Australia Car

Australian car repair Issues? Ask an auto mechanic for answers ASAP

Ask an Expert,
Get an Answer ASAP!

My v8 5.7 commodore wont idle. My v8 5.7 commodore wont

Customer Question
My v8 5.7 commodore...

My v8 5.7 commodore wont idle

Mechanic's Assistant: How many miles are on the car? What size is the engine?

My v8 5.7 commodore wont idle

Mechanic's Assistant: What year is your Commodore?

2004

Mechanic's Assistant: Are you fixing your Commodore yourself? What have you tried so far?

Yes i tried checking fuel pump relay and theres power there

Submitted: 4 months ago.Category: Australia Car
Show More
Show Less
Ask Your Own Australia Car Question
Answered in 21 minutes by:
3/30/2018
AU Auto Mechanic: Matt, Engineer replied 4 months ago
Matt
Matt, Engineer
Category: Australia Car
Satisfied Customers: 23,463
Experience: Automotive Engineer for 20 years, BEng hons degree,
Verified

Hello and welcome to Just Answer

This could be an airleak after the airflow meter, any air dragged in here isn't 'seen' by the ECU and so not compensated for and can lean the engine out causing rough running.
As its a mechanical fault it tends not to turn on the fault light and you can sometimes hear a 'hissing' noise with the engine running.

Check the hose clips for tightness and inspect the trunking for any cracks or splits and also all the vacuum system, the small bore pipes and fittings for cracks and missing parts.

The best way to locate a leak is to have the engine running and warm and then spray lighter gas /propane or brake cleaner around each joint in turn. If the engine rev's up you've found your leak.
Now you might think that spraying lighter gas around a hot engine isn’t wise, however the flash /ignition point of gas is about 400°C so you need a naked flame or spark to set it off and I’ve used this method for many years without incident.
Work your way through each possible joint one at a time and you should find it. I use a slightly flattened piece of brake pipe and some rubber hose from the can of lighter gas to provide a spraying 'wand' and allow a direct blast of gas into each area, especially those difficult to reach with large implements.

Air leaks are very temperature dependent as gaps can open up as things expand with temperature so depending on how the leak occurs ( on a hose joint with a clamp expansion will help seal and on a vacuum hose expansion will make a leak worse) so leaks can be better or 1 vacuum leak path that you won't find with the above test is if the brake servo is leaking
so try clamping off servo hose to see if this has any effect

It’s also worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a poorly pump will all result in insufficient fuel being delivered to the engine

Might also be worth cleaning out the throttle body as these get clogged up with carbon and some brake cleaner washed through helps free things off.

Might also be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can do a quick fault find if you unplug the meter and run the engine without it.
if the engine condition is the same then chances are the meter or the connection to it is faulty

It’s also worth cleaning the MAF sensor wires, as they can get coated with dirt over time which then offsets the reading
Use some contact cleaner or brake cleaner to spray onto the wires to remove the dirt – on no account touch the wires with anything as they are very fragile

Ask Your Own Australia Car Question
AU Auto Mechanic: Matt, Engineer replied 4 months ago

My goal is to give you the best advice that I can and I hope that I've helped today. Please remember to rate my service by selecting from the 5 stars at the top of the screen before you leave. If you need more help, use the reply box to let me know.
If you're not pleased, also let me know because rating bad does not result in a refund, there are better options. Rating now will not close this post nor prevent further replies
Thanks Matt

Ask Your Own Australia Car Question
Customer reply replied 4 months ago
It only idles for about four seconds
AU Auto Mechanic: Matt, Engineer replied 4 months ago

hello

can you keep it running if you step on the accelerator?

Ask Your Own Australia Car Question
Customer reply replied 4 months ago
Hiya sorry for the wait
Nah it doesnt we can rev it abit but it will cut out pretty quick
AU Auto Mechanic: Matt, Engineer replied 4 months ago

Ok then I'd next check fuel pressure, as even though you have 12v at the relay its possible the filter is clogged or the pump is faulty

as this is sounding like not enough fuel pressure

Ask Your Own Australia Car Question
AU Auto Mechanic: Matt, Engineer replied 4 months ago

Hi
do you still need help?
Bear in mind that the site takes a deposit from you at the beginning and this is held by the site until you rate my answer at which point the cash is split between the site and the expert. I am only paid for my work on this question if you rate my answer, using the star system at the top of the screen. Please do not forget! If you're not pleased, also let me know because rating bad does not result in a refund, there are better options. Rating now will not close this post nor prevent further replies
Thanks Matt

Ask Your Own Australia Car Question
Was this answer helpful?

