consistant starting issue
 

Hi all !
my 89 944 s2 has a starting issue , when i try to start it after a couple of days i turn key and it cranks and cranks and cranks then splutters into life .if i turn it off then restart it within 15-20 mins it will start no prob any longer and it struggles into life again .if i crank it a couple kill it then crank it straight away it starts ok every time , she is running superb other than this , does any one have any ideas? could it be fuel prssure regulater , any input greatly appreciated thanks !SmileWavy

S2 does take 2-3 seconds of cranking before it starts. My does this consistently. The regulator may be the problem but doubt it as you say the car is running good once started. The fuel pump should pressurize the system quick enough. Only if the fuel has leaked out of the fuel filter will the pump require more time to pressurize the system. I can't see a faulty regulator to do this in 20 minutes. The regulator can loose pressure quick but cannot drain the fuel filter. So check to see if you have any fuel leaks.

Also when cold once started does the car run OK cold? Or is the car running OK only once is warmed up?

I would check the fuel system, prehaps you are losing fuel pressure over time for some reason ? I would be interested to see if you pumped the gas pedal a couple of times and then try to start the car, if it started right away.

Hi, not sure on your S2 but my 944 has a check ball that is right above fuel pump that keeps the system pressurized. Maybe you have one and it is fualty and as the call sits for a long while and the fuel all leaks back into the tanK.

Mine was doing the same thing awhile back, drove me crazy.
I had been messing with the throttle cable and set it too tight when I was done. This had caused the TPS to always be in the open position.

Worth a try. With the engine off, move the throttle cable back, you should hear a click from the tps, if not, you might have found the problem.
To make sure, you can take the tps connector off, put an ohm meter on the bottom two pins of the tps (not the cable end), it should measure a short, pull the throttle cable back a bit and after the click, you should read an open.

thanks for the replys guys !
car runs fine when cold and warm, but is defo running rich.could this be related?
when i pump the gas pedal b 4 starting this makes no differance same results.
is there a fuel line check valve on the s2 ? this sounds like something.
the t.p.s (throttle position sw.)? is this where the throttle cable connects to the throttle body ? i will check that tomorrow,maybe previous keeper messed around with it !

any more input much appreciated

I had the exact same issue as marko. The PO had increased the idle using the throttle cam stop screw and it left the TPS idle switch open all the time. It started fine but ran like crap when cold. The TPS is a small black plastic box about the size of a matchbox on the underside of the throttle body (where the throttle cable connects). It should have a connector with 3 wires attached to it. Check out Clark's Garage for a detailed procedure on testing the TPS.

jmd_forest

thanks for that jmd i will check that , was she running rich when cold?
some thing else just dawned on me thow , during the winter when it was frosty / cold it would fire first time every time . hmm whats up with that now the weather has gotten kinda warm 20 celsius the prob has become very consistant !

there is a fuel check valve on the s2 just after the fuel pump !
just checked the porsche kat

That's what I was thinking.

The leakdown pressure test procedure at Clark's calls for 2 bar (20psig) at the end of 20 minutes. http://www.clarks-garage.com/shop-manual/fuel-01.htm

What you described would be classic behavior for a bad check valve.

The check valve can kill the pressure but will not drain the filter of fuel. The pump should then be able to build the pressure quickly, so somehow don't think the problem is the check valve.

SmileWavyhmm, hmm , good point ! the pump should be able to pressurize no matter what
if i sw on ignition get pump running and leave it for over a minute before trying to fire its the same. does any one know if it could be a leaking injector what the symptoms are of such a prob ?
sorry everyone your prob sick and tired of this 1 but tks 4 your patience , im a bit of a novice but am learning so much from you all .this is what porsche ownership is all about great stuff all consuming eat ,sleep, drink porsche

Yes, she was running rich. But right now, she's running rich all the time (new O2 sensor reading .965V after warmup) and I don't know why yet.

Although the pump should be easily able to pressurize the system in a few seconds, the check valve is there for a reason, to assist in warm starts. Do a leakdown test on the fuel system. Clark's Garage has a good procedure writeup. Instead of the fancy connector to the fuel rail access port, I used a short 3/8 inch hose and 2 hose clamps to connect the pressure gauge to the rail.

