Australia Car

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

Ask an Expert,
Get an Answer ASAP!

This answer was rated:

BOSS 5.4L 260 Going into limp ode after the car reaches temp…

BOSS 5.4L 260 Going...

BOSS 5.4L 260 Going into limp ode after the car reaches temp as the car is coming up to temp its fine the fans come on the temp goes down the fan goes off after this the revs start increasing and drops and goes into limp mode any help would be great

Mechanic's Assistant: Will the headlights turn on? Is the battery fully charged?

Yes new battery

Mechanic's Assistant: What is the make/model/year of your car?

The motor is out of a 2003 XR8 the car is replica GT40

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

New temp sensor second hand throttle body reset the PCM left the battery unplugged

Mechanic's Assistant: Anything else you want the mechanic to know before I connect you?

The temp sensor was originally replaced because the fan did not come on and I am just hoping I have not created this problem when I replaced the temp sensor but the fitting was correct and it was advertised as suited for this motor.

Show More
Show Less
Ask Your Own Australia Car Question
Answered in 2 minutes by:
1/15/2018
Gary
Gary, Australia Car Mechanic
Category: Australia Car
Satisfied Customers: 2,007
Experience: Senior Technician
Verified

Hello! My name is Gary.
Welcome to JustAnswer.
I'm reviewing your question now, and will post back with a reply shortly.

Ask Your Own Australia Car Question

Hello there,

Did you do the conversion wiring?

Your GT40 is a manual? Is the donor PCM from an an Auto or Manual trans vehicle?

Gary

Ask Your Own Australia Car Question
Customer reply replied 7 months ago
No the loom was supplied by the company supplying the kit roaring forties in Melbourne, I did not build the car I bought it already built
Customer reply replied 7 months ago
Sorry i it is manual and it has a modified tune by SCT

Ah ok, there is something amiss with the tune I'd say.

I would contact the tuner first.

Have you checked some basics like chassis grounds, and 12v feeds for any poor connections? You might find a connection physically "hot", which is a voltage drop.

I bet this little thing is a rocket with a quad cam in it.

Gary

Ask Your Own Australia Car Question
Customer reply replied 7 months ago
I checked voltages to the PCM for voltages checked all connections, check all earths including continuity to make sure good earth to engine etc all seems ok. Have not noticed any connections getting warm yet, but something else to check.
Yes when it was running it sure does get along.
Customer reply replied 7 months ago
The SCT flash tuner came with the car so would of guessed this keeps the modified tune and can be refreshed I did this when I noticed the fans did not come on when the car came to temp. I hope this is the correct tune and I have developed this fault by refreshing the PCM
Thanks
Stuart

Hi Stuart,

If the fault happens everytime it gets to operating temp, it could be as described above, which I have found a few different cars with "hot" connections, one was so hot it burnt my finger, not funny at the time.

A scan for codes would be the next step.

It may be a throttle body issue, or circuit wiring for throttle body.

Mid engine, low centre of g, must be fun.

Gary

Ask Your Own Australia Car Question
Customer reply replied 7 months ago
The SCT tuner has a feature to detect DCT but nothing comes up, but I will go through connections as you have described, this is the 3rd throttle bottle, I had the original which swapped with an aftermarket SS Induction unit, I thought that may have caused the issue and tried another throttle of a known good working one from another car. Rest PCM still goes into limp mode. Just for my own curiosity I am going to replace the ECT (OR CHT not sure which one this motor has) simply because the gauge reads 80 odd degrees but if it is a CHT this measures the physical heat of the head itself as far as I can tell. If this sensor reporting the reading back to the PCM it could be causing an issue.Have not driven the car much as I had to replace the suspension bushes as they perished cannot wait to get running again maybe take on a track day at Goulburn circuit
Thanks
Stuart

That could be a parameter that the tuner decides on.

CHT is generally higher than ECT.

A thread on the subject:

https://www.hptuners.com/forum/showthread.php?62438-ECT-vs-CHT-coolant-temperature-readings

Gary

Ask Your Own Australia Car Question
Customer reply replied 7 months ago
OK thanks thats what I thought,

Ok Stuart.

I'll leave it with you for now.

When dealing with custom setups, there is always some freak one off abnormality as the cause of ones woes.

