Possible MAF Issue-PSI3 Readings
#1
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Possible MAF Issue-PSI3 Readings
In the last day or so I have noticed that there has been a slight lumpiness/maybe a miss every now and then when on partial throttle, not very often, and the revs will sometimes drop off to about 600rpm then back up to the 750 area when coming out of gear(not every time). There are no CELs.
I had a look at the PSI3 on idle and had these figs that may give you some idea:-
IG (which i presume is the same as Ignition Advance IA)= 10-12 degrees.
LA= 12:1-13.5:1
Now I remember it has been said that stoich is 14.7:1 so am wondering how far into the rich I am going with this LA fig?
I did an ECU reset and the figures were pretty much the same.
What sounds like the problem in you guys' experience. I have read up and it sounds like it could be the MAF on its way, do these symptoms sound familiar? Anywhere else you can point me for diagnosis?
All help appreciated guys.
I had a look at the PSI3 on idle and had these figs that may give you some idea:-
IG (which i presume is the same as Ignition Advance IA)= 10-12 degrees.
LA= 12:1-13.5:1
Now I remember it has been said that stoich is 14.7:1 so am wondering how far into the rich I am going with this LA fig?
I did an ECU reset and the figures were pretty much the same.
What sounds like the problem in you guys' experience. I have read up and it sounds like it could be the MAF on its way, do these symptoms sound familiar? Anywhere else you can point me for diagnosis?
All help appreciated guys.
#7
Using the PSi for detailed diagnostics isn't easy...the IA isn't really ignition advance and the readings for the AFR are not stored. If you want to do a detailed diagnostics then it's delta dash or equivalent. Either that or swap the MAF for a working item and see if the situation improves.
Shaun
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#12
JohnD
I thought the SECS only displayed the difference between the data stored on the table and the Advance the ECU was running and the same went for Knock correction ?
Or am I dreaming, well it was quite a few years since I sat in my Bug with Bob Rawle LOL
I'll see what my SECS displays later
Shaun
I thought the SECS only displayed the difference between the data stored on the table and the Advance the ECU was running and the same went for Knock correction ?
Or am I dreaming, well it was quite a few years since I sat in my Bug with Bob Rawle LOL
I'll see what my SECS displays later
Shaun
#13
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[QUOTE=Midlife......;10222226]JohnD
I thought the SECS only displayed the difference between the data stored on the table and the Advance the ECU was running and the same went for Knock correction ?
Or am I dreaming, well it was quite a few years since I sat in my Bug with Bob Rawle LOL
I'll see what my SECS displays later
Shaun[/QUOT
The PSi3 shows real time ignition advance and, if you choose to display it, the Knock correction. The KC values you normally see are actually the extra advance put on by the ECU when accelerating.
Typically, cruising with low throttle and mid range revs you should see over 40deg. advance with no KC value. If you accelerate with part throttle the Kc value can be + 8 - 9deg. (The vacuum advance did all that sort of thing back in old days!)
The above is how I understand it, anyway
JohnD
I thought the SECS only displayed the difference between the data stored on the table and the Advance the ECU was running and the same went for Knock correction ?
Or am I dreaming, well it was quite a few years since I sat in my Bug with Bob Rawle LOL
I'll see what my SECS displays later
Shaun[/QUOT
The PSi3 shows real time ignition advance and, if you choose to display it, the Knock correction. The KC values you normally see are actually the extra advance put on by the ECU when accelerating.
Typically, cruising with low throttle and mid range revs you should see over 40deg. advance with no KC value. If you accelerate with part throttle the Kc value can be + 8 - 9deg. (The vacuum advance did all that sort of thing back in old days!)
The above is how I understand it, anyway
JohnD
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