Engine problem (full story, very long)

[Adams_16v]

alright folks, bit of a long one this, but tells the whole story, so i hope someone can give me some help or guidance!

some of u may remember me having idle problems and stalling at junctions etc. (i made a few posts about it, and i know many people have had the same problem)

well the initial problem was very occasionally, and all i had to do was pull over, let it idle for 30 secs and it would sort itself out and then be fine for weeks.

very occasionally the car wouldnt start. only happended on 2 occasions. a bump start started it, and it sounded rough as fuk for about 1 minute or so, then sort itself out and be ok, bar the dreaded cutting out and idling problem. on the last occasion of this, the car never became normal again, and i had the low idle and cutting out problem at all times

Well here is what i did!

changed the fuel filter.
changed the iscv. was ok for a while then back to usual.
also changed the speedo cable and road speed sensor, still the same.

then changed the potentiometer (from another valver, untouched)
changed the throttle body
changed the iscv (again), after this lot it was much better, after starting the car at first it idled at about 2krpm for a while then sorted itself out and was running spot on for the first 30mins drive, but then started to struggle at idle again, and the revs dropped low still at junctions, but not always to the point that made it cut out.

next i chaged the lambda, still the same.

then changed the cooland temp sensor and timing sensor, seemed much better on idle but after a drive it was the same again.

next changed the ecu for a mk1 clio 16v one instead of a 19 16v one, and also changed the map sensor, and upped the fuel pressure a bit.

now when i start the car from cold, it sounds rough as fuk, when it initially starts it doesnt rev up a little as normal (for like 1 second), it just starts and doesnt go above 700-800rpm sounding terrible (rally sl*g style ), but after a bit of constant gas up to 3.5krpm (about 10 secs worth) it seems much smoother, but still the revs drop really low after letting off the gas. this is before iv set off!

So after the engine sounds much better, and i drive it, the revs are dropping nicely to about 1200rpm and then slowly to about 900 as it should. no sign of cutting out or dropping revs at all.

once the engines warmed and i start to rev it a bit more over 4krpm the revs then dont drop anymore than about 1400rpm, and it idles at that until the engine is turned off and on again, when it then idles ok at 900rpm.

so in conclusion its much much better, but at first start its sounding rough as fuk, like its runnin on 3 cylinders, then its running ok, but after some gas above 4k revs when driving the revs then dont drop below 1400rpm even at idle

told u it was an essay lol! but just givin the whole story as im really wanting to get this sorted.

since i had the cams in and the engine rebuilt, it was running mint for months, although the cams were never timed, fuelling wasnt setup, and it wasnt chipped (although running mint, and quick as owt). since the rebuild the engine is very lumpy on idle though!

do you think this may be part of the reason? i was thinking of maybe taking it to renault! bit pricey tho, and im only a poor student!

Cheers for any help!

 

[steve a]

now when i start the car from cold, it sounds rough as fuk, when it initially starts it doesnt rev up a little as normal (for like 1 second), it just starts and doesnt go above 700-800rpm sounding terrible (rally sl*g style ), but after a bit of constant gas up to 3.5krpm (about 10 secs worth) it seems much smoother, but still the revs drop really low after letting off the gas. this is before iv set off!

So after the engine sounds much better, and i drive it, the revs are dropping nicely to about 1200rpm and then slowly to about 900 as it should. no sign of cutting out or dropping revs at all.

once the engines warmed and i start to rev it a bit more over 4krpm the revs then dont drop anymore than about 1400rpm, and it idles at that until the engine is turned off and on again, when it then idles ok at 900rpm.

-------------------------------------------------------------------------------------------------Exactly the same on my engine.

On start up from dead cold say over night the idle is rough as, like 3 cylinders. But if you hold the revs up for a min or two then its fine. I also have the "go above 4500rpm = 1400 idle" problem, believe thats the speedo cable though.

 

[Adams_16v]

hmmmmm, could be, although i have chanved this once, possibility that this one is fooked too though!

if both cars are the same then it must be something specific.

but the runnign rough as owt on start up is the key to the fault i reckon!

 

[steve a]

Its the PBV I recon with the 5th injector firing as well thats causing it to overfuel??

 

[Adams_16v]

is it worth havin this fuker on?

was thinking regarding havig the cams in and it needing to be setup yet! but with the mapping this can adjust fuelling anyway cant it!

i may get rid of the fuker then! i did read that someone removed theirs and was fine after. i was just thinking that i may need it!

 

[Adams_16v]

also it does smell rich when its first fired and sounding rough!

 

[steve a]

Well i had my pbv set up on the rr and i think its worth it, so i wouldnt ditch it if its already been set up.

Like you say though mine also smells rich on the "cold" start up.

 

[u33db]

I never had my PBV setup and it affected the idling of my car substantially - it cut out etc but since i took it off it has been fine. I reckon if you get the PBV setup right then fine, keep it on but otherwise its a bit pointless as its unlikely your fuelling will be anywhere near correct (like mine wasnt). Unfortunately, i think with cams you either need the PBV or a chip to adjust the fuelling appropriately so its kinda a choice youll need to make - either rip the PBV off and get a chip or pay for it to be setup correct.....

 

[Adams_16v]

wel its gonna be mapped in about 3-4 weeks so that should do it, but i might take it to the local RR to have it setup properly in the meantime. or i may even take it off.. pain in the ass!

cheers

 

[BenR]

WHy dont you just try taking the PBV off for a day, its only 5 mins to puta normal regulator in the rail.