How JustAnswer works

step-image
Describe your issueThe assistant will guide you
step-image
Chat 1:1 with an au auto mechanicLicensed Experts are available 24/7
step-image
100% satisfaction guaranteeGet all the answers you need
Ask Matt Your Own Question
Matt
Matt
Matt, Engineer
Category: Australia Car
Satisfied Customers: 23,463
23,463 Satisfied Customers
Experience: Automotive Engineer for 20 years, BEng hons degree,

Matt is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry.

Stephanie PElm City, NC

used your service this weekend with "Trecers" help. thank you ,thank you, thank you. replaced an A/C fan motor. Local Auto Zone had part. $15.00 "tracer" fee and $40.00 for parts, I saved several hundreds of dollers at a shop. i will recommend you and use you in the future.

David L.Richmond, TX

9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much.

PhilMarysville, CA

Lurch. Thank you very much. I had real doubts about this website but your promptness of response, quick followup and to the point answer with picture was incredible.

CharlesWalnut Creek, CA

As a single woman, I really appreciate an excellent and affordable opinion.
Thank you Geordie, I will not hesitate to contact justanswer in the future!

SueCharleston, WV

Another great insight to what may be the problem. I will have my mechanic take a look at it tomorrow. Thanks again, Frank...you do indeed know your stuff.

JimCastleberry, FL

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

< Previous | Next >

Meet the Experts:

Curtis

Curtis

Australia Car Mechanic

1,614 satisfied customers

Qualified Automotive Mechanic, LPG & Airconditioning Diagnostic Technician.

Glenn Bradley

Glenn Bradley

Australian Car Mechanic

699 satisfied customers

Ex Transmission Shop Owner, Driveline Specialist, 30+ years in the Australian Automotive Industry

Scott B

Scott B

Australia Car Mechanic

478 satisfied customers

Qualified Automotive Mechanic, Service Manager & Proprietor 20+ years

Technopro

Technopro

Australia Car Mechanic

149 satisfied customers

20 years of experience in Automotive Repair Techniques and Diagnosis Expert.

