I got an L83/6L80 in an older Land Rover Defender. I got my harness and programming done by Speartech who have been very helpful but I'm running into problems. It turns over and starts well but then stutters and dies, I can keep it going for a bit by pumping the gas but not for long.

I have HPTuners, but I'm just starting to learn. I confirmed the Vats were disabled along with the Starter Diagnostics. I managed to get a short scan in with three start attempts and it looks to me like it's fuel related. I'm using the FPCM and a Silverado pump and I have an inline pressure sensor supplied by Speartech. I can't hear the. pump run when I turn the key but I don't know if that's just because there's pressure in the lines or not, I thought I did hear it initially but could be mistaken.

Fuel Pressure (SAE)-198kpa or 29PSI, stays the same
Fuel Pressure Requested-500kpa or 72psi (fluctuates slightly)
Fuel Pressure Sensor-0.00V

Not sure what direction to go from here, pulling the pump is a huge job but I can get at the electrical connectors. I could really use some guidance here....

Thanks,
Sean

 

Clogged fuel filter?

 

Thanks, I don't even have one right now except for the one on the pump itself. It's a brand new aluminum tank that I made sure was meticulously clean. I'm suspect of the fuel pressure sensor not having any voltage, checked fuses as well. I was thinking I should check the fuel pump plug to make sure I'm getting power to the pump, I was also thinking of hooking the pump direct to the battery to see if I can hear it but I don't think I can actually see in there to do it.

Sean

 

I did a little more digging.
I can hear the pump prime when I turn the ignition on. Checked all fuses. Pulled one spark plug and it looked black and sooty, I'm sure I put new ones in a while back. Cleared all DTC's and tried to start, ran for a few seconds and died and got new dtc's again:

P018B-Fuel Temp Sensor B Circuit Intermittent
P0073-Ambient Air Temp Sensor Circuit High Input
P023F-Fuel Pump Secondary Circuit/Open
P0463-Fuel Level Sensor A Circuit High Input
U1510-GM Specific, sounds like HVAC communications failure or something unrelated.

Not sure where to go next, I don't think I can check fuel pressure with a gauge, no schrader valve to hook up to. Also, once I hear the fuel pump cycle it won't do it again unless I let it sit for a long time so I think that means it's holding pressure in the line??
Does anyone know if there is a way to test if the ECM is signalling the fuel pump to come on once running......?????

Speartech is going to start blocking my calls if I continue bugging them lol.

Thanks,
Sean

 

Well the fuel pressure sensor is what I believe drives the PWM fuel pump controller, so that is likely what the issue is. I believe that the fuel pressure PID that you are logging is the voltage coming from the sensor. Find the fuel pressure sensor and confirm that you have 12v+ and a good ground to the fuel pressure sensor. Then I would also try and get a volt reading off of the sensor itself. I think that you either have a bad sensor, or the sensor wiring isn't correct.

Hard to say because I'm not familiar with GEN5 motors, but I'd guess that the computer is trying to command 72 PSI in order to get the pressure up from 29 PSI in the lines. The low pressure fuel pressure should be 58 PSI, so that means that the high pressure pump isn't getting what it needs to run properly.

 

Thanks for the input, I'm stumped but I was thinking along the same line. I'm waiting for a callback from Speartech to see if they have any ideas but maybe I'll run out and get a new sensor while I wait.

I also found a FPCM troubleshooting guide I'll try after I replace the sensor, this is so deflating when you finally think you get to run your new engine.

Thanks again,
Sean

 

OK, new sensor in and now I'm getting:
Fuel Pressure Requested-60psi+-
Fuel Pressure SAE-58psi
Fuel Pressure Sensor still at 0.00V
Fuel Rail Pressure-around 2000psi

I am getting 5v reference at the sensor plug as well as a good ground, but now I got a couple more DTC's:
P018B
P018C
Both Fuel Pressure Sensor B Circuit, one is Range and the other Low. I'm reading that these tend to mean there is a problem in the circuit, fun, I guess I have to check all the wires now unless someone has another idea.......

Still only running for a few seconds.

Sean

 

Wires are all good.......anybody got a match lol. I'm stumped.

 

I got a match and a trailer. Let me know where I need to be to pick it up.

Seriously, just need to get the fuel issues sorted out. Sounds like you have a schematic for the engine controls including fuel system and have a DVM to take measurements? Would you consider yourself proficient in electrical diagnosis? If not, is there a trustworthy shop that is proficient and can do the diagnosis? It could help your sanity.

 

Fuel cut relay on this setup? If its been over cycling for some reason maybe the relay contacts are shot..

