Engine cranks but does not start - Holden Colorado

That would be worth a shot. Also de pin the wire at ecm and see if it still has 5v at that pin from ecm as that might be your 5v ref feed to ckp. Some diagrams will say ckp low ref or ckp sens ref. What i have found ckp low ref can be the ckp signal to ecm in some cases. If you have the pinout of ecm handy post it up for both conectors at ecm may save you some headaches.

Firstly merry Xmas to all.
My appologies for re-opening this thread but it is the closest I have found that describes my problem. If the issue was resolved then I'd love to hear what the final outcome was. My conversion is a Colorado/Dmax 4JJ1 motor, Mtr harness and ECM into 1996 HZJ75 Toyota troop carrier. ECM has had all immobiliser functions disabled so as to run as an engine only installation. So the problem I have is "Engine cranks but does not start". I have been through the service manual fault processes both section 1 and 2. The only thing I have been able to find is the ECM pulse and power to the injectors is missing. This tread covers the injector wiring and power question in detail and I have done checks as well. Injectors are -ve switched so I power is on at injector once ign is on. Wiring diagram confirms this. Power is provided from 2 internal sources to Inj 1 & 3 and 2 & 4. Each injector is then wired back to an individual -ve ECM switching terminal.

1. No power to injector when ignition is on or during cranking
2. No -ve pulse (ie Test lamp from bat +ve to injector -ve wire) with ign on or during cranking.
3. Continuity tested wiring harness from Inj plug to ECM plug. All good.

I don't have the ability to internally try to pulse the injector with a scanning tool. But intend to do this to prove the ECM was Ok or faulty.

I don't know what conditions need to be met for the ECM power and pulse to be provided to the injectors so am open to any thoughts and feedback.

Car ended up being taken to another workshop.

To this day I don't think it was ever fixed.

ok thanks, that's a pity.

So it seems we now have 3 ECU's displaying the same symptoms. I appreciate my ECU is not the same as the Colorado but it suggests the condition that needs to exist for power and pulse to occur at the injectors is likely/possibly to be the same.

I will pickup the fault finding at the CKP sensor, something I haven't done yet and also get a tech with a scanner that can manually pulse the injectors to confirm the ECU is ok. If anyone knows what conditions need to exist for the ECU to pulse the injectors then would appreciate your input.

It is worth commenting that because this is a motor conversion, I also did an intake and EGR clean so all the fuel lines were removed and required bleeding.
This was a considerable effort but I did get the engine to run for short periods (2-3 sec) quite consistently but wouldn't continue to run. The car then sat for a few days and here I am today. So something has changed or the fault has developed further.

Are you 100% positive the immobilizer function is off?

Cut out/missing injector pulse is a prominent mean to immobilize the engine on many MMY.

No I can't be absolutely 100% sure but am assuming it is. I sent the ECU to a tuning company who also has been providing the immobiliser delete service for many years so am taking their word for it that they have done the job. I will contact them after xmas and have a chat. Good suggestion tks.

As with the comments earlier about Injector charge voltage, I also assumed it would be 12v and as such could test with a low wattage test lamp. Novice mistake. Actual voltage (DVM) at injectors is 4.53vdc and test lamp won't glow at these voltages. Also found one of my test leads was open circuit, another NM. DVM showed injector coil ohms to be 0.5 as per service manual. So will put my CRO on the injector signal and see it there is a pulse when cracking. CKP and CMP cables and supply volts are Ok 5v solid.

Made a set of breakout leads for injectors 1 so that I have access to the connections. Tested again with DVM and found 4.53v on both sides of the injector as expected. Signal cable only synch to ground during the pulse cycle. Connected the CRO neg lead to ground (bat -ve) and input lead to signal lead to Injector 1. Turned on ignition and CRO read 4.53, same as the DVM. Cranking the engine the CRO showed pulse to 0v each time engine got to No 1 cyl then back to 4,53v for the rest of the cycle. So now I'm back thinking either the injectors are not triggering (physically stuck) or I have a HP fuel delivery problem to the injectors. I tested all the fuel systems earlier (both low pressure from the tank, HP to injectors and the return flow) and was happy there was no air and SCAN Kpa was as expected at the HP sensor.

