3.4L to 3.6L Conversion NIGHTMARE

[ziiz996]

I hired a reputable tuner to do the engine swap from 3.4 to 3.6 (dead 3.4). The tuner assured me that he had done many similar conversions before (to find out otherwise later on) and that he would be putting a newly remanufactured 3.6L 02+ Porsche engine in my 2000 C2 Cab with variocam plus (min 320 HP + Software upgrade to about 340HP). The original swap was supposed to take 2 weeks which turned into more like 2 months.

When I got the car back, aside from the fact that the new engine seemed less powerful than the older smaller engine (Tuner dynoed the car after 1500 miles at 242HP at the wheel and told me these numbers are normal for a new 3.6L and should get better after 2000 miles-they did not), the following also happened:

1. No cruise control

2. Coolant light flashes after every cold start

3. No HVAC control. It is always on. Cannot shut it off.

4. Cooling fans lo speed stage do not work. Only the Hi speed fans come on when the engine is getting very hot (way right of 180).

5. The car has a hard time doing warm-starts (30min to an hour after turning off the a warmed up motor)

6. I swear that there is no VarioCam Plus

7. PSM Light constantly on (C2 Cabs had no PSM switch, PSM was constantly on)

8. Disabled Check engine light (Off all the time even with ignition on before start)

9. Stereo Does not work

From one of Famous Loren's responses Loren mentioned that in order to do the conversion from 3.4 to 3.6, one has to replace other items (CPU, fuel pump, etc).

The tuner did eventually admit on one occasion your suggestions, but only after I brought the car back to him 5 or 6 times. He originally said that there is nothing wrong with the engine, but then he hinted once that he under-estimated the job and that there are other parts that needed to be replaced on the car to get it to fully work. But he won't tell me what they are.

I am at a point where I have to cut my losses with this tuner and take it somewhere else to complete the job. (And most likely deal with him later). Any recommendations?

I believe he did upgrade the DME to 7.8 but I don't know how he got the engine to work without rewiring aroung the VarioCam Plus.

P.S. I did pay an extra $3000 over Porsche's quote to replace the 3.4L at the dealership.

Edited November 12, 2007 by ziiz996

[Loren]

I guess step one would be to get a definitive list of what was replaced. That way we know what we are dealing with.

Many of those little problems could likely be solved (re-programming) or troubleshot with a PST2 or PIWIS tester.

The two big issues I can think of is the DME (really needs to be a DME 7.8 for a 3.6) and the returnless fuel system used on the 3.6 car and newer.

The other guy to ask about this is tholyoak (Todd Holyoak) - he has done several Boxster conversions and recently did a a 3.6 into a Boxster.

Now, he chose to use an older DME but I don't remeber if he solved the VarioCam Plus issue.

Where are you located?

[tholyoak]

Actually Loren my car runs the proper 7.8 Motronic setup. Originally I ran the 5.2.2 with an aftermarket controller, but that was just an interm solution until I obtained all the parts I need to integrate the 7.8 DME into my '99 Boxster. Your 2000 996 should have been a much simpler proposition.

You need to replace a lot of components to have everything work. If you send me a PM I would be glad to help you out. You will get some idea of what is required by looking at my posts on the boxster section

Sounds like they didn't modify the wiring harness properly or upgrade the necessary components so the 7.8 DME can communicate with the other systems properly.

Todd

[ziiz996]

I guess step one would be to get a definitive list of what was replaced. That way we know what we are dealing with.

Many of those little problems could likely be solved (re-programming) or troubleshot with a PST2 or PIWIS tester.

The two big issues I can think of is the DME (really needs to be a DME 7.8 for a 3.6) and the returnless fuel system used on the 3.6 car and newer.

The other guy to ask about this is tholyoak (Todd Holyoak) - he has done several Boxster conversions and recently did a a 3.6 into a Boxster.

Now, he chose to use an older DME but I don't remeber if he solved the VarioCam Plus issue.

Where are you located?