 

I'm 99% sure there isn't a fuel cut relay, I'll check when I call Speartech yet again.
I did rewire the entire truck from scratch and it all works so I'm okay with electrical, just not great at troubleshooting. I have a voltmeter as well as HPT, just don't know how to use either that well lol.

I need to get the wiring diagram from Speartech as some of the colors are a bit different from what I'm seeing or maybe I'm looking at the wrong diagrams, not sure if they'll give me that info. I think I have to revisit the sensor wiring and maybe pull the wires entirely. Everything I have found shows voltage from that sensor, it needs to give feedback to the FPCM and it's not showing any voltage. I checked what I could physically and then tested for continuity from the plug to the ECM but I couldn't figure out where the ground wire ends. It did give a strong signal if I tested it to the frame. Gotta get on Google this morning and learn how to test for shorts or broken circuits properly.

Thanks for chiming in,
Sean

 

If the ground is questionable, you have your answer. Anytime I've had a strange issue with wiring it has come from poor grounding. What were the readings when you tested the terminals in the connector?

 

Well Speartech sent me the circuit system testing instructions that I've gone through right to the end and unfortunately it says the ECM is bad if I did it correctly.

The one step I'm not 100% confident in is when I jump the 5v reference to the signal wire it says to get the scan tool reading. I used HP Tuners with a PID of fuel pressure sensor voltage, same way I've been measuring it all along, and it reads 0.00V when hooked up. I think this is a good reading but I'm second guessing it, probably because I don't want to admit my ECM is bad. Checked all the pins and they're good also.

So, I got 5v reference
The Fuel Line Pressure Sensor Low Reference is 0.8ohms to ground
The Fuel Line Pressure Sensor Signal also shows 0.8ohms end to end and when I put power through it I get battery voltage. I'm pretty sure this connection is my problem as power is going through the wire when jumped but the ECM is not getting it. I watched about 20 videos on this and they always seem to be around 2-3 volts at idle on the scanner, mine is always zero.

More money, more waiting.....

Thanks for all the input so far,
Sean

 

I ordered a new Ecm from the dealership so now I have to figure out how to program it. I have HPTuners so I know I can transfer my tune over, what I don't know is if I can write the operating system and serial number on to the new one. I've been looking all over google and the HPT website but nothing. I really want to learn more about tuning etc but have to do everything online which is pretty tough.

I found a local tuner that said you can do it but he needs it in the vehicle, by the time I tow it there and back I could just send the ECM to Speartech.

Anyone know how to do this that might help?

Thanks,
Sean

 

I seem to remember reading somewhere that you have to have a BCM to flash a new, unflashed ECM for a GenV. Plus, you'd have to relicense that ECM to be able to use HPTuners to put your tune in it. It may be cheaper to just send it back to Speartech.

 

I do have the BCM but not in my truck so it probably wouldn't do me any good haha. I think you may be right about sending it back, about $700CAD for me to get it done which really sucks. It would be nice to be able to do all this stuff for future use, normally I like to buy the tools to figure things out for myself but this might be a stretch.

Sean

 

I haven't had any time to work on this lately and I'm still waiting on my new ECM which I'll probably send to Speartech.

Something I haven't thought about, I swapped the intake and throttlebody over to an LT1 due to clearance issues. Is there something I would have to change in the tune for this or should it still run? It would be great to find out I don't need a new ECM.

Thanks,
Sean

 

I'm not a tuner, but I have heard the newer engines/MAFs are a lot more picky as to airflow changes than the older engines were. Have heard of people just changing the air intake to a non stock one and having it make drivability problems, so you may be on to something. Does sound odd that a fairly new ECM would crap out, but I guess things do happen. As far as what to change in the tune, I'm not going to be any help there. That 29psi of fuel pressure still sounds suspect though, so that may be it, although I can't say why that's all you have. Hope you get it figured out. I'm a little ways from my first start on my L83 swap, and hoping I don't run into any snags either.

 

Looking at my tune the Throttle Area Limit is set at 3690, I've found the LT1 to be 4703.9 sq mm but I want to confirm this better.

I still think my problem is the fuel pressure, and regardless of any other problems I think I need the signal from the Fuel Pressure Sensor in order for the FPCM to work. I don't see any way around a new ECM, I'll ship it off as soon as I get it.

Trying to see if any of the tuners have any idea here:

https://ls1tech.com/forums/pcm-diagn...look-scan.html

Sean

 

One thing that I just thought of. Have you done a crank relearn? Maybe the new ECU isn't synced or something?