'78 930 sitting since '86....

[Micker747]

I have bought a 930 that was stolen in '86 and hasn't driven since.. Unfortunately someone tried to get it going without succes!

So far I have confirmed it cranks, it sounds even in all cylinders and oil pressure comes up.
I took the metering head off and drained the tank for old fuel and flushed it w. some fresh fuel. The front pump didn't run, i changed that and the filter. The piston in the fuel metering unit was stuck and kept pooring fuel into the cylinders. I took it off and pressed it out with grease, cleaned it and put i back together.
Fresh oil and filter, new plugs, and it started. Obviously it smoked quite a bit, but now the problem is that it starts easily, but revs to 2-2500 rpm, then settles down, humps and can't take the gas. I tried to drive around the house, but it kept getting worse. Now it can hardly roll! Any ideas??
As always I appreciate your input

[jsveb]

Tillykke.

Have you checked the WUR? If you know the fuel head works. Then the control pressure may be the culprit. On my 78 the stock wur was jacked up. I ended up getting an adjustable unit from Brian Leask.

If you have got acces to an afr gauge, I would put that on, to see where you are at. This would also hint towards control pressures.

[Micker747]

Tak Jesper,

I haven't checked the WUR, isn't it just for cold/hot start capabilities? It can hardly idle after a minute or two and doesn't respond to throttle input!
The metering plate is a slight bit higher than exactly centre, but i didn't see any posibilities to adjust it. It closes about 1mm higher than centre

[Miguel Antonett]

^^^ +1 on the AFR gauge.
The high idle is a WUR symptom, the "can't take the gas" is a stuck metering plunger symptom, be sure the metering plate moved freely.

Please check the brakes before taking her for a spin.

[Micker747]

I have just measured the power at the front pump, it only shows around 9 volts even if the battery is above 12volts and new.. Ideas?

[quattrorunner]

Fuel system is still cruddy/gummed. It will work itself out running with seafoam or just take it apart and clean manually.

[Micker747]

Seafoam?

[slyguy]

replace the fuel filter, pull a plug or two see what they look like.

[quattrorunner]

PENNZOIL Sea Foam Fuel Satbilizer at West Marine

[IMR-Merlin]

If this is your first time running it. Fuel filter change.

Even if you just changed it, replace it again. There is going to be a TON of crap in a tank on a car that sat for so long.

[Micker747]

I have been working quite a bit on the car now, but I am defintely not there yet! There is some wiring issue, the original wiring harness at the battery had melted/corroded in the last bit closest to the battery and the power in the fuse box was down to about 11v, measuring 12.8v at the battery!
I have replaced it now, but the problems are still apparent. Before i had about 9v at the front pump, now it's up to 10v, still not ok. The relays don't get hot, but I will need others and check all the wiring. Perhaps this issue is also concerning the rear pump, WUR etc... Is the rear pump easily accesible?
Tomorrow I will check the power at the coil and rear fuses as well.
Suddenly it was running on all 6, but after just a few minutes drive it was humping and could barely idle. I love old cars;-)

[unclebilly]

Iss the distributor advance / retard seized?

[1979 930]

Originally Posted by Micker747

I have been working quite a bit on the car now, but I am defintely not there yet! There is some wiring issue, the original wiring harness at the battery had melted/corroded in the last bit closest to the battery and the power in the fuse box was down to about 11v, measuring 12.8v at the battery!
I have replaced it now, but the problems are still apparent. Before i had about 9v at the front pump, now it's up to 10v, still not ok. The relays don't get hot, but I will need others and check all the wiring. Perhaps this issue is also concerning the rear pump, WUR etc... Is the rear pump easily accesible?
Tomorrow I will check the power at the coil and rear fuses as well.
Suddenly it was running on all 6, but after just a few minutes drive it was humping and could barely idle. I love old cars;-)

Sounds like bad ground !!

[Micker747]

A little progress, I removed the huge alarm system, there were two fuses, and several connections in the alarm wiring harness for the power supply to the fuel pumps. It's back to stock now and I see 11,9v when the rear/front pumps are running. (measured at the pump terminals, engine off. Battery power at 12,7v. That's much better.
It started right up, idled fine on all six, but when I took it for a drive it died after just 2 minutes again and could not start.
I took the air filter box off and noticed that the pumps run when I press the metering plate, which is hard, but the injectors don't whine.... I guess the plunger is stuck again and doesn't open. I thought it could only get stuck open since it is pressed up by the metering arm!
How can it be it can run when cold then??

Hmm.... I guess the fuel head has to come off again! Do you know the correct position of the little spring on the axle of the metering arm? I guess it needs a preload. I was not the first to take this apart, so I might have put it wrong together.

[DSPTurtle]

Have you checked the dizzy cap and rotor?
You definitely should check the fuel pressure cause it sure sounds like your WUR isn't doing its job once the engine gets some heat in it. Your fuel pressure should be under 2bar when cold and around 3.5bar after the WUR warms up. If the WUR isn't working, the fuel pressure won't go up and will run the engine too rich an kill it. It sounds backwards, but that's reality.

[Micker747]

Yes, the dizzy cap and rotor are fine, but i need a fuel pressure gauge. Is it possible for the WUR to do the opposite and shut off the fuel to the injectors instead?? I heard the injectors before when i pushed the metering plate down, but after it has been running for 4-5 minutes there is no sound from the injectors The metering plate is hard and pumps are running, it is so strange!

Originally Posted by DSPTurtle

Have you checked the dizzy cap and rotor?
You definitely should check the fuel pressure cause it sure sounds like your WUR isn't doing its job once the engine gets some heat in it. Your fuel pressure should be under 2bar when cold and around 3.5bar after the WUR warms up. If the WUR isn't working, the fuel pressure won't go up and will run the engine too rich an kill it. It sounds backwards, but that's reality.

[Ronnie's.930]

I don't think the injectors ever make any noise as they are mechanical (not electronic) - I've never heard a sound from mine.

[jsveb]

My guess is, warm control pressure is to high. That could explain why you can drive it for two minutes.

Honestly, I would bite the bullet and order an adjustable wur from Brian Leask. Maybe rarlyl8 motorsports has got them in stock. That would give you a quick turn around.

Try and disconnect the power to the WUR, then the heater element does not get warm and the CP should, not change.

Also as suggested, get a CIS fuel pressure tester gauge

Good luck

[Micker747]

Thanks, will the low pressure really kill the engine and make it unable to start? After 30mins or so it could start again, but only humping, phut phut phut... I hope it's the WUR then, it's a shame a fuel pressure gauge test set cost 3 times here!

Originally Posted by DSPTurtle

Have you checked the dizzy cap and rotor?
You definitely should check the fuel pressure cause it sure sounds like your WUR isn't doing its job once the engine gets some heat in it. Your fuel pressure should be under 2bar when cold and around 3.5bar after the WUR warms up. If the WUR isn't working, the fuel pressure won't go up and will run the engine too rich an kill it. It sounds backwards, but that's reality.

[DSPTurtle]

Micker,
The WUR certainly can cause the fuel pressure to become too high, hence lean out the system instead of make it rich.
I know exactly what you are talking about with the screaming injectors. It's how I test mine to make sure there is good fuel pressure. However, there are times when they will not scream. Are you pushing down on the mixture screw or the plate itself. It should feel very stiff when the pumps are running. (The only real way to know if fuel is coming out is to pull an injector. If you don't have AC thats pretty simple. Otherwise it gets a little harder to get your hands in there...
From your pic in post 3, I assumed you had a pressure gauge since it sure looks like the end fitting on that fuel hose in the pic???