emaxxowns

when i had the car running it would not rev, a mechanic friend of mine advised me to try tapping on the AFM lightly as he's seen these have issues like that and it appeared to start working correctly after that as i could give it gas without it stalling. it started fine a couple times after that but it hasnt since

peanut

apologies for delay but Mother-in-law taken into Hospital tonight so bit of a panic on earlier.

Q Has the engine ever started with the alarm not connected ?

Q Has the engine ever run normally since you got it ?

Could you please list what you have tried so far .

EDIT I see thee have been a few posts since I was last here.
If hitting the AFM made the engine run normally then that could definitely be the cause of this issue. it probably needs cleaning and the wiper arm repositioning on the track . There is an excllent article describing how to test the AFM and refurbish it on Clarkes Garage website. http://www.clarks-garage.com

Dan Martinic

I've taken the lid off my AFM, cleaned inside, and re-adjusted the contact arm. Although the contact is very light, it's attached to a moving flap that has a pretty solid tension; I doubt tapping lightly would cause the contact to move, tricking the ECU & ultimately altering the A/F ratio enough to allow you to rev the motor. If it was that sensitive, every bump in the road would be a problem!

It's either sticking somehow or you have a loose contact. Take the air cleaner out and with a stick see how freely the air flap moves inside. There's tension but it shouldn't be like mud: it should be fairly loose and free. You may also have a bad connection at the plug which you can wiggle to test. Whileyou're playing, you might as well test the output of the AFM. Lots of good tutorials. I simply connect test wires (with little aligator clips on the ends) to 'connect' the plug and read the voltage while moving the flap. It's tight though so don't short anything. An oscilliscope is better, but you can at least see if it's got major drops.

Ultimately, you take out the AFM, pop the lid, and clean the track + inside contacts (there are three including the moving piece plus the wire connections) with contact cleaner and a piece of white paper. If you do this, buy some "sensor safe" sealant first to re-seal the lid.

Servicing my AFM like this solved a minor cold-running hiccup once for me. These AFMs are pretty old and could use refreshing! Otherwise, I'm surprised how good it continues to work

emaxxowns

No need to apologize for anything, it happens. I really appreciate the help since you're taking the time out of your day to assist a stranger.

i have not started the engine with the alarm not connected, i could give that a shot, i thought i had to leave it connected.

it hasnt run normally as i bought it knowing that it didnt run, the PO told me that the next thing he may look at was the alarm as the culprit but i tried doing the bypass that clarks shows and it didnt work. i dont know what else the PO may have done/tried.

so far all i have done was confirm the harness going to the ECU was all frayed so i replaced the 2 sensor wires using the instructions provided by Lindsay racing. after i replaced it the resistances check good from both the sensors and at the ECU end. I checked if the fuel rail had fuel going through it when cranking and it appears to leak out more when cranking, also confirmed that I am not getting spark at the distributor or at the coil. oddly(maybe) when i tried the alarm bypass and it didnt work, when i finally plugged the alarm back in and tried to start it after it sitting not connected for about a week is when it finally started. other than thinking it may be the ECU trying a known good one, and the thing with the AFM i think thats it. I was unsure if i did the sensor hardness install correctly im only assuming so because it did start at some point after.

Dan Martinic

Hey Peanut wish I saw your post just now.... would have saved me some phone-tapping lol

peanut

Dan get ya self a netbook lol

I don't know how you lot can type anything on a cell phone .. You should have seen the garbled message I texted my Wife last night ....made no sense at all.

My graphite track in my AFM has deteriorated considerably over the years... probably due to our terrible weather. the surface is crumbling like shavings from a pencil lead . I am still looking for something I can resurface it with cos I couldn't afford a new AFM.

There are modern replacements from later models that might substitute ....I'll have to look into that mod when I have some time
https://www.augmentautomotive.co.uk/...rsche-944-ecu/
https://rennlist.com/forums/944-turb...rger-type.html

Dan Martinic

If you ever wonder why my posts have so many "Edit" time stamps, now you know why

I am shocked at how well my AFM's carbon track looks. The engine has over 160,000 US miles ( >250,000 km). Even the traces from the wiper don't look too bad: you can see where it's tracked, but it's still dark black lines sitting on the surface. I kinda wish I didn't bend the wiper; frankly, I didn't feel comfortable doing that.

I've seen used ones come up as low as $50 from this side of the pond. Maybe the North American climates suit it better

emaxxowns

so i went ahead and cleaned the afm wiper track and also cleaned the contacts on the bottom of the wiper and instead of cranking now, it will try and fire up but not start, it did run for like 2 seconds on one of the tries. it no longer sits there just cranking, so this is some kind of progress i guess. i wonder if the sensor is just bad. or maybe the connector going to the harness?

peanut

if the engine hasn't run in a while it would be likely that all the important connections need cleaning especially all your ground points.

I would systematically clean the terminals in the connectors of AFM, TPS, injectors, engine coolant sensor , aux air valve, speed and crank position sensor connectors . Clean and file the spark plug electrodes clean the distributor cap terminals everything

emaxxowns

it wasnt driven at all but the car did run for a few minutes just fine a few weeks ago, and i shut it off, didnt stall. ill probably still have to tackle what you said

emaxxowns

just an update after some tinkering, i cleaned up the afm and after putting it back in it did the same thing, after cranking it some it would stop cranking after just like 1 crank. i replaced the ignition switch and the car starts now, time will tell if that was the problem

peanut

good move ! hopefully that was all it was