Back to my VR6 again but.....

[Neil L. 0]

Having had my 1994 vr6 SORN for the last 3yrs - ive decided to get it back on the road again!

The car was idling unevenly when i stopped using it so i decided to start my work with the engine.

I stripped everthing down to the injectors - soaked overnight in petrol. Then i cleaned the ISV and throttle body in carb cleaner thoroughly followed by the MAF ( which is fairly new anyway ). I then blow air through the K&N to clear any obstruction.

I replaced plugs with new and cleaned and checked HT Leads.

After cleaning everthing up (looks great now) i started the car up for first time in months!

The car idles on the 750rpm mark but does surge a bit up to the 1000 line when warmed up!

One thing i noticed is that the car revs normally if i gently use the gas pedal BUT if i put my foot down quickly, the car does not pick up speed and is very hesitant to speed up! 😕

Moving to the engine bay and using the throttle cable, again rev hard, i see that the K&N is moving and looks like struggling to suck enough air into the engine! Is this normal?

As well as this i think the car is running too rich - the plugs were fairly black (dry) when removed!

Would welcome your help with this problem as im eager to get the VR back on the road again!

Thanks.

[mic_VR 3]

Happy new year mate, good to be back?

 

Is the maf definitely working? Have you tried unplugging it whilst its running. If it has no effect then it would suggest it's had it.

 

The k&n will flex a bit under load but if its deflecting a lot I would change it back to standard if you've got it still.

 

How's the fuel? If its been in there a long time it may have gone bad and will create a load of symptoms of rough running. If you can drain the tank down, run some fresh fuel and cleaner through it that would be good

[seanl82 23]

Where are you located? May be worth seeing if someone close by could scan it with VCDS to see if it throws up anything mate.

[Neil L. 0]

Ok thanks for these replys.

I will try unplugging the MAF later and yes the small amount of fuel has prob been there for some time!

I ll fill with fresh and redex soon!

The K&N makes hell of a sucking noise lol - and moves quite a bit under hard throttle!

Wouldnt mind buying 2nd hand standard box - but is there any problems with buying a decent cone filter instead? I have a metal heat shield around filter aswell.

Cant get it on VCDS at my local because car is SORN still! So many other jobs before road worthy!

[Roger Chatfield 0]

If you are anywhere near Plymouth I'll happily pop round and scan it for you.

 

Rog.

[Neil L. 0]

Lol Swansea unfortunately! Thanks for offer!

[aki 0]

Hi

When i got mine out after 4 years standing it had very similar symptoms running rich and not picking up at all turned out to be the fuel pressure regulator in the fuel rail so i nice easy fix i fitted a 4 bar one to help atomisation abit

Andy

[Neil L. 0]

FPR was on my list actually! Where did you get yours from?

Been out to car today - filled with premium and added a generous drop of redex.

Started car and unclipped maf - engine cut co its not that!

Took KN off and put thin rag over front of Maf and car ran the same - cant be K&N then!

Unclipped fuel feed from rail - started car - fuel coming through - to the rail at least!

Changed ht leads with new - same!

After all this i couldnt then get the car to start at all - its cranking but not firing!!😑

Thought?

[aki 0]

This is all sounding very familiar sometimes mine would run then it wouldnt then it had no power at all

I checked the maf etc same as you and no fault codes on vag com

Natural conclusion fpr!

I got mine off ebay (probably not the best) but it worked and fixed the car i think it was around £20 so not enough to worry about

Andy

[aki 0]

Oh just check you have a spark first if you have then thats pretty much all it can be!

Fuel to rail

Injectors switching?

Andy

[Neil L. 0]

Ok - whats this injectors switching

lark?

Ordered 4bar FPR - noticed the vac line off the reg has only plastic ties holding it on - should this be properly clamped both ends?

Its also a bit tatty looking - perhaps new hose and clips?

The list goes on - thank god ive got 2 cars!!!

