HELP! 3.6 conversion No Spark now what?
 

After almost 2 months of waiting and spending the hard earned
$$$ I put oil in the tank made sure all connections were made and turned the key over, and over, and over. Nothing happend
except the engine cranking and building oil pressure via the
guage but nothing else. I am getting fuel because I hear
the pump running.

What now?

Could it be the DME?

I am getting voltage to the twin coils with the key on.

Frustrated and confused...

Connections on the distributors and engine wiring harness good and solid? They can get loose on the engine harness at times and cause problems.

About 3 days behind your situation. Hope to add oil and see if there is any spark this coming week.

JoeA

I have checked and rechecked and cant figure it out?

bout at the end of my rope not sure what to do next

Have you made sure that the switched connection(for DME) at the fuse panel is getting power when the ignition is in the full on position, and still gets juice while it's cranking.

Make sure the speed\ref sensor on the flywheel is the correct distance from the flywheel.

AFJuvat

I have not checked the switched power when cranking...

I set the distance of the reference sensor when installed
the tranny which was set at 1.0 MM is this right for a
95 993 engine?

I checked the voltage and it is not getting power when I
crank the engine. I am going to change the source to one
that does and try again...

Changed the switched lead and....

VROOMM!!!

Fired off on first try. A big

THANKS to all of those on the board who have given
input on my conversion. I could not have done it without
your help. I partially dismantled the car to get ready to
paint it week after next. I cant wait to get it on the road.
I am running just the cat and man is it loud. I LOVE IT!

More pics coming soon...

Hi Warspd. 1.0 is correct on the reference sensor. Also make certain that the accelerator cable is opening the throttle fully. Dan

Ok guys,

Hate to hijack this thread but its on the same subject and recent and hope someone can help with this?

I finished up the final wiring on the car and tried to start it. Turns over well until the battery told me it had not been used in a while. Its on the charger now and will be topped up tomorrow.

Turned it over until I got good oil pressure and then replaced the DME fuel pump relay. Tried to start it and get a fairly good whiff of fuel in the exhaust outlet but not even a hint of its trying to start.

This is a 3.6 that was in Bill Verburgs old SC. Was set up and running, just pulled to make way for a bigger engine. Everything had been sorted while it was in his car so I would hope that its nothing like the sensor distances.

I have good voltage on the fuel pump wire. Get 11v when I go to start so feel that the fuel pump has voltage. Due to the smell I feel that the fuel is getting to the cylinders.

Its got a PMS harness going from the DME computer/fuel relay to the front. All the wires are making good connection and have power when the switch is turned on. The damm connection to the tach is a bear and hope its making contact but do not believe that this would stop it from firing??

Where do I start to check for spark? Nothing at the plugs right now but what is a good proceedure to work backwards?

TIA,

Joe

Check for the same problem that warpspeed had. No power while cranking. Certain circuits in a 911 have power with the key on, but none while the engine is cranking. If you hooked into this circuit there will be no power for the DME and of course no spark is the result

Pete

I had to check for +12 volts when the engine was cranking and it had none so what I had to do was wire the lead right into
the ignition switch where I was getting the 12 volts with it
cranking and boom it started right up...

Ryan,

Which wire or circuit needed the 12v only during cranking?

I had a discussion with PMS about the hookup as their new instructions said to hook one wire up to constant 12v direct to the battery, another to switched 12v and a third to switched 12v min 10 amp. Turns out that they had gotten the wording wrong in the updated instructions and the "second" 12v connection was not switched but a constant 12v.

Any chance that the tach or oil temp connections could be causing problems or are the wires from the new harness to the gauges just to make the gauges move?

Thx,

Joe

I had the same symptoms when the lead to the DME to the battery power had a bad connection. The motor would crank, and I got spark everywhere but wouldn't fire. You should be able to crank it up and start it without the guages wired. I used a wiring harness out of a 93 and that was my finding.

Paul,

Thanks very much. I soldered every connection where able but will check the DME power lead again.

Getting to the back of the oil pressure gauge was not hard but the tach has a large moulded plug (not a single spade connector) so its not easy to get to the "sense" wire. Was hoping that a bad connection there was not the issue.

Will head back down to the shop and start checking somemore!

Thanks,

Joe

Joe

You need a 12 V constant source, usually hooked direct to the battery.
You also need a switched 12V source that keeps power during cranking, as noted above when picked up off the fuse panel several of the 12V sources that have power in run, don't have 12V during cranking

Also check your DME relay, it is a 2 pole relay, the first side closes when the key is turned on, this provides power to coils and other 12V components on the motor (idle valve etc). The second side closes when the DME senses engine rotation via the flywheel sensor. If rotation is sensed then the DME sends a ground to the other side of the DME relay, closing it and firing up the fuel pump.

The realy can be heard or felt to click when the key is first turned and again during cranking if that is functioning OK.


Also take a look at Ingo's page for a nice wiring diagram for the conversion harness.

Todd

Todd,

Thanks and was trying to find Ingo's website but its been changed. Will hunt up some of his recent posts and see if its there.

Edit: just found his site and its still blocked. Sent Ingo a PM and hope to get this figured out someday!

