Rudolph1

Hello!

I came to the end (close at least) of my LS7 adaptation. I installed this into my 01 C5Z, using few parts from the LS6 that came with the C5Z.

On one side, I am really happy because I have finished the installation of my brand new LS7 I buiilt on my own. I built the engine starting with a LS7 block new as well, plus all the extras, as PRC 265 LS7 heads, Callies rotating assembly for 428ci, WISECO -2.8cc forged pistons, LS7 intake, Vararam, close to 11.4 SCR, 7.8 pushrods, cam 235/251 0.647/0.651 113LSA, wet sump using my LS6 batwing, and the extra parts I needed from my old LS6.

Now, yesterday I tried to fire it up for the first time, but guess what...?! It just refueses to start. It only backfires through the exhaust, and some through the intake (looks like). It only cranks, not working at all.

It pretty much looks like a timing problem. The only thing I did to the PCM was to set the fuel injectors to the LS7 injector spec (39.7 lb/hr at 58 psig) as well as some timing adjustment to initial 36 degrees of advance. That is all, I left the same adjustments the puter had with the LS6 (MS3 cam, and full exhaust).

I can tell you what I checked already: a) Proper side coil pack's wiring; b) crank and cam sensor plugged because I checked this wery well during installation; c) spark plugs are the same that came with the LS6 (iridium AC Delco with just 2000 miles), d) fuel goes to the fuel rails with no problem; e) Sparkplugs wires are MSD red, great condition; f) cam sprocket 1X; g) reluctor Wheel 24X.

Now, what gets me to think a lot: a) Bad cam sensor (I use the one that came with the timing cover used I bought on ebay); b) check the proper connection of the crank sensor; c) I bought Katech harnesses for knock sensors, cam sensor and MAP extensión, but... Did I plugged it properly? I pressume I did, because the connectors are 1 way fitment, with close to 0 probabilty of interchangeability, right?; d) The LS7 fuel injector adapter harnesses I bought them on ebay, so I guess no problem.

Guys, some ideas to help me out are going to be more than thanked, base of what I have already suggest and comment.

Any experience, please share it, as frustration is right outside my door

Thanks in advance.

Rodolfo Lara Pohlenz

AS10TRK

Are you using the original PCM which came with the car?

Rudolph1

Yes, I am working with the OEM C5 PCM.

Thanks.

RLP

AS10TRK

RLP-
I put an 08 LS7 in my 2000 C5 FRC a couple of years ago and will list what I did so you can compare it to what you did with yours. From what I can see it looks like you did everything right, but obviously something is not working. It sounds like a timing issue of some sort to me; I am suspicious of something to do with the reluctor wheel/crank sensor. Here's what I did with my conversion:
C5 stock PCM
24X reluctor wheel(*extremely critical that this is indexed properly to the LS7 crank and welded in place)
C5 LS1 knock sensors must be installed on side of block to be compatible with the C5 PCM, adaptor harness required.
Cam sensor-The LS7 cam sensor is compatible with C5 PCM, but requires relocation from rear to front of motor, adaptor harness required.
LS7 injectors are compatible with C5 PCM, adaptor harness required.
Map Sensor - Existing C5 sensor at rear of stock motor must be relocated to front of LS7 motor, adaptor harness required.
Throttle body - LS7 throttle body will work with C5 PCM, adaptor harness required.
MAF/Intake Temp Sensors- These are separate on a C5 LS1 motor. A newer style LS3 MAF with built in temp sensor was used.
A 1X cam gear
Crank sensor from a 2005 LS2 was used
Hope this helps, mine has been running fine since the install about 4 yrs ago. You will love it once you get it running.

Rudolph1

Thank you very much for the replay.

All that you kindly listed, has been done to my Vette. Plus some other things involved into this motor adaptation.

Maybe, and I say maybe, the only thing not done by the book was the reluctor wheel installation using the Goodson tool, because of a problem with the seller of the rotating assembly. I ordered a 24X into my Callies crank, and I got at home a 58X. The seller apologized and send me an OEM 24X reluctor wheel for free, and I Installed it following the pattern of the piramed shaped holes, marking its position on the crank with a marker; this, of course, alligned with the bolt holes of the cranks. THIS, obviously when the 58X was installed so I could replicate the opertion but with the 24X wheel, and end up like this:



Looks pretty nice to me. I know the uncertanty factor of every measurement tool is different, but present is nontheless (talking about the special Goodson tool). Maybe the question might be, how much does the PCM can compensate of the Goodson uncertanty factor?. So, I think that by looking at my installation, it is not the problem. I wanted to add the picture of the 24X relcutor wheel I installed to en-route the help somewhere else... Well, only if somebody does not agree, of course. I could be wrong, for sure.

7LitreC5

The only time that I have run into something like this was when I switched from MSD coils to LS2 coils. If I remember I had to use the LS2 coil harness. I had swapped the harness side to side and it did not run right.

