Replaced fuel pump/lines, now no start

[sigchuck]

I recently replaced my tunnel lines and fuel pump as part of an exercise to remove and repair the fuel tank. Tank is clean, lines and new, and fuel pump are new. I jumped 87a to 30 to run pump and check for leaks. No leaks. I reassembled everything else, tried to start and nothing. The engine turns over quickly like it should, just no ignition. I also tried lifting the sensor plate with the key on, and while injectors squeal, I still get no ignition. Any thoughts other than maybe a bad pump?

Probably a dumb question - does banjo bolt need to be “clocked” to align holes with check valve?

Thanks, as always!

[lsf911]

Not sure what year car you have but lets assume you have a fuel accumulator. Remove the main line from the bottom of the accumulator and check fuel flow rate. At least that will tell you whether all your new work up front is correct and also verify the pump is working.

[sigchuck]

Sorry,’it’s an 83 911, so yes there is an accumulator. I’ll give that a try!

[Superman]

No, banjo fittings do not need to be 'clocked.' To see if the ignition system is working, I sometimes just hook up an inductive timing light. A motor needs just three things to run. Proper fuel/air mixture, spark, engine compression.

[otto_kretschmer]

some of checks you can do

Plumb the fuel return to the tank to a bucket and watch when you turn the key on. You should see fuel coming out.

Another thing you can do is pull an injector and put it in a clear bottle and try to start the engine. Make sure the bottle is empty before you start. After turning over a few seconds there should be fuel in the bottle.

[sigchuck]

Well, now the pump isn't running when I jump the relay.

I "upgraded" to a Bosch -044 pump in anticipation of future engine performance modifications. While I purchased on Amazon and "verified" it wasn't a counterfeit via videos, I'm pretty sure it must be. I'll double check electrical connections, but otherwise I think I'll purchase a replacement through Summit or another large retailer.

[OsoMoore]

You can quickly check the voltage at the pump with a meter. You just need a friend to lift the plate while you do it. That should 100% confirm or deny if the pump works.

[pmax]

Injector "squealing" means you have some fuel pressure.

Does it attempt to start or nothing at all ? I would check the ignition system.

[sigchuck]

Thanks, pmax, that does seem to make sense. I'm just not sure why I'm not getting any fuel pump squeal (044 is louder than stock, I have heard) when I jump the relay pins. It made noise during leak check, but isn't any longer (after I tried lifting sensor plate).

I'll check ignition system. There's absolutely no attempt to start. The engine turns over freely and quickly though. I did have to remove the fuse panel cover to get the tank in and out of the car, so maybe I knocked something loose. I did a quick check of all the fuses and they look good though, and swapped out the FP relay with a spare.

[boyt911sc]

Install a CIS pressure gauge and check the control and system fuel pressures. Disconnect the plug to the WUR during the test. A running FP means nothing unless you get the needed fuel pressures. Re-connect the plug to the WUR.

Hook up an inductive timing light to determine presence of ignition. Try to start the motor. Keep us posted.

Tony

[Walt Fricke]

Rule of car mechanics: Start with the spark. You say no spark, but just because the car won't start, or cough, doesn't mean you have no spark.

If you don't have a timing light handy: Pull a plug wire off of a plug, stick an old plug into the connector, and make sure the plug is grounded. You could also stick a rod or screw driver or something into the connector to serve as a pathway out to where you make a small gap you can watch. Or just pull a plug, use that. Have someone crank the car. If you see spark, check that box. If you don't, fix that and see if the car will start.

If, unlike Tony, me, and a bunch of long time CIS gearheads, you don't happen to have the CIS pressure testing system, do a Quick pump test:
Forget the jumper fuel pump relay business. Just pull the connector off of the back of the CIS roughly behind where the right side big connecting boot is. That plugs role is to prevent the pump from running if the engine isn't - when air passes through the intake and raises the sensor plate, it opens a circuit, allowing the pump to run in the ignition key run position. That will have fuel pump running when you turn the key to the run position (same deal as the jumpering), but quicker and less prone to error - now, which pin do I jumper to which other pin), And you can in essence switch things on and off back by the engine (though the reach is awkward, and plugging back in what you can only feel can call for several tries).

