Engine issue

[michael evans]

Cam sensor may need to be slightly moved. Do you have XFI or Classic Fast?

Use the "Attach files" button and select the log file.

Another reason to get the TR6

Something is messed up for me as I can post pictures but so far can't get a log file on here.

 

[RmvBfrFlght]

Zip it first or change the filename extension. Then post it.

RemoveBeforeFlight

 

[michael evans]

another try to post log

I am using the oil sensor to log my methoal.

 

[TurboBuRick]

That worked. Are you doing the tuning?

 

[michael evans]

No, I just came from Brain Lorenz's dyno

 

[TurboBuRick]

I'm no expert with XFI but here is what I see,

The timing spikes up to 35 below 1100 RPM. That could be the cause of the backfire. I would flatten out the spark map in that area to around 20*. Maybe lower if the motor is ok with it. This is an area that does not get much attention on a dyno. The wot pull looks good.

Im assuming the alky pressure being reported is not accurate., It's also very erratic then drops off when you are still in it.
Possible low on alky? This has nothing to do with backfire on decell but it could hurt the motor.

The other thing is battery volts seem low. May want to put a meter on alternator and compare readings with the xfi.

Hopefully someone else will chime in with their expertise...

 

[Blown&Injected]

I keep reading that backfire is usually lean fuel condition but backfire upon lifting from light to medium throttle seems specific...I too hope to learn more of this.

 

[Jerryl]

Define backfire: Exh or intake? Where on the log is this? Right after you let off?

As Rick stated; Voltage seems low, Alky PSI dropping regardless of accuracy (That's another issue)
I would suggest; Log Camsync, AFR Target, and ESC Rtd*, and put some tightly gapped non gimmick resistor type plugs in of your choice.

 

[Chuck Leeper]

Define backfire: Exh or intake? Where on the log is this? Right after you let off?

If exh, could be decel fuel cut is whacked, and is going dead rich, dumping that fuel into a hot exh system...Boom.

 

[michael evans]

Define backfire: Exh or intake? Where on the log is this? Right after you let off?

As Rick stated; Voltage seems low, Alky PSI dropping regardless of accuracy (That's another issue)
I would suggest; Log Camsync, AFR Target, and ESC Rtd*, and put some tightly gapped non gimmick resistor type plugs in of your choice.

Not a big backfire.(BTW it was out the tail pipe.) It was small like it did on the dyno and we swapped modules and coil to cure it.

I am checking the voltage right now as it also is worrying me.

I have the plugs and will change them also (AC42TS).

 

[michael evans]

What size gap should I put on them ?

Pushing 23 pounds of boost with factory coils.

 

[TurboBuRick]

From the looks of the log I figured it was exhaust back fire. No big map spike. There are a couple small blips in the map and rpm way down low in rpm. Looks like 2 backfires. One bigger followed by one smaller.

Exhaust back fire is either fuel in exhaust or too much timing. You are at 35* advanced below 1100. Do you know how to adjust this?

I can’t belive no one else has said anything about the timing....

 

[TurboBuRick]

Here is RPM, MAP, Timing and AFR from the above log.

 

[michael evans]

Since I could not sleep until I did some checking, I started the engine.

Only changed one thing and did not do anything on the XFI, removed the $6.00 a piece E3 spark plugs and put in AC42TS plugs in and the first noticed that the idle was about 200 RPMs lower.

I did check on the voltage thing also the dashboard said 13.3 volts but at the alternator and battery it was 13.97 volts. Will look into changes if I can.

Tomorrow I will take it for a drive to make some logs and try to check the MPG.

 

[CS99]

Just a thought. Powermaster makes alternator with built in adjustable voltage regulator. Really makes a big difference when everything get 14.4 volts or alittle more.

Sent from my VS987 using Tapatalk

 

[ttypewhite]

A couple things I would check is your crank sensor. Make sure that the reluctor ring hasn't come in contact with it. If it has, it needs to be replaced. Check your wires running down to the crank sensor and make sure it has not rubbed against one of your pullies. Also probe the wires from the cam sensor and ignition module. Those 3 wires run to the ignition module, and also shares a common ground that also runs to the ecu. What your experiencing can also be symptoms of a broken wire under the loom which are very difficult to track down. It would also be a good idea to put a timing gun on your balancer and verify what your getting at the crank, is what your getting on your laptop. Almost sounds like your timing is off.

 

[CS99]

Yes. Good idea on timing. There a thread somewhere that explains how to verify that timing is actually what that fast system says it is. Mine was off a few degrees.

Sent from my VS987 using Tapatalk

 

[michael evans]

Made a few hits.

Wish there was a way to overlay the logs

It did start easier and felt better to me I did see that the voltage did come up when I turned off the AC (about .3 volts).
If the Caspers harness does not help things, then a new alternator will.

Looks like I need a new alcohol pump (oil pressure reading) tank is more than 1/2 full.

Compared to the E3s, it not only started with less cranking it also idled about 200 RPMs lower. If Brain was not so far from me that I would like to put it back on him dyno.

 

[michael evans]

What determines the spark BTDC on the XFI ? I was thinking the RPM to Spark table but I looked at two logs and compared them and at 5150 RPMs one said 23.75 drgreese and the other (with only different plugs ) said 17.75 degrees

 

[TurboBuRick]

The base spark timing table is MAP vs RPM. I will take a look at it if you send over the .gct file.

Should keep alky tank full. It's design is prone to failure. The alky gets pulled away from the pick up due to the g force.
Julio sells a test kit for checking the health of the alky system. I think for around $100. Well worth it IMO.