Chugging 4Y-E. Suggestions??

[Hen]

The 4Y-E (ex. 89 Tarago) in my folks Hiace has developed a problem recently.

Engine was fitted 6 months ago and has run fine since. It still starts and idles fine. Sometimes it will rev fine and cleanly. However increasingly often recently it starts chugging under load. Most noticeable when giving it a bit of a prod, tends to go away/be less pronounced at light throttle. And now it does it just while free revving too. Sounds similar to running on only 3 cylinders. However I have removed each lead in turn and can still get the same problem, so I doubt it is a simple ignition problem.

The ECU is throwing no codes (that's a lie, it throws code 11, "Load signal circuit", but has done that ever since fitted and I can't work out why).

My current guess is fuel filter/injectors. It's a bit tricky to do much serious diagnosis as the engine is hard to get at. Any other suggestions?

Thanks
Hen

[oldcorollas]

air leaks?, dizzy cap grotty inside? all spark plugs fecked?

not using crap fuel?

[gerald1]

ok you probably know heaps more about cars and stuff than me - hey almost everyone does and i dont have a whole heap of hands on experience but just a suggestion and doesnt hurt to ask.
have you tried cleaning around the dizzy cap + cleaning the leads at the dizzy end and finally are you sure each lead is on correctly?

is it possible your dad/mum mighta had a look and put them on the wrong way. i was changing GF's spark plugs the other day and accidently put 1 and 2 the wrong way around - EVEN after numbering each one to avoid the problem. and it sort of sounded like that if you revved it. could explain why it happens all the time now??

sorry if this post is useless and im sure someone will come up with much better things to have a look at.

hope you find the problem and sort it out with the minimum of fuss

cya
gerald

[Hen]

Thanks for the quick replies gents.

Wrong plug leads can be ruled out, if you get it wrong there will always be one that wont reach.

I have to admit I haven't even pulled the plugs yet. So it could be as simple as fouled plugs or dodgy dizzy cap.

Air leaks is a right PITA to check. The intake pipe from throttle to AFM can be described as "custom" and is almost impossible to work on.

Will tinker more when time permits.

Thanks
Hen