High RPM followed by Poor Running
07-15-2002, 08:35 AM
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High RPM followed by Poor Running
Hi,
I hope you can point me in the right direction.
I have a 1982 Euro K-jetronic 928S (4664cc)
Apart from the many maintenace and repairs/service this car has had I
have a recent problem that is causing me problems.
Until recently the car started always.
Now its a little hard to start, it does start and it pulls very very well
for about 60 seconds then it barely ticks over.
If you switch it off (even for 5 seconds) and start it again, it starts
well, performs weell for another minute.
It has all new vacuum hoses, a rebuit injection head, new fuel pump and
filter, new fuel lines (the old ones were very dirty), it even does with
with the fuel pump relay bypassed so its on all the time.
When it dies you cannot rev up the car at all and if you floor the gas the car cuts out.
As long as the ignition is turned off for a few seconds it will start and
perform again, always but for no more than a minute (you can get it upto
6500rpm in second easily without hesitation.
Any pointers or advice welcome.
BTW I live in Malta which is a small island off southern Italy and I have
the only 928 on the island and i have to solve the problems myself!
Many thanks,
Mark
I hope you can point me in the right direction.
I have a 1982 Euro K-jetronic 928S (4664cc)
Apart from the many maintenace and repairs/service this car has had I
have a recent problem that is causing me problems.
Until recently the car started always.
Now its a little hard to start, it does start and it pulls very very well
for about 60 seconds then it barely ticks over.
If you switch it off (even for 5 seconds) and start it again, it starts
well, performs weell for another minute.
It has all new vacuum hoses, a rebuit injection head, new fuel pump and
filter, new fuel lines (the old ones were very dirty), it even does with
with the fuel pump relay bypassed so its on all the time.
When it dies you cannot rev up the car at all and if you floor the gas the car cuts out.
As long as the ignition is turned off for a few seconds it will start and
perform again, always but for no more than a minute (you can get it upto
6500rpm in second easily without hesitation.
Any pointers or advice welcome.
BTW I live in Malta which is a small island off southern Italy and I have
the only 928 on the island and i have to solve the problems myself!
Many thanks,
Mark
07-15-2002, 09:19 AM
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Join Date: Nov 2001
Location: Riyadh
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Mark,
You are just a year older than mine, so should be very similar. Have you changed petrol filter? checked fuel delivery rate (~1250cc/30 secs)? Mine did similar lately, but it took some heat soak, 10-15 minutes of use, then lost power. It was build up of control pressure at WUR, caused by a partial blockage. Get the Book on Bosch injection by Watson , and gauge set for CIS diagnosis. Work through the steps in Watson to find your problem, assuming it is petrol problem. One easy thing to check first is the line from WUR back to fuel distributor which enables the WUR to reduce pressure - looking in, comes off RH side of WUR, under spider to rear RH of distributor. If this is blocked, the control pressure will be wrong - high, giving you lean mixture.
jp
You are just a year older than mine, so should be very similar. Have you changed petrol filter? checked fuel delivery rate (~1250cc/30 secs)? Mine did similar lately, but it took some heat soak, 10-15 minutes of use, then lost power. It was build up of control pressure at WUR, caused by a partial blockage. Get the Book on Bosch injection by Watson , and gauge set for CIS diagnosis. Work through the steps in Watson to find your problem, assuming it is petrol problem. One easy thing to check first is the line from WUR back to fuel distributor which enables the WUR to reduce pressure - looking in, comes off RH side of WUR, under spider to rear RH of distributor. If this is blocked, the control pressure will be wrong - high, giving you lean mixture.
jp