Thanks Loren for your quick response. I am in Conntecticut. US I guess we can communicate through this post from here on, it will make it more valuable to the ROW.

Although the Tuner told mr that he had to swap DME's, and I got charged for that DME. I was not super >o that he did. So I took it to Porsche in Boston, MA and the Tech plugged in his computer, he said that his computer did say that I had a DME 7.8.

I also talked to a German Tuner in Germany and he said something about the Instrument cluster needing to be replaced. As well as the HVAC Control unit.

I also talked to TODD at LA Dismantlers (Owner) and he said that I needed to replace the Inst Cluster, The HVAC Dash Control Unit and The Gas Tank and Fuel Pump. But I wanted to hear your opinion.

[ziiz996]

Actually Loren my car runs the proper 7.8 Motronic setup. Originally I ran the 5.2.2 with an aftermarket controller, but that was just an interm solution until I obtained all the parts I need to integrate the 7.8 DME into my '99 Boxster. Your 2000 996 should have been a much simpler proposition.

You need to replace a lot of components to have everything work. If you send me a PM I would be glad to help you out. You will get some idea of what is required by looking at my posts on the boxster section

Sounds like they didn't modify the wiring harness properly or upgrade the necessary components so the 7.8 DME can communicate with the other systems properly.

Todd

Hi Todd,

Thank you for jumping in. I am not sure what a PM is? But read the message I sent back to Loren about what I heard should be done. I just wanna make sure to talk to you guys first.

[tholyoak]

As I have outlined in the Boxster section, you will need to replace the DME, the HVAC controller, the instrument cluster and the ABS controller (a 2001 ABS 5.3 setup will work but your cruise won't be operational, if you want the cruise to work you need to update to the later 5.7, 4 channel ABS. You don't need to upgrade to the returnless fuel system, your current setup can be modified to work, they both operate at 3.8 Bar. In addition to swapping parts, you need to make a bunch of wiring changes and add the comfort and DME CAN bus circuits.

A PM, is a personal message, one of the ways available to communicate with other members on the board.

Todd

[ziiz996]

As I have outlined in the Boxster section, you will need to replace the DME, the HVAC controller, the instrument cluster and the ABS controller (a 2001 ABS 5.3 setup will work but your cruise won't be operational, if you want the cruise to work you need to update to the later 5.7, 4 channel ABS. You don't need to upgrade to the returnless fuel system, your current setup can be modified to work, they both operate at 3.8 Bar. In addition to swapping parts, you need to make a bunch of wiring changes and add the comfort and DME CAN bus circuits.

A PM, is a personal message, one of the ways available to communicate with other members on the board.

Todd

Thx Todd.

1. What did you mean by "add the comfort circuit"?

2. How do you add DME Computer Aided Network bus circuits? Is this software? or Some kind of Hardware wiring/harness ?

Tuner told me that I have no CAN bus in my 00.

3.What kind of wiring is required in addition?

P.S. I think my ABS works, I heard it kick in a couple of times when I needed it.

Do you have variocam plus working on your Boxster? I used to own one 98. Loved it but not its power. Yours must be a blast to drive with a 3.6...

[tholyoak]

1. There are 2 CAN bus networks, the engine CAN bus connecting the ABS, the Instrument cluster and the DME, and the comfort CAN bus connecting the instrument cluster, the HVAC control, and the PCM

2. The can bus is simply a twisted wire pair, essentially multiple signals pass over the same wires rather than have a dedicated wire for each signal, you also need the components that can communicate in this fashion, this is why you need to upgrade the ABS, the cluster, the DME and the HVAC control

3. The 7.2 DME wiring integrates into the chassis differently than the 7.8 does, so you need to make sure the wiring mates up correctly at the different connectors

The ABS will work fine, it just doesn't send the proper signals to the cluster, for instance when you upgrade to the later cluster, the speed signal from the ABS sensors comes over the CAN bus from the ABS controller.

Yes my car is running the factory 7.8 DME controlling the motor, just as it would in a later 996. This weekend it is getting a new X51 engine installed to replace the standard 3.6 I have been running for the last year.

