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Can't get gas to the engine


robmck

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We're having a hard time diagnosing our 1976 2002's inability to get gas to the engine. I'm wondering if you could help. I'm new to 2002s.

 

Late last year, my fiancée and I purchased the car and it appeared to be in good order. The first few drives were great; we went through about a tank of gas each. Gradually, we noticed the car wasn't happy at 2000-3000 RPMs: the car stuttered and hesitated, while the AFR gauge went full lean. If we could get it over 4000 RPMs, then it was happy and roared. 

 

On our last drive of fall, the stuttering was really pronounced. It was hard going driving back home, but we got there. We backed it into the garage and as soon as it was in position, it died. (Very thoughtful of it to get back home). I popped the hood and noticed the inline gas filter was bone dry.

 

We've replaced all the fuel lines and a few other diagnostic tests (detailed below), and still can't get it to start (or get much gas into the fuel filter). 

 

First, some details about the car. It's a 1976 2002 that the previous owner had for over 25yrs. He drove it quite a lot, though it has been driven only rarely in the last 5 years. Here are the updates he made to the car:
 - Weber 38/38 DGES carb
 - New pistons
 - Cam regrind to get more valve lift and longer opening
 - Ported intake manifold & cylinder head to breathe better
 - Air injectors removed from exhaust manifold (improved exhaust flow)
 - Fuel return system disabled (lots of plugged lines; coal filter missing?)
 

Starting at the tank and working forward, here's what we've done:

 

1) Replaced the cloth-covered fuel line between the tank and the plastic tube.

 

2) Noticed that the return fuel line is plugged with a screw, the other end open (see photo below). The previous owner said that the tank is vented to the air, but I can't figure out where this is (threads on this forum say this can be done via the little plastic tube in the filler spout, but I don't see how this works). 

83B45FDB-.thumb.jpg.73e8de893f8e93642de740fb758ce692.jpg

 

3) Pulled the fuel sender. The filter at the bottom of the sender looked pretty full. 

 

This is the filter after I blew it out with the air compressor. How clear should it look when clean? Where can I source a new one?
WP_20180310_15_08_03_Pro.thumb.jpg.60448ce6583d03cd5422fa450dad3c2c.jpgWP_20180310_15_09_14_Pro.thumb.jpg.8ce6c6a860ad842c6259b867d3d0bec5.jpg

 

Based on darrinos's fantastic story (https://www.bmw2002faq.com/forums/topic/143766-not-getting-fuel/), I blew through the sender to make sure there was no fly or other obstruction in the 90 degree bend. It blew through clear.

 

While we're there: here's what the inside of the tank looks like. There are no leaks that we can find; the exterior of the tank looks great. Do we need to refurb or replace it? I've seen some mention in decade-old threads here that it's possible to get a new tank, but I'm not finding one. Any ideas?

WP_20180310_16_42_39_Pro.thumb.jpg.c71458f5586453a4f65ff045203a3498.jpg

 

4) Putting the tank back together (including that filter) and moving up to the engine compartment, we replaced all the fuel lines there. Inline fuel filter, too. We hooked up the line from the plastic tube in the firewall to a hand siphon pump and was able to easily pump fuel through. I'm guessing therefore that the fuel is flowing fine from the back.

 

5) Following a recommendation from the Restoring 2002s book, we pulled the spark plugs (to make it easier to crank), disconnected the output side of the mechanical fuel pump, pointed it at a measuring cup, and cranked the engine for 15s. It pumped about 10dl of fuel, which is what the books says. This made me think the pump was in good shape (though I'm still a little doubtful).

 

6) Hooked everything up with new spark plugs. We couldn't find a way to prime the carb - I tried to pour gas in what I thought was the vent port of the Weber, but it all came right out again. We decided to go ahead and crank it, but pretty quickly started getting blow-back through the air filter. It was then that we discovered that the nut on the distributor was loose and thus the distributor free to turn. (I'm now amazed that cable tension kept the timing for so long). 

We reset the static timing using the white/red lines on the driveshaft pulley, and a light connected in series in the points light. 

Cranked again, no more blowback, but after over a minute of cranking, we got nothing in the fuel filter.

 

7) I tried priming the carb using a syringe to squirt ~25ml of gas into the carb via the fuel line. That didn't seem successful (not a lot went in, and the car didn't start). Also tried to fill up the fuel filter, which is just prior to the carb. It filled, then emptied when we cranked, but no start, and it never re-filled.

 

8) On a lark, I disconnected the carb line, connected a clean, dry line to the carb, then tried blowing in it. It seemed completely blocked. Assuming there was no fuel in the bowls, I'd expect to have at least gotten some air through. But then, I was clearly reaching at this point; I've no idea if this should work. 