[aki 0]

Hi

They probably will be as if has run but if its a non runner standard checks are spark and fuel so if is sparking the next check is fuel,you have fuel at the rail so are the injectors working? You should have a constant live and a switched earth at the plug i have a set of noid lights for this but you can use a test light or multimeter to check them and make sure the ecu is switching them

As it was running just before it stopped its unlikely they arnt switching so as youve got a fpr on order just pop that in and try it

Mine was abit stuck in the rail be carefull not to damage the rail too much when you persuade the old one out

Andy

[aki 0]

Oh and new vac hose isnt going to do any harm they dont usually need clips as long as its a nice tight fit it will be ok

I used some silicone vac hose i had lying around from previous jobs

[Neil L. 0]

Ok thanks again!

Got feeling its not injectors - was running for some time before hand! But i wont rule it out totally!

Ill wait on FPR and see how it goes then! Ive heard their murder to remove in one piece!

Cheers

[Neil L. 0]

Ok changed FPR but while the car will run - its surging still and idling at the 6-700rpm mark!

When first started after replacing FPR i needed to pump the gas and rev the engine hard to keep it going but after starting for the second time the car idles very rough and now does not rev as before!

So in a nutshell the car was free reving first time but on restarting would only idle (surging) but not rev through the range.

One thing i noticed when replacing the FPR was that there seems tobe a bit of play when pushing it from the front - like it hasnt seated properly in the rail? Dont think the old one i removed was like this!

I used a g clamp to push it home - it was very tight - should there be any play in it?

Thanks

[jekel 10]

Ok changed FPR but while the car will run - its surging still and idling at the 6-700rpm mark!

When first started after replacing FPR i needed to pump the gas and rev the engine hard to keep it going but after starting for the second time the car idles very rough and now does not rev as before!

So in a nutshell the car was free reving first time but on restarting would only idle (surging) but not rev through the range.

One thing i noticed when replacing the FPR was that there seems tobe a bit of play when pushing it from the front - like it hasnt seated properly in the rail? Dont think the old one i removed was like this!

I used a g clamp to push it home - it was very tight - should there be any play in it?

Thanks

 

If you had to force it in with a clamp pound to a penny you've wrecked the seal and hence not sitting right, heat it with a hairdryer, nothing hotter than that, pull it out, and heat the (new) seals till soft and should push straight in. If you've can't push in easily by hand there's something wrong and it'll damage. Sounds like the smaller inner seal isn't seating, outer one might stop it leaking out from fuel rail but doesn't mean it's right.

They'll normally pull out OK when engine warm (warm not too hot) but will **** pressured fuel out so carefully does it, or release pressure at fuel hose

[Neil L. 0]

Theres no way this FPR is going to be just pushed in!

Took alot of force to get in there - plus the old valve needed adj grips to get that out aswell - ive read quite a few owners had same problem!

I admit i didnt heat the new seal up but i still dont think it would have gone straight in!

Anyway surely if the horse shoe shaped retainer clip goes back in means that the valve is in the rail enough?

Now its in i think it will be a struggle to get it back out without damaging it - i had to crush the sides slightly on the old one to get it out!

Well the outcome is still rough idling and reluctance to rev - im still yet to find the problem

Next will probably be pcv valve, lambda, and probably check wiring and earth points!

Nightmare trying to find the problem!

[Neil L. 0]

Right been back to the VR today and managed to get FPR back out without damage.

I applied oil to the seals again and pushed (hard) to get it back in - hey presto went in with a definate click this time - great!

On starting (5th time fired!) i again revved it hard (3500rpm) to keep the engine going! Then rough idling again! Its not the FPR then!

Then engine died after short time and on restarting the engine fires but will not rev - if i try the engine cuts out again!

The car then idles (rough) and then dies!

