5 GT Turbo EFI - GT Turbo

[Mark Davis]

I've been down to the fasteners today for new bolts/nuts etc so will try tomorrow and see how I go. I've ordered metal gasket just in case.

 

[Mark Davis]

Put it all back together today with new nuts/bolts for manifold/turbo. Leaks on cold start, must of always done that but seems to seal when up to temp.

Noticed fumes/vapour from underneath the exhaust manifold, everything is done up so I'm now starting to wonder if manifold has cracked. Do you think I should remove to check ? Would cracked manifold cause tappy symptoms ?

Cheers

Mark

 

[Mark Davis]

Blowing manifold gasket will make it sound like a sewing machine. I would check that as you may have lost some nuts after refitting it all.

Starting to think maybe this is the culprit, even when up to temp I can see fumes/vapour wafting up from exhaust manifold area. I wonder if it's cracked or gasket is fucked, its new but doesn't mean it hasn't distorted in some way. It was a CGB special.

 

[markg]

Cracked mani or blowing gasket could both be responsible for the tapping sound.

 

[Mark Davis]

Will take it all apart tomorrow to check. Boooo !

 

[DaveL485]

@DaveL485 - I may need your advice on ecu to adjust idle afrs slightly.

Easy, sent you a video you just need to tweak the cell where the crosshairs sit at idle on the fuel grid... use the + and - keys to go up and down 0.1 at a time. It only affects this one point of MAP/RPM, which you will pretty much only ever see at idle.
HOWEVER, bear in mind that because this is also idle, you have a number of other parameters feeding in to the fuel injection duty for this cell. I would suggest you get it up to temperature so none of the coolant enrichments are in play, check the air temp enrichments and so on. The fuel trim calculations are under Help/Documentation>Calculation Trace>Fuel Trim (tab)

 

[DaveL485]

I messed with this on my car, turned it down for a 14.5 AFR at hot idle, and then at cold start it would run fine until the post crank enrichment expired and then it would hunt like a sumbitch (going >15:1) - or stall if it was really cold. After much head scratching and faffing with open/closed loop, idle settings, and enrichments I've finally sorted it now but one tweak to the main map table took another ten tweaks to correct elsewhere lol

 

[Mark Davis]

Thanks @DaveL485 i changed the idle earlier when up to temp but only by a few percent enough to move it up to 13.5 idle. Seems to run fine. I saved a copy of the maps though and will send to you tomorrow.

Will take it all apart AGAIN tomorrow to check manifold. Fingers crossed.

Luckily metal gasket turned up in the post for exhaust/turbo manifold.

 

[Fordy]

Start up fueling is a knob, mostly because on only get so many chances a day to get it in test conditions.

I'd say get your up to temp main fuel idle perfect then adjust all the enrichments and idle control for warm up

 

[Mark Davis]

The cold start is fine, starts up no bother and idles straight away. Runs rich during warm up but then settles at 13.5 or so like it used to until I blew the exhaust/turbo gasket, was blowing so bad it leaned out. Oddly since fitting no gasket it started idling richer at 12ish. I've now adjusted the idle cell by a minimal amount to 13.5 whilst it was fully up to temp.

This tapping is really pissing me off and the change in idle afr since coming back from Scoffs indicates something is wrong. A lot of people warned me about wrapping manifold as they crack, I'm kind of hoping this is the case. The increased tapping started after quite a few hard runs whilst out timing 60-100, I'm wondering if it cracked then?

Also CTM matched the exhaust manifold for me so if it is cracked I guess I'm going to have to find a new one and get that ported too.

Going to crack on first thing to see what's what.

 

[DaveL485]

I'd say get your up to temp main fuel idle perfect then adjust all the enrichments and idle control for warm up

Indeed, but there is sooo many tweaks and twonks to make especially when you mess with the idle control values as well as the fuel trim! Always on a learning curve. Only yesterday did I figure out the high/low MAP coolant temp based enrichment to the interpolated value that affects the fuelling at idle to finally get my cold start somewhere close to what I want!

 

[DaveL485]

@Red21

R5GTT / C1J lump, which way around does the gasket go for the manifolds? Metal face to the manifold or metal face to the head?

On the 21 its metal face to the manifold, as it only goes one way so I assume the same. Can you confirm oh wise oracle of french tat?

 

[Red21]

@Red21

R5GTT / C1J lump, which way around does the gasket go for the manifolds? Metal face to the manifold or metal face to the head?

On the 21 its metal face to the manifold, as it only goes one way so I assume the same. Can you confirm oh wise oracle of french tat?

I can't remember, there are two ways of thinking on this.
First metal face out for heat protection and to allow expansion of the manifold without the slotted edges digging into the gasket causing premature failure and realising clamping pressure which then leads to lose studs.
The second is soft face out and the reason for this would be the head face is relatively smooth so the metal face of the gasket would seal easily seal against it, with the soft face allowing the uneven manifold face to seal.
I will check the books for you though.

 

[Mark Davis]

Hoping this is the tappy culprit, makes a lot of sense as didn't use washers and used random nuts instead of binx. Will set about sorting tomorrow with any luck and hope it's all good.

 

[Red21]

Well I checked my documents last night and there is no mention of gasket position, even in my old course notes?

 

[DaveL485]

Well I checked my documents last night and there is no mention of gasket position, even in my old course notes?

Well then the "which way does the gasket go" argument will continue one!

The other Renault Tech I asked ( @quadrastu ) said "Yeah metal to manifold is the rule unless it's a gasket that will only fit one way." As I said above i'll stick with metal to manifold as 1)thats the way the 21 one fits and its forced by the stud positioning 2)I've not had any issues with em like that one J or C series lumps and 3)It makes sense in my head (and although granted, that doesnt usually count for much, I did a degree in materials science many moons ago)

 

[andybond]

@Mart has something to say on this at one time I am sure ?

 

[Brigsy]

Metal to head as original. @the master which way do you fit it ??

 

[Mart]

@Mart has something to say on this at one time I am sure ?

Ha! Not getting involved in this old chestnut again

 

[andybond]

Ha! Not getting involved in this old chestnut again

I genuinely cannot remember what you said ?

PM me , and Ill post it as my own observations