Fixed Idle Issue...Now car is skipping!! :(

**B18cEG** · 05-12-2007 12:29 AM

have u got a multi meter? check the leads and they should read about 15kohms per meter of ignition lead, if its to do with voltage from the coil, i can let u borrow mine to test out if its the same as the one from a b18c, i changed it about 5000k's before removing the motor. i live in joondalup.

**FastFwd** · 05-12-2007 01:12 AM

Borrow your coil? or the volt meter. I have a volt meter but coil could be the prob...I live in carramar, like 5 mins from joons. When can we meet...?

**B18cEG** · 05-12-2007 09:12 AM

you can borrow the coil, its pretty much new. i thought u used to live in currumbine, anyways u wanna come past alberts joon today? let me know i let a PM.

**m0nty ITR** · 05-12-2007 09:43 AM

Originally Posted by 1996ek1

Why all your cars warmup at such high rpm ?
new CTR does this also, to about 2k rpm....

All K20s do it. It only takes about 2-3 minutes. I always let my car warm up before driving. I usually start driving when it drops below 1,500rpm.

**B18cEG** · 05-12-2007 04:34 PM

Originally Posted by m0nty ITR

All K20s do it. It only takes about 2-3 minutes. I always let my car warm up before driving. I usually start driving when it drops below 1,500rpm.

what does this have to do with anything?

**m0nty ITR** · 05-12-2007 04:45 PM

Originally Posted by B18cEG

what does this have to do with anything?

Because he asked. I quoted to avoid confusion. Should I have highlighted and selected bold text also to avoid confusion?

**FastFwd** · 05-12-2007 06:29 PM

Guys on topic please.....

**JohnL** · 05-12-2007 11:08 PM

aaronng said:
Hey that is very similar to what my car is doing...and yeh it did shoot a one meter flame out the rear. the car feels all normal if you tred lightly on the accelerator but if u push to hard it feels like it will almost die because the skips are soo huge. but then even if u tred lightly you can sorta get passed the skipping stage which usually is at around 4000rpm. but it can be at ANY RPM its just usually around there. but even still it just feels like the turbo is there pushing pressure into the motor (more air) but something isnt doing what its supposed to, to compensate for this extra pressure. But how would it skip a tooth on the timing belt? ive never heard of a car doing that.

If its running very rich its not too surprising if it shoots the occasional flame (not good, slightly embarrassing, but kind of cool!). You’re dumping a lot of hot un-burnt fuel through the exhaust in an oxygen deprived environment, then at the end of the pipe it finds oxygen and bang!

(I once had most of the pipe fall off my ‘Nota’ clubman sportscar, giving me an unsilenced pipe about two feet long exiting the side. The engine in this car (a highly tuned A series BMC engine, like a Mini’s but from an Austin Healey Sprite) could dump a lot of fuel down the pipe due to the valve timing. Sans most of the pipe, on the overun it would explode with very load bangs, shooting the most amazing blue flames! It made the best sounds reverberating in tunnels, hard on the throttle through the gears and then backing off with explosions, the flames lighting everything up like lightning flashes! Pity I couldn’t have left it like that for more than a day, but fun as it was it was too much, too embarrasing and made me police bait!).

If your engine is actually cutting out rather than just losing power and blowing black smoke it must be very, very rich. The cutting out (“skipping”) problem may be unrelated, but I doubt it, it’s too much of a co-incidence that it started misfiring when it started running rich.

Jumping a tooth or so on the belt would be rare but not unheard of. I’d be surprised if this were the problem, the belt would need to be quite loose I’d think. I’d be surprised if the timing were out that it would cause the engine to actually cut out rather than just lose power and run rough, but you never know?

I give that a go tonight. also wanna check sparks. maybe give them a clean, i dont think thats the problem but it just feels really weird. It actually feels like all the SPARKS just turn off if u push the Accelerator to hard....Its hard to explain ill take a movie tonight...But yeh i think the best bet is Vac lines. Maybe even something with my fuel pressure reg.