I had a mapping issue a few years back, that I couldn't get around, and even a dyno operator couldn't see the error in the data. Then I had a light bulb moment, went into data, changed the scaling for MAP, different car straight up.

Back on the dyno, got my lost 100hp back.

Yours being custom, I hope the loom is correct for current flow etc.

Gary

Ask Your Own Australia Car Question
Customer reply replied 7 months ago
Thanks Gary

Hi Stuart,

This is a fairly complex issue, sorry I can't offer any more at the moment.

At best, ***** ***** say the tuner needs to look at what is going on here.

Hopefully the fault is reproducible for him.

Kind regards

Gary

Ask Your Own Australia Car Question
Customer reply replied 7 months ago
Hi Gary
Thanks for your assistance I did not think it was going to be a straight forward problem, but I do have an update I just re-flashed the PCM using the modified tune (I think I used the strategy tune last time). The car idled perfectly fans came on like before, stayed on until the temp dropped a few degrees and then came back on as the temp increased slightly all normal.However after this the rpm's increased from idle to around 1200 rpm and it seemed to hunt a bit. Had the car running for about 1/2 an hour and I just switched it off but the good news it did not go into limp mode during this test. It seems like the PCM is still learning I might disconnect the battery again to reset and go through the whole process again.Cheers
Stuart

Hi Stuart,

That's good to hear.

If the car is now driveable, I'd take it for a short drive so some fuel trim learning can occur.

Do you have a working engine light as part of your instrument cluster?

Gary

Ask Your Own Australia Car Question
Customer reply replied 7 months ago
No I am not sure why they did not include this I will see if can work this out and rig up a light its a good idea.Thanks Stuart

Yes I would do that.

I've done it a few times on mine and mates conversions.

It's a good talking point when you key on, and your friends see an "engine light".

They assume you have quad webers.

Gary

Ask Your Own Australia Car Question

Hello again Stuart,

Do you need any further help?

I hope my advice has been of assist to you.

Kind regards.

Gary

Ask Your Own Australia Car Question
Customer reply replied 7 months ago
Thanks Gary that's all thanks I have a call to another GT40 owner who is a mechanic as well I see if he can assist.Cheers
Stuart

Ok Stuart.

I wish you well.

Gary

Gary
Gary, Australia Car Mechanic
Category: Australia Car
Satisfied Customers: 2,007
Experience: Senior Technician
Verified
Gary and 87 other Australia Car Specialists are ready to help you
Ask your own question now
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 Gary Your Own Question
Gary
Gary
Gary, Australia Car Mechanic
Category: Australia Car
Satisfied Customers: 2,007
2,007 Satisfied Customers
Experience: Senior Technician

