304 missing and surging on light throttle need ideas please!

Holden/Delco Tuning. ALDL, OBD 1.5. Circa 1989 to 2004.
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Jayme
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Re: 304 missing and surging on light throttle need ideas ple

Post by Jayme »

yeah in a VL, there is a 2 pulse output on the speedo itself. its clearly labelled if you look at the back of the speedo. I used it myself a few years back when I had a 304 VL.
kojab
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Re: 304 missing and surging on light throttle need ideas ple

Post by kojab »

Install a new oxygen sensor and I think you will fix it. The VS V8 will always run much sweeter with a healthy O2 sensor.

Also check your fuel pressure. Could be weak and running lean as others have mentioned.
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Holden202T
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Re: 304 missing and surging on light throttle need ideas ple

Post by Holden202T »

if the o2 sensor is going to fix the issue an easy test would be to disconnect it, that will stop it going closed loop and see if it makes a difference...?
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Jayme
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Re: 304 missing and surging on light throttle need ideas ple

Post by Jayme »

that wont stop is using its already learned BLM's.... better off unplugging the ECU for a while to reset fuel trips first.
kojab
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Re: 304 missing and surging on light throttle need ideas ple

Post by kojab »

Before posting I had read on page 1 that v151 had no o2 sensors fitted (I know the VS V8 only uses 1 sensor) and installing a new/good sensor might make the engine run normally.
vl5l
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Re: 304 missing and surging on light throttle need ideas ple

Post by vl5l »

just for fun i unplugged the map sensor and went for a drive it was a lot better (doe it go into limp mode without the map?), i checked the voltage and its 5v stable, i then gave it a new earth at the map plug, still playing up, i then checked the map output voltage and its starts about 1.6 volts and plays up when it gets to around 2 volts, the map hose has no leaks and is securely on both ends, i then had the map plugged in and unplugged the tps , this made it even worse, chad to clear codes 22 34 from the ecu after that.
it smells like its running really rich,

could the distributor be playing up?

as stated it has no oxy sensor, might fit one when its sorted, actually ill pillage one when i go out next and fit it, at this point anything is worth a shot
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VL400
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Re: 304 missing and surging on light throttle need ideas ple

Post by VL400 »

Yeah def go for an O2 sensor, if the problem goes away you will nned to work out why it took that to fix it (either by adding or removing fuel through the fuel trims). An ALDL interface would make fault finding much easier! And even more so once an O2 sensor is installed as it will show instantly if its richer or leaner than stoich, along with any learned fuel trims after driving it around.

Could even do as Jayme suggested and reset the ECU now even with no sensor installed, maybe it has some weird things learnt - its a long shot though, normally it takes a sensor to learn fuel trims :lol:
vl5l
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Re: 304 missing and surging on light throttle need ideas ple

Post by vl5l »

all fixed, changed the engine loom from vr to vp and its all good, i did buy an aldl cable but didnt need it
vl5l
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Re: 304 missing and surging on light throttle need ideas ple

Post by vl5l »

Still going well, was something screwed in the engine loom, at least if someone has the similar problem they know what fixed mine.
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