Problem with engine work (low boost) and AYC error

[robotech]

Car - evo4 with evo8 engine.

Have several problems. may be connected maybe not

1. Car on idle works or at least sounds unstable. electricity voltage jumps - I can see on dashboard lamps that is not stable - they become lighter and darker- flashing a bit. RPMs do not jump and are about 900rpm. if i pull gas pedal a bit till 1200rpm - lamps stop flashing. engine sounds stable then.

Could voltage jumps be caused by unstable engine work? Or opposite - a bit strange work of engine could be caused by not constant voltage?

2. AYC lamp is on. a while before sometimes engine engine lamp flashed sometimes, sometimes not. Check at official dealer showed error 41 TPS. TPS was changed - check engine stopped flash. i do not see it any more but AYC lamp still is on.

AYC lamp goes on only when i turn on the car is off and turns on after some 1min trip. What could that be?

3. Could that be that official mitsu service got only one error (that one with TPS) and didn't show another? ECU check is the only one diagnostics to get AYC errors, right? no other special AYC check diagnostics at official, right?

4. I've read that AYC could be on with incorrect break bulbs. if one of the bulbs is dead - possible to be the reason?

5. I've read that AYC code could be check myself by linking some pin in EBD and counting ayc flashing. any info how to do that?

6. when drive i can feel boost from some 2800rpm to some 3800rpm. on the 3800-4000 there is a feeling that car is n/a and there is no pressure.

could it be like engine is in some kind service mode due to ayc lamp is on?
could it be some kind of hole in airintake-ic-turbo system?

7. could be any of this problem be caused by full catalytic converter? i've ordered decat pipe already just to be sure. i have feeling mine has gone a lot of miles.

8. btw TPS could be installed incorrectly? any chance i did that incorrectly? after installation rpms - 900 as were before and check engine is not on any more.

Show car to some specialists could be great idea but mine evo4 is the only car in the town. And there are several 4's in my country.

official mitsubishi dealer checked the car and gave conclusion:
DTU ECU - 14 TPS
AYC DTC - 41 TPS OPEN

TPS was changed to new one.


Thank you a lot for your help!!

 

[HermaN]

1. There will always be a voltage drop on idle when the fans kick in, etc until the alternator catches up, this is not uncommon on idle, and as long as it does not go too low (ie below 12v) it should be fine, but idle should also be solid at about 850 RPM.

Does it hunt on idle? If idle is totally stable, but there is just a voltage drop when the fans kick in, this is normal.

2. Check the error codes for the AYC, connect pins 1& 4 together on the OBD port and put the key to the "on" position and count the flashes from the AYC light. Long flashes are 10's, short flashes are 1's. For example, 8 long flashes and 3 short ones are code 83 (AYC pump problem).

Most likely an issue with the AYC pump or pressure switch (codes 82/83).

3. The dealer should have been given all errors, however sometimes when the AYC light is on, error 41 (TPS) shows up amongst other things. Error 41 can be ignored when it comes up on the AYC diagnostics if there is an AYC fault.

Manually flash the codes as I explained above by using a wire to short pins 1 & 4 on the OBD/MUT port.

4. Yes, LED style or a broken brake light bulb can cause the AYC to come on, but if all your brake bulbs work, then that is not the problem. I am 99% sure it will be a pump failure (codes 82 and/or 83),it always is.

5. Yes, you can do that as I described in question 2.

6. No, the AYC will not cause this. Check for boost leaks.

7. No the cat is not related to any of the AYC or flat spot issues

8. If the CEL is off and idle is good, etc, your TPS will be fine.

I am 99.99% sure you have a faulty AYC pump or pressure switch, manually flash the error codes and come back with what you find.

If it is error codes 82 or 83 then you may well need a new pump (£3000),2nd hand pump (£300) or a refurb of your current pump (£250 + VAT and another £125 + VAT IF it needs a new solenoid),refubishment comes with a 12 month warranty from FQ Performance, so better than a 2nd hand pump that could fail in a week.

 

[robotech]

1. well, i have about 850-900 RPM. and lights in the car and even headlights are flashing a bit. i am sure this is not supposed to be like this. idle is stable. no RPM jums - about 850-900 RPM as i said. exhaust sounds a bit strange and unstable.

forgot to mention that among evo8 engine car has hks camshafts. several people said that possible that feeling of idle instability is caused by hks cams. but in any case lights are not supposed to flash.

sorry, what do you mean by "hunt on idle"?

2. ok, tomorrow will do that. mitsu dealer gave me error list with only one problem - TPS that is changed already so possible there is another code.

