'92 Dip still cutting out :-/

[lepews]

Well wot do u know.... after a day and a half of running perfectly the Dip started misfiring/cutting out again!

I was running in slow traffic yesterday, an it did it once while idling, and once while taking off at a traffic light.  I'm so confused...

I've cleaned the IACV valve thoroughly, I've replaced the FPR with the one from my '94 GLi (which never skipped a beat), and I swapped the ECU then swapped it back again as it made no difference.  I really have no idea where else to look now!

Coupla questions:
- has anyone had a coil failure?  Thinking of grabbing that from my GLi
- does the Dip alarm feature an immobiliser?  Anyone knows how to disable the alarm altogether?
- my inhibitor switch on the auto gearbox sometimes plays up - can always start in park but sometimes not in neutral.  Related?
- also thinking of taking the injectors out for a good cleanout.  Good or bad idea?

This is driving me nuts I really thought it was sorted...

As always thanks for any input - much appreciated!

[Tetleysmooth]

You didn't clean the throttle body though, where the butterfly is.
You really need to do that.

[lepews]

ok let's do that.  Can I just check - where do I spray the carb cleaner?  Can I do it with engine running or not?  Are we saying I take off the big rubber pipe coming from the air filter box and spray into the big metal opening?  Should I move the butterfly by hand?

So many questions... 

[Tetleysmooth]

I don't think the engine will run with the air trunking off.
Move the butterfly by hand. Use a piece of rag and carb cleaner and get all the muck out.
Try to do both sides of the butterfly and where it sits.

[lepews]

ok I've done that - let's drive it some more and see what happens I guess.

I still have a gut feeling it's something electrical / in the ignition though, from the way it cuts out then comes back..

[HMK]

What about the all important oiling of the unit with thin machine oil such as '3 in 1'

I presume you've read the 'How-To' thread in the FAQ section on doing this job

The general rule of thumb is that if it's an ignition type fault then it doesn't put the engine management fault light on........most other type of faults do ...........Mostly

[Dave the Builder]

You can't rule out that the 2 wires running to the AIV/ICV might have a slight break due to the flexing/movement of the engine.
 And sometimes ,ICV stick after cleaning as HMK points out.
could be a wire on the crank sensor  too with slight break again due to engine flexing,
 Have you looked at fuel pump conections yet too ?
plus make good engine earth path and good coil earth

  but i suspect ICV still sticking

[lepews]

yea I did oil the IACV valve after cleaning - as per the instruction found here in the How-to.

I have been playing with the wires going to the IACV valve while the engine's running, and nothing happens, so I assume these wires are ok.

I haven't got round to have a look at the fuel pump connections yet - that's in/near the tank right?  Gotta do some reading in Haynes to find out how to get there.  The engine earth strap is looking solid. 
The coil is my next suspect - the wires feeding it have been cut and two new wires with crimp connectors have been put on.  Looks dodgy, but can't fault them while engine is running either, so I think the connections are good.  The connector on the coil was missing its metal clip - already replaced it with the one from my GLi.  Good coil earth - do you mean the 2 bolts that hold the coil to the bodywork?

About the wire on the crank sensor - how / where do I check this one out?

Finally, after cleaning the throttle body yesterday, the car hasn't cut out since.  Drove home last night and back to work today, but then I haven't been in sticky hot traffic yet, which is when it seems to do it most, especially at low speeds, idling and taking off from stopped.

[Tetleysmooth]

Finally, after cleaning the throttle body yesterday, the car hasn't cut out since.  Drove home last night and back to work today, but then I haven't been in sticky hot traffic yet, which is when it seems to do it most, especially at low speeds, idling and taking off from stopped.

Have faith old chap. 

[lepews]

hmm it's still cutting out here and there, but definitely not as often as it did before.

I'm still scratching my head as to where to look next 
If only it would conk out once and not start again, so that the fault could actually be isolated...

[HMK]

Yeah, but is the EM light coming on or not

You may have already said & I haven't read the posts properly

If it isn't, then it's probably ignition - ie, poss coil

[Tetleysmooth]

Or a blocked breather pipe from the cam cover to throttle body.

[lepews]

As it goes, I haven't seem the EM light come on ever in this car (apart from diagnostics when switching ignition on of course).

I did have a good look at the cam cover to throttle body breather pipe when I cleaned the IACV and the throttle body, so I'm happy that it ain't blocked.

Gonna take the coil from the '94 GLi and swap it, maybe that'll help..  Only it's nice n easy to get it out of the GLi, but on the Dip it's a right PITA cos of all the AC stuff!

Last night, (it was a bit cooler here), it started misfiring as soon as I started it up, and carried on doing it all the way home (18 miles).  Today, (nice n sunny morning), it started fine and didn't miss a beat all the way to work (same 18 miles).  WTF?  Talk about a proper random problem...

[Tetleysmooth]

Having read that, I'm wondering if the coolant temp sensor is playing up.
Cold - car plays up.
Warm - car is fine.
Substitute that too while you're swapping the coil.

[lepews]

that's just the thing - one day it does it cold, the next day it does it warm!  There's just no pattern to it!  The only thing I think I can reliably say is that it always happens at low/mid revs or on idle, ie if I put my foot down all the way it usually goes ok.  That could point at dirty injectors, but if that was it then it would always run shite, not just some of the time..

By the coolant sensor, do you mean the one on the thermostat housing?  Cos I already swapped that with the one from the GLi!

Let's hope the coil makes a difference... pinkies crossed 

[Dave the Builder]

Give the ICV another clean/lube ,or substitute it if you can,still sounds like that's the problem, you may have cleaned it, but a tiny but of gunge can still make it stick.
what have you got to loose .

 i had the same and had to clean mine several times.carry a clean spare too.
(that is one sure fire way to never need it  )

[chrismec]

that's just the thing - one day it does it cold, the next day it does it warm!  There's just no pattern to it!  The only thing I think I can reliably say is that it always happens at low/mid revs or on idle, ie if I put my foot down all the way it usually goes ok.  That could point at dirty injectors, but if that was it then it would always run shite, not just some of the time..

By the coolant sensor, do you mean the one on the thermostat housing?  Cos I already swapped that with the one from the GLi!

Let's hope the coil makes a difference... pinkies crossed 

Not the one on thermo housing, it's just above alternator, two pin plug new switch less than a tenner and will transform the car
Always change them on my cars before I do anything else

[lepews]

so far so good... I changed the coil today and it's been running better than ever. 

A couple more days on the road will tell, but my hopes are high 

[lepews]

well I've driven quite a few miles and it's not cutting out anymore

So I think = BINGO!  It was the coil after all - since swapping it with the one from my GLi it's all good!  Finally Dippy's happy again..

Chrismec - what's the deal with that coolant sensor then?  How does it affect the car so much that you always change that first?  I'm curious...

And thanks again to everyone for all the help and suggestions!

cheers

Lepews

[Murph]

The coolant temp sensor (CTS) sends a signal to the engine ECU, the ECU uses the signal to determine the correct air/fuel ratio for the engine temp.

Inaccurate or missing signal = wrong fuel ratio.

Bottom line is that if the CTS is faulty the car will either run erratically or wont run at all.

[chrismec]

even if car is running fine it's still worth changing cts for what they cost

[lepews]

anyone got a part number? 

[Murph]

There are two types - take a look at yours and see if it has one or two terminals.

If you have one then you need Part No. 3439088
If you have two then you need Part No. 90510183

[lepews]

noice tah very much!