Todd

[ziiz996]

Todd,

Can you possibly run the 3.6 w/out CAN? Or did this tuner have to wire CAN from the DME to the Variocam+ connectors on engine? IF he did! then

Would Variocam+ (VC+) work? or

Does the DME revert to another mode if it can't activate VC+?

Have you dynoed your current 3.6? Just curious what you got for HP and FT/LB

If I install a new cluster, is it enough to get VC+ running? (Assuming the tuner did put in CAN?

The 00 cluster is running, but miserably (Porsche computer showed a different temp to Instrument Cluster then the one to DME.) So can I assume that the tuner only put CAN from DME to Engine but not to cluster?

My last Question is: Is CAN twisted pair added in parallel to the harness or is it included in the 02+ harness? If it is, can I run a special CAN to the Instrument Cluster? Would a 01 turbo be the ideal car to use parts from because it was the first car with VC+ before Porsche switched over the C2 to CAN technology?

P.S. If you noticed that I am asking you to speculate, it is because the tuner has been feeding me a lot of B%^ S&^^ and I can't get a consistent or straight answer out of him as to what he did to the car? I have been very patient with him to no avail...

[tholyoak]

Well if you don't integrate the proper systems I'm sure it will work, it just won't work properly, as it appears your case proves.

If the DME is wired correctly the communication between the DME and the motor will be fine, however all the signals received and transmitted back and forth from the cluster will not be communicated by the DME and you will have tons of OBDII errors and probably result in poor performance not to mention never being able to pass any sort of inspection. From your original post, it doesn't even sound like the engine harness has been integrated properly into the chassis.

I don't understand the logic of buying a Porsche and then hacking it up by doing things half assed (this is not directed at you, but your installer). Presumably you bought a porsche for the enjoyment you get from driving it, clearly not doing the integration of the larger motor in this fashion isn't going to get you back to that point. You could run the stock DME and components and add an aftermarket controller to control the VC+, I did this originally as I researched things since my car is my daily driver. It works OK, but I don't think you would be happy with it on a street car, a track car where you spend all your time at full throttle it would be fine but on a street car, your part throttle maps are much more important. So I would say either do it right or don't do it at all.

Yes the CAN network can be added afterwards, this is how you do the conversion properly. The can bus communicates between the various control units, not between the engine and the DME.

You don't want parts from a turbo.

Todd

Todd,

Can you possibly run the 3.6 w/out CAN? Or did this tuner have to wire CAN from the DME to the Variocam+ connectors on engine? IF he did! then

Would Variocam+ (VC+) work? or

Does the DME revert to another mode if it can't activate VC+?

Have you dynoed your current 3.6? Just curious what you got for HP and FT/LB

If I install a new cluster, is it enough to get VC+ running? (Assuming the tuner did put in CAN?

The 00 cluster is running, but miserably (Porsche computer showed a different temp to Instrument Cluster then the one to DME.) So can I assume that the tuner only put CAN from DME to Engine but not to cluster?

My last Question is: Is CAN twisted pair added in parallel to the harness or is it included in the 02+ harness? If it is, can I run a special CAN to the Instrument Cluster? Would a 01 turbo be the ideal car to use parts from because it was the first car with VC+ before Porsche switched over the C2 to CAN technology?

P.S. If you noticed that I am asking you to speculate, it is because the tuner has been feeding me a lot of B%^ S&^^ and I can't get a consistent or straight answer out of him as to what he did to the car? I have been very patient with him to no avail...

Edited November 13, 2007 by tholyoak

[ziiz996]

Todd,

When you get lemons, then make lemonade. In case you missed my original post: The 3.4 went to heaven. So I had to make a decision by either replacing the 3.4 w/ a 3.4 that has a history of problems or move on to a 3.6 with VC+. THe tuner swore up and down that he had made over 50 similar conversions and that I'll end up with a 320HP plus another 15 to 20 with software mods.

