VR V8 Ute rough idle

[Drewgong]

Gday I'm having a issue with my vr v8 auto ute. It idles fine at 700rpm as soon as it gets to 800 rpm it develops a miss/ running rough upto 1200rpm then its fine.
Its been to multiple mechanics and been on the dyno so far the following has been done.

tps, iac, coil, dizzy cap, plugs , leads, Battery, Alternator, injectors removed cleaned and tested, o2 sensor, full service, ive swapped over ignition control module fuel pressure reg and dampener even swapped out computer from a running car. Ive had a compression test done and its all in the normal range. Absolutely doing my head in.
Any help much appreciated or if anyone can recommend a mechanic in Newcastle or the Hunter Valley area that is a guru on the old 304

 

[AmericanGuyInAUte]

Stop throwing parts at it. It can often confuse the diagnosis. Scan the car's computer with a Diagnostic scanner that is able to display LIVE DATA. Take a video of the live data numbers and post it up. I will have a look. Most mechanics have no idea how to read live data numbers and without a CEL Code, they start guessing instead of figuring it out.

 

[Drewgong]

Stop throwing parts at it. It can often confuse the diagnosis. Scan the car's computer with a Diagnostic scanner that is able to display LIVE DATA. Take a video of the live data numbers and post it up. I will have a look. Most mechanics have no idea how to read live data numbers and without a CEL Code, they start guessing instead of figuring it out.

Will do mate can you recommend a scanner to buy hopefully a reasonably priced one

 

[gtrboyy]

Piece of thin wire or split into pins 5 & 6 above brake pedal....do a search on forum or youtube hoe to do it.

I wold want a refund is dropkick mechanics never checked fault codes or plugged in scanner to see what was playing.

FFS google & youtube often does half the job for you lol

 

[Drewgong]

Piece of thin wire or split into pins 5 & 6 above brake pedal....do a search on forum or youtube hoe to do it.

I wold want a refund is dropkick mechanics never checked fault codes or plugged in scanner to see what was playing.

FFS google & youtube often does half the job for you lol

There is no error codes

 

[AmericanGuyInAUte]

Will do mate can you recommend a scanner to buy hopefully a reasonably priced one

I would put up a separate post looking for a scanner that can read live data. Many only read codes. I've seen OBD2 generic scanners that read live data for under $100 dollars like this one https://www.ebay.com.au/itm/1144152...WHaEWobbFkirVOcL5+4hMLMdi9O9|tkp:BFBMoOfR1uth.

Do not order that. It's just an example.

Our cars are older and have an OBD2 port, BUT it may not be OBD2 complaint (Australian Laws might be different. In the USA all cars had to be OBD2 from 1995 and up). If it's not OBD2 complaint you may need a GM1 scanner which will be tougher. You can buy a cable and download a program to your laptop but it will be the most fiddly.

Does anyone know if a generic OBD2scanner will work and READ LIVE DATA?

 

[AmericanGuyInAUte]

Piece of thin wire or split into pins 5 & 6 above brake pedal....do a search on forum or youtube hoe to do it.

I wold want a refund is dropkick mechanics never checked fault codes or plugged in scanner to see what was playing.

FFS google & youtube often does half the job for you lol

Every mechanic will scan a car for code. Sadly only a small number of them will look at the LIVE DATA to actually see if there is a problem. Many are just lazy and many are just stupid and don't know what the numbers mean. For example, I had a problem with my UTe where the fuel economy was terrible and the computer had no codes. Looking at the live data I saw one of my O2 sensors was reading rich and one side was reading lean. Even if it tripped an O2 sensor code (it didn't), new O2 sensors would not have fixed the problem. Turned out to be a bad ground.

Coolant sensors, Map sensors, O2 sensors can send wrong signals which the computer will simply accept as factual but when we look at the live data, computer says , "I.m dumping in lots of fuel because its -20 degrees outside! You spark plugs won't foul because you need all the fuel to compensate for the cold weather. You're welcome!" we will know there is a problem.

 

[Deuce]

PCM hacking website will sell you the cable you need, and then with correct files loaded you can see EVERYTHING in tuner pro RT.
Possibly clean all your earth points for a starter. It's free and might surprise you with results.

 

[gtrboyy]

Every mechanic will scan a car for code. Sadly only a small number of them will look at the LIVE DATA to actually see if there is a problem. Many are just lazy and many are just stupid and don't know what the numbers mean. For example, I had a problem with my UTe where the fuel economy was terrible and the computer had no codes. Looking at the live data I saw one of my O2 sensors was reading rich and one side was reading lean. Even if it tripped an O2 sensor code (it didn't), new O2 sensors would not have fixed the problem. Turned out to be a bad ground.

Coolant sensors, Map sensors, O2 sensors can send wrong signals which the computer will simply accept as factual but when we look at the live data, computer says , "I.m dumping in lots of fuel because its -20 degrees outside! You spark plugs won't foul because you need all the fuel to compensate for the cold weather. You're welcome!" we will know there is a problem.

Even then if mechanic has half a brain & common sense they'll work it out or......google the model issues usually common fault will come up there,youtube or a forum just like earth issue you had.

Quite often we get posts saying they've spent heaps of coin been to several mechanics....ask about if checked for fault codes or how to do it *crickets* lol

 

[AmericanGuyInAUte]

Even then if mechanic has half a brain & common sense they'll work it out or......google the model issues usually common fault will come up there,youtube or a forum just like earth issue you had.

Quite often we get posts saying they've spent heaps of coin been to several mechanics....ask about if checked for fault codes or how to do it *crickets* lol

Actually....

Perhaps we can do a write up and title it "Do/Check This Before Buying Parts". It kills me to watch people change stuff at random. I've seen lots of people install fuel pumps who have perfectly fine fuel pressure but no injector pulse, ECU's for no starts, Coils/Ignition Modules for no fire etc etc... sometimes you get lucky... Since everyone here knows a lot of the common failures we could get a really useful guide. I'm happy to help!