Ideas please... Intermittent power loss...

[Bob]

In the last few days my truck has been misbehaving. Starts normally, and drives perfectly from a mechanical point of view. But it's losing power on acceleration under load. It will pull away fine in first, then in any other gear it won't pull on for maybe 3-4 seconds. Then it gets power back and away it goes. It doesn't lose revs as such, just holds at that level, but the engine goes quiet, instead of it's expected growl.
It's not consistent, it's happening at a variety of revs and only under load. If I dip the clutch during a flat moment, the revs rocket up.

I assume it's not an EGR issue,
Fuel filter gets changed regularly,
Must be throttle mechanism or fuel delivery at pump??

im reluctant to go to a dealer as funds are tight. But it's not good as I can't trust it to overtake now, or pull out with any degree of urgency..


thanks in advance

Bob

 

[Sag]

Have you checked your getting full throttle under the bonnet when your accelerater is fully pressed,I know it sounds stupid but I've seen it before.

 

[BobMurphy]

There are a couple of fine-gauze filters in the fuel pump - where the fuel line goes in. There is a sprung ball valve there as well that can make an annoying noise as the spring loses tension. I would check those filters as its quite easy and painless and may produce results.

I would also remove and clean all the connectors on the pump - I use 'Servisol' Electrical Contact Cleaner. It sounds as though there is an intermittent fault in the fuel delivery.

Bob.

 

[Shayne]

First thing I would check mainly because its the cheapest and easiest thing to fix would be the throttle body butterfly to see if its sticking .

 

[Beau]

It definitely sounds fuel related. When you dip the clutch in the revs shoot up because the load on the engine decreases and it can rev with less fuel needed than when under load. If you haven't checked before, I would check the filter inside your tank and work your way from there. It's very common for them to get blocked up.

 

[goodoldboy]

unrelated i know but ive just had a intermittent cold starting problem fixed - something that has plagued me for the last year.As soon as the temperature dropped below 3 deg. it wouldnt start/was difficult to start.keeping the fuel tank filled above half seemed to help but my trusty local mechanic (thanks Alfonso) had it in his garage for a few days & traced the problem to a loose connection in the fuse box cutting power to the pump/stop solenoid.Me , was convinced that it was the fuel pickup in the tank, a common problem on 90s , so beau dont be to sure its fuel supply related

 

[Bob]

Cheers for the replies lads. Will go searching on Saturday. I'm pretty certain the tank filter is fine, looked in there a few weeks ago on foot at another thread here. I'm thinking it's possible to be the intake on the pump alright. I'm using after market Blueprint filters, and I suspect they're not as fine as the Toyota originals. It might be letting more through to the pump gauze.

Oddly, I put the 12x6 trailer on this evening and gave the truck a bit of a push on to test it, pretty soon it stopped flat spotting, and ran normally, pulling like a train for a 50 mile round trip..

Bob & Goodolboy... I wonder if it may be electrical, as mechanical problems don't fix themselves, but electrical ones can mysteriously correct themselves

 

[Crispin]

I had those problems on the 120. After loads of looking they eventually found leaves stuck to the pickup in the tank.

 

[wobbly]

Has it been run on veg oil or bio at all?

 

[Bob]

Never had anything but the best in the tank. No veg or bio.

Anyway out I went today. New diesel filter, checked all fuel lines, checked pump intake, checked tank. All connections cleaned and checked. I took off the intercooler to see if the throttle had anything to do with it. All good with the butterfly, but I did find this little fellow had sheared. It's part of a sensor unit coming off the throttle body, and was snapped where you can see on the white tube.



Now I dont know quite what it does, but I repaired it anyway. Now it's running perfect once again. Hope it keeps up.

Gave the truck an oil change service and did the timing belt too while I was at it.

Got a decent gash in my hand from loosening the idler pulley.. came free with a bang!! Never anything easy!!



Hopefully the fuel problem is sorted. Time will tell.