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General => The garage => Topic started by: Deefadog on 26 January 2005, 16:09
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Hi all, I'll try and explain exactly what is going on with my car then hopefully someone can have an idea :) I think all these points are related somehow!
Problem 1 - From cold - Turn key and engine fires, but is very jeky and then cuts out. If i start it in the same way but hit the accelerator to help things along it fires up fine
Problem 2 - Once fired up she revs at around 950 rpm, the revs used to increse for a short while before, but now they don't, but if i slightly press the accelerator to increase the revs to around 1000 rpm and hold it there the rev counter moves up to 1100 and back down to 1000 all the time (like a heart beat) is this right?
Problem 3 - When driving from cold and i stop or dip the clutch the revs drop to around 750 and then climb back up to 950, this happens untill the engine is fully warmed then this disapears?
Hope someone can help!
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Try removing your ISV and giving it a good clean.
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yeh try that, use sum of that injector cleaner stuff, it does job,
most 16vs do rome, trot, hunt, what eva you wanna call it.
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Also if ya have trouble firing up, then try unplugging the cold start valve.
It is on the end of the inlet manifold, its like a 5th injector.
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Cheers guyz, ok i'l try them tomorrow!
So you think it all the problems mentioned are related together?
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that just sounds as if the ISV aint working so first off all check the ISV is buzzing with just the ignition on!
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This was the first thing i checked before posting (as it's a common problem). And it is buzzing away ok!
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In that case try giving it a clean as Corin said.
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I am doing it as we speak :) (damn, got my keyboard all mucky) :)
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Ok, cleaned it all out and the pipes coming from it, put it all back and it's now idleing at around 450rpm, so i am taking this as a good thing and i am going to reset the idel and hopefully it will be ok :)
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:( Still will not start from cold from the key! needs a little help fro the accelerator pedal! any ideas?
also, even with the idle screw is unscrewed fully the revs don't go above 950 rpm, take it out fully at the car dies!
Also with the isv disconnected the revs just fall all the way down and the engine cuts out! is this normal or is something a miss?
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Can anyone answer my above questions so i can rule these tings out?
Also i am thinking either injectors aor an air leak, would either of these cause my problems?
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Can anyone answer my above questions so i can rule these tings out?
Also i am thinking either injectors aor an air leak, would either of these cause my problems?
Sounds like an air leak. Check all your vaccuum lines and manifold pipes etc. They can sometimes be very difficult to find. Try moving pipes with the engine running, see how it effects the idle.
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Thanks richandhazel, as this only happens from cold i guess i need to check which vacume pipes are used during the cold period (are there any which are not used when the engine is fully warm)???
A good check I have been told is to spray wd40, the engine tone should change when i find a leak? any other tips like this
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Bringing this post back from the dead :)
As above I have cleaned the isv and replace the vacume pipes, and swapped over the overrun cut off and diagrpham switch, also engine has had a pro manual tune and is running fantastic apart from the start problem.
The start up is alot better, but still needs my help with the pedal! and until it's warmed up (drives a dream then), when driving and i come to stop if out of gear or foot on clutch the revs drop to around 500rpm and slowly creep back up or if i blip the accelerator they go back to normal idle!
any ideas? all that is left i can think of id the fuel filter (changing it on the weekend), accumulator (pricey), or injectors, but would these be the cause only when cold and not from hot?
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once you get it started will it idle on its own or will it cough n splutter for about 30s?
with mine in the mornings it'll fire as should on cold start but will then cough n splutter if i dont hold the accelerator down a little. my problem was caused after i had the WUR adjusted
i have a new fuel pump, inline pump & std WUR all ready to be fitted to see if this cures it
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yes, once started after a litle blip on the accelerator it will idel at normal then raise to 1150ish for a bit (have not timed it) then return to normal.
Once i set of on my journey and i come to a junction and put the clutch down or out of gear the revs dropt to around 550, blip the accelerator and they go back up to normal, this happens until the engine reaches temp (oil temp around 88ish)
It's like the isv kicks in a few seconds to late or something and needs me to knock the revs up slightly for it to do it's job!
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tbh it sounds like yours just needs the CO% adjusted
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Do you think it could be the warm up reg as this is suppose to increase the c0 on cold starts?
