my mk3 cranks and wants to start, but won't

Bru · 04-18-2015, 08:00 PM

Make sure that bundle of harness ground wires low down on the intake side of the manifold is tightened down otherwise you'll get weird things. I had mine hand tight and it was acting very squirrelly. When you install the cam position sensor or distributor follow the alignment method otherwise the timing will be off. The same goes for the camshafts and the crankshaft. They all need to be in time to work properly. The firing order is 1 5 3 6 2 4 on a distributor cap. The rotor cap will be pointing to 1 when installed properly and with 1 at the top of the compression stroke. The coil pack wire order from left to right is 1 6 3 4 2 5. Check for spark using a good spark plug held against a ground point while someone cranks the engine briefly. When you get it started and warmed up, jumper T1 to TE1 and set the timing with a timing light to 10deg BTDC at idle with the air conditioning off. You may want to check your fuel pressure to see if you have any. You can "hear" the fuel flowing at the rail by turning the ignition switch to the on position but not cranking and then jumper B+ to FP in the diagnostic block behind the fuse box. Mack sure all electrical plugs are plugged in. Lastly, if yours is a Turbo, you can wiggle the wires that go into the cam position sensor. I had one that was funny that way.

Here are links to the on line repair manual.

valve timing
http://www.cygnusx1.net/Supra/Librar...aspx?S=EM&P=29

ignition timing
http://www.cygnusx1.net/Supra/Librar...aspx?S=IG&P=20

non turbo distributor
http://www.cygnusx1.net/Supra/Librar...aspx?S=IG&P=17

turbo cam position sensor
http://www.cygnusx1.net/Supra/Librar...aspx?S=IG&P=21

04-18-2015, 08:00 PM	#7
Bru Bone Stock w Upgrades ;-) Join Date: Apr 2010 Location: Tampa Bay Posts: 213	Make sure that bundle of harness ground wires low down on the intake side of the manifold is tightened down otherwise you'll get weird things. I had mine hand tight and it was acting very squirrelly. When you install the cam position sensor or distributor follow the alignment method otherwise the timing will be off. The same goes for the camshafts and the crankshaft. They all need to be in time to work properly. The firing order is 1 5 3 6 2 4 on a distributor cap. The rotor cap will be pointing to 1 when installed properly and with 1 at the top of the compression stroke. The coil pack wire order from left to right is 1 6 3 4 2 5. Check for spark using a good spark plug held against a ground point while someone cranks the engine briefly. When you get it started and warmed up, jumper T1 to TE1 and set the timing with a timing light to 10deg BTDC at idle with the air conditioning off. You may want to check your fuel pressure to see if you have any. You can "hear" the fuel flowing at the rail by turning the ignition switch to the on position but not cranking and then jumper B+ to FP in the diagnostic block behind the fuse box. Mack sure all electrical plugs are plugged in. Lastly, if yours is a Turbo, you can wiggle the wires that go into the cam position sensor. I had one that was funny that way. Here are links to the on line repair manual. valve timing http://www.cygnusx1.net/Supra/Librar...aspx?S=EM&P=29 ignition timing http://www.cygnusx1.net/Supra/Librar...aspx?S=IG&P=20 non turbo distributor http://www.cygnusx1.net/Supra/Librar...aspx?S=IG&P=17 turbo cam position sensor http://www.cygnusx1.net/Supra/Librar...aspx?S=IG&P=21 Last edited by Bru; 04-23-2015 at 07:24 AM.