Have come across a problem. After changing the down pipes and middle section of exhaust and removing the AIV's the car wont boost correctly. Have had it on consult and it came up with a o2 sensor fault so have replaced that yet it still wont boost correctly. had the car running at 1.25bar and now it wont go past 0.9bar. When it gets there it just starts misfiring.

Have changed the plugs, checked all the connectors, tried another PTU but wasnt that, doubnle checked the boost pipes against another zed and there correct.

Anyone had this problem b4?? need some help please.

anyone????

Coil packs or injectors might be playing up?

 

PS, this is in the wrong section. ;)

Coil packs or injectors might be playing up?

 

PS, this is in the wrong section. ;)

Moved ;)

 

Could it possibly be a boost leak?

 

Steve :)

Have tried all the above but still have the same problem :cry:

Does the uk spec have to have the AIV's connected???

 

Am ready to tear my head off :rofl: please keep suggestions coming as want to get car right before JAE.

i got the same prob. was thinking overfuel but im certain its not.

Have tried all the above but still have the same problem :cry:

Does the uk spec have to have the AIV's connected???

 

Am ready to tear my head off :rofl: please keep suggestions coming as want to get car right before JAE.

UK with AIVs disconnected here and no problems :cool:

 

Steve :)

removing AIV wont cause any running probs, but will cause cats to run hotter and you could fail mot on emissions as it runs the idle emissions but does nothing at higher revs. Check and clean the ECU temp sender.

removing AIV wont cause any running probs, but will cause cats to run hotter and you could fail mot on emissions as it runs the idle emissions but does nothing at higher revs. Check and clean the ECU temp sender.

 

No cats on car, removed them when i changed exhaust. Will check and clean temp sender and see what happens.

thanks.

surely with all the zed techs on here someone can help with somemore suggestions please.

boost leak

surely with all the zed techs on here someone can help with somemore suggestions please.

 

Did you clean the ECU temp sender as suggested? Its the yellow connector on the hard water pipe.

 

There is a dozen reasons why it isnt boosting properly and to try and diagnose the problem without actually looking at the car is a prosess of illimination.

 

I had a simillar problem with mine, i pin pointed it to the injectors, it was 1 of the plastic caps that directs the spray had cracked and was covering the jet so that cylinder wasnt fueling correctly at boost.

 

I noticed you said you was running at 1.25 bar of boost. What mods have you got ie chip, tubs, injectors, boost jets etc if you are running stock then you proberbly maxed out. Start looking in that direction too.

 

Another thing to look at is the fuel pressure regulator it may not be keeping the correct amount of fuel pressure, just another suggestion

i had the same once it was the injector connectors the next it was temp sensor, two sec jopbs that rectified the situation!

 

ask the tunnel run chaps the problems it caused me lol!!

Also check your spark plug gaps. With higher boost you need to drop from the 1.1 mm to 0.8'ish

Did you clean the ECU temp sender as suggested? Its the yellow connector on the hard water pipe.

 

There is a dozen reasons why it isnt boosting properly and to try and diagnose the problem without actually looking at the car is a prosess of illimination.

 

I had a simillar problem with mine, i pin pointed it to the injectors, it was 1 of the plastic caps that directs the spray had cracked and was covering the jet so that cylinder wasnt fueling correctly at boost.

 

I noticed you said you was running at 1.25 bar of boost. What mods have you got ie chip, tubs, injectors, boost jets etc if you are running stock then you proberbly maxed out. Start looking in that direction too.

 

Another thing to look at is the fuel pressure regulator it may not be keeping the correct amount of fuel pressure, just another suggestion

 

Cleaned the connectors and no change although the wiring was a bit on the bad side :eek: . Have also redone the timing as that was waaayyy out.

I have still got standard tubs as far as i know and have done the usuall first mods like:

J Dixon chip

K&N air filter

stainless full exhaust

Boost jets (waiting to put apexi on)

From mount intercooler

iridium hks plugs

 

still got the detting problem tho under boost. Hope to get it fixed soon but if not will have tro be missing JAE this year :cry:

I know this is for a supra but its a good guide.

 

http://www.mkivsupra.net/vbb/showthread.php?t=35931

I know this is for a supra but its a good guide.

 

http://www.mkivsupra.net/vbb/showthread.php?t=35931

 

Cheers mate, had thought about coil packs and lucky for me i have managed to get some more to try.

Please keep the suggestions coming

thanks.....

mine has recently started doing this, it misses at certain intervals of revs, main one is at about 4000rpm, but does miss whilst boosting, also not pulling well at the moment (prob safety boost), i need some coil ack to change and see if that makes a difference

My Z has been missing on boost for ages now and after trying everything i spent a good couple of hours cleaning/adjusting the injector connectors, i used some battery terminal spray, which works a treat id recommend it, but after a week or so the missfiring started again, so i have found that i have to redo the injector connectors almost every weekend, if i do she runs like a dream, if i dont she runs like a dog, so i ahve finally come to the conclusion that i need a new EFI harness or i need to replace the connectors and splice them into my harness.

My Z has been missing on boost for ages now and after trying everything i spent a good couple of hours cleaning/adjusting the injector connectors, i used some battery terminal spray, which works a treat id recommend it, but after a week or so the missfiring started again, so i have found that i have to redo the injector connectors almost every weekend, if i do she runs like a dream, if i dont she runs like a dog, so i ahve finally come to the conclusion that i need a new EFI harness or i need to replace the connectors and splice them into my harness.

 

have changed the coil packs and the car is running like a dream. Has taken a lot of the elimination process but finally got there.

Every day you learn something else about these cars,lol

have changed the coil packs and the car is running like a dream. Has taken a lot of the elimination process but finally got there.

Every day you learn something else about these cars,lol

got any spare ones lol

got any spare ones lol

 

will have when i have worked out which pack/packs were no good. the remainding good ones u can have if ya like.

will have when i have worked out which pack/packs were no good. the remainding good ones u can have if ya like.

 

that would be great bud, cheers

that would be great bud, cheers

 

If your off to jae i'll bring em down wi me.