down on power- 1.8 16v

[wcrado 0]

just taken my car for a rolling road session, straight away the tuner told me it was sounding flat, hey presto, it was only putting out 130bhp at the flywheel. i've fitted new merc injectors, a 50mm inlet manifold which i've ported, drilled airbox with k&n, milltek 4-branch and system, and we took the head off and gasket matched and smoothed the inlet and exhaust ports. the tuner knew straight away it wasn't running right and agrees that it should be alot more powerful, it's down 6bhp on standard for christssake! all the fuelling is set correctly,it's putting out awesome emissions, with low hydrocarbons which i was told means the valves are in good nick and seated nicely.the timing has been checked with the rocker cover off, there's a good spark pattern and i've had the ecu tested and it's all good. i really don't know where else to go now. i'm gonna check the compression, cos it has done 140k miles, but if that's ok then i don't know what to do. any advice grateful.

[Kevin Bacon 5]

140K..pah...it's just run in mate...

 

Have you checked the fuel pressure on the rolling road? It might be OK at idle and moderate speeds but I had a problem with the pump on my old valver where it just wasn't delivering the required bar at high rpm.

 

If not that, is the cam timing OK? Base CO OK? 1800s love being set to 2.0% CO...ignore other settings...2 is best by far.

[flusted 0]

Mine made 120bhp when the woodruff key sheared in the top cambelt wheel!all the marks lined up but it was gutless! Good way of telling if its cam timing is that your mpg will be crap.Stealth tuned mine up and i got 162bhp after the cam wheel was replaced

[wcrado 0]

well it's definitely not the cam timing, cos i had that checked with the rocker cover off and was told it's lining up perfectly. no idea if the woodruff key has sheared in the cam pulley, how would i check that?? the cambelt cover is off at the mo, so what do i look for? how exactly does this cause a drop in performance anyway? it does feel very gutless, and it just sounds horrible, like its struggling, almost like it's firing on 3 cylinders. as for the base CO level, i know for a fact it's set on 1.0%as i had the fuelling adjusted straight away. i will up it to 2.0% on this advice, but surely this can't be the whole cause of the problem?? there is one thing i haven't mentioned... during the modifications we did actually cause damage to the distributor, and the best we could lay our hands on was an audi 80 16v dizzy, so thats whats on the car now. according to the engine tuner though, it worked fine with the car and this wasn't the problem. i can't think of anything else! i fitted merc e190 injectors on the advice of this forum, as my old injectors weren't up to scratch, could this be causing it? they fitted in fine, but the old ones had little metal caps on the end, and we did leave those off.

[davidwort 0]

well it's definitely not the cam timing, cos i had that checked with the rocker cover off and was told it's lining up perfectly. no idea if the woodruff key has sheared in the cam pulley, how would i check that?? the cambelt cover is off at the mo, so what do i look for? how exactly does this cause a drop in performance anyway? it does feel very gutless, and it just sounds horrible, like its struggling, almost like it's firing on 3 cylinders. as for the base CO level, i know for a fact it's set on 1.0%as i had the fuelling adjusted straight away. i will up it to 2.0% on this advice, but surely this can't be the whole cause of the problem?? there is one thing i haven't mentioned... during the modifications we did actually cause damage to the distributor, and the best we could lay our hands on was an audi 80 16v dizzy, so thats whats on the car now. according to the engine tuner though, it worked fine with the car and this wasn't the problem. i can't think of anything else! i fitted merc e190 injectors on the advice of this forum, as my old injectors weren't up to scratch, could this be causing it? they fitted in fine, but the old ones had little metal caps on the end, and we did leave those off.

 

You really do need the injector spray pattern checked and the fuel pressure, also the metering head could be dodgy, worth swapping it with another to eliminate that, have you done a compression test?

At the top end valvers tend to run a bit lean, so it's a good idea to get the CO adjusted, MOT max is 3.5 so you can bump it up quite a bit.

Adjusting the control pressure by tweaking the screw in the back of the warm up regulator is best for top end lean running, you'll get a richer mixture throughout the rev range but probably a bit more power at the top end. Doesn't sound like it's just top end running that's your problem though.

Oh, and the 50mm manifold is not great for torque on a 1.8, you can get away with it on a lighter mk2 golf or on a heavily modded 2L, but it won't make you go any better in a 1.8 Corrado.

 

David.

[MillSpeed 0]

How do you go about adjusting the CO?

[Baz2004 0]

my old injectors weren't up to scratch.

 

How was this evident?

 

 

the 50mm manifold is not great for torque on a 1.8,

 

Very true I never liked how my 1.8 ran with this mod lost its bite + noise at low end. Id say the 4 branch might counter this effect but you’d be better off with the 42 or Tbs if you wanted to modify the intake.

[davidwort 0]

How do you go about adjusting the CO?

 

you stick a small sized allen key (needs to be long) in here and twist, only small amount. You really need a CO meter but if the engine is in fairly good tune otherwise you can do it pretty much by ear (runs smoothest).

 

David.

[MillSpeed 0]

A ha, that's the fella! Don't think I used a long enough allen key last night. The 3mm one wouldn't fit in the hole, there was some sort of red insert in the way. Was wondering if it's the remains of a cap that someone's butchered?