4. now all bulbs are ok, so not the bulbs

6. boost leaks can cause that i can feel boost till some 4000 but than car goes like goes not have turbo and feels as it's hard for the engine to increase revs?

7. ok, than cat will be removed just in case.

thank you

1. There will always be a voltage drop on idle when the fans kick in, etc until the alternator catches up, this is not uncommon on idle, and as long as it does not go too low (ie below 12v) it should be fine, but idle should also be solid at about 850 RPM.

Does it hunt on idle? If idle is totally stable, but there is just a voltage drop when the fans kick in, this is normal.

2. Check the error codes for the AYC, connect pins 1& 4 together on the OBD port and put the key to the "on" position and count the flashes from the AYC light. Long flashes are 10's, short flashes are 1's. For example, 8 long flashes and 3 short ones are code 83 (AYC pump problem).

Most likely an issue with the AYC pump or pressure switch (codes 82/83).

3. The dealer should have been given all errors, however sometimes when the AYC light is on, error 41 (TPS) shows up amongst other things. Error 41 can be ignored when it comes up on the AYC diagnostics if there is an AYC fault.

Manually flash the codes as I explained above by using a wire to short pins 1 & 4 on the OBD/MUT port.

4. Yes, LED style or a broken brake light bulb can cause the AYC to come on, but if all your brake bulbs work, then that is not the problem. I am 99% sure it will be a pump failure (codes 82 and/or 83),it always is.

5. Yes, you can do that as I described in question 2.

6. No, the AYC will not cause this. Check for boost leaks.

7. No the cat is not related to any of the AYC or flat spot issues

8. If the CEL is off and idle is good, etc, your TPS will be fine.

I am 99.99% sure you have a faulty AYC pump or pressure switch, manually flash the error codes and come back with what you find.

If it is error codes 82 or 83 then you may well need a new pump (£3000),2nd hand pump (£300) or a refurb of your current pump (£250 + VAT and another £125 + VAT IF it needs a new solenoid),refubishment comes with a 12 month warranty from FQ Performance, so better than a 2nd hand pump that could fail in a week.

 

[HermaN]

Your idle will be lumpy with HKS cams for sure, hence idle sounds "unstable" (lumpy),this can be mapped out if you wanted to get rid of it, but most people like the lumpy idle of a cammed car.

As for the lights dimming when fans kick in or air con goes on, it does it on my car too, and various other Evo's I've been in, when the fan kicks in it creates a voltage drop because the alternator can't keep up on idle, hence the lights dim, but this is not a problem.

Mine has been like that for years and even cars with new alternators have done it, the only time I've not seen an Evo do it is with a brand new battery, but once it's 2-3 days old it starts doing it again, once the alternator catches up it works fine again.

If you have a solid idle at 850-900 RPM just leave it, it is not a problem, lots of Evos I have seen do this, espescially older ones.

Yes, boost leaks can cause the issue you are having past 4000 RPM, the car will feel gutless as all the boost is lost. Pressurise the intake system and make sure there are no leaks.

 

[robotech]

Your idle will be lumpy with HKS cams for sure, hence idle sounds "unstable" (lumpy),this can be mapped out if you wanted to get rid of it, but most people like the lumpy idle of a cammed car.

As for the lights dimming when fans kick in or air con goes on, it does it on my car too, and various other Evo's I've been in, when the fan kicks in it creates a voltage drop because the alternator can't keep up on idle, hence the lights dim, but this is not a problem.

Mine has been like that for years and even cars with new alternators have done it, the only time I've not seen an Evo do it is with a brand new battery, but once it's 2-3 days old it starts doing it again, once the alternator catches up it works fine again.

If you have a solid idle at 850-900 RPM just leave it, it is not a problem, lots of Evos I have seen do this, espescially older ones.

Yes, boost leaks can cause the issue you are having past 4000 RPM, the car will feel gutless as all the boost is lost. Pressurise the intake system and make sure there are no leaks.

than lumpy idle does not bother me if that's normal.

but lights dimming really strange - fans do not kick and air con not as well. lights dimming all the time on the idle. even if i turn off the headlights so that the consumption of energy lowers - lights on the dashboard continues to dim. my friend tells me it's alternator. planning to check voltage this week in special alternator-repair garage. if not than i'll leave it like that.

most important for me to find out there is the boost leak and solve ayc problem so i can have fun in winter. in my country winters are snowy.

thank you

 

[robotech]

question - knock detection sensor if is not ok it will give error and will check engine be on? we suspect that possible no boost after some 4000rpm could be caused by this.