intermittent idle dip at operating temp and find fault.

[Bill Lee]

A 7da 2.0 1997 aac pet man t4, my van is in relative good repair, but for some time a problem with the idle area has eluded me even with vagcom and physical tests and all with positive results leaving just why it behaved this way-until it stopped starting.
The van would start and run well up until warm, then it would drop momentarily almost stalling, regain in the same second until 5 to 10 seconds and do it again...regularly.
Basically the suspects (left) are injector tips, ecu, immo, CSV, ecm, iacv and a 'throttle bypass valve'.
Although I will need some info on what the actual components are for CSV ecm as I think these may be more likely the problem. Or injectors.
Essentially theres no spark from the coil but worked before it stopped. Dissy new. The order is slightly unclear 1432 with tdc and dizzy mark,rotor aligned. 1 being THE NEXT lead along?!? right.
Anyway all other things tested or evaluated show working order. Not much is left. Vagcoms only lead before was that ecu needed joining with immo which I did, its silent now.

Maybe you know the symptom.

[supclean]

Hello Bill
Do you have power at the coil with the ignition on

[Bill Lee]

Voltage is detected from lead when on. Previously tested with THE instructions, its within guidelines.

(Aside..there was no connected heat/hose pipe from exhaust to air intake compartment, whatever it did was never known, fixed that today)

I also moved these pipes from the side, HELP ME PUT THEM BACK ENTIRELY please.

This is its function....an egr function!?.

[Bill Lee]

I need those small pipes back in, one loops back but the other goes out, which color is it ????

[supclean]

Ok Bill so you have power to the coil but no spark when cranking
Does the ecu pulse the coil?
Difficult to tell from the photo which hoses you are talking about
The hose that I am looking at looks like the speedo cable as well as the window washer hose

[Bill Lee]

I'm not sure how to take an accurate reading of power to the coil, one I did says a little number when ON, but the reading I get is a drop in output whilst turning, through the lead from the (coil) ignition transformer. Something aliken to 15.5 to 10.0. ;amps or volts of any n° ,I don't know yet.
Sparkys, leads all have approx. same output value with a multimeter.

I don't get it, standby current, useable current IS there.

The thin tubes...

Ran vagcom ... Silence. I might disconnect some senders to get some reaction. Pulsing the coil ..!?... A slight description is required for that one.

[Bill Lee]

This will throw water on the fire.............
Took my 'now' virtually brand new dizzy off an cranked her over, the pic is where it inserts, is it reasonable to think it turns the dizzy around......

Checked elec. to all places and the leads weren't giving a signal, yet had the same ohms checked.
Inside won't turn. What now!

[supclean]

Yes 10v cranking voltage should be ok
Pulsing the coil is when the ecu switches the coil on & off which produces spark
The way it works is the hall sensor in the distributor sends an on off signal to the ecu and in turn the ecu switches the coil on and off to produce spark
If your distributors not turning next check your cam belt If that's ok then best to take your rocker cover off to see what's going on

[Sunny43.5]

If the centre part of the dizzy is not spinning when you are turning the engine over as stated above you have some major breakage inside .

[Bill Lee]

Can't find what's broken. Clutching at straws.
Blog says..Intermittent shaft wasn't lined up making the dizzy out of alignment!?!.
What is the connection point?

The connection point isn't as pictured, there's a cog on the right THAT SPINS the dizzy, so I'm wrong, it is working, although something unexpected is the new rotor+cap. Fitting the rotor I must have pushed it on a little too far and it was lower than the connections inside it.....but its still not fixed so I guess a bit more effort in timing might be in order. Will take the new sender in for tests.

On added thing is the ignition cranking also has the engine warning light flashes once attempted (and failed) maybe this indicates something, reading about it but there's not much specifically for my vehical.

[Bill Lee]

Just adding the transformer didn't pass all tests, but the thing about it is the tests showed it was within parameters but as soon as the ignition turns the engine, nothing. So I got a new one.

This is also associated to a flat spot whilst driving. Hopefully it will identify the weird intermittent decrease in the idle. Worse, everything else will need replacing.

[supclean]

Good to hear you don't have any major mechanical issues
Next step is to go back to basics and check to see if you have healthy spark at the coil
If not check that you have power and good grounds at both your coil and distributor
Then get a hold of a led test light and test at the coil to see if the ecu is switching the coil on and off
IMO you need to establish this before looking elsewhere

[Bill Lee]

hahahahahahah.......Ha..ha..ha....hahahahaha...whe eeeee!!!

GeeeWhizzz, can I stay at your house. The insuperable amount of associated things that account to the same problem area that MAY be ... THE problem. And that's not all, in retrospect only vagcom and forums are useful the rest are in the bin. Added to that it a 97' with service manual beaut body, but a few years have been missed, so one can see a few OTHER new parts under the chassis.

Little more than...NEED.. will be the only word you understand, as I have a worn path to collect parts that isn't far away needing my feet just getting warm..��

I've gotta wait for that part in the mail.

[Bill Lee]

UPDATE...the ignition transformer/coil was the loose cannon since its replaced now, hopefully it will rectify the issue......but I speak rubbish, to soon and unprofessionally . Testing the new stuff I had to film a spark plug whilst turning the key, as I only have one set of arms.
When turned ON the current produced a strong spark from the plug!! Just on....it still made a starting spark when cranked afterwards. On film.
Do I assume the coil was the problem or something more suspect like the ecu caused a melt down?
Help

[supclean]

Not sure of any suspects Will the start Check that your rotor lines up where should at no 1 Then double check you connect your leads in the correct firing order Very easy to make a mistake here