Also, there was an issue similar to this on the 944online forum earlier today. Turned out to be the coil was weak and got weaker with heat.

jmd_forest

ok so i decided to order the fuel check valve and a fuel pressure reg. while i was at it , i changed the reg. last week still the same maybe a slight bit better , going to change the check valve this weekend and hope !!

:mad:aaaggghhhh !!!! "BUGGER"
STILL THE SAME WITH NEW F.P.R AND CHECK VALVE.
back to the drawing board ah well . any body out there with an opinion on this it really is driving me nuts now. it starts every time once i give it a couple of cranks then ignition off and ignition back on she fires and runs great .and if try to start within 30 mins its fine anything longer and have to do the cranking routine .
could it have any thing to do with engine temp sensor it has gotten completly consistant since air temp has increased , used to be fine on a cold frosty morning fire up straight away

any opinions and i mean any are greatly appreciated .
THANK YOU IN ADVANCEhttp://forums.pelicanparts.com/uploa...1214949643.jpg

When cold try to crank it until it catches and starts. Do not stop the cranking unless you crank over 10seconds. If it starts and runs great straight away then probably the temperature sensor is OK. If not then sensor could be suspect. Let us know if you can start this way and how long it takes to fire up.

Also check the battery condition, assess starter motor condition and battery wiring. Any weakness here can cause hard starting. The S2 is a big engine and requires decent spin in order to fire up.

just went out to start her up now to c how many seconds it would crank before it fired . turn ignition on for about 10 -15 sec then turned key all the way to try and start it and it started straight away!!!!!:eek: bloody typical it has not started that good since the winter. i doubt it is fixed. normally it would take 5 or so seconds of cranking then when it fired it would splutter like it was clearing its throat then it would settle down and run fine , a bit rich thow! :rolleyes:

Looks like you may need to just freshen up the electrics. If the car fails to start outright then is like most cars will be more difficult to start as you risk flooding the engine. Once this happen try to press the accelerator while attempting another start, this will allow more air in and may aid the starting.

It very well could be the injector harness. Could be shorting out some times. Only way to know for sure though is with a noid light. Had this happen on my late 85. Cheap to fix...you can get the new plugs at any napa. just took a couple of hours to troubleshoot.

do ya think a weak coil could be an issue ?
but the thing is it starts no prob on the second try of cranking every time and when the engine is hot . could a leaking injector be an issue flooding 1 cylinder and the couple of cranks i give it first time is clearing out the cylinder . is there any way of testing for this ?
im prob just grasping at straws at this stage .
it is just 1 of an ever growing list of issues arrising with the s2 at mo :confused:

--times like this I recommend measuring everything (AFM voltage, temp sensor resistances, AFM response, fuel pressure and leak down - every thing you can think of). Get your hands on the S/S2 Diagnostics and Troubleshooting Guide in the Factory Service Manual and run through it all. It's kind of fun and it's a great feeling to know what's good.

You tried a new dme relay, right?

D.M.E. RELAY WHATS THAT ????
only messing yeah of course the first thing i tried .im goanna get busy this week coming, and as ya say measure and test everything make sure i havent missed something silly .
i will post up on how i get on .SmileWavy

it starts up after about 5 -6 seconds if i give it gas ,it is ok but if i dont , it splutters then idles normal . the battery is good as is the condition of the wiring that i can see , where is the engine block ground ? would a bad connection on ignition sw. or alarm immob. relay affect it only when starting .
but it starts great in winter on cold frosty mornings great within 20 mins of shut down when engine is still quite hot i have changed - plugs,leads,f.p.r and fuel pump check valve .:confused:

would a dodgy harness not affect the drivability of the engine ?
she is driving great just a stubborn starter .;)

Not quite clear what you saying. Lets clarify:
Does it start without giving gas and then idles OK after cranking for 5-6 seconds?
Is this behavior consistent?

If the car runs great I suspect fueling system is OK. If the car starts always after 5-6 seconds I suspect the battery is not up to it anymore. I qualified electrician should be able to assess the battery condition. Try another battery that is known to be new and in good condition.

