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[BigDov]

Reaching out for a little bit of help here, got a little issue with our 1996 x25xe omega.

Little background first, car did have a misfire and tick on idle when we bought it which we thought was a dead injector or tappet, but we were going to work the top end anyway for a lil bit more power.

So we've carried out the top end rebuild by fitted 2 sets of "g" cams, 3.0l lower divider, 3.0L litter fuel rail/ Manifold, 4.0 bar FPR and a long plenum, timed the engine up( what a ball ache that was) and she fired up after the first few cranks, all was well, but at that point we didn't have the AFM plumbed in( was connected but was just so we would start the car to hear it running), the Multi-rams were unfitted as were most of the vac pipes heading towards the rams, the ICV pipe work was also un plugged( ICV was connected to the plenum but due to fitting the longer plenum the original pipe work no longer reached so was left unplugged), but she ran, did run a lil rich but she was running, that was a few days ago.

Since then( or tonight) we have put the multi rams back in, connected all the vac pipes, got a rather rough/ crud method of plumbing in the ICV into the plenum trumpets and we started her up, she idled at 2k for a while but once she warmed up the rev's continued to rise till she idled at around 3-3.5k and at this point was bellowing smoke out the back( smelt of rotten eggs mixed with petrol) so assumed the cats had died due to the rich mixture. At this point we scratched out heads as everything worked before fitting the 3.0 parts, so we assumed the parts fitted to the 3.0 long plenum were faulty( starting with the ICV) so swapped that over, and sure enough the idle was more "steady" and more inline with what we would expect, but more importantly the fuelling was back on track and the smoke had ceased, but still wouldn't idle properly, once it came off the warm up cycle the rev's would start to drop and then get to around 1k and then the engine would spit and sputter then die, so we then swapped the throttle position sensor, again the rev's seemed a little better, but would still stall when the rev's dropped. at this point we changed the solenoid and valve which operates inside the plenum( at the back) with the old 2.5 one as the 3.0 one was rather dirty and did come with a cable tie attached to the mech which we didn't know what it was for so cut it off, but we knew the 2.5 one was great, but still no success on getting the car to idle under 1k.

Even removed the ICV completely and all that did was just stall the car after starting, so were assuming that the ICV's fine.

Which brings us to where we stand atm.

We have done the paper clip test and got the following codes.

144   Immobiliser No Signal
145   Immobiliser Wrong Signal
73   Mass Air Flow Sensor Voltage Low
33   Exhaust Gas Recirculation (EGR) Valve Voltage Low
31   No Engine RPM Signal

33 will be due to the EGR being unplugged due to again teh 3.0 long plenum not using a different opening/ pipe so its plumbed into the union but not plugged in so its not operating atm.
73 we're assuming as we did originally forget to plug the AFM in after rebuilding the car.

31 has thrown us tho as the RPM on the clocks work fine.

SO now we're at a loss, when the car is running it runs great, we just can't get it to idle without applying a little throttle to keep it above 1k, and the idle issue only seems to start after all the vac pipes were plumbed in and the air box and everything else put back in place( all vac pipes and solinoid/ control units are plugged in where they should go)


Any help will be greatly appreciated as we don;t really know what could be causing it apart from possibly the aggressive lift of the G cams, but would have thought the momentum of the flywheel would be enough to keep it going at least.

[dbug]

Disconnect MAF sensor - if it runs better, there's your problem, dodgy maf.  Don't try cleaning it you will only bu**er it up completely.  Replace with new or good used

[AND181]

Great.....I'll try that tonight when i get in from work, we just assumed that as it was running right before we worked in the top end, it would be alright after we put everything back together. I'll be over the moon if it's just the AFM.

Thanks

[JamesV6CDX]

I very much doubt the maf has failed so coincidently.

It will be relating to the work done. And it sounds like a big air leak!!

Out of interest why 4 g cams? The correct setup is G cams on the inlet, A cams on the exhaust.

Retrace your steps. Plenum seals x 6 all present and intact? Servo hose secure?

[JamesV6CDX]

Tell me more about this "crude method" of fitting the ICV... It sounds directly related!

I'm not sure why you'd try and run the engine with so much disconnected?

[Gaffers]

MAF voltage low indicates that is it either disconnected (or the connecter is faulty) or is fubared

[BigDov]

The crude method is just an extension of the factory pipe so that it reaches the shorter plenum pipes, unplugging the pipe the car just stalls not long after starting.

All seals are present and correct, everything plugged in bar the egr as per above.

We did initially try to start the car with the afm disconnected but it wouldnt fire, but that was just after rebuilding and priming the engine.

[BigDov]

little update with this.

Fixed the ICV by properly plumbing it into the front trumpet of the plenum as it should be, connected up the egr valve and then started the car, and now it seems to idle at 1500-2000, we did unplug the maf which seems to have some effect as the idle drops to what we would expect, still not perfect( drops to 800-1000, still try's to stall but the car won't allow it but does dump a load of fuel into the exhausts, plug the maf back in and the idle rises back to the 1500-2000 rpm.

The above does point towards the AFM being faulty, but as it ran fine before the work was carried out we can;t see how its just went fubar, think what we are going to do is remove the plenum again( will have to come off as one of the rocker covers isn;t sealed properly so is dripping oil down the back of the engine so its needing reseated) and just check all the pipes and what not that are down the rear of the block as I positive i can hear a slight blow from down the back but we can;t see anything that is disconnected or that can be causing it.

Will try and keep you guys updated as to what we find, as we will get to the bottom of this eventually.

[BigDov]

Ok little update to this.

We changed the maf, ordered the correct ICV pipe from germany still no difference to the high idle so we were at a loose end.

Ended up buying "My Naff Code Reader" to see the live data from the sensors and low and behold our isse was shown as soon as it was plugged it, at throttle close the TPS was showing a value of 4.78v with the simulated full load switch = active with the simulated idle switch being inactive.

Unplugged the TPS sensor and the idle went down to 600 RMP, with a little hunting, so plugged in a TPS sensor we had lying around and the voltage read 4 volts but turned it to where it was at near zero, and the idle switch was now active and the idle was a steady 600 with no issues apart from the slight hum/ vibration from the G cams. turned it up to where it would report the 4v and low and behold our high idle was back.

Turns out the rod that connects into the TPS sensor on the TB that was attached to the long plenum is rotated 90 degree's from the stock one on the x25xe that we removed, also the flap open in the opposite direction so when at WOT on the long plenum TB the car is registering 0% throttle, so needing to refit the old x25xe Tb to rectify out issue and the old meega will be back on the road