I bought a TT 18 months ago with Blown Head Gaskets, It did run before the Engine was removed, Have had the Heads Reco,d and reassambled. All fitted back up. We cant get it to go. I put a new DET sensor in to replace the melted one. We have put the Consult on and shows code 55. We have fuel pressure through the fuel filter and the injectors click fine. we have tested the wires from the ptu to ecu and ptu to coils all ok, The coils have power to them and when turning the crank angle sensor show a small pulse on the mutli meter. but when fitted with a spark plug and earthed show no spark at all. it did have an alarm which has been removed. have replaced the ptu with another one have tested them both and seem ok. have new battery in and winds over fine. The air flow readout in the car shows airflow when winding over and can see valve moving through sparkplug hole. have rechecked earths seem ok. Any Ideas??
I've been helping steve build this engine for the past month. The PTU wiring checks out, but the PTU was thought of as faulty. Steve has got a replacement S1 PTU for now, so now the onus is on whether the PTU is in fact working or not. Code 55 was achieved, but there is still an intermittant DET sensor error (34) which needs to be followed up. DET sensor is NEW. This error should not prevent the engine from firing. From here, may I suggest the following course of discussion: - can the PTU be bypassed temporarily, just for the purpose of getting a spark (for example jumping the PTU input wire to the Output side, straight to the coil?) -Fuel pumpo is pumping, and fuel is getting to the cylinders. -Injectors click when activated with the CAS, so we can assume fuel is not the problem. -For now, Since the engine has been rebuilt, Compression does not seem a problem. Compression test would seem superfluous.
Its just that if the hydraulic lifters have been serviced and incorrect procedure used it can prevent the valves from fully closing. This is self correcting once the engine is running, but you need to get the motor started for this to occur. Just a suggestion, it happened to me when I used the procedure that was in the tech section at that time.
Use a multimeter on diode test function and check continuity between pins on the PTU. You'll only get continuity one way and all readings should be within a few ohms of each other. Make sure PTU pins are bright and shiny, not just clean.... as pins may have a non conductive coating from old age.
Make sure you're not pushing the fuel the wrong way. Should go filter -> damper -> rail -> reg -> return. Very easy to set it up filter -> reg -> rail -> damper -> return and then it won't start.
I have had both PTUs tested and they are both up to specs, I have added extra earths to the Engine with no success. When the Heads were done several, valves needed replacing and some valve seats were damaged and needed reseating. The Head bloke said they are not brilliant but usable. When we wind it over for a while there is a fuel smell in the shed, so I guess theres fuel in the cylinders. there is a definite compression sound through the Exhaust when winding over so i think its ok for compression.
You cannot jump input to output of PTU, the PTU is a powerful resistor. The resistance increases voltage for spark, no resistance no voltage. If you have a spark plug on the coil pack and earthing it to the motor and there is a weak spark then i'ld look somewhere towards the earth for the coil pack. All the ECU does is send a signal which is obviously happening. Once again check the earth strap from the PTU. Using the FSM chart you should see which one of the wires on the PTU is the earth, one side has 6 one side has 7 wires, the one side that has 7 wires has an earth, shave a bit of wire rubber from it and insert multimeter there and the other end on any earth of the vehicle. Should have no resistance. Check compression while the spark plugs are out.
You don't want to hear this but a blown head gasket with a z32 could also mean fried piston rings or warped heads. But if the heads were compression tested which is usually done when getting repaired then you should still check the compression of the rings.
We have used a new Bottom End, The Heads were Pressure Tested and Machined etc. Tonight I have Rechecked the Earths . When I rechecked The power to the Coils it now has none, I have checked the Relay in the Fuse Box ( Green One ) It is no longer switching when Ign turned on, Now has no power to Relay. The ECU has a Red LED on when Ign turned on.Still turns over ok and Battery has 12.5 volts when sitting. Cant check when Cranking as Im alone.
Check the eng cont fuse, efi fuse and also engine earth points. Are the plugs fouled, if you have been cranking it excessively they probably are.
Yep, plugs were very wet, Have cleaned them up, I have checked the fuses in the relay box ( LH front Guard ) and the ones behind the Rh strut tower. Is there another fuse box somewhere?
There is another fuse box in the driver footwell. If the plugs were fouled, they need to be replaced, the fuel soaks into them, the spark then travels and grounds internally in the core of the plug rather than its traditional route. Sometimes they will go again, but if very wet they are ussually dead. Remove the cas and with it plugged in and key on, give it a spin, you should hear the pump fire up, the injectors ticking and with fresh plugs they should be firing. If you have all this, it should start providing compression leakage is minimal.
Try to set your phone camera up to capture a video image of your multimetre whilst you crank it over. I believe you will need 11.9 volts for it to fire.
Have you had the ecu out for any reason? This hopefuly isnt your problem but it happened to me in Warwick. The harness plug at the ecu came slightly adrift and caused me and others (thanks again for your help guys) all sorts of head aches. My point being that the faults you describe is what i found with the ecu plug problem.
Negatory I don't believe any battery would maintain 11.9 volts while engine cranking. I've seen my engine start with less than 10v showing on the turbo timer while cranking.
I think your right pexzed my vg30det drops to below 11V to 10something mapping the volts on the Haltech. Note-New battery and good alternator.
