Bit of a knock

[rascacio]

Hi there
I'm looking for some help/advice from seasoned Hilux owners concerning a knocking problem thats just developed on my 2.4 ssrx auto 1993. Here's the story so far.

Friday morning 6.30am starts perfectly as normal and off I go. 1 mile later as approaching a roundabout and slowing down the engine cuts out.
Re-starts(but sluggishly) but theres a very slight tapping sound which gets louder with more revs. Switch off and arrange a recovery to my yard.

1 hour later I try to start it and it starts perfectly and ticks over perfectly.Oil pressure normal.(Plenty of oil) After a couple of minutes standing with the throttle up button on (around 1200 revs) I set it back to normal tickover and its sweet. Then give it a blip on the throttle and when it hits about 1750 to 2000 revs theres a loud knock/tapping which appears to be on top of engine. Definitely rev related.

I took the rocker cover off and ran it and all the valves SEEM to be working ok but thats all I can tell at the moment. Replaced cover and thats it.

So before I decide what to do I am looking for any advice from anyone who may have experianced similar symptoms.

I've had it a year and never had the slightest problem with it and EVERYTHING works except the electric aerial which some scrote bent over, so I would love to sort it out.

I've been through the forums but would like some more up to date advice if possible.

Thanks in advance for any feedback.

[stormforce]

could be dirty injectors.
When was the truck last serviced?
I would get the fuel filter changed but fill it right up with atf or redex before fitting then prime it with the plunger on top.
Once3 done go and drive it like you stole it to give the fuel system a good clean.
Another problem is it may be sucking in some air from somewhere so check all the fuel lines etc.
Do you get a hissing when releasing the filler cap if so it may be the tank breather blocked

[rascacio]

Did a service about 1500mls ago. Did the 'Redex Trip' as well and use it regularly. Any more info on how the injectors could cause the noise would be most appreciated.

[NiftyNev]

When was the timing belt last changed?

Nev

[rascacio]

The timing belt is nearly due in fact I have it bought it already and was planning to do it in the next couple of weeks. I suppose it could have moved a tooth but I have never had this problem before. The last belt problem I had was on a Pajero when the balancer belt went and blew a rocker. If the belt has jumped would it cause the symptoms I've described ? and if so will there be any valve damage ? particularly as it starts perfectly and idles perfectly and even up to around 1500/1750 rpm it sounds like a sewing machine !!!

[NiftyNev]

If the belt is on it's way out for whatever reason then it's possible that the timing is out and this can cause top end noise if the pistons are hitting the valves. I don't think you have a choice but to check it considering it's about due anyway. Maybe there is a problem with the tensioner or idler and the belt is starting to fall apart. This can happen if either has a bearing problem. If the belt breaks you are really in trouble.

Nev

[rascacio]

Thanks for that. I will be having a look at the belt situation when I get chance, maybe next week so I am just gathering as much info as poss before I start because if the job looks like its getting too big I'll have to think again. I'd normally do all the work myself but I am recovering from 2 broken ribs at the moment so my mobility is restricted. So if it looks like it's going to get too big an operation I'll have to re-asess the plan.

[surfenstein]

whilst your there check the bottom pulley,damper bolts and keyway,it could be loose causing the timing belt to jump around too.