Car faltering

julian · Post by **julian** » Fri Dec 28, 2007 6:15 pm

Hi All,
On the way to the coast around 150km away a problem started showing. When just cruising along at around 110kmh the car would occasionally falter just for a brief moment, like it was losing power completely but then correcting and continuing on. It was a 30 degree day.

On the way back (38 degrees and windy) the problem became more frequent and more severe to the point where I had to pull off the highway.
Oil levels and pressure, and water levels and temperature normal for a hot day. I think when I was forced to pull over I saw a bit of smoke puff out the back, but it could have been a bit of dust as it was pretty windy.
No abnormal smells or noises.
Checked battery while engine on ~13.5V, engine off ~12.5 and cranked normal.

There was no way to predict the problem, but in retrospect it seemed to happen more when car was in positive manifold pressure (ie boost). I rarely find the need to use full throttle in the country, and with this problem was not keen to try.

I am thinking there is a problem with the turbo or possibly fuel delivery/ECU.
Any thoughts?

Could this be at all related to the vacuum problem I am experiencing?, in this thread: showthread.php?t=8360

sven '2' · Post by **sven '2'** » Fri Dec 28, 2007 6:45 pm

sounds like a trip to Rising Sun - first thing would be check ECU for fault codes / fuel pump / filters / route of fuel lines etc - all the normal things.

(sort of) knowing the car, I'm guessing you have all those aspects (save the ECU check) squared away anyways, but start with the basics. Hear hooves, think horses not zebras type of thing...

38 is hot, but not really that hot - I had a similar experience on the far West Coast with my EA82T (pre IC) - had more to do with low range 4000-5000 RPM intermittently for hours on end in 44C+ heat. Was ok when it cooled to a more comfortable 39C the next day but.

goodluck - how did the AC go by the way??

sven

Matatak · Post by **Matatak** » Fri Dec 28, 2007 7:00 pm

sounds liek ur spark may be dropping out...that culd explain the puff of smoke. excess fuel kinda thing

Rising sun sounds like it culd be on the cards liek Sven '2' says

julian · Post by **julian** » Sun Dec 30, 2007 3:07 pm

New symptom,
If I use the horn when driving, even for just a moment then the car will falter, and if i use it when idling I can stall the engine.
WTF?

Busdriver · Post by **Busdriver** » Sun Dec 30, 2007 3:11 pm

Get a new horn!

Or maybe something weird like a short in another cable forcing current (spark?) to go to earth through the horn ?

SuBaRiNo · Post by **SuBaRiNo** » Sun Dec 30, 2007 3:30 pm

Check your Earth cables. Chassy to Battery, Battery to Motor.

Dave

julian · Post by **julian** » Thu Jan 03, 2008 12:35 am

Earth leads all good.
Would a buggered coil lead to such problems?

D3V1L · Post by **D3V1L** » Thu Jan 03, 2008 1:29 am

it can of course..i had a problem in my lib for a while and new coil fixed it..but if the horn is causing isues it sounds like a short may be lingering

dave

Busdriver · Post by **Busdriver** » Thu Jan 03, 2008 7:15 pm

Apart from the horn, does switching anything else on that increases the current load affect the problem? e.g headlights? If no, then maybe the short is in or around the steering column, as when you push the horn you are completing a curcuit that goes up and down the steering column.

sven '2' · Post by **sven '2'** » Thu Jan 03, 2008 7:31 pm

Try this...attach a lead from the steering pinion in the engine bay to ground.

bet you a cold pint of Pale at the Ed the horn will work and your car will not stall!

Of course you cannot then drive it - if the above works, concentrate on the horn earth, usually resolved by fiddling with the stering shaft nut to the steering wheel

As for the stray current, well like dave said, start with the basics of earths, coil etc

...and never underestimate the cost benefit of an good auto electrician (there is one on Belair road) - 30min of his/her time and $50 of your money maybe well worth the days of frustration...

goodluck!

sven

julian · Post by **julian** » Thu Jan 03, 2008 11:12 pm

I am stumped. Problem is intermittent, and horn use does not always cause car to falter. Rising sun booked for tomorrow morning.

SUBYDAZZ · Post by **SUBYDAZZ** » Fri Jan 04, 2008 4:18 pm

Alternator dying?

julian · Post by **julian** » Mon Jan 07, 2008 4:58 pm

Well after some advice from the ever helpful Steve at risingsun, the problem hasn't shown for several days. Cleaned contacts to AFM under bonnet, and the ECU plugs, now just chasing down the earth lead to the ECU as this may have something to do with the intermittent fault when using the horn.