Also did you check for any vacuum leaks? Also the idle solenoid may be bit sticky and needs a clean!!!

very consistant very.
yeah she starts without giving it gas but it will splutter like it clearing its throat
i had a prob with bad batt clamp couple months ago fitted new 1 and recharged the batt which is less than 2 year old so i dont suspect the batt but i will test another in it just to rule it out.
did not check for vac leak as not to sure how to ! or anything about the vac systems on the car ,what function does vac sys perform (stupid question ??)
my brake pedal is also quite spongey .
the idle solenoid same as throttle control sw.?
thanks makis appreciate your time and knowledge SmileWavy

Yes if it splutters consistently but starts then is possible that the idle solenoid is sticking. A clean with some carb cleaner will not harm. The problem is difficult to get to it on the S2 as is under the inlet manifold. You can try to disconnect the main air hose after the AFM spray some carb cleaner through the small hose that leads to the the solenoid. Spaying some carb cleaner into the throttle body won't harm either. After that connect main hose to AFM and start the engine to clear the carb cleaner. You may repeat this a few times and at the end add some WD40 so that the solenoid gets some lubrication.

thanks for the advice ,i will try that see what happens and let ya know .

Think I have the same problem on my car, and I'm thinkin its due to the fact that my fuel rail is leaking(fuel pump has to repressurize fuel rail). Still have to manage getting a new one before I'll know for sure.

what exactly are your symptoms ace? do you defo have dodgy fuel rail ?
by way of update ( i hope im not tempting faith ) i did the carb cleaner / wd40 thing on wed night , went out this eve try and fire it up and see what was what , she fired up straight away no cranking . i will have to drive it over the weekend under normal conditions before i start getting excited thinking it sorted .
but try the carb cleaner first cheapest form of starting the diagnoseshttp://forums.pelicanparts.com/suppo...ys/men_ani.gifhttp://forums.pelicanparts.com/suppo...ys/men_ani.gifhttp://forums.pelicanparts.com/suppo...ys/men_ani.gif

yep temped faith !!!
problem persists even after carb cleaner .i started checking and measuring stuff and came accross a dodgy looking connection on the d.m.e thermostat in the engine block. i cleaned the connection and it seemed to start much better for a while, the prob has been less consistant since i was at it . i measured resistance on ohm meter and got differant readings
from the ones listed on clarkes.a short to ground on one leg . anyway could this be the prob ?the stat in the block seems to be seeping some goey stuff and the pin seems to be scorched. anyway i ordered a new one from p.p and hoping it has someyhing to do with it .i will replace it and see what happens !
will post how i get on .http://forums.pelicanparts.com/suppo...oilet_claw.gif

I feel your pain! Electrical faults on a 26 year old system are a horses arse.

I was fault finding mine last night and couldn't get her to start. I want straight to the garage after work this afternoon. Turned her key and she started with out a hiccup. I did nothing! Bugger of a thing. :confused:

Keep plodding, eventually we'll get there.

im going to figure it out no matter what, i aint going to give up .im learning lots and thats is giving me some kind of satisfaction , im really looking forward to the feeling i will get when i figure this out !!!!!
i think it important to keep posting aswell because to many posts dont have the final fix post and i find that very frustrating when looking at them for info "IF YA FIX IT POST IT"SmileWavy

Hard starting
 

Did you resolve this problem?
I have a similar issue with my 87 951. It must crank a several seconds to start. Or crank a couple of seconds, key off then key back to start and starts right up and it runs fine. Opening the rail end cap, fuel is not pressured but just dribbles.
I jumpered the dme to run the pump and could not see any fuel leaking along lines form tank to rail.
I've replaced the filter, check valve, regulator and dme relay to no avail. I have a replacement dampner and an injector reseal kit which I may try next.

sorry for the delay ,
i had ordered a new d.m.e thermostat and been waiting for it to come in !
replaced it yesterday the first start was not that promising, but started it again tonight and she fired up first crank but it to early to make a call on it yet , it been a bit cooler lately and it only started getting worse since the ambient temp. started going up ! so it could just be the temp at the mo. i will know for sure by monday ! fingers crossed SmileWavy

did you try the leak down test on clarkes ?
i replaced f.p.r ,fuel pump check valve and it passed the test with flying colours, but it still persisted . try the carb cleaner thing and check the d.m.e thermo in side of the engine block see what type of condition its in ! let me know if the damper makes any differance , i did'nt replace mine:confused:

no joy im afraid , still a lot of cranking going on :(
back to the drawing board, have to try and come up with another idea to throw money at !! any body any suggestions ????? im out of ideas on what to do next:confused:

Have you measured fuel pressure and fuel pressure leakdown yet? I would start there. Much more satisfying to measure than to throw parts at it. And of course, cheaper.