He obviously lied. And he ran into problems and kept them hidden from me. But he failed to realize that my car was maintained by Porsche and was fully operational and documented before the engine started making metal on metal noises. The engine really never died As soon as I heard the noise I stopped the car and got it towed to Porsche Service who told me that I needed a new engine.

So I figured for an Xtra 3K I can get a bigger, newer more advanced and powerful engine. I really wanted a GT3 engine but the price was not justified.

I will never buy another Carrera again. Their engines are not truly made to be driven. Wet Sump, mass produced, etc. I will either get a GT3 or a Turbo. GT3 more likely.

I ordered an instrument cluster 02 to 04. Do you think by just swapping the clusters, some magic is going to happen? or

Do I have to run the CAN twisted Pair to it. I cannot trudt the tuner any more, I am not getting a straight answer out of him.

Thanks Todd.

Well if you don't integrate the proper systems I'm sure it will work, it just won't work properly, as it appears your case proves.

If the DME is wired correctly the communication between the DME and the motor will be fine, however all the signals received and transmitted back and forth from the cluster will not be communicated by the DME and you will have tons of OBDII errors and probably result in poor performance not to mention never being able to pass any sort of inspection. From your original post, it doesn't even sound like the engine harness has been integrated properly into the chassis.

I don't understand the logic of buying a Porsche and then hacking it up by doing things half assed (this is not directed at you, but your installer). Presumably you bought a porsche for the enjoyment you get from driving it, clearly not doing the integration of the larger motor in this fashion isn't going to get you back to that point. You could run the stock DME and components and add an aftermarket controller to control the VC+, I did this originally as I researched things since my car is my daily driver. It works OK, but I don't think you would be happy with it on a street car, a track car where you spend all your time at full throttle it would be fine but on a street car, your part throttle maps are much more important. So I would say either do it right or don't do it at all.

Yes the CAN network can be added afterwards, this is how you do the conversion properly. The can bus communicates between the various control units, not between the engine and the DME.

You don't want parts from a turbo.

Todd

[tholyoak]

I understand your rationale, I just feel sorry for you that someone has hacked your car.

I wouldn't make that broad generalization about the M96 engines. They have some issues, but so has every other engine Porsche has ever made.

At least the replacement cost is reasonable, if you have a problem with a 964/993 or GT3 engine it is going to cost you ~$35k to get a new one of those.

Unfortunately you can't just swap clusters, the connectors on the 2001 and earlier 996 are different than the 2002 on clusters, running the can bus is not a difficult task it is just a pair of wires between the DME and the cluster and the ABS controller and another set between the cluster and the HVAC controller. The updated cluster is more than just a set of gauges, it asks as a gateway for the CAN bus network allowing all the independent controllers to communicate.

Todd

[ziiz996]

My Dear Todd You are so correct...

I removed the existing cluster (Thx to Loren's instructions it was a 10 min Job) and the cconnectors ARE DIFFERENT.

When you swapped your cluster what did you do? How involved is this job? I like to know if possible.

I am interested to know so I can make a decision on moving on. Would a turbo 01 with VC+ have similar clusters to 02-04 or pre 02?

I am lucky that I bought an 02-04 silver faced 6 speed cluster at a good deal.

Now that I have an updated DME would it make sense to buy the harness for the cluster?

Thx Todd again.

I understand your rationale, I just feel sorry for you that someone has hacked your car.

I wouldn't make that broad generalization about the M96 engines. They have some issues, but so has every other engine Porsche has ever made.

At least the replacement cost is reasonable, if you have a problem with a 964/993 or GT3 engine it is going to cost you ~$35k to get a new one of those.

Unfortunately you can't just swap clusters, the connectors on the 2001 and earlier 996 are different than the 2002 on clusters, running the can bus is not a difficult task it is just a pair of wires between the DME and the cluster and the ABS controller and another set between the cluster and the HVAC controller. The updated cluster is more than just a set of gauges, it asks as a gateway for the CAN bus network allowing all the independent controllers to communicate.

