cough cough splutter

[mitchp]

ok, not sure if any of you guys have had a similar problem before.

Took the car (98 4.0) on a 460 mile round trip 3 weeks ago (ran beautifully), left it in the garage for 2 weeks while away on holiday.

I've driven it today and it felt really flat all through the rev range. On restarting the car it was missing on one or more cylinders and wouldnt idle without dying. After leaving it for 5 minutes it restarted ok, but still sounded and felt a bit lumpy like it was still missing. Drove it home, restarted it a bit later and it was missing again and wouldnt tick over. There was some black smoke from the exhaust which i assume is caused by unburnt fuel?

I'm just about to go clean the stepper motor and have a nose around the ht & plugs etc.

Any ideas what might be up??

The worst bit is that I had some chav in a civic type R all over my back bumper on the way home and I didnt have the means to shake him off

[mitchp]

Just cleaned the stepper motor/seat and cleaned the distributor contacts and rotor arm and checked ht connections... still the same

[Cider Andy]

It's a mystery and very difficult to diagnose, so it's worth trying a few things that cost nothing. As the car was running fine until it was parked for two weeks, I'd suspect an electrical problem. Try disconnecting the ECU for a few minutes to reset it. It might have got itself into limp home mode for some reason.

[mitchp]

thanks for the suggestion. Still no go tho. What method would i use to test the airflow meter or temp sender?

Mitch

[Cider Andy]

Temperature sender is a pain to test and you need a decent thermometer to test it with. I spent ages doing it and still wasn't sure about the result, although the graph it produced was a close match to what it should have been doing. Your best bet is to just replace it: there's one for sale on Ebay at the moment, price looks reasonable.

The airflow mass meter can be tested in situ with a multimeter. Reconditioned units are expensive as are repairs, so it's easier to swap with someone - it's a one minute job to remove it. If you do borrow one, reset the ECU after fitting it.

[mitchp]

Just got the ecu fault code reader on the ecu.

I'm getting an error code 19 which is 'Throttle sensor output too low when airflow high' = Faulty airflow meter or throttle sensor.

How do I now go about diagnosing which part is at fault, and where can I get a recon or repair/replace of each part?

Any help greatly appreciated, oh and thanks to Rich for sending me the ecu reader!

Thanks

Mitch

[rfisher]

Hi Mitch,

Glad the reader has helped.

You need to do tests 17, 18 and 19 of the so called 'continuity tests'.

I've emailed you the relevant diagrams.

[Cider Andy]

The throttle potentiometer is a very simple device electrically, that's mechanically operated and which wears out. Problems with it tend to appear gradually. The AFM is a little more complex and has no moving parts: I would suspect the AFM first. If you have Steve Heath's 'bible' and a multimeter you should be able to work out which, if any, is at fault. Or at least which is not at fault.

[mitchp]

After performing the relevant tests it would appear that the AF meter is faulty + running with it disconnected made a difference (it actually idled)

Next thing is... does anybody have a spare knocking around??

[Cider Andy]

Ebay item number 260018649219

[mitchp]

Hi Guys,

Finally got an AFM (£35 ebay - Thanks CiderAndy!!)

Just went to the garage, spanner in hand and..... Battery is flat -aaaarrgh.

Can somebody let me know 'the way' to get in?

Cheers

[Cider Andy]

Mitch, YHM!

Do you have a multimeter? You may need one to trim the CO level on the AFM.

[mitchp]

ahhh, what a day.

Got the car open (cheers Andy)

Fitted the AFM

Jump started the car.... ran fine for 2 minutes

Then started running on what sounded like 3 cylinders, wouldnt rev, wouldnt idle and then died and refused to restart off its own battery or a jump start.

I've put the battery on charge now for the night and i will try again tomorrow.

I'm thinking that maybe the coil is shot?

[Cider Andy]

Have you charged the battery, Mitch? The immobiliser can play up if it's had a low supply to it: it likes a fresh battery connected, not a flat one charged up whilst still connected.

Did the fuel pump spin up when you switched on the ignition? Was the pump still running when it refused to start? Silly question, but does it have any fuel in it?

[mitchp]

Battery is on charge as I write. Having another attempt today - It's been sat in the garage for far too many sunny days now!

Pump span up as normal (for about 2 secs) but didnt sound quite the same as normal, so maybe proper pressure isnt being achieved.

The point you make about the fuel - It does have just under a quarter of a tank in there, but i had to roll the car (backwards) out of the garage onto quite a slope. A combination of not much fuel and a lack of battery power may mean the fuel isnt getting to the engine?

I will let you know later....

[Cider Andy]

Mine starts picking up air out of the tank when the fuel gauge reads just under quarter full. It's out of fuel before the gauge is halfway between empty and quarter full. I'd say it's worth putting a gallon of fuel in, could be that simple.

[mitchp]

OK, gassed it up, connected the freshly charged battery, tucked the ecu neatly into its slot, turned the key and.......... BINGO!!

All is well again!!

Andy, cant thank you enough for your help, especially finding the AFM so cheaply. And thanks to Rich for the loan of the ECU fault code reader (will be in the post tuesday) and the workshop notes.

The sun is out and it the car is finally ready to rumble...