[wcrado 0]

my old injectors weren't up to scratch.

How was this evident?

 

i hope you genuinely want to know the answer to this, rather than just pick holes in my plea for help! i need as much useful information as i can get my hands on! basically the idle screw was wound all the way in, the metering head screw was wound all the way in, but i was still getting below 1.0% co2 and the idle wouldn't drop below 1000rpm, unless i leaned the mixture more, but at less than 1.0% co2 i didn't want to do this. in other words, the injectors were fucked. clogged right up and not delivering nearly enough fuel. so i took the advice of this forum before buying new injectors and bought the merc ones, which are brass, so they don't corrode, nearly £10 cheaper per injector, and according to the club gti forum give a slight increase in performance

[wcrado 0]

Adjusting the control pressure by tweaking the screw in the back of the warm up regulator is best for top end lean running

can you explain this a bit better? i had a good look around the warm up regulator but couldn't find any screw. maybe a diagram like the one above would help me!!! does any body who's reading this know if it could be down to the distributor? like i said, it's running an audi 80 16v dizzy as it was the best we could get hold of. could this be responsible, or can i eliminate this?

[Baz2004 0]

Was a genuine enquiry as it wouldn’t be evident from looking at them, I had trouble in the past with high idle speeds even with a leaned mix, I was considering new injectors having replaced my fuel lines at the time but found a broken idle control switch was the cause of my problems.

[h100vw 0]

On the back of the WUR is a thin metal cap. Under this is a 4 or 5mm allen key. With this you can adjust the warm control pressure. Reducing it will increase fuelling throughout and increasing the control pressure will.......... have a guess.

 

TBH I don't think you should mess with this if you don't understand how it works. If you have access to a K-jet fuel pressure gauge then at least if you get it wrong you can restore the original settings..

 

Gavin

[davidwort 0]

Adjusting the control pressure by tweaking the screw in the back of the warm up regulator is best for top end lean running

can you explain this a bit better? i had a good look around the warm up regulator but couldn't find any screw. maybe a diagram like the one above would help me!!! does any body who's reading this know if it could be down to the distributor? like i said, it's running an audi 80 16v dizzy as it was the best we could get hold of. could this be responsible, or can i eliminate this?

 

This might help:

 

http://www.volvoclub.org.uk/tech/fuel_i ... tronic.htm

 

It's possible the WUR is faulty, but not sure if this would cause your symptoms, although you can tweak this it's set at the factory and shouldn't be played with if you have a problem elsewhere, I agree.

the adjustment screw is under a brass tamper proof cap on the back of the unit and needs to be carefully drilled through to expose it, you need to remove the unit to do this.

 

I'd suggest starting by eliminating the cheapest things to fix or replace.

Are all of your vacuum lines and joints in good condition, are you sure the plugs, leads dizzy, rotor arm etc all OK?

Are you sure the injectors have the right spray pattern? Do you have any air leaks in the inlet anywhere?

It does sound like a fuelling rather than electrical problem though.

 

David.

[wcrado 0]

i'm pretty sure i've got no air leaks anywhere, the idle is stable, and all the gaskets have been replaced recently. plugs and leads are in good condition, brand new dizzy cap but waiting on the rotor arm. getting the injector spray pattern tested a.s.a.p and also a fuel pressure test. compression is reading fine. the thing is, the engine just sounds horrible. it sounds like it's mis-firing, it just sounds really airy and feels really gutless. after porting the head and fitting the exhaust system and 4 branch all i can honestly say has happened is i've lost low range power. i could feel some torque before, but now there's none! top end doesn't feel much different though. although it doesn't feel like it's lost that much power, it just felt and sounded right before, like it was doing what it should. it just doesn't seem right at all now, and anyone could tell this just by listening to it or driving it. Alan jeffery, the rolling road tuner i took it to seemed conviced the timing was out, cos thats what it sounds like. but he checked it with the rocker cover off and it proved to be ok, so i'm just wondering if what flusted said earlier in this thread, that he had the same gutless low power problem, and that it turned out to be the woodruff key sheared off in the top cam wheel, could be an option for me to check out. we weren't exactly delicate with the head when we were grinding out the ports. any ideas on how to get this checked out and whether it's worthwhile? i did richen the mixture on the metering head a bit last nite but it's done nothing.

[flusted 0]

The bottom pulleys can slip aswell.Take out no1 spark plug and stick a screw driver down there,then turn engine over till screwdriver is right at the very top (tdc) then check the bottom pulley mark lines up.

stealth took my cam cover off and could tell the top woodruff key was sheared by looking where no1 lobes where facing,i think they should be nearly level with the cam caps when lookin from distributor end,also make sure the cam to cam dots do line up

[wcrado 0]

ok cheers. i prob won't go about checking it myself thou. got it booked in to have it looked at next week and i'll mention the woodruff key possibly shearing. hopefully it'll be that! i just want to know whats causing this. you'd think i would have gained something from these mods, but i've just lost torque! it's a bit more reluctant to start if it's been left more than a few minutes as well, and it's just so gutless. i have to rev the crap out of it just to actually accelerate! got to wrap up the 4 branch in heat wrap as well, cos it's running so hot since that went on