93 typhoon backfire

[DariusD8793]

My 93 typhoon I recently bought back fires in the exhaust constantly and I can’t figure out the problem. It has a TT chip, new 60lbs injectors, new racetronix fuel pump, and a 3 bar map sensor and a plx wideband. It was backfiring before I replaced the injectors and everything else.
There were no codes until I replaced the cap and rotor and it now has code 42. Can this code cause backfiring or is there something else I should check to figure this problem out?

 

[Slyclone]

Timing? Brown/tan wire passenger foot well. Distributors off code 42 may be EST set timing procedure

 

[DaveP's Ghost]

Firing order correct?

 

[DariusD8793]

Timing? Brown/tan wire passenger foot well. Distributors off code 42 may be EST set timing procedure

That’s what I’m thinking. Is there a procedure i should follow to setting the timing, if so do you know the procedure? Thanks!

 

[DariusD8793]

Firing order correct?

yes

 

[2500avalanche]

Check your timing. I am guessing that is the issue. Is it backfiring at idle or under accelration?

 

[Slyclone]

That’s what I’m thinking. Is there a procedure i should follow to setting the timing, if so do you know the procedure? Thanks!

Yes, your going to need a 9/16 or 14mm distributor wrench. Possibly a " stubby " type of your really unsure.

In the pass. Side foot well there's a brown and tan wire under the carpet where your feet go- towards the TOP/end of the carpet closest to the under dash. Pull that shit back and the wire is right there. Single wire, black connector. Remove carefully.

Using a timing gun? Assuming you know how to shoot timing your going to want to use that 14mm or 9/16 and loosen the distributor ever so slightly. Shoot timing from driver side in between alternator and fan. There's index marks on the balancer the strobe light will enhance the visual ability to see the marks. Based on the location you want to adjust the timing very lightly by Turing the top of the distributor back or forward watching the index mark on balancer. Once you with on time, you just plug the black connector back in ( turn vehicle off) and the computer handles timing from there.

That should get you close to where you want to be. You mentioned turbo tweak. There could be something that we all don't see also, that could be causing the back fire such as : improper or over fueling, incorrect setting and or incorrect readings. I'm not 100% firmilliar with a PLX. You should see correct air fuel values.

You can check, and double check your wires again. I know I put one on the wrong spot once. It happens.

 

[DariusD8793]

Check your timing. I am guessing that is the issue. Is it backfiring at idle or under accelration?

At idle, I’ve never taken the truck out because it backfires.

 

[MotoCam360]

At idle, I’ve never taken the truck out because it backfires.

Since the TT chip was installed, has the vehicle battery ever died? If so, the chip loses it's settings

 

[gmemony2]

Since you have had the backfire prior to installing all the upgrades, your best bet as everyone has said is to set your base timing and work forward from there.

If you don't have a scanmaster g I suggest you get something of the like to get your counts on everything and make sure the truck is running properly.

Then working with TT to get the base tune set would be a good idea. He's really good about doing that or you can talk to people on that board for tips.

Honestly, figuring out that backfire prior to doing any upgrades would have been the best thing to do. No chip or box or new tune will fix that.

GL

 

[DaveP's Ghost]

Before you set timing using the factory marks, be sure the balancer ring hasn't slipped. If it has, you (or anyone before you) will never get the timing correct.

 

[DariusD8793]

Since the TT chip was installed, has the vehicle battery ever died? If so, the chip loses it's settings

No it never died, but it was doing it before I installed the chip and I only put the chip in because the fuel system wasn’t holding pressure, so I put new injector and a new fuel pump to fix it that issue

 

[DariusD8793]

Before you set timing using the factory marks, be sure the balancer ring hasn't slipped. If it has, you (or anyone before you) will never get the timing correct.

Okay I’ll check it thanks!

 

[DariusD8793]

Since you have had the backfire prior to installing all the upgrades, your best bet as everyone has said is to set your base timing and work forward from there.

If you don't have a scanmaster g I suggest you get something of the like to get your counts on everything and make sure the truck is running properly.

Then working with TT to get the base tune set would be a good idea. He's really good about doing that or you can talk to people on that board for tips.

Honestly, figuring out that backfire prior to doing any upgrades would have been the best thing to do. No chip or box or new tune will fix that.

GL

I’m going to check the timing this weekend. The only reason I put the chip in was for the new injectors and fuel pump because it wasn’t holding any fuel pressure and running lean, I figured I’m better off putting those in now instead of buying stock stuff just to take it back out. Thank you!

 

[wildphil]

Listen to Dave about the slipped ring on the balancer. I had it happen on two of the three SyTy that I have owned. It happens very often and will screw up trying to get the timing set for sure.

 

[DariusD8793]

Okay. Great. HOW do you "check it"?

Seems like you're just blowing the suggestion off as something I pulled out of my ass. It's not. This is a well-known condition with the SyTy. The detonation shears the rubber, and the ring slips. There's no f-ing way to "check the timing" if the balancer ring has slipped.

I'll add something else: Have you noticed that there are TWO marks on the balancer ring? Do you know which one is the correct one to use, and where the other one should be when the timing is set correctly? If the incorrect one is used, I'm not sure it would even start, but possibly this is the problem?

Regardless, the balancer ring is important that it be in the correct position in relationship to the crankshaft. I've owned 7 of these, and been working on SyTy a really long time. So have the 3 guys that "liked" my post regarding the balancer ring. I've found at least a dozen slipped balancers on SyTy. In most cases it took 30 seconds to determine. If my primary method for checking isn't positive, but I am still suspicious, I go to a back-up method that is pretty conclusive and takes about 2 minutes. I'm purposely not disclosing how to check it. Tell me how you verified that the marks are correct, and if it still backfires, we'll think of some other ideas for the backfire.

Well I was going to determine the best way to tell if the balancer slipped and go from there, but I’m confused on how you said there’s no way to “check it” but then you have “two methods”? That doesnt make sense and I wasn’t trying to blow you off and already knew about the balancer spinning. I was just acknowledging your comment and thanking you for your response and didn’t mean to offend you. Thank you again Dave

 

[DaveP's Ghost]

To check for balancer ring slipped:

Method #1: Grab it, and try to turn it by hand. It almost always is so loose that it does. (Easier said than done. Can't really reach it from the top with the fan in place, and from the bottom the lower heat exchanger, exhaust crossover, and sway bar get in the way.)

Method #2: Rotate the engine while watching the marks. (You can bump it with the starter to get close, and a socket on the alternator pulley for the last few degrees.) The first mark "goes by", line up the second mark in the bottom of the deep notch on the timing tab. Remove #1 spark plug. Probe for the piston with a skinny screw driver. The piston should be at the very top of the bore, just below the plug hole. If it isn't, the ring has slipped. (It doesn't matter if #1 is on firing or overlap. TDC is TDC. If the marks are lined up, the piston should be at the top of the bore.)