1HZ fuel problem - motor dies when reaching max revs

Submitted: Wednesday, Feb 11, 2009 at 14:21
ThreadID: 65894 Views:6673 Replies:6 FollowUps:4
This Thread has been Archived
Hi,
I have a 1HZ '97 80 series with a DTS turbo fitted. 5 months ago the motor started using more fuel than normal and seemed to be down on power about 20%. All filters have been changed several times since this problem surfaced and the fuel filter inspected. Tanks and lines flushed. Nothing unusual in the fuel filter, in fact, mechanic said it was very clean at last check. He has done a "hot set", (not entirely sure what is involved there) and that improved response around town slightly, but on the highway it is a slug, I now drop to 85kph up a particular hill whereas it used to hold 98kph.
I used to be able to count on 900ks minimum total distance from both standard fuel tanks before empty no matter what type of driving - highway, offroad or outback touring on dirt tracks (CSR and the like). Now, the best I can get is 750ks no matter how easy I take it. No additional mods or gear has been added to the vehicle for several years, always serviced, doesn't use oil or loose water, still builds turbo boost as it always has. The only other problem is when I need max revs (e.g. 2nd gear - foot flat to the boards) the motor will suddenly die back to idle, a huge cloud of grey smoke will come out of the exhaust and it will take 20 seconds or so to return to normal. Engine has done almost 300k ks.
Could the fuel pump need an overhaul? As this is very expensive, it's not something that I want to do if it is not the problem.
Any ideas??
Tony
Back Expand Un-Read 0 Moderator

Reply By: Member - Tour Boy ( Bundy QLD) - Wednesday, Feb 11, 2009 at 15:04

Wednesday, Feb 11, 2009 at 15:04
When your mech checked the fuel system did he remove and clean the primary gauze filter in the end of the fuel line where it enters the pump?

I'm willing to bet it has a restriction /cr@p in it.

Cheers
Dave
Cheers,
Dave
2010 Isuzu FTS800 Expedition camper
2015 Fortuner
Had 72 cruisers in my time

Lifetime Member
My Profile  My Blog  Send Message

AnswerID: 348597

Follow Up By: Ozhumvee - Wednesday, Feb 11, 2009 at 17:56

Wednesday, Feb 11, 2009 at 17:56
If it isn't the filter mentioned above it will probably be time for an injection pump reco job.
The other indicator of overhaul required with 1hz is if the engine is hard to start (or no start) after being driven and allowed to sit for 10-15 mins. They will start fine cold and hot but if hot and allowed to sit for the short period will not start until fully cooled.
Peter
1996 Oka Motorhome

Member
My Profile  My Position  Send Message

0
FollowupID: 616814

Follow Up By: Tony J - Thursday, Feb 12, 2009 at 09:59

Thursday, Feb 12, 2009 at 09:59
Yep, he said he did that.
Motor starts easily at all times, hot, cold and in between.
0
FollowupID: 616929

Reply By: ross - Wednesday, Feb 11, 2009 at 18:11

Wednesday, Feb 11, 2009 at 18:11
The fuel pump would be a prime suspect if its all original at 300000klms

They can be removed and bench tested for pressure.

Generally the pump will seem ok when cool,but whe it gets nice and hot,they lose pressure and its most noticeable at higher rpm.

The injectors are usually done at the same time as the pump to get the best from an overhaul or servce.
AnswerID: 348620

Reply By: Falco80 - Wednesday, Feb 11, 2009 at 18:26

Wednesday, Feb 11, 2009 at 18:26
Lift pump on it's way out maybe?
AnswerID: 348623

Reply By: furph - Wednesday, Feb 11, 2009 at 20:02

Wednesday, Feb 11, 2009 at 20:02
I would start by looking at the the valve clearances.
When was it last checked?
furph
AnswerID: 348630

Reply By: Member - DOZER- Wednesday, Feb 11, 2009 at 23:52

Wednesday, Feb 11, 2009 at 23:52
300 is a good innings for a pump, you should get out of it for less than 1k if you go to a good diesel place....there are filters in the tanks aswell, when you say the motor dies when pushed hard, this has to be fuel running out in the pump...i would try cleaning both the filters mentioned, unless of cource you can swap to aux and the problem goes, then its tank...do u use algai treatment in the fuel??
Andrew
b4 you bag me out, walk a mile in my shoes, then your a mile away and have my shoes :)

Member
My Profile  My Position  Send Message
Classifieds: Bt50/Ranger Speedy grande2 18x8 alloys (x4), Landcruiser 200 series/100 series 4 alloy rims with tyres and nuts GC

AnswerID: 348673

Follow Up By: Tony J - Thursday, Feb 12, 2009 at 10:01

Thursday, Feb 12, 2009 at 10:01
I use an injector cleaner which says on the bottle that it kills algai. I have the same problem no matter which tank I use. Most annoying is the loss of power when highway running.
0
FollowupID: 616930

Follow Up By: Member - DOZER- Thursday, Feb 12, 2009 at 13:41

Thursday, Feb 12, 2009 at 13:41
Then it is in the pump, possibly the lift pump that cant keep fuel up to the fuel pump, or the filter on the steel pipe thatgoes into the pump. Might also be worth taking off the electric switch that cuts fuel, they sometimes get clogged there. 250-300k kms is usually rebuild time for a 1hz pump
Andrew
b4 you bag me out, walk a mile in my shoes, then your a mile away and have my shoes :)

Member
My Profile  My Position  Send Message
Classifieds: Bt50/Ranger Speedy grande2 18x8 alloys (x4), Landcruiser 200 series/100 series 4 alloy rims with tyres and nuts GC

0
FollowupID: 616952

Reply By: Sea-Dog - Thursday, Feb 12, 2009 at 17:05

Thursday, Feb 12, 2009 at 17:05
Does your air intake have a plastic right angle elbow in it? A few aftermarket turbo installs suffer a similar fate when being pushed as the suction makes this elbow collapse in on itself, thus restricting air flow... when the revs are released the plastic goes back to how it was... The fix for some is to simply replace the elbow with a silicone joint... worth a look.
AnswerID: 348746

Sponsored Links

Popular Products (14)