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My 930 came home last night on a flatbed truck I had just accelerated from a stoplight, shifted to second gear and then lost power. The engine was still idling roughly but any attempt to press on the accelerator resulted in a very rough engine with a lot blackish smoke out the tailpipe. The engine will start again but will only go to about 2000rpm and wont't stay there. I am guessing that either the check valve, pressure regulator has failed or one of the fuel pumps.
I won't have time to troubleshoot till this weekend but intend to check the pressure first then pull out the pumps and check valve if the pressure is down.

Is there a way to tell which pump might have failed, assuming one is still OK?

Can anybody recommend a pressure gauge setup similar to the ones sold for 944's and 928's which hook a permanent small gauge onto the fuel rail?

D

Ok I have the intercooler out and the aircleaner out, theres now room to work! The fuel pumps pass the volume test (nearly 1/2 gallon in 30secs). Now I am trying to figure out which fuel line to T into to check system and control pressure.
Does anyone have a diagram of where to T in a pressure gauge on a 930 to make these two tests?

Brent 930

It's the line from the middle of the fuel head going to the WUR. Here is where you will check for all fuel pressures and if need be adj. the system pressure by re shiming the poppet valve on the right side of the fuel head. Of course you should have a CIS tester(around $90), mity vac (around $50),temp gauge ($?)to know the ambient temps for the cold start and measuring cup($?)to make these checks. This is the heart of the CIS fuel system and is good that you know how it works.

Brent

D

Thanks Brent. I assume by CIS tester you mean a pressure gauge set up? And is the mity vac just a vacuum tester?

Brent 930

Yes, but it will pump air too though you will need a gauge to read the pressure.

John from WA

Have you checked all the intake seals? I big giant air leak could cause some of those symptoms.

John

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John,
Thanks for the advice, I have found a suspicious vacuum line which may have been loose (the one running to the distributor, so perhaps I wasn't getting ignition advance? But before putting it back together just to see if the vacuum line was the problem I am waiting for my CIS pressure test kit to arrive and run the fuel pressure tests.

jrogers

There is a vacuum diagram in the engine compartment. If you lift the engine lid and look up at the bottom side of it, there is one on the right side, at least on my 87.

Eric 930

Don't over look your fuel pump relays. My car did the exact same thing a couple of months ago. I had it towed home. Come to find out the relay for the front fuel pump somehow vibrated out. These cars will run a little if the back pump goes out but if the front pump goes it will barely idle and yes spit a lot of black smoke. If your front pump is out you should be able to here the back pump because it will be running dry and not lubricated properly from the lack of gas. An easy way to check the relays is just to swap the front and rear relays. If you swap them and it doesn't do anything you know its the relay. My car sat for a month because I thought the front pump was out. Hope this helps.

Eric

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The problem may be with the Control Pressure Regulator (WUR). I noted yesterday while running some tests that after I shut down the pumps that fuel is spilling out of the short vaccuum line out the top of the WUR to the air cleaner housing. I don't think thats supposed to happen! The WUR's are available as new or rebuilt, so does anyone know if there is a "rebuild kit" available somewhere?

Brent 930

Wow, that is a good one, no that isn't suppose to happen. You won't be able to get a kit and do it yourself. Try specialtauto.com and call if you don't see yours there. It will cost around $160 not including shipping with the core return.

Goodluck

Eric 930

I reccomend buying a new WUR. I just replaced mine and I heard alot of bad things about the rebuilt ones. There are several companies that advertise in Excellence mag. that sell these at a decent price(high 200's). Eric

D

New WUR arrived this morning. With any luck I'll have the car back together by this weekend!
Thanks for all the help.

D

Got the new wur in. Fuel pressure is at 95psi system, 45psi control and about 25psi residual after 20 minutes. But the car will not start! It sure seems like it is flooding as there is a strong gas smell at the exhaust pipe. I have a strong spark, but it shows no sign of firing. What should I look for now?