Sadly dont have a log for MAF voltage

I do for my own car which something I just noticed, showed much less knock correction running on Optimax than SUL




[Edited by *Sonic* - 8/5/2003 11:30:03 PM]

 

Would a leaking DV be responsible for intermittent boost drop off??

Car intermittently varies boost to around 8 - 10psi
Basically the boost is not reliable at the moment. Darent rely on it either.

Usual for my car is around 14.5.

Had it on Delta Dash to check for any error codes or Lamba failure- all fine..

Its a Forge VTA.. going to put my recirc back on for now to see if it is responsible.

 

Put your recirc back on, but it could be your boost solenoid sticking

 

8-10psi sound to me like ECU panic mode? Especially in this weather.
You don't have a KnockLink type thing, do you?

 

yeah have a KL.

Not ECU "limp" mode - it would have shown on delta dash/select..

 

There seems to be an intermediate 'limp home' that doesn't appear on DD or anything - Merv & I 'played' with it for a bit on the PE RR & boost would just be dropped - no error codes reported - then after a while (or an ignition cycle) it would be back to full boost. Was totally repeatable! What caused the ECU to pull back was 5 degree retard over only a very brief period - no knock according to the ECU - it just didn't seem to like it! What was actually causing it was the APS induction kit, but I found it would also happen on hot days when accelerating from a queue even without the APS (not even really pushing it, just trying to get up speed to join a motorway from a busy roundabout). Heavily depended on the fuel (my local Optimax is frequently crud )

 

ah cheers nom.. a couple of mates put it down to bad fuel..

could well be that..

have swapped shell stations, and am going to add some OB for a week to see if it clears..

**to add: on DD, it showed 6 degrees of knock correction which coincided with boost being low, and the ingition timing being off..
I have the logs at home.

[Edited by chrome - 8/5/2003 6:20:47 PM]

 

On DD, you should have a very suspicious looking goings-on with the wastegate around the retard points, I suspect (at least, you will if you catch the point at which the ECU panics!)

 

Nom

I have the logs, I understand the Knock Correction now, and a few other bits, on the stuff Im actually logging, Im still trying to learn more about how the other parameters, like Wastegate etc 'should' be on normal runs, and also what parameters are 'safe' ones

btw the Knock Correction was -6, and dropped to -8 at its lowest point, and interestingly the knock link didnt light up

Steve

 

right.
put my recirc back on, and still got unreliable boost..

hm.

OB is next step.

 

Just checked the logs again

When the car is stuck at 8PSI the Wastgate reading is zero

when the car starts to read normal boost (ie not stuck in the 8PSI max) the Wastegate readings go up to about 72%

 

Yup, that's panic mode alright! It just lets the wastegate do its own thang, which is open at crack pressure, that being around 8psi. Be happy your ECU has a sensitive soul there
I suspect it's a dodgy batch of fuel - it doesn't seem to take a lot in this weather, certainly with a TMIC, to get this 'reaction'. Unless your MAFs going peculiar, which could easily cause the same thing. How's the log for the MAF voltage? I think it should be up at around 4.2V at WOT/good rpm/highish gear, but don't have a MAF to compare with I'm afraid . If that's looks OK though, I'd go with the 'dodgy batch of fuel' diagnosis

 

any other ideas to try looking at in the meantime??

 

sonic- you down at mansfield anytime soon?

 

sounds like my MAF is on the way out.. gonna try one out (-p20spd) to double check..

 

Hi Mate

not sure if I am down Mansfield, dont think I am till next month, but even then it would be a longshot

Burr has a spare Maf but is still in France AFAIK

 

it was more to get her back on DD with a borrowed MAF sensor.. just to check..

thats all
altho I will be going to rallyday on the 16th, but havent got a weekend free to get up to Stevens until after my hols (Sep15)


p20spd- Maybe I could drive up one evening next week? what time do ya get in from work?
I promise Ill be as quick as poss.. and get out your way..


also got to drive down to gatwick, and dont want the MAF to go then!!!!

[Edited by chrome - 8/8/2003 6:44:20 PM]