Todd

[tholyoak]

I rewired the harness and added the new connectors to add the later cluster. In order to integrate the later cluster you will have to do the same. The turbo cluster is different than the non-turbo. The 2002-on cluster is the same for all 996 except there is one for tiptronic and one for the 6 speed. The coupe, cab and C4 of the same trans type use the same cluster.

I really think that if the engine and DME are installed properly the engine should run more or less correctly. The necessity of the cluster the HVAC and ABS updates are to get everything to work properly (like the A/C, check engine lights, speedo, tach etc) and not have any control unit errors.

As I used to live in Woburn,MA I am interested in the shop that did this work. Care to share?

Todd

My Dear Todd You are so correct...

I removed the existing cluster (Thx to Loren's instructions it was a 10 min Job) and the cconnectors ARE DIFFERENT.

When you swapped your cluster what did you do? How involved is this job? I like to know if possible.

I am interested to know so I can make a decision on moving on. Would a turbo 01 with VC+ have similar clusters to 02-04 or pre 02?

I am lucky that I bought an 02-04 silver faced 6 speed cluster at a good deal.

Now that I have an updated DME would it make sense to buy the harness for the cluster?

Thx Todd again.

I understand your rationale, I just feel sorry for you that someone has hacked your car.

I wouldn't make that broad generalization about the M96 engines. They have some issues, but so has every other engine Porsche has ever made.

At least the replacement cost is reasonable, if you have a problem with a 964/993 or GT3 engine it is going to cost you ~$35k to get a new one of those.

Unfortunately you can't just swap clusters, the connectors on the 2001 and earlier 996 are different than the 2002 on clusters, running the can bus is not a difficult task it is just a pair of wires between the DME and the cluster and the ABS controller and another set between the cluster and the HVAC controller. The updated cluster is more than just a set of gauges, it asks as a gateway for the CAN bus network allowing all the independent controllers to communicate.

Todd

[ziiz996]

TODD,

Where did you get the 3 Male connectors for the back of the instr Cluster?

And how on earth did you figure out the wiring for the new connectors?

I am not sure if the car is running the way it should because from my readings on VarioCam plus it does need the feedback from the new instrument cluster to change the the valve settings under 3K rpm to the new settings over 3k. I thought it was a function of RPM, Throttle position and oil pressure. And I also read that the A/C is disabled under full throttle which makes emprical for the new cluster to be present according to your statement that the Inst Clust controls the A/C.

I have driven many post 02 996's and they are extremely smoother than my car. I have a new engine so I can't say that the power is more or less than those cars, However the Dyno figures were pretty mediocre in my opinion and the car runs hotter than it should be because the lo speed cooling fans never come on.

If I get stuck in traffic more than 10 min, the car start overheating until the Hi speed fans finally kick in. The temp readings off the existing cluster are 8 degrees higher than what you see on the DME via PST2!!! Porsche computer. So the DME always thinks that the temp is 8 degrees cooler.

By the way do you know ( or Loren?) the lo speed fans kickoff temperature? And the Hi speed temps as well?

Are both left and right fans supposed to come on together? at lo and ho speed? They used to, before the idiot buchered my car. He is not worth mentionning on this highly reputable site.

J.

I rewired the harness and added the new connectors to add the later cluster. In order to integrate the later cluster you will have to do the same. The turbo cluster is different than the non-turbo. The 2002-on cluster is the same for all 996 except there is one for tiptronic and one for the 6 speed. The coupe, cab and C4 of the same trans type use the same cluster.

I really think that if the engine and DME are installed properly the engine should run more or less correctly. The necessity of the cluster the HVAC and ABS updates are to get everything to work properly (like the A/C, check engine lights, speedo, tach etc) and not have any control unit errors.

As I used to live in Woburn,MA I am interested in the shop that did this work. Care to share?

Todd

[tholyoak]

Where did you get the 3 Male connectors for the back of the instr Cluster?

I have a complete chassis harness from a 2003 car. You need the blue and green connector, the other one you only need like 4 pins from for a non tiptronic so the original 3rd connector can be made to work.

