Lack of power

[cavs]

A while back I posted a message about my 1998 Bighorn with the 4JX1 motor. It has a distinct lack of power but in all other regards goes fine. Idles ok and burns clean. I have had it in the shop on and off for over a month and they have checked everything they can think off and no luck.

Things checked so far include, injectors calibration checked and ok, new air and fuel filters, has a new oil pump. Turbo boost checked & ok. Oil pump / cam timing checked ok, balance shaft timing corrected. It has been on 3 different Tech 2 machines and shows no fault.

In all have had 2 Holden dealers, an auto electrician and G Guy motors involved and no-one is able to work it out.

Has anyone else had this sort of trouble or have ideas about what it could be??

Cheers

[Graham]

No experience in this, but has cylinder compression been checked?
Exhaust system checked for leaks/obstructions?

Has the testing been done on a dyno where it has real road resistance ( you said tech 2 machine, but I don't know what that is)

are your brakes/handbrake dragging?

You're not towing a horsefloat by accident?

Ok, I've gone off the beaten track for sure now, I'll go now.

G.

[geeves]

There was an interesting artical a while back on the heui injection system used in that motor but unfortuanatly I didnt save it But essentialy that engine has too much intelegence for its own good. There are sensors measureing just about everything so the computer can compensate so a very sick engine still runs smoothly with no smoke. My money (no more than 2 cents) would be on one of the temperature sensors that could be telling the motor its not up to running temp but as this could be a normal reading it wont show as a fault.Anouther thing that realy affects these engines is too thick an oil. In Wellington Diesel and turbo on Petone esplanade have a good reputation and might be able to help.

[cavs]

Hi

thanks for that Graham. Yep cylinder compression checked and ok. Breaks also ok.

Tech 2 machine is a diagnostic tool as I understand it. Will check the rear-view mirror for that horse float!!

I have seen the article on the HEUI engine ad yep too cleaver by far. I'll get the temperature sensor checked. I took the Bighorn to Turbo & Diesel in the first instance and they would not look at it as they did not have the diagnostic tool.

Cheers

Martin

[geeves]

Suprised diesel and turbo couldnt look at this but I supose you cant have everything for everything. Could be worth trying the other diesel workshops around wellington This injection system is also used on some ford trucks and cattipilar engines
I just lifted this off of aust4wd forum it might help

G'day John - greetings and salutations for the New Year - may your travels be plentiful and enjoyable. My 2000 SE auto model TD Jack returns consistent figures around 25mpg on the open raod at normal speed limits. Around town stop start is more like 21 /22 mpg mark or around 12/12.5 l/100km. Towing a Windsor Sunchaser up the HUme via Canberra to Batemans Bay & return averaged 22.1 mpg at speeds varying from 90-95kph. I've covered only 30000 km so far and have recorded these sort of fuel consumptions regualrly with obvious variations in high wind with van in tow. As u can see not a major change with or without van - only troubles I've experiences was with lack of power because they put in wrong oil spec at first service which by the book is a 10-30 oil but this clogged the injectors Isuza recommended dealer use 5-30 oil and I've never had a problem since. Apparently the heavier oil is a problem to the computer when its cold and until the oil warm up the wrong mixture goes in - or that's at least how my layman's brain interprets it. Felt like the transmission was slipping or had no power when I first experienced it but the oil was the cause of the problem I had a problem with a dead short in a trailer blowing a 15 amp fuse and shutting down the whole system as brakes and transmission lights are on same fuse - see my comments earlier in this forum 4th Dec. I found this disconcerting and the dealer has taken this up with Isuzu - but no reply as yet. Only other problem is with an intermittent ABS sensor problem which will be replaced tomorrow. Otherwise I'm very happy with the vehicle in all respects. I also upgraded the power of headlights lights which I thought were very average but a fine now. Hope this helps a bit cheers Ron

[cavs]

Thanks for that

yep, had the wrong oil in it at first. Had filters and oils changed twice to flush the system. Using synthetic Q9000 now. OK??

Re-reading the powershop article, www.thepowershop.com/HEUI.htm
I find it hard to believe that it is not an injector problem but having spent alot having that checked am at a loss as to what to do next.

Do you know how many temperature sensors there are?

Cheers

[geeves]

unfortuanatly I dont as I have a 2.8 with electronic nothing.
Only option now would be ring round all the diesel specialists and see if anyone is ably to help There is a Isuzu truck specialist across the road from diesel and turbo but wether or not they can help I dont know