Help! Big problem with my Spec S

[-BigDave-]

So it started with a hesitation when I pressed the accelerator. Then it progressed to having a rough idle when warmed up. The idle was fine when cold but its now a bit rough when cold as well. The main problem now is that when I have the throttle just open to try and cruise along in whatever gear, the car starts to sputter and run like ****. The car revs up ok (seems to be down on power though) but just as I try to hold the revs at a certain point it all goes to sh*t. When the car is stationary and out of gear, and the throttle is opened, the same happens; it revs fine but can't hold the revs in any one place without starting to sputter and stutter like crazy. At first I thought it was the AFM because when the car was idling rough if I plugged out the AFM it idled ok when warm. Tired cleaning it several times and then replacing it.

I've replaced the following:

Spark plugs
Lambda/O2 sensor
Air Flow Meter/Mass Air Flow Sensor. Did this twice with 2 seperate 2nd hand units that I was assured were both in good working order.
Cleaned the throttle body and intake plenum down with throttle body cleaner
Replaced the fuel filter under the bonnet

I've also inspected the spark plug cables and they're fine. The distributor seems to be ok as well, little bit of corrosion but nothing major as far as I can see.

Few questions:
Should I invest in a brand new AFM or would it be a waste of money? Does it sound like an AFM issue?
Should the inside of my intake plenum be very sutty/black with dust? (because it was and I'm a bit worried)
Should i try cleaning the injectors with a fuel additive?
Does it sound like a fueling issue or air flow issue?

And finally: WHAT THE F**K IS WRONG WITH MY CAR!? Because i'm fit to throw a brick through the window at this stage!

Any help appreciated!

 

[Clarkey]

Sounds like a dizzy/coil problem tbh. Worth checking the o2 is working right though. Get it on a CONSULT and see whats going on.

 

[Cris69]

Also check that the cat isn't blocked, some times can cause same sort of issue!!
The plug leads are the easiest things to replace, if the leads get hot they could be breaking down inside!
Sorry not much help..

 

[-BigDave-]

Lambda has also been replaced actually. Made no difference.
Running a decat so not the cat problems. It's the same with or without the cat.

Just drove it again there. Runing perfect when cold but as soon as it begins to warm up it runs like ****.

Does an idle air control valve affect the car when its driving and not just idling?

 

[Auss15]

No, the idle control valve only comes into play on idle and when aircon is on at idle

 

[-BigDave-]

Ok thanks for that. Does it sound like a worn throttle body? Or maybe a faulty throttle position sensor?

 

[Auss15]

Check your TPS with a multi meter to work out that, should be around .05v on closed throttle..

 

[spoonman]

Check your TPS with a multi meter to work out that, should be around .05v on closed throttle..

muppet.......... .45v on throttle closed (.35 - .65 the ecu understands as closed)

have you checked your timing by the way? if you have fluffed with the dizzy?

 

[spoonman]

what does your water temp gauge read,,, all good??? that sender could be sending funny signals to your ecu and telling your engine its cold when its hot?, have you adjusted the idle screws on the TB without knowing what your adjusting?

Lambda has also been replaced actually. Made no difference.
Running a decat so not the cat problems. It's the same with or without the cat.

Just drove it again there. Runing perfect when cold but as soon as it begins to warm up it runs like ****.

Does an idle air control valve affect the car when its driving and not just idling?

 

[Auss15]

muppet.......... .45v on throttle closed (.35 - .65 the ecu understands as closed)

..Doh....45v to .5v .....5v is what is pretty standard, that's what I was trying to say...I'm tired and old....

 

[-BigDave-]

Temp gauge is normal. Upto halfway when at full operating temperature. I didn't touch the tps until yesterday and I put it back in in a slightly different position and that has caused the cold idle to jump upto 2000 so I must readjust that first to get that back to normal.

wiuld it be the water/ collar temp sensor no? I wS told that might be it but a lot of people have dismissed it do I didn't touch it.

Whats makibg me me think it's the throttle body or tps is that it's sputter like crazy when the throttle is just barely open. Taking it to a guy today anyway and we'll see what he says.

 

[Auss15]

Sounds like you have the TPS in the wrong position, it's easily done if you take it off and misalign it on the refit..

 

[-BigDave-]

That's what's causing the 2k cold idle I know but not the other problems cause I didn't touch the tps before yesterday and this is going on with a few weeks.

 

[Auss15]

I would then have a look at the AFM, maybe borrow one to see if that's the problem....the stock AFM's do spit the dummy and it's well known.

 

[-BigDave-]

Replaced it twice with 2 2nd hand ones that I was told were in perfect working order but that's no gaurentee at the same time. A code should come up if AFM is goosed ya?

 

[spoonman]

check your tps voltage and then get back to us

 

[-BigDave-]

Called to a guy who has diagnostics for jap imports earlier and he said call tomorrow and leave it to him for a day, which I can't do. Plus he wants €100 just to check it over and do a diagnostic so I'll be giving him a miss. Going to borrow a multimeter tomorrow and test AFM and the TPS. Going to check fuel pump and fuel regulator after that. Not spending another cent until I can actually pin point the problem. Thanks for the help.

 

[S15_SAM]

Check your timing too! Sounds very odd though and I would check for water damage in ecu's etc.

 

[Auss15]

Worth buying yourself a multi meter, very handy tool to have and these days they a pretty cheap

 

[-BigDave-]

Does the method of bridging 2 pins on the diagnostic plug with a paper clip and getting fault codes from the check engine light actually work? As per the jull technical guides. I'll have a go anyway see if it gives me a code.