Rich running could cause problems with the plugs sooting up and not firing, could be contributory?

Maybe, (thinking out loud), perhaps it’s not really running rich (?), but the plugs may simply be failing to ignite the fuel in the chamber, then the un-ignited fuel gets dumped into the exhaust, which then occasionally ignites when it exits the pipe?

The higher the compression pressure in the combustion chamber (which maxes at peak torque output with a more open throttle, typically in the middle of the rev range more or less, depending on tune) the more easily the spark will ignite the mixture, but, the higher the compression pressure the more likely a plug will fail to actually produce a spark (this is why a bad plug might make a spark outside the motor but not work when fitted to the motor, i.e. higher air pressure inhibits spark production). This might be caused by the plugs themselves, or it could be that the voltage and / or amperage being fed to them isn’t up to scratch? If this is the case, then it could be anything from the plugs back to the dizzy, e.g. leads, ‘igniter’, etc…

A turbo motor will produce very high compression pressures (especially at peak torque output), so depend heavily on the ignition system providing a very strong spark.

Is it blowing a lot of black smoke? If not then it’s probably not running rich (at least not rich enough to cause your problem). If it might not be running rich then this begs the question; are you absolutely certain that it is rich, and might not possibly be running lean?? If it is then this is a much worse problem than running rich, it can easily wreck the engine (especially a supercharged engine, and your turbo is a kind of supercharger, to state the obvious).

Running lean can also cause misfiring, but I wouldn’t tend to associate it with shooting a flame out the pipe. However, if it runs SO lean that the fuel isn’t igniting in the chamber (either because of the leanness, ignition problems, or both), then you’re still injecting fuel but you’re dumping that un-burnt fuel down the pipe, and it may then ignite when it reaches the end?

It occurs to me that if it were running lean then it might fit one of your symptoms; if you accelerate slowly and it doesn’t misfire, but if you accelerate harder and it does, this might mean that the mixture isn’t richening up enough under harder load, or that it might be richening up, but the base mixture is so lean it doesn’t richen up enough to prevent the engine cutting out (but on the other hand, if it is running rich then the enrichment process might cause it to run so rich that it cuts out?).

This is why carb engines have an ‘acceleration pump’ that squirts an extra shot of fuel down the throat of the carb on hard acceleration, i.e. to richen it up for the extra demand / need for additional fuel required on harder acceleration (mixtures significantly above adiabatic are required for hard acceleration, but not for cruising on light throttle, or even consistent high speed with a wide open throttle). If you disconnect the acceleration pump on a carb, then with careful / gentle throttle you'll be able to accelerate sedately right up to max speed and / or max HP, try harder and acceleration will be poor at best, but at worst the engine will shut down until you back off. Fuel injected engines do a similar thing, but the enrichment is controlled by the ECU. Remember that the ECU relies on what it’s told by the sensors.

One thing i have noticed is ever since i took of the fuel feed to the left side of the fuel rail (standing looking towards the motor) is hasnt been right since then. I had to take that off to get it out of the way to remove the throttlebody. Cheers

What???

Hope this helps!
Regards,
John.

**FastFwd** · 06-12-2007 06:40 AM

Johnl Thanks heeps for all your help defiantly giving you a rating if i can find out how...B18cEG (jason) came round last night and help me fix it. He bought over his dizzy, leeds, sparks, map sensor...tried them all and we couldn't fix it.

But after alot of fiddling we found my Fuel pressure reg was running 20-25psi...I don't know how it go that low. i haven't touched it since the last place did a tune. So we pumped that upto about 48ish atm. And the other issue was the "throttle position switch" wasn't dialed in correctly so it was giving my ecu the incorrect amount of voltage..soo we set that correct and now she runs like a dream....

But i dont think i would have been able to fix it last night without jason.