Fuel Delivery Issues

[bash555]

Anybody ever experience fuel delivery issues?

Here's what's happening:

Go around hard turns, begins to stutter/cough a bit.
Last night, coming back from airport, while driving on the highway at about 70, it begins to sputter and cough while driving straight. As I begin to look for an offramp, it really starts losing power. I get it off the highway and into a gas station as it dies. My gas needle has never been all that reliable so I decide to see how much gas she will take.
4 gallons and it's full. dam, not empty.
But, it starts right back up like nothing is wrong and drives another 60+miles w/o a hitch.
Drove fine this morning.

Sooo,

1) is there a fuel screen in the tank?

2) the fuel pump was supposedly replaced about 3 weeks ago, but I don't think they replaced the after filter. (dumb****s, dont trust any service shop)

Any other ideas or reccomendations guys?


Oh yeah, here's another weird trick since it came back from the shop; when I press on the brake pedal, my tach, gas gauge and brake lights all go out; but my gen light comes on.

Thanks again for the support!

Dave B.

[robphelan]

Dave.. well i think i can help with the brake pedal issue... replace #8 fuse (i think - or possibly#9, can't remember) and it should do the trick...

I had this same problem a couple of weeks ago and someone from this BB told me about it. Your fuse might look good but change it anyway. Mine looked fine.

As soon as I changed it, my tach worked like a charm.

[Dave at Pelican Parts]

For the sputtering, try wiggling every wire in the engine bay. And the wires that go to the pump. A similar intermittent problem in my car turned out to be a bad wire.

--DD

[bash555]

well, I have yet to work on the car, but I did notice a definable characteristic.

When I turn hard left, it sputters bad.

When I turn hard right like an onramp sweeper to get on the highway, no problems at all.

Sputters occasionally when driving straight.

I guess I need to find a track that lets me race roundy round the wrong way!

dave

[scg]

Wouldn't hard left put more fuel around the pickups??? Being "directionally challenged", I could be mistaken....

I'd look for loose wires, as Dave mentions

[nyum96]

On the fuel issue, Same problem here. Did the gas station thing, no luck on being out of gas. My problem was a clogged fuel screen at the bottom of the tank. It was clogged and collapsed. Rust in the tank? My pump was also going because the PO never installed a fuel filter. If your problem is not related to the clogged fuel screen, "de-rust" your tank anyways. One less problem to worry about.

[bash555]

ok, this may be long...

so, I went ahead to start the process of pumping whats left of the gas in my tank.
I put a long fuel line on the feed line inside the engine bay and hotwired the fuel pump.
I didn't have far to go, the tank was only 1/4 full.

Anyways, I shined my flashlight down into the gas tank to look around. The thing looks factory fresh, clean as a whistle.

It was the end of the day, so I said f*** it and put my gas back in. Besides, I don't have a new fuel sock for the tank yet.
Coming to the point here, after re-assembling my feed fuel line int the engine bay; and after firing it up to check for leaks; I now see air bubbles in the return side headed back to the fuel pump.

Shouldn't those go away? All I did was rev it in the driveway and they are still there.

It's a '71 1.7Litre

So, at this point; I believe this is what I am going to do.

1) Replace fuel sock.
What is Pelican Parts Part #; can't find in online catalog.

2) Replace all injector seals.

3) Replace Throttle Switch (Car has 160+ on it, it has to be gone by now)

4) Replace Fuel Pressure Regualtor. (I really suspect this part.)

5) I have the worst idle, but PP has no AAR's. I guess I will rebuild mine per brad.

6) Replace Intake Manifold Hoses - PP does not stock these either. Can I use the 2.0L ones?

7) ReplaceThrottle Body gasket - again, PP does not stock, what am I supposed to do here?

8) ah, i forgot wwhat i was gonna put here, i was busy placing an order.

anyways, cheers to all

nighty night

[Ron Meier]

#1 - It's a VW part - numbers were listed in another thread
#2 - Cheap
#3 - Not Cheap - pull cover off and look at tracks and contacts - believe there is an article on it.
#4 - Usually very reliable - check with guage first
#5 - Only used on cold startup for extra air - plug hoses off at plenum - It's supposed to be closed when engine warm.
#6 - Believe 2.0 is larger diameter than 1.7/1.8s - they're around - Also VW part.
#7 - Form a Gasket or Silicone
#8 - Can't offer help here.

Fuel lines do not return to pump - pressure relief port and the injector return line are teed to the return line to the tank. Air bubbles could be coming from a loose connection on the suction side of the pump (between tank and pump) - after that it is pressure to the regulator - the return is under zero pressure.

[pbanders]

If you have 160K on it and do not know when/if the trigger contact points were replaced, then I'd replace them, too.

[Dave at Pelican Parts]

The 1.7 "injector boots" (the large vacuum hoses) are NLA. If you use 2.0 ones, you will have to clamp them pretty strongly to keep them from leaking. You can try radiator hose (heat it in a cup of water in the microwave to soften it) and clamping them. Or some other solution...

