Dear abla ol-up is an adverb there. And there is no rule that you must use -da after -up.

Ex: Bağırıp beni rahatsız etme.

You mean I invented the rule myself?

I made a correction ol-up is an adverb. And you can use -da after it. But it is not a rule. But if you use it you can only use it as a conjuction.

maybe tunci can help us.

I had this understanding the -Ip form takes all its grammatical markers from the predicate verb (including negation) if the conjunction de is not put between them to prevent it. But it seems now it is not such a strict rule.

gokuyum, thanks.

Give an example please. I dont understand what you mean.

Zengo´yu görüp de korkmamak imkansızdı.

> görmek ve korkmamak

Zengo´yu görüp korkmamak imkansızdı.

> görmemek ve korkmamak

Lewis´s grammar says this.

He says wrong. -de is a conjuction but it also powers the meaning of action. There is no real difference between those sentences.

It was impossible not to be afraid when you saw Zengo.

So good I asked. I was so certain about this.

Lets wait and see what the others say about this matter.

Honestly, I was in a dilemma on locating "da" on that particular sentence when I corrected that statement recently however when I checked smilar usage in a "trusted newspaper" I saw it "one word [attached onto verb -Ipta] " and gone for it. But when Abla brought this issue up to discussion I had a chance to review it and Gokuyum´s digging into it helped me to rethink about it. And now I am inclining into "seperate dA ".

* Another thing ; Although sometimes conjunction "de" is pronounced as "te" [verbally]  whereas in written language it has to be seperated.

* But Locative "de" can not be seperated in both written and verbal language.

* The best way to check " dA " whether it should be written seperately or one word is ;

If the meaning of the word is almost the same when you remove "dA" from the word , then it is conjunction.

Zamanı olupta bana yardım edebilecekler lütfen bana yazsın.

Zamanı olup bana yardım edebilecekler lütfen bana yazsın.

I dont see much difference between two statements.

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* Under the light of all these,  the function of "da" in our sentence the clitic "de" follows "Ip" and it denotes and emphasize the relation between the actions.

1.Condition --> One must have time

2.Condition --> One must be capable [able to] help me.

3. wish [demand] --> I wish someone write to me

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If we put them all together ;

I wish someone, who is [at the position of ] able to help me providing that having enough time [to help me] , write [contact] to me please.

So my final conclusion on function of "da" in this context is "providing that"