BA surge when at operating temp

[dsheps83]

had a few issues with this poor car,  BA Straight 6

 

 

My latest is when its cold runs fine has heaps of power, once it gets to operating temp it isn't as powerful, and surges can be felt above 60kph. when I had cam issues is swapped out the cams and the cradle caps with the vct actuators from a slightly later model, which where a slightly different design. the surge happens every 5 to 6 seconds when cruising at highway speed. 

 

Could the vct from a later model be the cause? stil had the same oil holes?

 

Have Checked

 

Fuel pump - New

fuel pressure regulator - Swapped

coils - Swapped
spark plugs with diaelectric grease - 5000km old
knock sensor - Swapped
crank angle sensor - Swapped
cam angle sensors - Swapped
throttle body (tps) - Swapped
fuel filter - New
fuel pump relay - Swapped
injectors - Swapped
02 sensor - New

 

None of these changes made a difference and the swapped items work fine on my other running car

 

Except the fuel related items I was confident that it wasn't any of these as it runs perfect until it gets to its operating temp, somewhere around the 70c to 75c mark it starts the surge.

 

when it gets out of warm up mode does the timing with the cams change?

 

[k31th]

has it had a tune to cope with the different cam sensors and cams?

[dsheps83]

the cams were stock cams from a later version of the BA, an 04 model as I have found out they have different vct actuators but everything looked like it lined up the same, as the car wasnt running properly before I did all this I cant say it was or wasnt this

 

But to answer your question, No as I beleive the cams have the same profile

[skidxr6t]

three types of VCT actuators if I recall right, one with a bolt hole and one without. then a third type that is shorter.

 

did you change the oil after changing the vct actuators?

 

have you flattened the accelerator while cranking engine for about 10 seconds? it resets something todo with the actuators

 

finally can you scan for fault codes?

[dsheps83]

yeah there seems to be two different lengths that bolt on, I changed from one to the other changing the caps that they mount in. I did change the oil not sure if it was straight after or down the track a bit, is this going somewhere cos I do believe when I changed the oil the issue wasn't as bad, running penrite 10w-50 I think which made it slighty better.

 

the reason why I changed the actuators was after cleaning them they still didn't move much and had another set from the motor I was getting the cams off, which moved a lot better

 

Haven't done the hold the accelerator part might go do that now.

 

And no codes display with the surging going on, I have an old ford flash that I can install the software on the laptop and take it for a spin, but if im not getting any codes I probably wouldn't see any issue even looking at the right sensors would I?

[dsheps83]

well just to update this I feel like a complete idiot at the moment,

 

I thought well I have some vct sprockets here I'll just swap em out.

 

well, when I took the rocker cover off and went to undo the cam sprocket bolt I noticed it wasn't tight, so I pulled the bolt out cleaned it put loctite and did it back up, went for a drive now its all good!!!!!

 

I assume it wasn't tight enough to seal the oil passageway. as I left the car sitting for a long time I don't remember how I didn't have it done up, whether the cam kept turning the motor or I got distracted and never checked the tension I dunno.

 

Thanks for the suggestions

[k31th]

I'd also look at the timing chain position to be 100% sure if you left it loose for a while. Good job on solving it, though!

[dsheps83]

yeah would have been a good idea, but I already put it back together and been driving it around, 

 

thought I would update, antoehr thing to check for anyone else that comes across this issue after changing thier cam