--DD

[bash555]

Thanks guys;

Dave-
ok, will do on the clamping thing. Why doesn't the on-line catalog suggest this?

Brad-
Thanks, Yes, I just repalced them to get home from LA to Napa.
btw, do you know the rpm limit were they start floating?
just curious

Ron-
Thanks for the help; but what happened on #8.
#5, cool, that will help be diagnose for now.

Thanks again guys, will let everyone know what happpens.

Dave

[Dave at Pelican Parts]

The 1.7 manifold boot thing is pretty recent--more so than the last major catalog update.

--DD

[Ron Meier]

#8 - You forgot what you were gonna put - I didn't

[bash555]

Well,

Thanks Ron on #8; I just thought you might be telepathic; o well.

OK,
I replaced,

1) Throttle Position Sensor - I believe thsi was the culprit of the bucking; but it still doesn't explain why it fixed the fuel cut while turning left was fixed.

2) Fuel Pressure Regulator - Measured my previous one; it was set at 35psi.
Now then, everyone says it needs to be at 29.5 per the manual.
So I set the new one at 29.5; and my timing at 28 full advance at 3500.
Guess what, it ran like ****; stumbling all over the place.
So, I set the FPR back up to 34lbs and set the timing by feel with the air bypass screw at about 1.5 turns; and guess what ; it runs like a champ; better than when I bought it 3 years ago.

Now, I still need to replace the left side manifold gasket and left side manifold to plenum hose where I have slight vacum leaks.
I also have a slight one at the throttle body.

I say slight because it takes a fair amount of time between when I spray the starting fluid at the offending leak and when the idle picks up.
Yes, I do this while having a fully charged fire exstinguisher nearby.

3) I have new fuel sock; but have not replaced due to me waiting to see if new TPS would fix problem.

4) The AAR is working mostly and I plumbed new hose in with SS clamps.

5) Still need to check fuse # 8 per robphelan


Curious question for all of you:

Anybody running the Pertonix?
Anybody running aftermarket coils? Which ones?


Thanks again to all of yer support;

Cheers!

David B.


yes, i too believe my yellow rusty car is faster!!

[Ron Meier]

I have run Pertronix, Permatune and Allison. I prefer the Allison Optical over the others but it is twice as expensive. All eliminate the flippin' dwell adjustment.

On my 2.5 Stroker, I'm gonna run the Compufire DIS system - distributor is nothing but the trigger for individual coils. Yeh it was double the Allison price - Oh well.

[jkeyzer]

For the intake runner hoses, go to NAPA and get a foot or so of straight 1 3/8" radiator hose. It worked for me.

[bash555]

Hey Ron,

Do you know for sure if the Compufire DIS will work on the stock distributor??
If so, I may just step up, I like their products.


So far, I ahve not been able to get their points replacement to work on the stock distrib..
To start, you have to shorten the rotor length so there is room for the magnetic wheel to fit.
But then, the Hall Cell module is to far away from the wheel to get a signal.
When I have time again, I may try shimming it up a hair.

Thanks jkeyser, that was my next choice; will do.

Anybody else have their favorite ignition setup??

[Ron Meier]

Compufire says no. A local VW Speed Shop said they woudl should me how to install the guts out of the 009 that comes with it in a stock dizzy. I was gonna use it with carbs, so the stock dizzy wasn't necessary. It might be overkill on an FI engine.

Their points replacement should be a drop in, but....,

All in all, I would go with the Allison/Crane Optical - easy.

[SGB]

After reading about distributors (stock, 009, and 050), and ignition switching options (points, pertronix, allison, and crane) and I'm still not sure about the advantages or disadvantages of the various combinations. I paid very few beans for a pertronix from JC Whitney many years ago and put it in a Bosche 009. It worked great I thought. Eventually, the shaft started to wobble, so I replaced with an 050 that a friend with a Combi Bus gave me. I couldnt get the magnet off the 009 shaft, but a whole pertronix unit was still cheap at JCW, so I got another to put in the 050. That has worked without incident since about 1994. What adavantages beyond points replacement do the others serve? What are the advantages of the others? Are they worth the $ ? Why? Iwas following an Allison system that included a dizzy on evil-bay for a while, but decided that an 050 was good and shouldnt be replaced with one that I associated more with drag racers and muscle cars.

[bash555]

Well, from a geometry point of view, there is more crank resolution with the compufire unit than the pertronix unit.

Basically, with the magnets the furthest from the shaft will give a more ignition angle; but it will also magnify any wobble and play there might be in the distributor shaft.

Also, with a more correct dwell; there is more time to charge the coil.

Also, I would rather have a least a Bosch Blue coil if not more.

I noticed a big jump once I put in a Jacobs Energy coil; but I am also running a bit rich at 33psi at the rail.