Matt

Matt

Engineer

23,463 satisfied customers

Automotive Engineer for 20 years, BEng hons degree,

Mark

Mark

Mechanic

618 satisfied customers

29 Years as a Vehicle Mechanic in Australian Military

Mechanic Martyn

Mechanic Martyn

Australia Car Mechanic

325 satisfied customers

Advanced trade certificate in Automotive engineering

< Previous | Next >

Related Australia Car Questions
Holden commodore ve ss 6 litre codes c1210 and code
holden commodore ve ss 6 litre codes c1210 and code c1235,can you help me with thes codes … read more
Cesar Jimenez
Cesar Jimenez
Owner/CEO
Vocational, Technical or Trade School
175 satisfied customers
Stalling on idle and when accelerating. Its on and both.
Yes ive put new coils leads sparkplugs replaced fuel injectors … read more
Gary
Gary
Senior Technician
Vocational, Technical or Trade School
101 satisfied customers
I have a holden commodore 2003 vy v8 5.7 ls1, put a cold air
put a cold air box on it and reprogrammed the ecu the check engine light comes on for a short time when you accelerate hard its all good when you take your foot of so its decelerating and a down hill the light comes on but leaves no code … read more
Gary
Gary
Senior Technician
Vocational, Technical or Trade School
101 satisfied customers
My sons car actully Starts sometimes esp when cold. But
Hi My sons car actully Starts sometimes esp when cold. But after driving for a short time, wont start again. … read more
Gary
Gary
Senior Technician
Vocational, Technical or Trade School
101 satisfied customers
Have a 1998 vt commodore it just died on me, fuel tank full
HI have a 1998 vt commodore it just died on me , fuel tank full suspecting fuel pump problem, wandering location of pump and dismanteling process... … read more
rpmdiag
rpmdiag
High school
7,865 satisfied customers
Stops at random, dead throttle, misfires and shakes at
Stops at random, dead throttle, misfires and shakes at restart then stops, foot to floor doesn't help, wait 20 mins to half hour then starts normally. … read more
Gary
Gary
Senior Technician
Vocational, Technical or Trade School
101 satisfied customers
Vt commodore cuts out or refusees to start - intermittently.
Vt commodore cuts out or refusees to start - intermittently. I have an led test light attached to fuel pump relay output (purple wire) to indicate whether power absent, when cranking and no power indi… read more
Gary
Gary
Senior Technician
Vocational, Technical or Trade School
101 satisfied customers
Holden Commodore: HiI have a full supply problem with my
Hi I have a full supply problem with my 98 VT Commodore. Fuel pump gets fuel to rail but nothing comes out of the return line. The car will start with aerostart but can't start by itself. Thanks, Tim.… read more
mechanicaltone
mechanicaltone
143 satisfied customers
Jump started it once my sound system fuse blew..car wont start..theres
i got a vt commodore and wen i jump started it once my sound system fuse blew and now the car wont start it just turns over like theres no spark… read more
Andrew
Andrew
Vocational, Technical or Trade Scho
256 satisfied customers
Petrol..idle checked fuses and replaced 2 relays now wont turn over
i have vr commodore with lpg and petrol will turn over but wont idle checked fuses and replaced 2 relays now wont turn over… read more
Andrew
Andrew
Vocational, Technical or Trade Scho
256 satisfied customers
Commodore..a backfiring problem and it wont idle keeps stalling wen
i have a VL commodore dual fuel its got a backfiring problem and it wont idle keeps stalling wen idling any suggestions on how to fix this… read more
kenbam
kenbam
Bachelor's Degree
49 satisfied customers
Calais: V8 Sedan and need to replace the original fuel tank..fitted
Hi, I have a 1989 VN Calais V8 Sedan and need to replace the original fuel tank. Would this be an 85l tank? - How do I tell which tank it is fitted with?… read more
James
James
Vocational, Technical or Trade Scho
576 satisfied customers
3.8: vk holden with a 202..will improve fuel consumption..ecotec
I have a VK holden with a 202 in it, UI want to know if there is a relativly cheap connversion that can be done that will improve fuel consumption? I was thinking down the path of a 3.8 lt ecotec, can… read more
James
James
Vocational, Technical or Trade Scho
576 satisfied customers
Falcon: the t5 manual out of a vr-vs commodore a direct swap..fitted
is the t5 manual out of a vr-vs commodore a direct swap into my au xr8 falcon fitted with a t5 manual (is very tired)… read more
Mark
Mark
Mechanic
Vocational, Technical or Trade School
618 satisfied customers
A holden commodore vz 2004, i go to the shop then come..wont start
just brought a holden commodore vz 2004, i go to the shop then come back lock it then go to get in again and it wont start.… read more
James
James
Vocational, Technical or Trade Scho
576 satisfied customers
A VN V8 Commodore will start, idle for less than a minute then
A VN V8 Commodore will start, idle for less than a minute then stop. It wont start again unless left for a while. There is spark at all plugs, the fuel pump primes before starting and I can smell fuel… read more
Mark
Mark
Mechanic
Vocational, Technical or Trade School
618 satisfied customers
A vb commodore its my burnout car its a v8 and the block..cuts..stalls
hi i have a vb commodore its my burnout car its a v8 and the block is a vn commodore block but its got all the 308 carby gear on it and all i know performance wise it has a 750 holley on it and when i… read more
James
James
Vocational, Technical or Trade Scho
576 satisfied customers
VZ Berlina wont start. when turn ignition on it says very
VZ Berlina wont start. when turn ignition on it says "very low fuel - fuel gauge error". It has a full tank of petrol - like car in drive - no kick at all… read more
James
James
Vocational, Technical or Trade Scho
576 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x