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  Stainless Exhaust

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Stainless Steel Exhaust System on 1994 24v Estate

When I bought this car, it was eighteen months old, it had already received one catalytic converter under warranty - some of the early ones rattled. Since then I have had a total of four catalytic converters fitted! The immediate result of this has been an acute interest in OBD, lambda sensors and a severe dent in the beer coupon collection!

The first pair of cats were fitted by a Ford Main Dealer with one pair of lambdas - I still do not know for sure which pair were replaced but it seems plausible that it was the rear set due to a few tell tale signs and the fact that in less than 30k I need another set! Original parts were used and the job came in at over £1000. The 24v Scorpio has a habit of not releasing the cats from the manifold. This requires the removal of the exhaust manifold and sometimes these break and sheared studs are not unknown. One of the exhaust manifolds got broken as did a couple of studs, hence the additional expense.Underside from Cats

A few weeks ago the car failed on emissions again and it became apparent that the only way it was going to get fixed was at least one new cat. The original exhaust system was beginning to show it's age and I doubted it would make it through the trauma of a pair of cats being fitted.

This time I thought I'd take a close look at after market parts and decided on a stainless steel exhaust, CES catalytic converters and four lambda sensors from Cats Direct ( Within the list it has been reported that these particular cats don't fit. I took the issue up with Cats Direct and CES and they said that they had sold close on 50 units and not heard of this problem. I then ordered the parts from Cats Direct and when they arrived arranged for Custom Performance Ltd to fit them along with one of their exhaust systems.

Custom Performance ( is owned by the Parradine family that built the Parradine 525s in 2000 (see their history page for more information) but now concentrate on exhausts and tuning rather that building cars. I turned up at 7:30 am (they like to start early) and a start was made - within a couple of hours it was obvious that problems were mounting. John Parradine tossed me the keys to a car (no, it wasn't the 525s) and said "We will give you a call later!"

The passenger side manifolds needed to be removed, again, to release the catalytic converter, they kept the exhaust manifold in one piece and only one stud sheared. I ordered gaskets from FordPartsUK (, Roger was most helpful and got the bits out on a Special (before 12 delivery). They didn't arrive and after a telephone call it transpired that the Post Office "didn't collect the parcel in time for delivery" - just typical when you really need it!

John at Custom Performance kept the old exhaust manifold gaskets to show me where one had been blowing - one of the stubs wasn't quite true - so they ground it for me.

I have got the car back now and the exhaust note is most definately louder - it sounds more like a V6 should. There is a very annoying rattle that we are trying to trace, you can hear it but it's source is not at all obvious and, of course, it disappears when you put the car on the ramps!

ClearanceI am pleased with the result? Yes, very. There is still one or two bits to sort out and I will update anything significant. The cost? I have change out of £850 this time around and that includes a stainless steel exhaust and two extra lambda sensors - still a lot of money but considerably cheaper than last time and I also think it is fair to say I have received a much better level of service.

A quick look with the OBD Explorer shows healthy lambdas so the rewiring has obviously gone OK - I need to run for a few days and have a good look at everything. Personally, I can not recommend Explorer highly enough - this bit of kit can save you an absolute fortune. A few weeks back I went to look at a second Scorpio 24v. It looked very nice and the engine sounded sweet. Explorer however, showed that the lambda's were shot, absolutely no switching on bank 2 and bank 1 only had pimples on the trace. I'm sure the seller thought I was trying it on but there was no way I was going to buy it. Still, I expect someone has bought it purely on it's looks and performance, they will have a shock at the next MOT!

For my part, this was the result at the next MOT:

Fast Idle Test Limits Actual Value    
Engine Speed: 2500-3000 rpm 2855    
CO: < 0.30% vol 0.00% vol    
HC: < 200 ppm 7 ppm vol    
Lda 0.970-1.030 1.005    
Natural Idle Test        
Engine Speed 450-1500 rpm 720 rpm    
  < 0.50% vol 0.48 % vol

The natural idle CO is high but I seem to have developed an idle fault (again) - idle is fluctuating between 1200 - 600 ish and this probably accounts for the higher than expected reading?

Thanks to Ian F for this page



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