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Dave 86 930 Fl Dave 86 930 Fl is offline
River Rat
Dave 86 930 Fl's Avatar
Join Date: Dec 2005
Location: 1000 Islands NY
Posts: 405
Running Like a Scaulded Dog


I finally got the old 930 running again this weekend. I purchased the CIS gauge kit and the Porsche fittings for the fuel pumps, so I could check the various fuels pressures necessary for a healthy 930. First step, check the fuel pressure at the rear pump as per the Porsche manual, but there were complications. After disconnecting the plug at the back of the metering plate and turning the ignition key on, the front fuel pump was not running. Interesting Ö so I switched the fuel pump relays and now the back fuel pump was not running. I thought I had two good relays (checked and rechecked), but obviously I was wrong. So, armed with two new relays I measured the fuel pump pressure and it was a solid 4 bar, which was within the acceptable range of 2-4 bar. I had my money on a bad rear fuel pump, but this car has fooled me many times before.

I did take the red cap off of the bad (intermittent) relay and one of the contact wires looked like it has been cooked. I touched the wire with my fingernail and it moved away from the terminal Ö Now my confidence is rising, but I cautiously move forward with the rest of the tests.

I disconnected the fuel gauge from the pump and connected up between the fuel distributor and the wur Ö A brand new Brian Leask adjustable wur. Started the car for the first time in 14 months and watched the fuel gauge as the wur transitioned through its warm-up cycle, which precisely matched the specifications for my vehicle. I did have to make some adjustments to the AFR, which was accomplished with the Innovate wide band sensor. The Leask wur also has the rpm switch and I started with the 4000 rpm pill, which I can tune to put off the fuel enrichment cycle required for boost conditions.

Iíve only driven the car about 30 miles since itís been running, but it has never run as smooth as it is right now. The wur is working great, but I need to run some log files and take a look at some fine tuning. Iím currently running about 14.4 AFR at idle and cruise Ö Whereas; on boost Iím seeing around 11.9 with the 4000 rpm pill. Once I start getting some log files, Iíll try changing the pill to 4200 rpms and see how that works.

Kudos to Brian Leask, as the entire package that he provided (adjustable wur, rpm switch & manuals) was absolutely perfect. How about lessons learned, one for sure is I will be replacing my fuel pump relays and fuse every year whether I need it or not. These cars are a real trip, one that I enjoy the challenge of diagnosing, just maybe not so often.

If anyone has any questions, please ask.

Regards, Dave
1986 930 - K27-7200, Andial Intercooler, Tial Wastegate, Electronic Boost Controller, B&B headers, Bodart Zork, Leask Adjustable WUR, Full Elephant Racing Suspension w/Adustable Spring Plates and Von Shocks, Wevo Transmission Mounts, Fuel Safe Fuel Cell, Forgelines (9"/11"), Hargett Shifter, Innovate AFR, Cobra CF Seats, DAS Rollbar, Coleman Floating Rotors, Lightweight Interior, Forgeline 17" x 9"/11", 2800 lbs.
Old 03-02-2009, 03:47 PM
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