 

[madmat]

I took the pvb out and it fixed the exact problem you are describing instantly, its not had any problem since and this was 2 months ago. I did post sayin to give it a try the first time you posted, im sure itll work. I havent put it back in since it seems to cause no problems even when cold.

 

[Paul C]

Craig i would say that your best option is to get it fully mapped up and the cams timed. i know this is not gonna be cheap mate but it will be your best way to getting the engine all set up and should running well and all the components working together.

Paul

 

[16 valver]

Ive had a few problems with my engine aswell with idling, but its sorted now.

Ive re-adjusted the TPS (throttle position sensor) and after that it was running much better. The TPS is the red thing just behind the airbox with 3 wires coming out of it and going into an connector. There is one wire with a little bit of current, thats the one you need. One wire is a switched 12V and the other is about 5V when the engine is running.

To adjust it, youll need to start the engine and unscrew the 2 small screws from the TPS, so you can move it a little bit. The current you should measure is between 0,12V and 0,16V. So when youve re-positioned the TPS check again its between 0,12 and 0,16V and it should idle a lot better.

About the 1400 rpm. when hot, thats usually caused by a bad ground on the speed sensor in the speedo cable. Just get a good ground on the black wire and, 95% of the times its fixed...

 

[Tom_16v]

Doubt the problem (whatever it is!) has anything to do with you mods mate.

My idling problems was similar to yours, when standard, and still now thats it tuned......

 

[Adams_16v]

sweet as, cheers for all the help, sorry madmat i must have forgot about u mentioning about removing it!

nxt question is: how do i remove the PBV. just take the fuel pipes off (after theres no fuel in em) and connecting both points together basically?

what about the red material covered pipe that goes into the fuel rail (or into the inlet manifold), what goes on there? iv only had a quick look as iv got to go to work now!

Thanks

 

[madmat]

its under the inlet manifold, u have to stick ur hand under there and just unplug the wire going to the valve. I took the bonnet off and dropped radiator when i did it, but i think you could probably do it without.

 

[Andy GDI]

the problem with the idle staying at 1400 rpm and not returing to idle until engine is turned off and restarted is the road speed sensor earth.......



now this is actually earthed behind the stereo.......



I thinks its a grey and white wire....



if there is a loose one there its that......



you need to re-earth that cable....



I have seen this EXACT problem before and this cured it...



take the radio out and check.



when the car goes over a set speed, the ecu changed the fueling (idle etc etc)... and when you stop it thinks your still doing road speeds... so does not let idle again...



Andy

GDI

 

[Adams_16v]

thanks andy. i was messing with a new stereo the other day so none in at present, ill check the earth is ok tomorrow, and also take the PBV off and throw it away hehe.

Fingers crossed it should be running sweet as then! about time after all the bits iv changed!

Just to clarify with taking the PBV off.

do i need to remove it and simply connect the end of pipe (1) to the location that pipe (2) start? as in the pic ? what happens with the red pipe (3), what goes in its place? if anything ?

http://homepages.nildram.co.uk/~cadams/images/pbv.jpg

thanks

 

[Andy GDI]

you need the original pressure regulator to go back on, then just connect that to vacume...

the thing thats in there is just a pipe to carry the fuel... if you connect that to vacume the inlet manifold will fill up with fuel!!!!

 

[Adams_16v]

damn i havent got one as the car came with the PBV on already!

think i get ya. maybe i need to see the original regulator first to see how it fits!

 

[Andy GDI]

needs to be like this... the rest can be left.... as long as the vacume to the pbv is closed as well and there is no fuel lines left open etc

http://erc.qmuc.ac.uk/cliosport/gallery/full/1083454899__118-1809_IMG.jpg

 

[Daz]

mmmm, clean.. hehe.

 

[Adams_16v]

ah right. so ill get an original pressure regulator first, then connect as in ur pic. got that bit.

what do i do with the fuel pipes iv labeled [1]and [2]?

i really need to learn more about how engines work! lol

cheers andy, much appreciated!

 

[madmat]

justy readin what everyone else has posted, its not the pbv i disconnected it was the wire to the cold start valve, that was what was causin it to overfuel, thats what i described as just unpluggin. Sorry bout that, but id still try that first .

 

[u33db]

Youll find that the longer pipe (2) connects to another pipe at the other end of the fuel rail - this is the return to tank pipe. Directly opposite youll see a small pipe coming off the end of the fuel rail that has been blocked up - just reconnect this to original section of the RTT pipe that dissappears beneith the inlet manifold. Apologies for the vague description but youll see what i mean by looking at it.

I think i may have a spare regulator lying about if you want it. It came off my 1.6 megane but should fit your 1.8 as the megane uses the same fuel rail setup. Let me know if you and ill try and find it.....

 

[steve a]

Yeah craig i wouldnt disconect the pbv straight away. First of all you could set the pressure back to standard 3 bar. And if that doesnt work disconect the cold start /5th injector.

 

[Rasclart]

I would do as AndyGDI said fella

If he has solved this problem numerous times before.

 

[Adams_16v]

yeah im gonna hve a look at the earth now. ill also change the fuel pressure a bit, untill i get the time to go get it setup properly!

cheers

 

[bondy]

check rotor arm and cap and dizzy could be cracked and fuking about when warm