 

9) I pulled out the filter in the carb (right under the fuel input & return ports). It looked nice and clean.

 

Does anyone have any other ideas?

 

At this point, I'm wondering if it's the fuel pump after all (though, it did work when pumping into a cup, but maybe can't handle any back pressure?), or something wonky in the carb. Before we order a new fuel pump, or pull the top off the carb (we didn't have new top gasket handy).  

 

And, while I've got your attention (assuming anyone read to the end of this overly-long post), here's the fuel pump. Is it normal for it to be mounted with that big block between the pump and the engine? I can't tell from the shop & Haynes manuals as they often shoot it from the other side.

 

5aa6be01a49f2_WP_20180310_19_04_25_Rich1.thumb.jpg.4387ea66f117ad54d85aaa6a8e34e88f.jpg

 

Thanks all!

 

And thanks to everyone in the past: this site has been a fantastic source of information in older threads. It's been fun learning more about 2002 mechanicals.

Edited by robmck
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11 minutes ago, robmck said:

Is it normal for it to be mounted with that big block between the pump and the engine?

 

That insulator block is correct for your engine.

 

If your car won't kick over using a spray of starter fluid down the carb throat, I would focus more on ignition issues, pull a spark plug and ground it on the block to see if you have spark, etc.  Also check to see if you have 12V switched power to the electric choke on your carb, the other connection is the Idle jet shut-off solenoid, if this doesn't have power, it won't run.

 

Mark92131

1970 BMW 1600 (Nevada)

 

 

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1 hour ago, robmck said:

I tried to pour gas in what I thought was the vent port of the Weber, but it all came right out again.

If 38/38 Webers are constructed the same as 32/36s (and I think they are) the float chamber vent is inside the carb throat, towards the front of the car.  Look down the throat and you'll see a small opening divided by a metal ferrule.  On the right side you'll see the two brass air correction jets, and on the left is a dark hole.  That's where you pour/squirt gas into the float chamber to fill it (I use an ear syringe) Try filling the float chamber with gas and see if it'll start.  If it does, you can narrow down the problem to something between the fuel pump (which you've already verified that it will pump gas all the way from the tank) and the carb's float chamber.  

 

If it doesn't start, then do a check to make sure you have spark.

 

If it starts and runs just long enough to use up the gas in the carb (30 sec or so) here's another thing to check. There should be a large brass nut beneath the fuel inlet nipple on your Weber; removing the bolt should reveal a filter screen.  If it's plugged, no gas will get into the carb.  Check it and clean as necessary, then disconnect the fuel line from the output side of the fuel pump and blow through it.  You should hear the sound of rushing air inside the carb.  If you don't, there's still a blockage somewhere.  Could be a stuck float or needle valve inside the carb.

 

One more thing--you said that last fall when you drove the car it started running roughly at lower rpms, but was OK above 4000 or so.  I'd check the two idle jets on that carb; pull 'em out, clean the jets and then squirt carb cleaner down their mounting holes in case there's crud in there.  

 

Let us know whatcha find--and incidentally your detailed explanation of what you've done helps us immeasurably in trying to do long distance diagnosis.

 

cheers, and welcome to the '02 fraternity/sorority

 

mike

Edited by mike

'69 Nevada sunroof-Wolfgang-bought new
'73 Sahara sunroof-Ludwig-since '78
'91 Brillantrot 318is sunroof-Georg Friederich 
Fiat Topolini (Benito & Luigi), Renault 4CVs (Anatole, Lucky Pierre, Brigette) & Kermit, the Bugeye Sprite

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1 hour ago, robmck said:

We're having a hard time diagnosing our 1976 2002's inability to get gas to the engine. I'm wondering if you could help. I'm new to 2002s.

 

Late last year, my fiancée and I purchased the car and it appeared to be in good order. The first few drives were great; we went through about a tank of gas each. Gradually, we noticed the car wasn't happy at 2000-3000 RPMs: the car stuttered and hesitated, while the AFR gauge went full lean. If we could get it over 4000 RPMs, then it was happy and roared. 

 

Bear in mind a misfire will allow the AFRs to swing lean. 

1 hour ago, robmck said:

 

On our last drive of fall, the stuttering was really pronounced. It was hard going driving back home, but we got there. We backed it into the garage and as soon as it was in position, it died. (Very thoughtful of it to get back home). I popped the hood and noticed the inline gas filter was bone dry.

 

I'd think the tank screen was clogged with rust.