Thx,

Joe

Some snipits from posts I have made about this in the past

The DME relay should get a switched power source that is present during cranking that goes to term 86 on the DME relay. This same switched 12V source goes to term 2 of the 6 pin plug on the 964 dme harness

Fuel pump should get power from DME relay term 87b during cranking, this also provides 12 V to term 5 on the 964 14 pin plug on the DME harness. As I stated I don't know without looking at the 993 wiring diagrams how this translates to a 993 swap but it should give you an idea where to look.

If your flywheel sensor is set up properly and sensing engine rotation the wire going to DME relay term 85b should go to ground with engine rotation.


Your DME relay needs 2 sources of power,
term 30 should have voltage direct from the battery (best idea is to use a fused link and run a line straight from battery + to term 30 on relay)
other is the switched 12 V source to the DME relay term 86 (mentioned above) that must have 12 V during cranking, this is usually picked up off the fuse panel in the trunk once you verify it is a circut with power during starting.


You need to check terminal 87b not 87, there are two 12 V out terminals on the DME relay. When you turn the car on you should hear the first pole of the DME relay close, when cranking the second pole should close. If the wire to 85b is going to ground with engine rotation and term 86 has power when cranking you most likely have a bad DME relay

If you can't find Ingo's site, I can get you a copy of the harness diagram and send it to you tomorrow.

Todd

Todd,

Thanks very much for the help. Am heading out the door to work on the car right now. Let me take some measurements with the VOM and get back to you tonight.

I found Ingo's website that was listed on his Pelican parts profile (http://sswl.di.com/~ingo)but its blocked for anyone to view. Emailed him to ask if its up on another site.

Joe

Here are Ingos wiring diagrams
http://forums.pelicanparts.com/uploa...1095974213.jpg

http://forums.pelicanparts.com/uploa...1095974228.jpg

http://forums.pelicanparts.com/uploa...1095974239.jpg

Back from the shop and not good news. Checked out various ways of hooking the wires up and none of them made any difference.

Not sure if I am getting power to the fuel pump but when I touch the green wire from the PMS harness to a hot terminal I can hear the pump running so feel that it is working.

Checked for voltage at the coils and getting a good 12. 2v there before cranking and 11.6v while cranking. Had an extra DME relay and pulled the cover off to see what is actually happening instead of going by the "feel method." Turn the key to on and the top relay coil clicks close. Turn the key to start and one way I had it wired up the bottom coil did not close. Moved the wire to another "switched" circuit and it did close in the "start" position but no difference in the way the engine sounded and it did not start.

Still smell gas out the exhaust... Just about had enough of this fun and if I do not come up with any brainstorms may take the car to Patrick and let them figure it out. I am concerned that the DME brain is tits-up and that I could spend another year trying to figure it out without getting it started.

Thanks for the ideas guys, if anyone has anymore please send them across tonight!

Joe

Joe

You may want to pull all 12 plugs (I know fun) but when I had a bad DME that had a bad injetor driver the plugs were fouled and even with the new DME the car wouldn't fire. Pulled the plugs, and wiped them down, and it fired right up.If the plugs are wet enough could be a problem. I only mention this since you state you smell fuel.

I'm also curious why you have only 2 V at the coils before cranking, should be 12v, maybe just a typo.

Todd

Todd,

Was a typo, and seeing a good 12v at the coils. Will pull one of the plugs today and see if its wet then proceed.

Good idea... Hope my DME is not bad!

Thanks,

Joe

Ladies and gents,

Just got the call from Patrick Motorsports. Good and bad news! I worked on the car last week after all these postings and got to the point where I was out of ideas and time at the same time. Took it to Patrick and said "make it run"...

Good news is that the engine is running for the first time in over a year! There is a God! I have not seen, heard nor driven it but if Jim says its running and sounds good I believe him!

The rest of the story is that the reason it would not start was that the sensor on the flywheel was not working. Jim is not totally sure why it was not working but part of the problem is mine. I was under the impression (silly me) that since my transmission bellhousing was already notched for the sensors that came on my 3.2 DME that it did not need any futher work or notching.

Seems that the 3.6 sensor is just a RCH larger than the sensor on the 3.2 and when the engine was installed on the gearbox it pushed the larger sensor out of alignment. He also said that something else may have happened but who cares at this point in time.

Also he said that one of the coil wires was defective. This means that only one set (upper or lower) of spark plugs have been firing and for who knows how long. Bill, wonder how long you were driving the car on one set of spark plugs!!??? :)

Anyway, major progress is being made and I will be able to drive the car later this week or next. Am going to let them do some other work (possibly the backdate bodywork or extra cooler up front) while I am out working so I can just put the key in and drive when I return.

Thanks for everyone's help and wanted to pass this along about the difference in the sensor sizes...

JoeA

Great news Joe!:)

The firing of all plug wires was checked regularly. I have a nifty little inductive probe that lets me check all the wires in seconds.

Believe me, I would know it if ione set wasn't firing;)

Bill,

Not sure what happened but Jim said that the main coil wire to one of the dizzy heads was not flowing any current. He borrowed a "spare" one he had on another motor (he had what appeared to be 20+ 911 engines around the shop!) and it worked fine. Looked for a "extra spare" and did not have one so got a new one.

He had a handful of extra sensors and sold me a used one at a good price so it was a good choice to take it to a shop.

Now I cannot wait to drive it, but with the front and rear impact bumpers pulled and a 'glass hood, its a lot lighter than when I last drove it. To boot the 3.6 has a lot more power so it should be very interesting! Will let you know when it happens!

Thanks,

Joe