New to the site, can't believe i didnt join sooner, seems to have every classic ford covered, so hopefully someone can help me, because i'm at the point where im thinking about trading my car in and buying a new one.

anyways, it the mk4 1990 efi with iscv on the inlet manifold, i've fitted a recon engine, so swapped all the working parts from my old engine over, tps,iscv,map etc except crank sensor. The car cuts out when braking, and idles horrible, done ecu re-learn, base idle setting, checked for leaks with brake cleaner but no better.
if i disconnect tps, the revs pick up a little, but idles better, replaced it, still the same.
Also the emission are better with the tps disconnected.
Co-2.66
co2-10.00
o2-5.5
hc-0847

With tps disconnected.
co-1.45
co2-12.4
o2-2.69
hc- 0557

I really dont want to get rid of the car, had it nearly 6 years, buts its getting dangerous when dying at roundabouts.

 

Used a code reader today, but keeps reading code 11, all systems ok. Would this mean the fault isn't with the ecu?
Why would the engine run smoother with the tps disconnected? What sensor does it use Instead?

 

Could be iscv try disconnecting it see if it makes a difference

 

If I disconnect it, the revs die to around 700rpm, when connected goes up to around 1200, then settles a t around 1000. So think its working

 

I have said it before and I will say it again.... An Internet forum is a bloody nightmare for diagnosing these sort of things..... . However in a bid to help, I will throw in my 2p worth.

Have you tried the road speed sensor? It sounds like an intermittant fault.
Have you tried cleaning the iscv with carb cleaner?
Have you tried cleaning inside the throttle body with carb cleaner?
Does it sound like there are any air leaks anywhere?

Finally..... You might receive more replies in the tech q and a area as the Xr room is a bit dead of late.....

Good luck mate

 

No air leaks, but will try cleaning the iscv and throttle body sometime today.
Should the efi have a speed sensor? Not got one on mine, just the cable and the red plastic speedo drive

 

Cleaned out throttle body and iscv. Retested engine running test with code reader, came up code 13. Not sure what that means, in the tester manual, says air vane temp sensor,autodata says coolant temp sensor, and some websites says iscv did not respond.

Think cleaning out iscv has killed it somehow, when it's disconnect, engine speed stays the same, and when connected, engine speed doesn't change

 

Changed iscv and coolant temp sensor, genuine ford £130. Car doesn't cut out anymore, but idles lumpy, and back fires at constant speeds.
Can I get this thread moved to tech q and a? Love the car, but can't afford to keep chucking money at it.