I have owed the EL XR8 for about 2 years now. Its is a manual and has done 196000kms. This is my second XR8, as I owned a EF auto before this. When I bought the car it came with about 18g worth of stereo gear mods. And It now weighs close to the 1900kg mark with a full tank of fuel hahaha.

OK
This is the first time my mechanic has toyed with a 5ltr but most things have worked out pretty good we still have a few issues to sort but most of it is in tuning. Tuning seems to be the major issue as the car has to go to another workshop for this.

The Engine Mods are:

80mm MAF (Not on ATM. 70mm of AU)
75mm Throttle body
Explorer Upper & lower Intake manifold(Match ported)
GT40P Heads(decked to 58cc. Has about 10.5:1 compression)
Yella Terra Adjustable 1.6 Roller Rockers
Comp Magnum 281HR Cam
Comp Springs to suit cam

Still has standard bottom end.

I am using the Capa Eliminator Chip.

The ISSUE

When accelerate at half throttle around the 2500RPM mark it has a dead spot and it pops and f@rt then suddenly accelerates cleanly again. This was happening really bad with the 80mm MAF but not so much with the 70mm. Other then this the car goes fantastic.
I have the car back now as they couldn't work out why this was happening.

Now we were using a TPS from a AU as i had one on the car before we did the engine. After a few beers with my mechanic we decided to check voltages on it and they were way to high.
Now is it at all posible that this could be part of the issue??

I will post some pics and dyno sheets tonight if i don't get distracted. Any help would be appreciated thank you.

 

 

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Last edited by ALIENATE on Tue Nov 25, 2008 6:25 pm, edited 1 time in total.

First of all. What size injectors and who tuned the chip?
Did your mechanic have a wide band O2 on it?
It sounds like a lean flat spot(hence the 80mm MAF will make it worse) and with those mods you'd be pushing your luck with 19lb injectors and you really need to upgrade your fuel pump if it hasn't been already.

This is the exact thing that is happening with mine aswell, does it get to that point then wont rev anymore and it will sit an cough a bit untill you put your foot down further, then its all good? Mine was on the dyno and it showed it was leaning out at that point then when foot went down a little bit more it went back to normal AFR.

It has 24lb injectors and i have borsch 044 fuel pump.
How about fuel pressure reg??
My mechanic built the engine but it was tuned at Special Vehical Services in Cairns QLD. And I'm not sure what O2 was on it!!

 

 

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nah it drives though it but now i just drive around the lean spot so I don't hit it.

I'd be looking at the tune. fuel pump/injectors would come into play up top. Sounds to me like your mass airflow transfer functions need a tweek. MAF doesn't seem to like a poor intake pulse and reversion.

Yep and box that pod mate.

Check your spark plug gaps as i had the same problem when i bought my car.

That filter adaptor on your MAF looks suspect. It looks like it's smaller than the I.D. of MAF itself? if so it will cause turbulence into the MAF.....bad.
Apart from this, if the EEC is still trying to hang onto closed loop at the point the problem is occurring it may need the WOT breakpoint dropped a little.
Ask the tuner what they used for the MAF transfer? They should have been able to use an ELGT transfer function for that MAF with minimal tweeking and also GT injector slopes.

Yeah the pod will be boxed when we fix the problem.



If by I.D you mean the opening of the MAF then it is very close to the same size. I have used that adaptor for ages and never had a problem. So I don't think that would be an issue



They should have access to this ELGT transfer function? And what about the 80mm MAF?
Are you a Tuner XR9UTE? You seem to be full of info!

They should have the ELGT transfer yes. if not use an AU MAF transfer which they should also have. What 80mm MAF have you got?
I'm not a tuner...someone called me an EFI guru so I thought I'd just make some s**t up.

I bought my 80mm from BPT.

Sorry didn't mean to offend with the tuner statement....

lol lol lol....... don't worry Pete knows his stuff..... actually better than some professional Ford advertised tuners, who knows may be even Holdens ......

Make s**t up? Whats a `Ford advertised tuner`? Cool guy who can do burnouts with credit cards? Too many warranty handballs to the dealer eh? Diffs, gearboxes,tailshafts,pistons, turbos,cranks,valve springs, `Ford make s**t cars.`is the spiel from the owners. You guys have a lot to answer for. Im sorry but some of the modded s**t from `Ford Tuners` kills em. And Ford Australia pays for it. Which means so does the taxpayer.

What the hell are you babbling on about?

Don't worry, I was just taking the piss out of myself...you didn't offend me
Ok that'll be a Marauder MAF.. Ive got a transfer function for one of those if your tuner guy needs it.

I know what Tom is saying and I agree completely! Unfortunately it's the times we live in...everybody blames someone else for something they have done. Conscience is not in most peoples' vocabulary these days!