And how on earth did you figure out the wiring for the new connectors?

Time, patience and wiring diagrams.

I don't know what else to say, until you get things installed properly it is just guessing what is wrong with the car. If you can get the car to me, I would be glad to help out with it, otherwise I don't know what other information I can offer.

Todd

[tholyoak]

The issue with the temp and the cooling fans most likely is a result of not correctly wiring up the coolant temp sensor. The 3.6 uses a single NTC element, the signal is provided to the DME which interprets the resistance as a temp and controls the actuation of the blowers and also sends the temp signal to the cluster via the CAN network. The older motors use a double NTC element, one part is used for the dme, the other is the signal directly to the temp gauge and warning lights on the cluster. Not knowing what was done, leads me to believe this is the most likely problem. The other possibility would be the incorrect HVAC controls, since the fans are also cycled by the AC may be leading to the lack of the low speed fans.

Todd

[wrljet]

I have a complete chassis harness from a 2003 car. You need the blue and green connector, the other one you only need like 4 pins from for a non tiptronic so the original 3rd connector can be made to work.

Todd

Is there any chance you can get me the part numbers off the

five connector shells that mate with the DME 7.8 controller?

Thanks,

Bill

[tholyoak]

999.650.294.40 (black), 999.650.294.40 (gray) for some reason both these 9 pin connectors have the same part number but the additional number provided B09A02 and B09A07 is different,

999.650.299.40, 999.650.302.40, 999.650.297.40

I have been told they are not available as spare parts, if you find out differently I would appreciate it if you let me know

Todd

[ziiz996]

Hi Todd, Thanks again. As far as going to Kansas, that could be accomplished maybe in better weather. In the meanwhile:

What did the harness cost you? And Where did you get it?

Do you have wiring diagrams for those connectors (Old to New?);

I am starting to think that it makes more sense to completely replace he harness with an 02-04 if I can get a deal on it. What do you think?

I will send you a PM to tell you the name of the shop. I have to run it by someone first.

Try to get me the connection conversions There are only 14 pins on the old and I believe 16 or 18 on the new connector. I can PM you an MS Word Table that shows old versus new pin connections and you can fill the info in Word and PM it back to me.

By the way, the current 3.6 that you have had how many miles on it when you bought it?

And how on earth did you figure out the wiring for the new connectors?

Time, patience and wiring diagrams.

I don't know what else to say, until you get things installed properly it is just guessing what is wrong with the car. If you can get the car to me, I would be glad to help out with it, otherwise I don't know what other information I can offer.

Todd

[Loren]

You will need the DME schematic for a 7.8 DME and you will need pin removal/insertion tools.

[ziiz996]

Where do I get those tools? I was able to connect with an 04 Cluster and the 3 new connectors in back. Do you or Todd have the 1 X 1 conversion schematics?

Loren, Do you think I should replace the whole harness?

J.

You will need the DME schematic for a 7.8 DME and you will need pin removal/insertion tools.

[Loren]

LOL - 1 to 1 conversion schematics? Those don't exist unless you or Todd whats to create them. You need a service manual with schematics.

Please read through Todd's posts (in other threads) to see where he got the pin tools.

Replacing a car harness is a 2 day job - even for someone that is familiar with it. I don't recommend it.

[Richard Hamilton]

Also, you can only get vehicle-specific wiring looms. You have to quote the VIN when ordering and they are made for your car. They are also horrendously expensive.

[ziiz996]

LOL - 1 to 1 conversion schematics? Those don't exist unless you or Todd whats to create them. You need a service manual with schematics.

Please read through Todd's posts (in other threads) to see where he got the pin tools.

Replacing a car harness is a 2 day job - even for someone that is familiar with it. I don't recommend it.

Sorry Loren,

I thought you and or Todd documented your work. I am sure Todd didn't just start wiring his cluster after having a few scotches at 2AM on a Sunday.

He must have some kind of a 1 X 1!

If not I will share this info with the ROW when I get mine converted.

J.