View Full Version : Ive got no spark on two of the 3 coils what to try next
Gtotwinturbo
09-30-2014, 09:41 AM
Swapped the coil with another coil to see if the spark changes but it doesnt always sparks on top coil so i know coil packs good, ptu changed what other things could i do or try next im
Thinking ive got a bad wire which goes to the ptu whats best way to test
Unlikely to be wiring, more than likely a fault in the ECU (assuming your PTU is OK). Anyway, there are some pretty simple continuity checks you can do to rule out wiring
http://www.stealth316.com/images/ignptu-obl.jpg
From the link :
Stealth 316 - Power Transistor Unit (http://www.stealth316.com/2-pwrtransunit.htm)
Terminals OC1, 2 and 3 (the 3 pin plug on the PTU) correspond to coil negative terminals for each ignition coil. While you're there, check your +12v to each ignition coil and to the PTU, check the ground to the PTU as well.
Without an oscilloscope you can't really do a lot more testing than that, so if that all tests OK then you can head to the ECU, pull it out and inspect for faults. If you really want you can continuity check your PTU IB1, 2 and 3 back to the ECU.
1st gen or 2nd gen?
Gtotwinturbo
09-30-2014, 07:16 PM
Hello thanks for reply its a 91 first gen ive already got that same link on my phone but dont clearly understand it can you explain in clear steps preff with photos. On how exactly to do the tests. To rule out wiring. Whats worst things it could be 1.wiring 2.cas.3ecu.4timing.5 immobiliser
When i had it light tested from cas it was giving signal to ptu but seemed like there was a break on 1 wire from cas & ptu thats why we went and bought ptu. Where does the wiring go exactly can wiring not just be added if i know exactly which wire goes to where im thinking can i not just bridge from cas to ptu a new wire just to test it if that works then i know i just need to sort wiring out
On a 1st gen timing will never stop your injector pulse or spark as long as the camshaft is turning. An immobiliser should never stop spark to only 2 coils.
Before you do anything else, go pull the engine ECU out and check for leaking capacitors, if they're leaking then have it repaired first. While you're there, check for fault codes. If these check out OK, post back and we'll go from there.
Stealth 316 - Reading Diagnostic Codes - 1991-1993 3S models (http://www.stealth316.com/2-diagcodes91-93.htm)
You've got a digital multimeter right? And what's a light test?
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