D2 V8 engine being sluggish

kurgan · Feb 1, 2020

My D2 V8 fitted with a Thor engine and auto box has started to become sluggish on acceleration with higher than average revs. This happens on flat roads and especially on incline.
It also has a tendency to dip the revs when slowing down almost to the point where you think it's going to stall (it has on occasion).
My wife said today it was struggling to reach 70mph.
Otherwise it's a smooth running car for being 22 years old this year.

Any ideas?

norseman · Feb 1, 2020

Mileage ?
The combination of increased revs & poor performance suggests (to me) an auto - box problem.
For a start is the 'box fluid level to the mark & what colour is it ?
Also (silly question) does the car roll freely ?

kurgan · Feb 1, 2020

Hi Norseman

Mileage is 148k
I'll check the fluid tomorrow morning. Only had the car a couple of months.
Not a silly question, roll freely (under engine power?)
Also noticed when driving along at 30mph the revs drop to 750rpm while on my D1 V8 the revs are around 1000rpm.

JUKE179r · Feb 3, 2020

Could be a multitude of issues concerning the V8 engine. It's easy to check...
Start with check/replace the air filter.
Clean out the throttle body and IAC valve with carb cleaner.
Check plastic oil separator isn't clogged in the RHD side of the engine's valve cover.

23850d1419192554-how-install-oil-separator-oil-separator-2.jpg

After that, it's delving deeper into checking for fault codes, MAF outputs, O2 sensors, conditions of spark plugs, spark plug wires and coil packs.

kurgan · Feb 3, 2020

JUKE179r said:
Could be a multitude of issues concerning the V8 engine. It's easy to check...
Start with check/replace the air filter.
Clean out the throttle body and IAC valve with carb cleaner.
Check plastic oil separator isn't clogged in the RHD side of the engine's valve cover.

After that, it's delving deeper into checking for fault codes, MAF outputs, O2 sensors, conditions of spark plugs, spark plug wires and coil packs.

Thanks for this, I'm new to the Thor engine layout. Are there any pictures to show where these parts are located. I'm used to a 14CUX engine.

norseman · Feb 3, 2020

kurgan said:
Hi Norseman

Mileage is 148k
I'll check the fluid tomorrow morning. Only had the car a couple of months.
Not a silly question, roll freely (under engine power?)
Also noticed when driving along at 30mph the revs drop to 750rpm while on my D1 V8 the revs are around 1000rpm.

ref. 'silly question' I meant does the car roll easily when not under power (thinking binding brakes?)
More importantly … was the performance as you describe when you acquired the car a couple of months ago, because at 148k the camshaft is going to have varying degrees of wear, ranging from general to severe depending on the car's servicing schedule in the hands of previous owners.
As for the revs. question 750 does seem to be low at that road-speed, but then again I've not owned a D2 & don't know if the overall gearing is different to a D1.

D2 V8 engine being sluggish

kurgan

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norseman

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kurgan

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JUKE179r

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kurgan

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norseman

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