Aloha TimUTimU wrote: ↑Wed Apr 27, 2022 8:44 am Aloha John,
Are you getting spark from the coil so that you can identify which side of the spark-chain to start troubleshooting?
Checks:
- Loose engine earth straps (plural) - Commonly the one at the top-rear of the valve cover can get loose.
- Loose Battery terminals.
- Worn distributor cap & rotor button. Could also be gunked-up from an oil leak behind the rotor boss.
- Main Relay - One pin 87 can go faulty.
- Crankshaft Position Sensor - A faulty sensor will causes a loss of spark.
- Flywheel Speed Sensor - A faulty sensor will allow the car to start, but it will die soon after.
- Coolant Temp Sensor (blue head) - A faulty/disconnected CTS will stop the engine (unsure about spark).
- OBC Relay (under the dash) - A faulty OBC relay can cut power to the main relay.
- Cracked solder joint in the ECU
If you haven't already seen it, this article is an excellent troubleshooting guide:
https://hpsimotorsports.com/blogs/tech- ... ch-article
(PDF attached for posterity)
Bosch Motronic Fuel Injection Tech Article - HPSI Motorsport.pdf
Got my replacement CPS and Speed Sensor today. Installed and car still wouldn’t crank/stay running. Went into troubleshooting mode. Checked, fuel, coil, plugs, wires, injector input, battery voltage still couldn’t figure out why it wouldn’t start but crank.
Starting thinking about things I had done/installed since the last time it ran. Checked fuel pump, OBC and display unit, tail lights and head lights, radio, amp, etc. finally broke out the ETM and started tracing and probing. Everything pointed to a possible bad relay. Started swapping them out one at a time and still no luck.
Decided to look up known “good” replacement units and realized that I mixed up a 4 prong and a 5 prong up when I removed the relays to clean them some time ago. Funny thing is the car started, ran like crap and then shut off.
So, long story short; I spent the better part of 3 hours trying to figure out what the problem was only to realize I had introduced this problem by putting the relays in the wrong locations! After starting the car several times, called it a night and came in the house around 1130 at night.
I’m in the process of labeling relays and electrical fittings just in case I have another issue like this. One thing for sure, the car will not run with a faulty CPS.