Pull the most convenient injector out, run pump, raise plate very briefly.


If it squirts, well now you need to do stuff like Tony says, because with spark and fuel, if it doesn't run either the distributor has been all screwed up (unlikely unless you had just removed it) or somehow the CIS has gotten all out of whack.

My SC once refused to start on a winter night in the parking lot as I left work to go home. Hmm. With basically no tools I was able to do these two checks. Confirmed spark. Confirmed fuel pump wasn't working. Called Triple A for flatbed. Bought new pump, installed, all well a few days later.

One thing does occur to me, since you have an '83, is the mini-brain frequency valve system, most of which is under the rear of the passenger seat. If that is completely disconnected, or without any power, the car will be hard to start, because the system has switches telling it that you are trying to start it, and to richen the mixture.

Similarly, there is a cold start injector system to consider. With the engine cold, a solenoid type injector squirts some fuel into the plastic air box where the air is distributed to the six manifolds, three to a side. The sensor on the left rear chain housing of the engine controls this, making sure that you can't squirt with a hot engine, nor squirt too long if a cold engine won't start pretty much right up. If the cold start injector won't work, you might not get it going, though usually if you crank long enough it will start - ditto with the electronic stuff not working.

But usually these two systems lead to hard starting, not no starting.

I get the conundrum: car ran fine, fuel lines replaced (you were able to do this with the transmission in place?) and fuel pump replaced. Fuel pump seems to run, but car won't start. Didn't mess with distributor, CD box, wiring, fuses. I see you wondered about dislodging something on the fuse box panel. But if you have spark, and fuel coming out an injector, you have to go over what else you might have done. If you hooked the fuel lines in the rear by the tranny up wrong (is that possible), shouldn't have fuel coming out of any injector.

[sigchuck]

Guys, the information and responses are truly invaluable. Thanks to everyone that took the time to read and post advice.

Now, it’s time for me to confess that a brown fuel pump ground wire looks like a faded red power wire (because all red wires are of course hot, right?), and that a black must always be ground. Yes, I reversed the polarity on my pump and it still ran, but of course didn’t flow any fuel. Fortunately checked the wiring diagram before heading out for a new pump. Interestingly enough, the factory terminals are different sizes making it all but impossible to mix up the terminals for the old pump. New pump also had different sized terminals, but in opposite locations.

Thanks again for all the help, and especially for baring with me!

[Walt Fricke]

Confession is good for the soul.

Other than the + and - terminals, fuel pumps are symmetrical externally.

I don't recall whether the positive screw terminal is the larger or smaller, because the different size ring connectors take the need to know out of the equation. You can't put the small ring on the larger terminal. All the replacement pumps I've had use the same protocol as the originals.

Are you saying that the screw terminals on your new pump has these size differences reversed?

[sigchuck]

Walt, exactly. I did use a Bosch 044 pump instead of the Bosch factory replacement, but I mistakenly assumed the post size protocol would have remained the same.

Kind of frustrating, but probably the best outcome, so I’m happy.

[piscator]

Gas in tank? ;-)

[Walt Fricke]

Well, my Bosch 044 was set up the same as always. Isn't there a + cast into the plastic up around these posts? It seems unlikely Bosch would up and change these very useful post size differences. Manufacturers would have designed their wiring with these sizes in mind.

You have it pumping fuel ad running, so problem solved. And while I don't remember where the ground wire is attached to a ground, is isn't fused so nothing you did up there would change that.

But if, indeed, Bosch - or any of the other sellers with pumps which look pretty much just like the Bosch, have reversed things, a whole lot of us would like to know that so this doesn't happen to us.

Is there any indication that one or both of the ring connectors have been replaced? If the smaller was replaced with a larger one, then you couldn't use connector size to get it right.

[Superman]

Originally Posted by Walt Fricke

If you don't have a timing light handy: Pull a plug wire off of a plug, stick an old plug into the connector, and make sure the plug is grounded. .

Respectfully, and FWIW, I greatly prefer leaving the ignition wire on the plug and using a timing light. I have seen instances where there is a spark if the plug is at atmospheric pressure, and no spark if the plug is in the pressurized combustion chamber.