gjohnson

iTrader: (4)

Ok, well I thought I had made it into the clear but I guess not. Here's the deal. I have a 97 Nissan 240sx that I swapped in a 2005 L33 with a T56 set up DBW. My engine harness is from a 2004 Silverado 1500 and so is my Tac, Pedal and PCM, but not the same truck.
I've almosted finished my swap, but here are my issues. When I turn the key to run the Throttle plate opens and shuts and the fuel pump primes. I fire the engine and it revs up to around 2000 Rpms sometimes 2500and then it drops to about a 1000 or so for a second or two. Then she shuts off. I have no response at all from the gas pedal and everytime I try to restart her she does the same.

I hooked up a OBD2 scanner and it reads no codes at all. I don't know where to start.

I thought it was my altenator wire not being connected, because I read somewhere that the PCM has to detect that the system is charging or it would send the PCM into Limp mode. But I finally removed pins A and C from the wire and plugged it in and theres no change.

sciff5

iTrader: (1)

did you disable vats?

pdsq98gt

Do you have the MAF installed? I would also double check that your pedal, tac module, pcm, and TB are all compatible parts. I've had a junkyard 6.0 come with a pcm that said it was a 4.8l yukon in the VIN.

gjohnson

iTrader: (4)

I had another member here on the forums reflash my PCM and he removed the VAT's and all emissions. I don't have a MAF.

How would I check the parts for compatability? I bought my PCM, pedal anf Tac from the same junkyard. The sent me the PCM and pedal together and forgot the pedal and harness. I had to call back and the claimed they pulled the tac moduel and harness from the samr truck like I had initially requested, but as far as I know I really have no way of verifying.

pdsq98gt

It's because you don't have a maf in there. The truck pcm uses mass airflow as a sanity check for the electonic throttle. You need to have a couple of codes deleted and tables altered to keep the pcm from killing the throttle on you. Or you could just put a maf on there and it will work like a charm.

gjohnson

iTrader: (4)

I guess I will need to check with him to see if the tables were altered when the MAF was deleted or not. Maybe I'm just confused and I should have a MAF.

Well, would the pedal respond with the key in the Run position or does the pedal only respond when the engine is running.
If the MAF wasn't deleted from my PCM shouldn't I be throwing a MAF code or something? My PCM is not throwing any codes.

branndonw

iTrader: (3)

The pedal will respond with the key in the run position, engine off. The ECM has gone into reduced engine power mode and is ignoring input from the pedal. Install the MAF and it should come out of REP mode and start working.

gjohnson

iTrader: (4)

Is there anyone to remove the PCM from REP mode so that I can verify that the pedal is actually working without buying a MAF and rewiring my harness for 1?

Also, I spoke to the member that did my tune and he said that he did remove the MAF error reporting, but he's not sure how that would affect the DBW pedal operation. He's done it many times on DBC setup's but there wasn't any info out there that he could find on how it operates in the DBW setup.

I guess I might just have to buy a MAF and find out.

gjohnson

iTrader: (4)

Or is there anyone to verify that the PCM is actually in REP mode? Like I said before I've tried to pull the codes, but there are none. I assume that is because the error reporting for the MAF was removed.

Sorry, I'm just trying to isolate the problem the best I can, so I'm just not out spending money trouble shooting when I'm already about $1000 over budget. Thanks guys.

pdsq98gt

Ask your tuner if he set the p1514 dtc to "no error reported" and maxed out the calculated airflow p1514 table. I think that is what finally did the trick for me on the one of these I ran into.

gjohnson

iTrader: (4)

So are you running a DBW setup without a MAF?

gjohnson

iTrader: (4)

Ok, I asked my tuner about that and he said that code is set for not reporting, but he didn't change anything in the flow tables.

gjohnson

iTrader: (4)

Ok, I'm still trying to figure out if I have an issue with my TAC as well, because it doesn't seem to respond with the key is in the RUN position as well. I called a local junkyard and they have a MAF I can pickup on my lunch break for $25, which an't bad.

Is it safe to assume that since the PCM is not throwing a code for the TAC like U0107 (Communication with TAC lost) that I don't have an issue with the pedal? Sorry, I'm just a little worried that the junkyard that shipped me the pedal, PCM and TAC lied and the TAC and Pedal were not from the same truck as the PCM and are not compatiable.

jason dearduff

i had the same problem on my 67 mustang. it turned out i was not getting true 12 volts to the pcm. check with mulimeter not test lite. every wire under the dash would drop below 12volts when starter engauged. i ended up running a seperate wire and installing a toggle type switch for the timebeing.

sciff5

iTrader: (1)

Do truck motors not have VATS? Is that why no one is agreeing with me? Most of the time with ls1s the VATS is what people overlook and they go around checking everything just to find out they just need to disable it

gjohnson

iTrader: (4)

Well, my tuner removed the Vats so hopefully that's not the issue. Do vats disable the DBW Pedal?

gjohnson

iTrader: (4)

Does anyone know what this sensor is on the Truck intake? I don't beleive I have 1 on the LS1 intake.

poconojoe

iTrader: (43)

That's the evap solenoid and unless your running an evap system on your fuel tank (and you're not) You don't need it.

branndonw

iTrader: (3)

The fact that you are not getting any codes tells me the TAC and APP are working as they should. If they weren't, you would be getting TAC motor control and APP1 and APP2 codes. If your pedal was mismatched with your ECM you would definitely be getting APP 1 & 2 codes. Also, you stated that when you turn the key to run, the throttle blade opens and then shuts. That tells me that the ECM is able to control the throttle blade, so a problem with the TAC is unlikely. To me, all the evidence is pointing towards the abscence of the MAF. Install the MAF and turn on all the codes that were turned off and it should start working.

fast400

iTrader: (1)

The battery voltage has much to do with it...ask me how I know
If your alternator is not producing or hooked up incorrectly, your pedal won't work. I diagnosed for hours before finally hooking up my alt and belt...problem resolved.