Jump to content
SAU Community

Recommended Posts

Engine Problem – Holden VL with RB20T – R31

Car was running fine. Parked for couple of hours. Next, hard to start, injectors noisy & closing, won’t rev over 1500rpm, won’t idle.

Changed o2 sensor, ECU, Crank Angle sensor, Air Flow, Checked Timing Belt/marks OK, BOV, Air Hoses/Tubes, What the F*** is wrong with my car?????

Link to comment
https://www.sau.com.au/forums/topic/54880-rb20t-problems/
Share on other sites

I hooked up an injector cleaning machine & its graphs show Injector pressure is high & flow rate is good. I also used a snapon vantage scope & it shows Injector pulses are eratic. I will double check all the wiring tomorrow. Thanks

did you do the wiring yourself?

id make sure that the wiring is all connected good...

maybe fuel filter.. but i doubt it as you said it was running fine...

in mine it would rev over like 3000rpm when i did the conversion... change fuel filter and off she went.

Link to comment
https://www.sau.com.au/forums/topic/54880-rb20t-problems/#findComment-1072639
Share on other sites

Is AFM air flow meter? This has checked out ok. All sensors have good connections. Injectors have 2.4 ohms on each. All have same voltage.I hooked up an injector cleaning machine & its graphs show Injector pressure is high & flow rate is good. I also used a snapon vantage scope & it shows Injector pulses are eratic. I will double check all the wiring tomorrow. Thanks

Double-check that your AFM is connected...
Link to comment
https://www.sau.com.au/forums/topic/54880-rb20t-problems/#findComment-1072644
Share on other sites

Not sure, car is in workshop up the road. The motor has red rocker cover with large plenum - 2nd motor type in series, if that helps. I will check plenum tomorrow & let you know.
That sounds like the NICS engine. They have 2 inlet runners for varaible inlet runners. One runner is controlled by a butterfly setup, and they have a tendency to jam, but usually in the "long" position, so the engine runs like a dog down low, but generally runs OK up high (presumably if you can get there).

Get your mechanic to chek that the butterflies in the runners are operating OK.

Link to comment
https://www.sau.com.au/forums/topic/54880-rb20t-problems/#findComment-1072681
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Bit of a pity we don't have good images of the back/front of the PCB ~ that said, I found a YT vid of a teardown to replace dicky clock switches, and got enough of a glimpse to realize this PCB is the front-end to a connected to what I'll call PCBA, and as such this is all digital on this PCB..ergo, battery voltage probably doesn't make an appearance here ; that is, I'd expect them to do something on PCBA wrt power conditioning for the adjustment/display/switch PCB.... ....given what's transpired..ie; some permutation of 12vdc on a 5vdc with or without correct polarity...would explain why the zener said "no" and exploded. The transistor Q5 (M33) is likely to be a digital switching transistor...that is, package has builtin bias resistors to ensure it saturates as soon as base threshold voltage is reached (minimal rise/fall time)....and wrt the question 'what else could've fried?' ....well, I know there's an MCU on this board (display, I/O at a guess), and you hope they isolated it from this scenario...I got my crayons out, it looks a bit like this...   ...not a lot to see, or rather, everything you'd like to see disappears down a via to the other side...base drive for the transistor comes from somewhere else, what this transistor is switching is somewhere else...but the zener circuit is exclusive to all this ~ it's providing a set voltage (current limited by the 1K3 resistor R19)...and disappears somewhere else down the via I marked V out ; if the errant voltage 'jumped' the diode in the millisecond before it exploded, whatever that V out via feeds may have seen a spike... ....I'll just imagine that Q5 was switched off at the time, thus no damage should've been done....but whatever that zener feeds has to be checked... HTH
    • I think Fitmit had some, have a look on there (theyre Australian as well)
    • Hah, fair enough! But if you learn with this one you can drive any other OEM manual. No modern luxury features like auto rev-matching or hillstart assist to give you a false sense of confidence. And a heavy car with not that much torque so it stalls easily. 
    • Actually, I'd say all three are the automatic option. Just the different trim levels. The manual would be RSFS, no? 
×
×
  • Create New...