 

1 hour ago, robmck said:

 

We've replaced all the fuel lines and a few other diagnostic tests (detailed below), and still can't get it to start (or get much gas into the fuel filter). 

 

Whereabouts is the filter?

 

 

1 hour ago, robmck said:

 

First, some details about the car. It's a 1976 2002 that the previous owner had for over 25yrs. He drove it quite a lot, though it has been driven only rarely in the last 5 years. Here are the updates he made to the car:
 - Weber 38/38 DGES carb
 - New pistons
 - Cam regrind to get more valve lift and longer opening
 - Ported intake manifold & cylinder head to breathe better
 - Air injectors removed from exhaust manifold (improved exhaust flow)
 - Fuel return system disabled (lots of plugged lines; coal filter missing?)
 

Starting at the tank and working forward, here's what we've done:

 

1) Replaced the cloth-covered fuel line between the tank and the plastic tube.

 

2) Noticed that the return fuel line is plugged with a screw, the other end open (see photo below). The previous owner said that the tank is vented to the air, but I can't figure out where this is (threads on this forum say this can be done via the little plastic tube in the filler spout, but I don't see how this works). 

83B45FDB-.thumb.jpg.73e8de893f8e93642de740fb758ce692.jpg

 

Your venting used to look something like this.

 

http://www.realoem.com/bmw/enUS/showparts?id=ST16-USA-03-1973-114-BMW-2002&diagId=16_0386

 

 

1 hour ago, robmck said:

3) Pulled the fuel sender. The filter at the bottom of the sender looked pretty full. 

 

This is the filter after I blew it out with the air compressor. How clear should it look when clean? Where can I source a new one?
WP_20180310_15_08_03_Pro.thumb.jpg.60448ce6583d03cd5422fa450dad3c2c.jpgWP_20180310_15_09_14_Pro.thumb.jpg.8ce6c6a860ad842c6259b867d3d0bec5.jpg

 

That looks clean enough for now I think, if you can see daylight through it. I'm not running that screen anymore, but I'm not suggesting it's a good idea, esp if your tank is flaking.

 

1 hour ago, robmck said:

Based on darrinos's fantastic story (https://www.bmw2002faq.com/forums/topic/143766-not-getting-fuel/), I blew through the sender to make sure there was no fly or other obstruction in the 90 degree bend. It blew through clear.

 

While we're there: here's what the inside of the tank looks like. There are no leaks that we can find; the exterior of the tank looks great. Do we need to refurb or replace it? I've seen some mention in decade-old threads here that it's possible to get a new tank, but I'm not finding one. Any ideas?

 

Tanks come up for sale here frequently. Ascertain if you have rust flaking off. If so, you should red-kote (epoxy) it or replace.

 

 

1 hour ago, robmck said:

 

6) Hooked everything up with new spark plugs. We couldn't find a way to prime the carb - I tried to pour gas in what I thought was the vent port of the Weber, but it all came right out again. We decided to go ahead and crank it, but pretty quickly started getting blow-back through the air filter. It was then that we discovered that the nut on the distributor was loose and thus the distributor free to turn. (I'm now amazed that cable tension kept the timing for so long). 

We reset the static timing using the white/red lines on the driveshaft pulley, and a light connected in series in the points light. 

Cranked again, no more blowback, but after over a minute of cranking, we got nothing in the fuel filter.

 

Advance the timing. Just pour gas down the carb throat to prime. Not too much. Or ether.  Keep fire extinguisher handy. 

 

I wouldn't blame the pump yet.

 

Good luck!

 

 

1 hour ago, robmck said:

 

7) I tried priming the carb using a syringe to squirt ~25ml of gas into the carb via the fuel line. That didn't seem successful (not a lot went in, and the car didn't start). Also tried to fill up the fuel filter, which is just prior to the carb. It filled, then emptied when we cranked, but no start, and it never re-filled.

 

8) On a lark, I disconnected the carb line, connected a clean, dry line to the carb, then tried blowing in it. It seemed completely blocked. Assuming there was no fuel in the bowls, I'd expect to have at least gotten some air through. But then, I was clearly reaching at this point; I've no idea if this should work. 

 

9) I pulled out the filter in the carb (right under the fuel input & return ports). It looked nice and clean.

 

Does anyone have any other ideas?

 

At this point, I'm wondering if it's the fuel pump after all (though, it did work when pumping into a cup, but maybe can't handle any back pressure?), or something wonky in the carb. Before we order a new fuel pump, or pull the top off the carb (we didn't have new top gasket handy).  

 

And, while I've got your attention (assuming anyone read to the end of this overly-long post), here's the fuel pump. Is it normal for it to be mounted with that big block between the pump and the engine? I can't tell from the shop & Haynes manuals as they often shoot it from the other side.

