legacycentral bbs

Just got done swapping a 4.11 trans into the car and putting a catch can on the car. In the turbo/intercooler came off the car and a handful of sensors have been unplugged. Anyways, we put everything back on and now we cant get it running right.

The car cranks, it stumbles, and if I hold the starter and throttle open it will roughly run. We are only getting a knock sensor code which we have had before and it still started (runs like shit but started fine). We were getting a cranck sensor code because we damaged the sensor putting the trans in but we sense rewired the crack (twice) and no long get the code.

I think it should be noted that the long term fuel trims reads -50% on revscan (it has a revtronix stage 2 chip). It only says -50% in the varable section not the table.

I have no idea whats wrong with this thing. We also removed the hard the fuel rail return line and replaced it with a soft line for packing reasons. In the process damaged the fuel tube conencting the two rails?

Too much fuel or not enough?

Try changing the fuel trims to 0% in the chip. Does it start then?

Alphius wrote:Too much fuel or not enough?

Try changing the fuel trims to 0% in the chip. Does it start then?

How the hell do i do this? I tried typing in the variable but it wouldn't let me. The long tirm table only had a value of -1% and wouldnt let me type in +50% (i guess i should have tired somethig else).

I tried "clearing the codes" via revscan. The codes would go away but the -50% fuel trim was still there

What modifications do you have on that motor? You said it ran before, but ran like shit.....can you elaborate on that?

Legacy777 wrote:What modifications do you have on that motor? You said it ran before, but ran like shit.....can you elaborate on that?

I believe you are referring to an different thread I had (which was related to the map/baro sensor and boost controller). I have since fixed that and had the car running decently for an extended period of time with no issues.

This issue only started after doing the trans swap/catch can install which required some disassembly of the engine. The motor will "start" but the RPM is so low that the tach doesnt even move (~250rpm is my guess). And will die shortly after it "started"

Engine Mods:
VF12
Revtronix Stage 2
Liquid to Air intercooler
Air box elimination ("coffee can mod")
Storm anti slosh baffling
Walbro 225
550 injectors

If the issue only happen after the trans swap and that's all you changed I would double check all the things that were disconnected or might have been damaged.

I will say that the voltages coming off the crank sensor are very small, so depending on the damage and repairs you made to the wiring, that may be your problem. How did you repair the wiring that was bad?

Legacy777 wrote:If the issue only happen after the trans swap and that's all you changed I would double check all the things that were disconnected or might have been damaged.

I will say that the voltages coming off the crank sensor are very small, so depending on the damage and repairs you made to the wiring, that may be your problem. How did you repair the wiring that was bad?

Cut off the connectors and hard wired the sensor to the harness. We hooked it up wrong the first two trys and were getting crank sensor codes. Once we got it right the code went away.

Ok, well all I can suggest is to just look over everything again to see if something was not connected or if you notice anything out of place.

cafifty wrote:

Alphius wrote:Too much fuel or not enough?

Try changing the fuel trims to 0% in the chip. Does it start then?

How the hell do i do this? I tried typing in the variable but it wouldn't let me. The long tirm table only had a value of -1% and wouldnt let me type in +50% (i guess i should have tired somethig else).

I tried "clearing the codes" via revscan. The codes would go away but the -50% fuel trim was still there

Is the field blue? You can only change the blue fields. I don't know if your version of the chip lets you change that field, mine does but I have the very latest code on mine.

Double click on the value you want to change, then type in just a number without the percent sign after it.

You could also try completely resetting the ECU. You can do that from RevScan as well.

We are running low on time before our next race while at work on of the guys created a troubleshooting list. Figured it worth sharing for further reference

1. Spark/Ignition/Electrical

a. Coil
b. Grounds
i. Proper voltage to ecu
c. Sensors
i. Cam
ii. Crank
iii. Neutral safety
iv. MAF
d. Firing order, timing
e. General spark
f. Fouled plugs
g. No backed out connector pins,

2. Timing/Mechanical

a. Proper timing (no jumped timing belt teeth, specifically on the crank)
b. Correct fuel routing
c. Blockages in fuel system
i. no damage to fuel cross over line
ii. connect fuel presure (connect the green connectors in the car will go in diag mode which leaves the pump on there is a service port were we can read the fuel pressure)



On the subject of firing order. The coil pack is pretty obvious on which plug goes where. But i notice the injector connectors could easily get swapped on the pass side and it would be hard to tell. Is there any easy way to tell? We tried swapping these and and it didnt seem to help so we ruled it out.

Alphius wrote:

cafifty wrote:

Alphius wrote:Too much fuel or not enough?

Try changing the fuel trims to 0% in the chip. Does it start then?

How the hell do i do this? I tried typing in the variable but it wouldn't let me. The long tirm table only had a value of -1% and wouldnt let me type in +50% (i guess i should have tired somethig else).

I tried "clearing the codes" via revscan. The codes would go away but the -50% fuel trim was still there

Is the field blue? You can only change the blue fields. I don't know if your version of the chip lets you change that field, mine does but I have the very latest code on mine.

Double click on the value you want to change, then type in just a number without the percent sign after it.

You could also try completely resetting the ECU. You can do that from RevScan as well.

I am looking at revscan right now and the blue fuel trims are the "full throttle" ones. I believe the -50% was reading in the non "full throttle" one which isn't calibratable..

True, was that short term or long term? You can calibrate the long term by going to the "Long Term Fuel" table in the lefthand menu and clicking on each of the load bins 1-7. 1-3 all change together as one when you edit 3. 4-7 are independently changeable.

Follow up: I found that I pinched the driver side fuel rail feed line during the trans swap. I also found (and this was more likely the problem) that we wired the crank position sensor wrong...

Thanks for following up. So everything working fine now?

Legacy777 wrote:Thanks for following up. So everything working fine now?

At the time yes. Now i need to figure out if i can replace the center diff in a 4.11 trans with one from a 3.90

I think it depends on the year as they changed little bits.

Legacy777 wrote:I think it depends on the year as they changed little bits.

Yeah i think i am good. I have a 98 rs trans which from what i read is the phase 1 trans that will swap with the 3.90 center diff.