Im now running out of ideas - apart from trying to get it vagcom'd! NB car is SORN (3yrs)

[jekel 10]

Told ya it would come out go in/come out ok, I would'nt have oiled seals, bit of WD at most, if your having to force it, it needs heating. I know as I did exactingly the same as you and most until tried heat, amazing difference makes, same goes for crack pipe and anything push in rubber fit.

Most common things are crank sensor and cam sensor. Crank will normally be a non starter but not always, get both out check seated right, just put new engine and every new sensor in mine, started just after numerous efforts would'nt idle, when had look at everything my mate had put crank in in bad light, a mm of the old sealing ring cracked off still in there, sensor sitting mm too far out and that was whole prob.

If ya not prepared to renew every sensor, MAF, coilpack etc. like I did it'll be cheaper to have VAGcommed.

The lambda doesn't kick in for bout 15 secs, does it run better for that 15 secs, unplug it does it run better?

Unplug TPS, should notice big diff., but it'll still run, normally idle at about 3000, no diff. it or wiring knackered.

Also fact MAF not totally kaput does'nt mean it's fine, can ya borrow another and try, lot of people keep spares. Lambda's a pig to change normally got to take pipe off, heat red hot, cut wires and get a socket on it, so I'd try the rst first, and if ya do change it check CAT isn't blocked, ideally decat it, good induction kit and remap it

[Neil L. 0]

Thanks for this reply - helpful!

Yeh few things i can do myself before having it Com'd ! I need to kook at the extensive history to see whats been done already!

Few things uve said i ll try! MAF quite new - i had loads replaced when i used it as my daily, various sensors are newish.

What is the TPS?

Also where are the most important earthing points to look at?

Thanks

[g0ldf1ng3r 15]

apologies for only skimming the thread but have you checked your oil pressure & verified the sump pickup is working correctly

 

when my VR went to stealth for head work Vince managed to identify a problem with my sump oil pump such that is was causing the system to over pressurise & then the engine would cut out

 

Vince asked if I had ever experienced it cutting out when still cold if given a good rev but I explained I never go over 3.5k rpm until oil temp is over 70. he explained a tell tale sign of a problem with the sump pick up is that VR's will cut out if rev'd hard when still cold

 

when he pressure tested mine, prior to new sump pump, it was 9 bar! should be about 1.5 IIRC

[Neil L. 0]

No have heard of that so not investigated !

Another to add to list!!

Have noticed the bonnet earth wire has completely snaped! Would this effect the idling etc

This is why i need other earth locations to check them aswell!

If the car was road legal id take it to my local vw man!

TPS?

[g0ldf1ng3r 15]

No have heard of that so not investigated !

Another to add to list!!

Have noticed the bonnet earth wire has completely snaped! Would this effect the idling etc

This is why i need other earth locations to check them aswell!

If the car was road legal id take it to my local vw man!

TPS?

 

as far as I am aware the bonnet earth cable is something to do with increasing radio reception - cant recall where I read that but am sure it was on here somewhere

 

mine are snapped on both the VR & valver

[seanl82 23]

Throttle Position Sensor. Bonnet earth cable won't cause any problems at all, but check the battery earth that bolts directly to the chassis leg next to it. There are also earth points around the starter motor, and on the right hand side of the block as you look at it. If you can remove them all, wire brush the terminals and studs/bolts and reassemble, checking the cabling is intact etc.

[jekel 10]

Thanks for this reply - helpful!

Yeh few things i can do myself before having it Com'd ! I need to kook at the extensive history to see whats been done already!

Few things uve said i ll try! MAF quite new - i had loads replaced when i used it as my daily, various sensors are newish.

What is the TPS?

Also where are the most important earthing points to look at?

Thanks

 

Throttle Position Sensor, on the throttle body. Disconnect the blue temp sensor too, should default to 70 degrees, any improvement? Test the ohms, there's things on here tell you what should be at 0 degrees, 100 etc., I'd go through simple, easy and cheap things first. Fuel filter ok, pump straining at all? Fuel relay ok, 109 relay ok? ECU connector and multiplug connector ok?