 

5aa6be01a49f2_WP_20180310_19_04_25_Rich1.thumb.jpg.4387ea66f117ad54d85aaa6a8e34e88f.jpg

 

Thanks all!

 

And thanks to everyone in the past: this site has been a fantastic source of information in older threads. It's been fun learning more about 2002 mechanicals.

 

Ray

Stop reading this! Don't you have anything better to do?? :P
Two running things. Two broken things.

 

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That fuel pump has been on there a long time and it looks like the one with the removable cover.  And I think there is a screen in the chamber.  It may be full of flakes too.  Mike S, I am sure you have discussed this type of pump in the past.  Is there a screen in there?

A radiator shop is a good place to take a leak.

 

I have no idea what I'm doing but I know I'm really good at it.

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With a test light or meter check to see if you have voltage at the idle cutoff solenoid with the key in the run position, if so pour a tsp or 2 of gas down the throat of the carb and see if it will fire and run for a few seconds if so then push the choke plate open with your finger (assuming it's closed) and pump the throttle at the firewall a few times while looking down the carb throat do you see a stream of gas from the accelerator pump? if not the carb is probable dry which would indicate the float/needle valve is stuck shut and needs to be put right. 

If everybody in the room is thinking the same thing, then someone is not thinking.

 

George S Patton 

Planning the Normandy Break out 1944

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Contact a radiator shop to see if they refurb tanks. Where I live I took my radiator and heater core and tank to a crusty local place. They had a million radiators lying all over and said “Just leave it there”

 

I left thinking I’d never see them again but yhey all came back beautifully rehab’d for dirt cheap!

 

Randy

1975 - 2366762 Born 7/75

See the whole restoration at:

http://www.rwwbmw2002.shutterfly.com

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39 minutes ago, worzella said:

Contact a radiator shop to see if they refurb tanks. Where I live I took my radiator and heater core and tank to a crusty local place. They had a million radiators lying all over and said “Just leave it there”

 

I left thinking I’d never see them again but yhey all came back beautifully rehab’d for dirt cheap!

 

Randy

I did that, twice. In a span of 20 years on two separate tanks.

 

The second time it was more than dirt cheap, but still worth it.

 

?

Ray

Stop reading this! Don't you have anything better to do?? :P
Two running things. Two broken things.

 

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1 hour ago, jimk said:

And I think there is a screen in the chamber.  It may be full of flakes too.

 

You are correct, Jim.  That is the old, Swan Neck style pump usually seen on side draft cars (works perfectly well on a downdraft)  There is a plastic filter under that domed cover plate....it could be clogged.  

 

That pump is rebuildable with a kit from an air-cooled VW parts supplier.  (use the original return spring, though)

 

Ed

'69 Granada... long, long ago  

'71 Manila..such a great car

'67 Granada 2000CS...way cool

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I'll add my 2 cents.   Back to the basics.  Fuel, spark, timing.   

 

Fuel. Pump works as tested.  as long as there is flow, fuel should get to the carb.  The only backpressure is from the carb itself and the pump can easily handle that.  (Do you smell gas?)   

Spark.  Make sure you are getting spark.  You are getting spark, right?   Right?   Old school. Ground out a spark plug wire against the block and make sure you get an arc there.  Arc?  Good.  No arc?  New list of things to look at.  

Timing.  You said that the distributor had spun around.  This distributor drift could explain the poor performance on your last drive.   However, you would be getting ignition of some kind even of the timing was way off.  (Picture flames coming through the carb like on TV...or odd popping sounds coming through the exhaust because ignition is happening with the exhaust valve open.)    

 

So....  Get a can of starter fluid and spray it into the two chambers on the carb like you are killing a giant spider.  If you are getting spark, you WILL get turnover and at least sputtering.  If you are not getting a spark you will get nothing.  If you get some really unexpected pops, your timing is way off.     

 

All of the other things - clogged screens, crud in tank, etc., are secondary.  The car ran before.  You need to make it run again, even if just for a minute, before you start ripping parts off and rebuilding or refinishing them.   

 

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Current: '74 2002,75 2002, 88 E28 M5(2), 92 E34 M5, 02 E39 M5, 01 E39T M5, 08 E93 328i, 08 E61 535i, 09 E93 335i, 09 E91 328ix, 12 E70 3.5i  '67 Alfa Romeo Spider; '69 Alfa Romeo Spider, '08 Dodge 1500 SLT. Past BMWs: '74 2002tii, '74 2002, '76 E12 530i, '78 E12 528i, '85 E28 535is, '93 E34 528iT, '94 E34 528i, '99 E36 328ic (2) '99 E39 528iT, '03 E46 330i convt., '07 E90 328i

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4 hours ago, jimk said:

Mike S, I am sure you have discussed this type of pump in the past.  Is there a screen in there?