I assume that you installed the timing set dot to dot.

Rudolph1

During the day, meal time, while I was eating some delicious "guitlacoche" "quesadillas" haha! Something came to my mind, and it is that when I bought my car, I had to fix some problems with the crank sensor wiring, because it was hitting with the header. I have SLP headers, which are a real nightmare, and the header kit came with a kit to relocate some wiring (headers were already in the car when I bought it). Back then I had to remove the headers, in order to remove the starter, and I remember that I mixed (did not remember the place wires used to be) all the wires going to the starter... To the point that in some cases (while I found the proper routing) I even cause back firing when I tried to start it. This takes me to ask, besides the obvious crank sensor wires... Is any wire there that could be causing the car to do what it does now??? Coil packs grounds? OR something with the fuel system???? Help me out here bud.

I will check for sure the cam sensor, as maybe it is bad. It looks in good conditions tough, but not sure.

I will try to move the starter a bit to check for proper connection of the crank sensor... Maybe something went wrong here... Who knows...!

Any other suggestion?

Rudolph1

How are you my friend?

Well, I used the Coil packs of my old LS6, and I have checked that by mistake, I did not swap the supply wire. All perfect here.

I think that the problem may be in the starter wires, because it has "plugged" like 7 Probably am talking from my ..s, but I could swear 4 years ago, when I had problems with some wire next to the starter and I did not installed properly the whole thing, some problem alike came on

Thanks bud.

Rodolfo

7LitreC5

Hopefully is something as simple as messed up wiring!

Rudolph1

I hope so too!

Katech_Zach

Unplug the Katech cam adapter harness at the vehicle harness side, remove the push pin blocking reverse installation and plug it back in 180 degrees. Try starting it again. The A and C terminals are purposely reversed in the harness for conversion in most applications, but some vehicles have them already reversed. Flipping it will tell you.

Rudolph1

Woow!! Thank so much for the replay Jason. That info is of great help.

I will try to take a look at it during the week, and for sure this coming sunday I will, as work and family does not allow me to play with the toy on from monday to friday

Thank you so much for the heads up. I will keep you informed for sure.

Rodolfo LP

Rudolph1

I am more than happy to report that the car has finallly start, and the problem as Jason suggested was the cam harness. All I did was to remove the intake, and take a look into Katech's cam harness and the cam harness connector from the car, and as suggested flip the Katech connector.

I want to really thank Jason for this "heads up", as It did work, but on the other side, would be a good idea if Katech could put into the harness envelope or plastic bag a note, to be taken this into consideration by the end user.

Now the problem is that once running the car got the following codes:
P0343 H C related to cam sensor high voltage, and P0107 H C Map Sensor. I would like to think that this problem is related to the harnesse's extension in lenght, as I got as well a RAF-U1000 H C.

Any comments on the codes, guys?

Thanks a lot for the help.

RLP

ZZ06

May need to R2 that harness.

Rudolph1

First of all I would like to let you know that the car is running fine and with 0 codes now. After this, I would like to apologize as the human being I am, as I did a really silly mistake.

Looking at the 2 kind of codes (cam sensor and map sensor), and none of the them changing from (H) and (C) to at least (H), I started to suspect that they were mixed... And well, they were.

The Katech harness for cam sensor was plugged into the PCM harness provision for MAP sensor, and the Katech MAP harness was plugged into the cam PCM harness provision. "my bad". For the sake of the problem, I did have to flip the connection in the Katech MAP harness, as I would not plugged in the PCM MAP provision, so, minor mods to the Katech MAP harness were done.

Now 0 codes, and the cars screams for tune! Next sunday will be the day.

Now, to contribute to the post and leave info, looking at the car's PCM harness, the short wiring is for the MAP sensor, and the next to it, twice in lenght, is for the Cam sensor. The connections are pretty much the same, except for some inner plastics of the connectors, but when you are going to use extensions, as you read before, not all of them come to plug and play. OBVIOUSLY, if no need for extensions, disregard this message.

Thanks a lot again to Jason and Mark, as well as to they guys of the forum that provided help in this thread.

Rodolfo Lara P

jerkyboy

Congrats on getting it figured out! I'm saving this post for when I run my adapters. Please let us know how it runs after a tune!

Katech_Zach

It's on the instruction sheet that is with the part. Did you buy this part directly from us or did you buy it through somebody else or used? I take it there was no instruction sheet in the bag?

Rudolph1

Too bad in my case, the sheet was not inside the plastic bag. And yup, I purchased this directly with Katech, brand new (you can check into your system for my name). The problem in here might had been that all things I get them shipped to a Suite Box I have in Hidalgo, Tx (close to the border), and after that customs takes over. Maybe, there is where the sheet got lost, as they open everything to check if there is something out of order After all is clear to pass, I receive my package in my home, which is Mexico City.

The important thing here is that you provided the help, and stood up for what you guys sell, which is top of the line. Super great service Jason.

Rodolfo Lara Pohlenz