Spins)

And last I checked my lug nuts/studs are not lose lol idk what the hell is going on..

Scanned for transmission codes and got "Power exceeds module" or something like that and he said he's never scanned a manual car that was capable of producing trouble codes.

**atufo1475** · 09-20-2013, 08:18 PM

P.S sorry if it sounds rude about the .050 thing I wasn't trying to be at all! (just re-read and don't like the way it sounds) I greatly appreciate the help everyone is giving me!

Thanks guys!

**Injuneer** · 09-22-2013, 07:37 PM

DTC 84 only has that description if you have an auto trans. Since you have a manual trans it means your Skip Shift solenoid has been disconnected (isn't everyone's??

).

DTC 43 is a problem with the knock sensor circuit. When that codes sets you get almost continuous knock retard, based on the engine operating conditions. You could feel that as a loss of power. Needs to be corrected, and it's easy to track down.

DTC 27 is a problem with the EGR vacuum solenoid. Did you delete the EGR system? And there is no "QDM" on a 95. The last year that there was a quad driver module in the ECM was 1993.

I'm surprised the technician didn't realize any of this.

You need to use Shoebox's code list, which is specifically for the LT1. You can't rely on the generic code lists that are programmed into general purpose scanners.

http://shbox.com/1/Dtcs.htm

With regard to the ABS system, it has nothing to do with your lug nuts/studs being loose. DTC 51 means the rear ABS motor spins free. I'm no pro with ABS, but the "nut" would be the part that is driven by the screw in the ABS motor pack (drivers side front fender) that drives the nut that moves the two rear brake pistons and "home" them. The screw turned to elevate the nut, and the nut never reached the top of the screw, at which point it would have shown resistance to turning the screw.

The T56 from 1994 on has trouble codes for the skip shift solenoid, the reverse lockout solenoid, and the vSS sensor.

**atufo1475** · 09-22-2013, 08:05 PM

Okay thank you! Really needed some more information.

And yeah he could never really get the car to backfire, yet again it was wet and I have rather bald tires so he was a bit hesitant.

But on his scanner it wasn't really accurate about what the codes were for except for egr and abs.

But the numbers were obviously correct.

And yeah I've been unsure on the shift shift solenoid.

Is it normal for the shift shift light to go on occasionally in 1st gear?

And yeah I found a list on ls1 tech with a better breakdown of all the codes.

So basically I should be looking into my knock module.

But injuneer this is crazy..

I pulled the cover for the knock module, and it was missing the gasket, there was only a little bit of it left.

So I through some rtv all over it and let it dry, took my car out and it hardly does the backfire/misfire at wot!

Does that make any sense?

I did notice some grills that looked like speaker grills on the top, but figured those were there to dissipate heat?

Any of this sound normal to you?

But thank thanks for replying!

**fullforce** · 09-22-2013, 10:37 PM

Just a guess but maybe its running lean? and now that you opened up the exhaust a little more it leaned it outjust enough to make it pop? I doubt it but who knows.
If it was my car id probly be looking for another opti though, or getting that one warrantied.