Yep, there's a filter screen inside not only the dismantleable fuel pump, but also the one that's crimped together, the latter accessible after removing the sheet metal top.  But Rob indicated in his original post that when he cranked the engine with the outlet fuel pump hose poked into a catch can, it pumped fuel just fine, meaning that filter shouldn't be clogged (but it's still worth a look just to make sure).

 

mike

'69 Nevada sunroof-Wolfgang-bought new
'73 Sahara sunroof-Ludwig-since '78
'91 Brillantrot 318is sunroof-Georg Friederich 
Fiat Topolini (Benito & Luigi), Renault 4CVs (Anatole, Lucky Pierre, Brigette) & Kermit, the Bugeye Sprite

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I would try taking the gas cap off.  If the venting is not working properly the pump will not be able pull against a un-vented tank
A previous owner plugged the line from the evaporator tank in the engine bay. After a short drive there was so much negative pressure in the gas tank, I couldn't get the gas cap off (electric fuel pump in trunk was pretty efficient) I took the plug out of this line in the engine bay and found a fitting for it on the air filter housing. That immediately equalized the gas tank pressure.



Sent from my STH100-1 using Tapatalk

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Common things happen commonly. Remove the fuel line from the output of the fuel pump, use a small funnel and gravity feed the carburetor with gasoline. If the car subsequently starts then you either have a clogged fuel line , cloth filter or a bad fuel pump. If the car starts with gas in the carburetor, you can hook a second line to the fuel pump outlet and run it into a can. Then start the motor and while the motor is running see if there is fuel pump output. I think it maybe time for a fuel pump rebuild given the symptoms you have described.

Best regards, Peter

The First thing is to have an untroubled mind. The Second thing is to know your purpose. Illigitimati Non Carborundum

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It's alive!

 

 

Thanks Mike for the tips on finding the bowl vent. We were able to use the syringe to fill up the bowl. 

 

 

Thanks to everyone (Hodgepodge, Mike, Ray, others) on reminding us to get back to basics and look at the ignition. Having not done static timing on the car before, and the Haynes picture is really blown out, and the BMW shop manual doesn't seem to show it, we had a hard time sorting out where to time it. The ball on the flywheel is hard to notice unless you're already there. The pulley had two sets of lines painted on it (previous owner), but we were not sure what they corresponded to. We did find the notches cut in the side of the pulley, they didn't seem right.

 

I gave up and pulled the valve cover off and watched the camshaft to find #1 TDC. Turns out one of the pulley lines (but not the one we used previously to time it) was TDC, when lined up with the little pointer above the pulley. Turns out the other line is the advance timing (but not quite as advanced as the ball on the flywheel, which came up just after the line). I also realized that last time I had set the timing, I hadn't popped the distributor cap off to see where the rotor was pointing so I could make sure I was setting the distributor for cylinder 1, so it was nicely timed for cylinder 2. 

 

So: Timing sorted, it started right up as quickly as if we had just driven it that morning, and sounded impatient to get on the road again. Looking at the fuel filter, we could see the pump working nicely. We quickly dumped the tools in the back seat, just in case, and headed out for a short test drive. It ran well; a bit better than on our last drive. It does still show full lean at cruise (50mph, 3000rpm, 4th gear; traffic wouldn't let us go faster). If we tried to jump on the gas to accelerate, it would stutter heavily. You either needed to put your foot in it or downshift, then it was happy. 

 

Still haven't checked the idle jets per Mike's suggestion. I've not done that before: do you have to recalibrate anything when you reinstall them, or do you just take 'em out, clean 'em, and shove 'em back in?  It may also need some more refined timing - I tried using the timing gun, but it wasn't bright enough to see down the hole, let alone show the ball. Will have to try at night sometime. 

 

I'm still not sure I believe the AFR meter yet (it's a cheesy 80s LED based thing). Unfortunately, the water temp gauge is reading really low, so I don't know what it's running at. If we're running lean a lot, I worry about overheating - though we have the safety net of a bigger 320 radiator. Will try cleaning up the contacts on the sensor.

 

 

Thanks, Ray for the link describing the venting. This explains the grey box mounted in the trunk (Expansion tank). Also, you asked about the location of the fuel filter: it's just floating inline between fuel pump and carb. It's not one of those that is mounted to the side of the engine compartment. 

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