VL Commodore RB30E- Car misses and runs rough.

[bogan_style]

1987 Holden VL Commodore SL Automatic.

My vl is running really rough, feels like it only runs on 4 cylinders and sounds like a subaru. It used to only do it once it had warmed up and when the engine was under load. In neutral it revs well and runs fine, but once u go to drive it runs like sh*t.

Ive replaced the fuel filter, fuel regulator, fuel regulator solenoid valve as i thought it was a lack of fuel problem. (cant get hold of a electric fuel pump pressure gauge to test pressures of pumps).

I did an ECU diagnoses check with the LED's and it comes up with fault codes 23, 24, 31. I dont care about 31 because thats just aircon, im not sure why 24 shows up because it starts fine in neutral etc so there doesnt seem to be a neutral switch problem. But fault code 23 is the Throttle position switch/circuit. So i thought great atleast i know whats causing it, i did the continuity test on the top 2 prongs on the switch itself, and when u crack the throttle it breaks the continuity, (i.e it works fine). I thought maybe one of the wires to the ECU or Automatic control unit had a break in it so wasnt sending the info, so i did continuity check on all the wires to the plugs and they are all fine. Why am i getting a Fault code 23? any ideas?

I then went through the fuel and engine management section in my Gregorys manual and did every check on every sensor, All are in perfect working order according to the test results. These include TPS, AFM, O2, CAS, Power transistor, AAC etc.

Ive really come to a dead end on what can be causing it, and im still getting a faulty TPS signal on the ECU. Is there any chance that the TPS can pass the continuity tests but still be faulty in some way? any help wold be much appreciated.

[photo]

hey mate, you sound pretty cluey about whats goin on, but just in case you havent checked your injector leads and the injectors themselves that might also have something to do with it. you can get an injector test light to check the pulsing of the lead itself, but if thats all in good order you might wanna also check that the injector is actually working correctly and is not blocked. you can do this by running the engine and pulling off a lead at a time, obviously if it gets worse than thats not the problem and you can move on to the next one. also check your plugs for tell tale signs of what might be happening inside the engine. hope this helps. luv the rb`s!

[bogan_style]

cheers mate, will have a go after work today.

[bogan_style]

Checked all the injectors, they all have 2-3ohms of resistance between the 2 prongs, they shold be between 2-7ohms. so theyre sweet as. Then while the engine was running i unplugged each one at a time and each one caused the engine to start missing. so they are all doing there job to.

I then got a spare spark plug and adjusted the gap to 6-7mm roughly to see if the coil pack was packing enough balls to jump the gap and it did that fine off the #1 cyl high tension lead.

Also went and played roung with a few things and did another ECU diagnosis check, and now the only fault code that is appearing is 31, which is air con system. but not phased about that. So now ALL the sensors are defianately working and none of the circits have breaks in them. BUT still the car starts to miss and run like shit when you put load on the engine, you can creep along a flat road with only the slightest amount of throttle and itll drive fine, as soon as you put your foot down a little more to get up and go it hesitates nd starts playing up, (like it cant get enough fuel to accelerate), or if you try go up a hill etc.

The only thing it can be is fuel pressure im guessing, do these pumps wear out slowly and cant provide enough pressure to the rail?, from what ive heard/ seen they work fine or just plain not work at all, never in-between. Ive allready swapped the regulator over with another working one with no results. and from what i can see the 2 hoses on the regulator arent split anywhere (ill buy new hose lines anyway just incase).

FU**ING CONFUSING SHIT! haha

[calais24/7]

I havent read through your posts but try the afm and the cas.

[detox_nath83]

throttle position sensor is cancelled when u press the throttle to the floor and release it. i have not read it all either.

Check timing is on factory 15 degrees. your dizzy cup contacts are clean and not white dust/pitted.(inside cup) and rotor arm is in good working order,,,,

usually problems under load is leads so do an ohm reading on these.
fuel filter?? and AFM can cause all dramas as well as CAS so check these as well as the loom plugs.(under the rubber boot where they r crimped on the wires)

[bogan_style]

wholey #### haha, after days of pain staking loom and sensor testing all it took was for me to adjust my idle with the sun going down and out of the corner of my eye notice a little flashing coming from down the #6 cylinder plug hole. ALL tht shit was caused by a pin whole blown through the side of the plug lead insulation and when i tried to accelerate it was arcing through tht pin hole to the cylinder head wall!...stoaked that ive fixed it now and it runs mint, gutted i didnt notice that small pin hole earlier, simplest problem can #### the enigine performance so much haha. she runs way better than b4 this all started though, cuz ive gone through changing and cleaning points etc.

cheers for all the help guys

[calais24/7]

Glad it was only such a small thing

[detox_nath83]

fkn leads.... always good to have a look in your bay when dark... i like doing it to c the turbo/exhaust glow after a nice night out. wooommmpppaaaaaaaaaaa.

Good on ya man

[HOLD3N]

wouldnt have picked that. Very satisfying when you trouble shoot and fix these sorts of things.