Also can i rule out -
main injectors
cold start injector
fuel pump
Fuel accumulator
cheers
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the fact that once started it idles normally means you can rule out the pump & accumulator
id be looking at the cold start valve. have you tried starting with the cold start disconnected. a duff one drips fuel so overnight it floods the car making it hard to start in the morning
get your CO% checked & set to 2%. this is what causes the revs to dip when appraoching junctions etc
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Thanks Gambit!
At least it's not going to be an expensive fix :) I think the cold start valve was abot £30 including VAT at GSF!
I'll get the CO% adjusted
If i disconnect the cold start valve, i assume you mean the electrical connection to it? if so if it was duff woul it not still drip fuel connected or disconnected?
Thanks for your help mate, i'll let you know what happens :)
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yes it would still drip but it you dont get the extra squirt of fuel in the morning which is flooding the car as there already is fuel there from dripping overnight - dunno if that makes sense??
disconnect it and leave it overnight then tell us what its like to start the next day
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I see, makes perfect sense, I'll let you know how it goes!
cheers
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It made no difference :(
Just starter motor turning over and a few coughs and splutters, then stalls!
So i guess there either lack of fuel getting to the engine or lack of air?
Any suggestions
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maybe your cold start valve doesnt work at all then
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Is there a way to check this?
What is the thing that acts a bit like a choke then?, because about 5 seconds after she starts then the revs increase for a short period!
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basically this is what happens on cold starts
on turn of ignition, cold start valve opens and sprays in an extra helping of fuel to help start the car
once running the fuelling is increased for 7sec's the warm up regulator controls this, and the ISV operates in conjunction with this - so you get the slightly higher idle for a small amount of time
i assume you can test the cold start the same way you'd test an injector (spray it into a jar). ive never tested one before as mine have always worked.
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So if i get increased idle at start up then the warm up regulator and isv is woking correctly!
I'll test the cold start if i can, there is no mention of it in the haynes (but i could have missed it) :)
*Edit - just found it on the online bently site - http://volkswagen.msk.ru/vw_doc/eva2/FU01/ch6.2.html
I'll test and see :)
This all started back months ago when i had the valve seals changed to stop the smoke! anything involved in this that could have messed up the cold start?
Damn it, wish i had spares for everything, so i can rule each one out :) lol
I am going to change the fuel filter tomorrow since i have not changed this since i had the car, maybe that is clogged up and not letting the fuel through at start? I know i am just guessing here but this is the cheapest an easiest solution :)
Thanks again for the help, nearly there with this motor :)
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Cold start injector tested and it works fine!
Anything else it could be mate?
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Also new fuel filter fitted! still the same! (better throttle response though)
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i take it you've had it all setup correctly?
the fact that you've tested and found there is no probs with the fueling can only lead me to suspect that your not getting a strong enough spark. which usually points to coil probs
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Yes I finally found a VW specialist down my way, he is also a specialist in Mk1 & Mk2 gti's :) Runs fantastic! when i get her started :grin:
I was thinking the same with the coil, i'll test it!
Also what about the plugs?, I got the beru ones like you said about 6 months nback, but my oil seals had gone then and now they are fixed do you think i should check the plugs and make sure they are not mucky from the oil leak?
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aye take the plugs out and just give them a good clean with a wire brush, and wipe any excess oil off them.
also, give the dizzy cap n rotor a clean up while your at it
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I will do, cheers.
Have you any more pics of your motor? would love to see them if you do, 89ners are the best :)
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should be new pics hopefully this weekend when i get the split rims on to it for the summer!
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nice! let me know!
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OK, think i found the problem, either the battery, which i had tested and is fine?? or the starter motor.
I charged the battery all day and did not start it for at least 24hrs, chare rate was nearly 14Volts and she started fine!
I think that my short journeys back and forth too work (15 mins) is not enough to charge the battery fully and once left over night and looses a little more, thus giving the bad starting.
the averge voltage reading every morning is around 12.2 Volts ( een after i have fully charged it) and about the same when i come home from work, so the alteanator is charging it.
Questions:
What is the voltage on the battery that will start the starter motor fully?
Could my starter motor be on it's way out, thus needing a bit more voltage than normal to make it fully work?
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BUMP ;)
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i have the same problem so would be interested in hearing the answers too
bump! :grin:
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The only answer i have found so far is to chrage it overnight! she starts fine then :)
When yours is fully charged, does it start from the key from cold?