Gary 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

960 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
Driving down the highway and it goes into limp home mode.
Driving down the highway and it goes into limp home mode … read more
HDGENE
HDGENE
Master Technician/Lead Technician
Associate Degree
2,835 satisfied customers
I have a 2001 escape that wont rev over 3000 rpm even when
Hi I have a 2001 escape that wont rev over 3000 rpm even when locked in 1st gear, Have replaced the spark plugs and it is running on all 6 cylinders fine, have checked for intake and exhaust blockages… read more
Chad Farhat
Chad Farhat
Owner
Associate Degree
5,582 satisfied customers
I just changed my alternator. ..disconnecting the battery
I just changed my alternator. ..disconnecting the battery first ....replaced the new alternator connect everything that was needed .ok … read more
Jonbo88
Jonbo88
Ford Transmission tech ford certified
Associate Degree
3 satisfied customers
When my 2005 r51 manual pathy gets to running temp or 30mins
when my 2005 r51 manual pathy gets to running temp or 30mins up the highway I cant accelerate to overtake or even sudden deceleration will cause limp mode, I have changed the crank angle sensor and cl… read more
indy-tech
indy-tech
Shop owner, technician
Vocational, Technical or Trade Scho
11 satisfied customers
2001 Nissan Navara D22 3ltre diesel. limp mode problem. Some
2001 Nissan Navara D22 3ltre diesel. limp mode problem. Some times when truck is first started engine light comes on straight away a goes into limp mode. But mostly when truck reaches running temp.eng… read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
I have a 2013 triton twin cab ute glx. On a recent trip
I have a 2013 triton twin cab ute glx. On a recent trip towing a avan camper . First day was pulling it comfortably in 5th gear when the temp went up on a gradual climb. It got to the top white mark o… read more
Scott
Scott
Self Employed Motor Mechanic
Vocational, Technical or Trade Scho
245 satisfied customers
Mitsubishi magna: , I have a 2004 auto Magna, the car is
Hi, I have a 2004 auto Magna, the car is going into limp mode, 3rd gear only and the neutral light flashing every 1 second. Is this most likely a faulty sensor issue and is it safe to drive it somewhe… read more
Doug C.
Doug C.
Technician
Vocational, Technical or Trade Scho
49 satisfied customers
Volkswagen crafter: Matt I have just Replaced the DPF filter
Hi Matt I have just Replaced the DPF filter in my VW Crafter 2007. But the light are still on and the car runs in limp mode… read more
Kevin
Kevin
workshop foreman /master tech/mot tester
1 satisfied customers
Hyundai Excel: We have a 99 excel that my daughter drives,
We have a 99 excel that my daughter drives, she is always complaining of it not up shiftinf, revving high before shifting, we have not used it for a couple of months and now it only selects 2nd and th… read more
sprinkles08
sprinkles08
Technician
High School or GED
11 satisfied customers
holden baina: I have just replaced the head on a 2002 barina
I have just replaced the head on a 2002 barina and when i satart the car it runs well as soon as i rev it quickly the service lightcar with spanner comes on and the computer goes into limp mode, and w… read more
Matt
Matt
Engineer
Bachelor's Degree
960 satisfied customers
holden barina xc: barina xc hits limp mode once warm-egr ok
barina xc hits limp mode once warm-egr ok and working although fault codes state it as the problem-engine runs great at start up good idle when warm-hits 90 degrees and limp mode kicks in- turn off en… read more
Mechanic Martyn
Mechanic Martyn
Australia Car Mechanic
Vocational, Technical or Trade Scho
325 satisfied customers
Hi, quick q, boss 260 xr8. Aug 03 model, done 85k and auto.Mainly when
Hi, quick q, boss 260 xr8. Aug 03 model, done 85k and auto. Mainly when warm but can do this from cold start. Engine seems to run on 6 or 7 cylinders at idle and up to about 1000 rpm. Then It's on all… read more
Matt
Matt
Engineer
Bachelor's Degree
960 satisfied customers
VZ SS ute had clunking when slowing..accelerate..rev
VZ SS ute had clunking when slowing, then slight flat spot when accelerating and now it wont accelerate at all. It will rev fine in park. RACV came out checked fuses etc and transmission oil nil smell… read more
Glenn Bradley
Glenn Bradley
Australian Car Mechanic
Vocational, Technical or Trade Scho
699 satisfied customers
1991 land cruiser: drives..tow..temps..a v8 to to keep the power
I own a 1991 landcruiser ute which has a after market tubo installed it does get hot but sitting on 90kms/hr it drives very well . I reguarly tow a large boat in extreme temps which does not help the … read more
Engineering Pro
Engineering Pro
Automotive Development Engineer
Bachelor\u0027s Degree
1,366 satisfied customers
Ford au falcon my au falcon series 1, 6 cyl, transmission
my au falcon series 1, 6 cyl, transmission goes into "limp mode" after 20 mins of driving. have fitted external oil cooler and checked oil level. what could be problem?… read more
Glenn Bradley
Glenn Bradley
Australian Car Mechanic
Vocational, Technical or Trade Scho
699 satisfied customers
My 1989 hilux R22 petrol keeps climbingvery slowly..temp gauge
Hey guys, The temperature on my 1989 hilux R22 petrol keeps climbingvery slowly. I have stopped when it has reached about 1mm below the top of the white area of the temp gauge. The temp goes up whethe… read more
kenbam
kenbam
Bachelor's Degree
49 satisfied customers
2000 model patrol 3 turbo diesel..rebuilt..converter..temp sensor
hi i have a 2000 model patrol 3L turbo diesel i rebuilt motor and when i put it back in the transmission will lock up tourque converter once engine warms up. when you disconect the temp sensor for tra… read more
kenbam
kenbam
Bachelor's Degree
49 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