Timing Question?

[ccool416]

I have a 95 xlt ave the following mods..K&N intake, Msd distributor and coil and ignition, Jet module, headers, etc...My truck kicks ass, I can brake traction easily with brand new 33x12.50 mud tires on 15x10 inch Mickey Thompsons..Anyways I smell strong gas from my exhaust,almost like it's not all burning? Is this normal? should I advance my timing? I have read a few times people suggesting to advance timing by 10 degrees...Is it worth it? Also I have no cats..The smell makes me not want to run with the back window down..

 

[Broncobill78]

Did it do this before you installed the module ? If you can *smell* fuel in the exhaust then it's obviously running rich, but before jumping to that conclusion are you SURE it's in the exhaust and not a leak in either the supply or return line OR that it's not an injector or coming from a bad schrader valve ? If you're certain it's in the exhaust then sure, you have a problem there. The chip *should* be keeping you pretty close to 14:1 regardless of whatever other mods it allows and at that ratio you shouldn't be smelling it. Not knowing what Jet chips allow or ignore I have no idea just how it does it's thing but I'd take a guess at either the chip or a faulty O2 sensor. How old is the sensor, they do have a limited service life and it may well be that the chip either ignores input from the O2 sensor or blocks it from illuminating the MIL, which leads to the question of whether or not the ck engine light (MIL) is on or if there are any stored codes. Have you ck'd ?

10 degrees is an awful lot, I don't know that I'd suggest advancing it by that much on top of what you're already running and certainly not on something as processor orientated as a 95'. Until you start changing the cam & intake you really shouldn't need to mess with the timing very much and certainly not by that much. You can certainly try goofing around with a few degrees either way and see if it helps but I wouldn't expect very much from those experiments. When you replaced the distributor *how* did you time it and to what degree did you time it ? Did you change everything at once or piece by piece ?

 

[ccool416]

Did it do this before you installed the module ? If you can *smell* fuel in the exhaust then it's obviously running rich, but before jumping to that conclusion are you SURE it's in the exhaust and not a leak in either the supply or return line OR that it's not an injector or coming from a bad schrader valve ? If you're certain it's in the exhaust then sure, you have a problem there. The chip *should* be keeping you pretty close to 14:1 regardless of whatever other mods it allows and at that ratio you shouldn't be smelling it. Not knowing what Jet chips allow or ignore I have no idea just how it does it's thing but I'd take a guess at either the chip or a faulty O2 sensor. How old is the sensor, they do have a limited service life and it may well be that the chip either ignores input from the O2 sensor or blocks it from illuminating the MIL, which leads to the question of whether or not the ck engine light (MIL) is on or if there are any stored codes. Have you ck'd ?
10 degrees is an awful lot, I don't know that I'd suggest advancing it by that much on top of what you're already running and certainly not on something as processor orientated as a 95'. Until you start changing the cam & intake you really shouldn't need to mess with the timing very much and certainly not by that much. You can certainly try goofing around with a few degrees either way and see if it helps but I wouldn't expect very much from those experiments. When you replaced the distributor *how* did you time it and to what degree did you time it ? Did you change everything at once or piece by piece ?

well, actually I have had the chip for years..as well as my disributor. I pulled it out as 1 piece kept the timing the same. Recenty I took off the heads and had them re-done new timing chain new oil pan gasket. Did all the fliuds and put on headers..I actually did alot more and all in one shot..The gas smell has been since I put it all back together...I have replaced the o2 sensors before, It has been a few years though..No engine light is on, I will check the codes this weekend. When they went bad the first time, the mil came on...I am pretty sure it is from the exhaust, it is noticeable as soon as i roll down the rear window when driving. How can my truck be running so good if the fuel is not burning properly?

 

[Broncobill78]

When you added the headers did you change the exhaust ? If you change from the stock side-exit and shoot it straight out the back this is a very common problem. The low-pressure area behind the truck tends to swirl the exhaust and if you open the rear window it will **** it right back into the cab. If this started right after changing the exhaust outlet location then I'd say that's the problem.

 

[mbtech2003]

spec. timing is 10deg BTDC with the timing bug out. i'm running about 16-17 deg BTDC right now. but with 92-93 fuel (wich i run). if u do advance the timing alot u will haveto switch to prem. gas so ur engine doesnt ping.

Oh with no cats ur gonna get a fuel smell, no mater what u do.