If anyone has any thoughts on what I'm missing then please jump in.

Decided to go over the air bleeding checks again.
1. Removed the return flow from the low pressure lift pump. No return bubbles.
2. Cracked open the HP supply to injectors at fuel rail. Each showed fuel present.
3. Checked FRP reading. 162540kpa
4. Removed the leak-off pipe from each injector. Leak-off from each was the same.

So from what I can see there is fuel at the injectors, fuel pressure and ECM injector pulse 4.53v DC and injector coils all 0.5 ohms. Only thing left that I can think of is to do a "Force Trigger" from the ECM to see if the injector is actually operating via the pulse from the ECM. Unfortunately I don't have a SCAN tool I can use but do have a regulated power supply so can manually trigger them. Not quite the same but will prove the injectors are not stuck.

Injectors are not stuck and can hear them operate when voltage is applied. Last thing is to ""Force trigger" the injectors through the ECM module. Have this booked in for the 9th. Xmas/New year break and everyone is away.

Had a similar problem in 2012. After much expense etc found the problem was a burnt earth pin in the engine compartment loom to body loom plug located on the firewall LHS.

Thanks for your input and yes it could be a very simple fix at the end of the day. I'm looking at the obvious things that are most likely directly related to the engine starting and because there is an ECM involved, invariably it all gets very complicated. But one things is for sure, it will get solved.

Another related cause reported by others that seems very common across all makes is a sticky/faulty SCV (Suction Control Valve) on the injector pump. Took mine off, checked the coil (about 2 ohms), tested operation (5vDC power supply) or 6v dolphin battery, cleaned by submersing the nozzle in a clean glass container with diesel while pulsing ( got some crap out). Unfortunately still no engine fire-up.

Tested a "Force Injector trigger" today and all worked fine including the injectors so no ECU, cable or injector issue. Double checked pulsing while cranking with LED light, no pulses. Something I thought I checked earlier with a CRO and saw pulses however would appear it is not the case. Now looking for reason why ECU refuses to send pulse signal to injector. ECU must be missing a critical input so am suspecting Crank or Cam angle sensor yet scanner shows no codes.

I had another look at the NoiD lamp test my mechanic did so I can understand where I went wrong. Reconnected my CRO and DVM on the control wire of Injector 1. both showed zero V. Ign on and both showed 4.53vDC. Started cranking and DVM couldn't show a stead result but CRO was showing a SOLID zero volts on the control wire when pulsing #1 and 4.53v for the rest of the engine cycle. Does any one know what the operating voltage range of the NoiD lamps are? I can't explain why they don't show a pulse yet my CRO shows a solid pulse. Sharp edges, no induced noise etc etc. Also tested the Cam angle sensor and showed a good 5v supply and nice pulses on the signal wire.

For any one who has been following this thread please bear in mind that this is a Conversion of a 4JJ1 Isuzu Dmax motor into a Toyota Troop Carrier and not a conventional DMAX motor problem solving issue. Ok so having put my problem into the right prospective I can say I have solved the issue and motor is running sweetly. Part of the conversion required me to have the ECU immobilizer deleted and as such there was a critical change needed to the wiring harness. The guys who did the ECU programing forgot to include the wiring diagram with the returned ECU so here I am ferreting out every conservable sensor and controller signal I can find and it all came down to having to snip a ground cable in the ECU harness. ECU J2 plug and pin 63 is an ECU ground and it needs to be cut otherwise the immobilizer programing is not complete. As soon as I did that the engine roared to life first crank. All good, only took 6 weeks but I now know every nook and cranny of the 4JJ1 fuel and electrical systems.