We are trying to sort out a problem with a friends VL, what it is doing, is that after cold start up, it fires on the first compression and run fine untill it warms up and it looses injection pulse, we do have spark and good fuel pressure, we have battery voltage at the injectors ok, now i cant find the reverse polarity relay, where is this located? the loom is very suspect and i do know this can be a problem, a good loom is being fitted as a precaution, can the CAS cause this problem and maintain spark? any other thoughts?
The CAS can cause heaps of problems, if you pull the dizzy out you might find the bearing seized etc, and the mass amount of heat is causing the cas to stop injector pulse, Do the cas first, or even borrow a dizzy from some one, If you have the battery in the standard place, then just work your way down the positive battery wire, take all the black of it and you'll find it, I had this problem with my car, but i couldn't get it to start at all unless on Start you *******.
As it starts cold no problem and only looses injection pulse when it warms up and we do still have good spark, the suspect loom is being changed a hopefully good distributor is being fitted , the reverse polarity relay has been checked and is ok, when the dist is fitted next weekend we will see what happens, i will re post results, thanks guys.
Quote:
Originally Posted by mhpautos
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As it starts cold no problem and only looses injection pulse when it warms up and we do still have good spark, the suspect loom is being changed a hopefully good distributor is being fitted , the reverse polarity relay has been checked and is ok, when the dist is fitted next weekend we will see what happens, i will re post results, thanks guys.
where did you find the reverse polarity relay?
unplug the 02 sensor if you think the injector pulse is becoming to small.
normally around 60degC this will happen as it starts to run in Closed loop.
turbo ECU's will do this at 3m30s after engine start signal received if the CTS is unplugged. 3EA/M will not, they require a good CTS connection and actively monitor it for warmup mixtures and timing control.
The CTS can be unplugged if the you want to increase injector pulse.
BUT: This only works on the early model ECU's, note: not necessarily S1 or S2 vehicles. on later model ecu's the CTS circuit will either peg the mixtures rich, and timing at 35deg or simply run lean until warmed (4mins) and peg warmup timing to 15deg.
relay was beside battery bank of 3 one metal 2 plastic was advised that the metal relay was the reverse polarity relay, we changed it for a known good relay. would you suggest a new CTS as well?
Cold Temp Sensor (CTS) is cheap enough just to throw one in for good measure, I usually just read the resistance across the terminals as the engine warms up. Do the same in some water coming up to boiling point. Often connectors are cracked and corroded on the plug before CTS dies.
check bodgy brothers haven't installed a resistor in the CTS wiring loom to the ECU.
if you suspect CTS, an airpocket in the cooling system can be a cause until the thermostat opens, normally problem goes away though. make sure system is bleed properly anyway, it will prevent a cracked head.
The injectors source 12v directly from the fuse box relay, the pulse is directly sent from the ecu (15 pin connector with all thick wires on it).
check drivers side engine mount has 3 earth connections on it, and they are all on the same bolt.
