2.8D (non turbo) blow back

[Jameson200]

Can you diagnose this problem?

First, let me say how fantastic these forums are – I’ve been helped immensely (and saved a lot!) by diagnosing problems from reading about other people’s experiences. This is the first time I’ve ever become personally involved in a forum, so here goes!

1996 2.8D Hilux LN107R (Non Turbo) 273K

Last week I started to notice and intermittent popping noise coming from the engine. It almost sounds as if the engine is misfiring, but its not. It is also blowing air back through the air intake manifold while doing its popping thing. This has become progressively worse to the point that tonight it was pretty much constantly doing it.

Its like the crank case pressure is getting to high and venting out out via the intake.

I was advised to check the breather pipe that goes from the rocker cover to the intake manifold its not blocked and all clear. I have also checked all the vacuum lines and they appear to be fine with no leaks or breakages.

I'm pretty sure that this engine does not have an EGR valve? although you guys may know different.

There is also a intermittent squeal noise which seems to come from the rear of the engine. It is like a loose fan belt noise. However the belts are tensioned correctly and don't appear to be slipping. Not sure if it could be related but thought best to include all symptoms.

Can anyone tell me what might cause the ‘blowback’ symptoms at the inlet manifold? Could this possibly be linked to the squeal? and finally could this be damaging my engine in anyway?

Any help/insight would be appreciated.

James.

[john253a]

Black smoke is over fuelling
When was timing belt done?
There are vac line you need check arnt blocked that go to manifold
And also how are your brakes? As a leak there will slow the vac pump to put more air into sump

[TOYZX]

When was the last time the value clearances or compression were checked? Could have a leaking or burnt out inlet valve. If an inlet valve isn't seating properly weather it be from carbon build up or a hole blown in it, each time that cylinder hits the compression/fire stroke it will pop back thru that leaking valve. Do a compression test, it will soon show up any internal problems. Cheers Luke.

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[Jameson200]

Hi John, Luke

Thanks for your suggestions.

I don't get any black smoke from the exhaust at all really and my brakes seem to be working fine. Not noticed any difference in pedal pressure or braking response.

Will check the compression and let you know what I find. I'm not sure when the timing belt was done. The guy I got it from told me that it will doing at 300k. Just to note I have noticed that if a slightly rev the engine the problem goes away, seems to be more prominent at idle.

[Gipsy]

Sounds like timing issue, any work done on the engine?

[Jameson200]

I have only owned the vehicle for a month. The guy I got it from said that the engine had been replaced as the original blew up after fitting a turbo. It's been running fine up until now. How would the timing suddenly go out? Do reckon the belt may be worn and it could have slipped a tooth? Probably a good idea replace it anyway?

[Gipsy]

Yes some proper diagnostics in order, maybe a simple fix but who knows with an unreliable history.

[Jameson200]

Well Luke compression test done and it's not looking good. Well it's good on 3 cylinders lol.

1 - 120psi
2 - 485psi
3 - 485psi
4 - 460psi

Looks like the heads coming off. Question is do I recondition it or just get a new one.

Had a quote for a new head inc cam, vrs and bolts for $1050 AUD. Not a bad price considering I can just bolt on and go.

What you think?

[Gipsy]

Depends WHY the low compression? If it is just a valve, easy.... crack or holed pistons.... rebuild! Either way the head is coming off! Maybe a camera through the injector port will give more clues?

Also, it is most likely your injectors are shot at around $1600_2000. Is his the "new engine or the one the previous owner "blew up?

Either way you may be in for some $$$ so carefully consider the next step cos the expenses rise quickly, do you have the money or is it better to cut your losses and look for a new vehicle?

[Gipsy]

I would be looking for an engine with a guarantee, maybe a turbo later model for$2 grand cos that's what it will cost as a minimum! Also look at alternatives such as commodore models, plenty of scope here with engine transplants.

[TOYZX]

There ya have it! Either way you choose it wont do any harm pulling the head off for a look. If the bores r fine and just has a burnt valve then ya may get out of it cheaper but as stated costs can easily blow out!

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[john253a]

I was quoted 4K Just for short no head/fuel system no warranty
If I wanted warranty I needed complete fuel system reco @ 2k just for injector pump
New head was another $1000
This was through hm engines
To get the full warranty I would have to spend around 9k I to installer approx 10k an agent or I onseller to install, this was 1.5 year ago,

Reco bottom end and injector pump,
new head, injectors, water & oil pump, timing belt, radiator and all hoses

I ended up welding up my crank grinding where the woodruff key goes and it's now done but over 30,000km since then

[Gipsy]

So maybe more than the vehicle is worth, check for wreckers with a guarantee?

[john253a]

I've seen from 1500-3500 with some form of warranty,
Where as I've seen full v6 conversion with driveshafts for 1000-2000
Low kms LS motors you'll do for 10k with patrol transfer case if you hand on the tools + engineeres cirt price

All comes down to price
Cheapest option is a 22r but why buy a diesel and the price just to fit a petrol

[Jameson200]

Update;

Well I thought what the hell. Motor's broke anyway so the heads coming off. So I rolled up my sleeves and got the spanners out. I'm glad I removed it. I had some sort of foreign body that had become trapped under the intake valve. (Will try and post some pics tonight)

What concerns me is I don't know what it is or where its come from. I guess that it could have been swimming around in the engine oil for a long time and eventually got stuck under a valve.

Next steps, strip down the head and check all the valves, seats etc. Also, while its all in bits I think may as well install new timing belt kit.

Question is for timing belt kits, gasket kits etc. Genuine Toyota or aftermarket? Guess it depends on cost.

[Gipsy]

Sounds like good news, what is the foreign object? Metal? You may be lucky with head recon. Check the bores thoroughly cos you won't want to do it again. It didn't come from the oil, more likely a ham fisted spanner monkey. Also maybe this IS the original? Did you check the numbers on the plate?

[Gipsy]

Consider the new head, it will cost more than you think to replace valves, guides, plane the head surface etc.

Bolt and go seems like the best way.

[Jameson200]

So, I finally got my new head delivered this week.

Hopefully all going well will get it all back together this weekend. I have the new head, VRS kit and bolts. I am also going to do the timing belt and water pump while its all in bits.

I've been reading a lot about making sure the new cam shaft has proper lubrication so as not to damage the lobes. You guys have any tips no that would be much appreciated?

I think apart from that i'm good to go, may rig up a hoist tonight as the head ways a tonne...

Again, thanks for all the comments and help so far. I must say that this forum has been very informative and helpful.

[TOYZX]

Just go buy a tube of assembly lube and give all the lobes and bearing faces a smear of it and she'll be good till the oil get up there.

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[Jameson200]

Just go buy a tube of assembly lube and give all the lobes and bearing faces a smear of it and she'll be good till the oil get up there.

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Cheers mate, will do.