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Right i've got some similar problems so i'm gonna join in with this one.
A good battery should in fact kick 13.5 volts when fully charged, sometimes even more.
Perhaps your fuel pump or starter motor or both are a bit ill, meaning that the fuel pump is not working hard enough as you turn the starter cos its not gettin enough juice cos one or the other is drawing too much current cos its a bit knackered...
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Try flicking the ignition on and off several times before actually spinning the starter - each time you do this the pump primes for a few seconds, this will ensure fuel pressure is up and ready to start.
Coil: not difficult to test the resistances, specs are in the haynes. Just because the coil is sparking when u got a plug out doesn't mean the plug sparks when its in the engine and under compression.
Mine doesn't start at all. Fuel pump works. ISV works. Ignition system checked and tested, all works. No air leaks. Airflow flap working. Help! Please post any solutions!
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So you're happy with the ignition system and its sparking ok and when it should..........therefore it must be fuel.
By airflowflap and ISV would I be right in assuming that this is a 16V?
Have you tried cracking the supply line to the metering unit and confirming fuel pressure? If thats ok, then I would pull an injector, stick it in a jar and see if fuel is spraying out when you turn it over.
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It goes now! Was nothing actually wrong with it, just low battery voltage and a bit of a damp day and it flooded itself - I guess where these injection systems are fairly basic - don't get offended anyone :wink: - theres nothing that really stops the injectors if the car doesn't actually start - it just keeps pumping it in..
Anyway i'm gonna give it a new coil anyway, have also got a new battery, a big fat diesel one which means I can just do short journeys on the starter motor :grin: and am going to check and clean all earth straps and wires.
As regards ISV problems and the extra fuel valve:
The fuel injection specialist who helped me has on more than one occasion completely cut off the ISV: blocked its tube into the inlet ducting, disconnected it, and simply set the idle up using the idle speed and mixture screws. This achieved a satisfactory idle - a little slow when cold, a little quick when hot, but stable and usable.
Also, a useful point the specialist gave me. Provided the ISV is all working ok or at least operating, it is possible to deduce something from the engine behaviour when the throttle is closed: if the revs drop too low and then pick back up to normal tickover, the fuel mixture is too rich. If the revs drop to a point above normal idle and then gradually settle to idle, the fuel mixture is too lean. If perfect, the ISV should catch the revs right on the nail, eg engine speed drops perfectly to normal idle with no hesitation.
Extra fuel valve/cold start valve: gives an extra squirt of fuel at actual start up. Can be responsible for flooding and can be disconnected for start up, especially when the weather is warmer and its not so needed.
Warm up regulator - this is the bigger valve and is likely to cause problems if disconnected. It uses a bimetallic spring as a temperature sensor, and is linked to the fuel meter/distributor so that it richens the fuel mixture as necessary while the car warms up - this is why the pipes are connected to the fuel dizzy. If you've got problems in the first few minutes, look here, if its the first few seconds, look at the cold start valve.
Finally, as richandhazel just said, its really easy to check injector performance. Spray should be even cone shaped, with no drips or dribbles, and must not leak when engine switched off - all of these will cause flooding or droplets in the cylinders - bad for performance and bad for the engine on a long term basis - neat fuel washes the oil off of the cylinder bores, giving greater ring/bore wear.
Phew.. thats all for the mo...
:grin: :grin: :grin:
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Wow! GLAD YOU SORTED IT, THAT'S GREAT ADVICE!!!
"if the revs drop too low and then pick back up to normal tickover, the fuel mixture is too rich."
That's what is happeing to mine! up until the oil temp reaches 60 Degrees and then it is perfect! But my mechanc said the ixture was right! how to i turn it down a tad?
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jus dconnected my wur and car runs a lot smoother. Will this do any damage long term by having this dconnected? Whats it for
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You just confused the hell out of me as you answered the wrong thread, but the right one if you know what i mean :)
The WUR as far as i am aware is the auto choke :) that connector heats up a coil in side, allows more fuel and air through i think?
Ity will do no damge! - that's from Gambit :) because i was worried also!
Not 100% on it!
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Check your fuel pump relay. Mine was knackered. Once you turn the ignition on it starts pumping fuel, even if the engine doesn't start.
It ends up thinning your oil because the fuel just drains to your sump....