Im back again....... boosting issues

[bounds_w]

Im starting to loose my patience with this engine now. Really need some help if anyone can advise.

Some of you might have seen my other threads which have resulted in a complete engine rebuild. But I just cant get this last piece to work and im getting the point where I need to take it to a garage (maybe a specialist like rogue) as im running out of ideas here !

Ok, so its a REV 1 Tubby, with a fresh engine rebuild.

I just cannot get the engine to run on boost properly. When starting to boost, the engine cuts, the rev counter drops, and the ECU light comes on - its like the engine has cut out for split second, then it comes back. Some times it back fires when the engine comes back to life if you keep the throttle open, sometimes not.

There is a FCD fitted, but im only trying to run stock boost.

There is good even compression across all cylinders.

To try and rule out all ignition components -
New NGK iridium plugs
New Denso leads from GTS Chris
New dizzy
New rota arm
New coil

still no change.

I have good vacuum on idle, and quick responce to "0" when blipping the throttle. All vacuum hoses are new along with all gaskets and an uprated intercooler with hard pipes, so im pretty sure there are no leaks.

The ECU stores no codes, so im flat out of luck.

The engine appears to die quicker when I try and boost fast and hard in second. If I try and pull boost from low revs in 3rd, I might start to build some pressue before it dies. Sometimes I almost think its ok.... then no

Im starting to think that for some reason all the power to the engine is being cut somehow.

Really running out of ideas... please help !

[madmr2man]

Sorry to hear you're having issues.

Have you checked out your air flow meter?

Sent from my GT-I9300 using Tapatalk 2

[MRturboTom]

Is the exhaust/cat standard?

I would remove the fcd altogether for the moment to rule it out.

Where are you located?

[littlemisstubby]

I would remove the fcd altogether for the moment to rule it out.

+1. It might be wired in ok but it can still be fubar, causing issues.

Oh, then check the AFM.

[bounds_w]

Sorry to hear you're having issues.
Have you checked out your air flow meter?
Sent from my GT-I9300 using Tapatalk 2

I did the resistance check before the rebuild and it was within spec. But im not ruling it out. Problem is ive brought so many new parts ill be making a loss at sale soon !!

Is the exhaust/cat standard?
I would remove the fcd altogether for the moment to rule it out.
Where are you located?

Exhaust is aftermarket. No cat. Also has gts chris tubular mani

Im northampton mate.

I would remove the fcd altogether for the moment to rule it out.

+1. It might be wired in ok but it can still be fubar, causing issues.
Oh, then check the AFM.

OK, can do this, nice and easy.

thats tomorrows jobs then !

[MRturboTom]

I'd be interested to come and help but I'm away for 3 weeks!

[bounds_w]

I'd be interested to come and help but I'm away for 3 weeks!

Thanks for the offer mate.

Its such a nightmare. Ive dropepd and stripped the old engine, then built and dropped in the new one, but this last stretch has been a nightmare.

The car is a friends who is relocated to Canada now, so its not even my car which can be frustrating when im now spending to try and get it 100%.

EDIT : Oh yeah - Its just passed an MOT the other day, so everything that side is ok, Its just this damn boosting issue !

Thanks again. (lets see where I am in 3 weeks !! lol)

[bounds_w]

OK - so ive got this resolved now, but thought I would just drop a quick update here. I bit the bullet and called the guys are rogue motorsport, they came to collect the car and take a look at the issue. They really know there stuff, and it turned out to be a fault wiht the ECU spider earth. Once this had been fixed, that car is all up and running - PUKKA !

Hope this helps someone else having issues one day.

Also a big thanks to everyone for their help on here.

[chris]

good to hear the problems have been sorted

[_Al_]

Strange. That earth is a popular complaint after engine rebuilds as it's effortless to overlook it, but I've never heard it associated with those symptoms before. Those have "boost spike" written all over them.

Did you ever check codes to see why the engine flagged the light on the dash?

[Chris_D]

Shame I missed this thread first time round, I was just about to post up about the Earth.

If the ECU light shows while running but doesn't store a code it's an indication of a problem within the ECU or the power to it.

[bounds_w]

I know this might have looked like a load / boost related issue, and this is what I thought it was too. But this spider earth is attached to the back of the intake manifold - and passes through into the ECU, so when the engine was loading up, and moving in the mounts, this wire was being moved and causing these engine cut issues.

It probably would have taken me weeks and a whole heap of new parts to find this fault, so its been worth my while letting a pro take a look - and it showed, as they found and fixed the issue in no time.

Happy days

thanks again to all who offered assistance

[jimGTS]

When that ground isn't grounded, it causes the car to crank when in the acc position!! Caught me out once!
I've not heard it related to your problems.

You saying it was grounded but became loose with engine movement?