87 cabby stalled out today

[mbailey]

Well I did some work on my new ride today. been having idling issues so after digging around on here & in the Bentley manual I replaced all the old rotten vac. lines & pulled the idle bypass screw out and found the O-ring almost turned to dust replaced that. she seemed to be doing great so seeing as I had to take my son to a back to school function we pulled the top down and took off. while waiting in parking lot traffic I noticed a strange whine that sounded as if it were coming from beneath the car. she sputtered a few times and then died. I turned the key off & then tried to start her again to no avail. tried again & she started right up. found a parking spot and went inside after about an hour we come back & she starts right up and seem to do fine all the way home. any ideas I'm thinking fuel pump but which one from my understanding these cars have 2. any advice will be appreciated

[Briano1234]

a whine form the rear is due to the in-tank pump being bad, causing the main pump to over work.....
The fact that it shut down may mean that it to is bad.

Change the in-tank first and run about half a bottle of marvel Mystery Oil in the tank....



OPPSSSS almost forgot... buy a fuel pump relay and keep in your glove box

[kamzcab86]

I concur: in-tank fuel pump. But, my advice is always preventitive maintenance: If you don't do it now, you'll be doing it later, so replace the external main pump too... if you can.

[gull]

+1 on the in-tank pump. I had the same problem with my car and replacing the in-tank pump fixed it.

[mbailey]

I replaced the in tank pump & so far so good. she still don't want to idle when first started any ideas what to check first?

[gull]

I replaced the in tank pump & so far so good. she still don't want to idle when first started any ideas what to check first?

Assuming you've checked the normal tune-up stuff (spark plugs, distributor cap & rotor)...

Often this means the base mixture is incorrect for some reason. For the first few minutes the FI system is using only the "best guess" provided by the base mixture settings. After a few minutes, the O2 sensor warms up and provides feedback for adjusting the mixture dynamically.

So, I would start by looking for vacuum leaks -- rotted vacuum hoses, bad injector seals, cracks in the accordion boots between the airflow meter and the throttle body. Any of these will provide "false air" and make the system run lean.

While you have the intake tract taken apart, clean the throttle body and the AFM, and make sure the AFM plate is centered.

If that doesn't fix it, I would check the fuel system pressures. This will let you know if you have a bad control pressure regulator (aka. "warm-up regulator") or a weak main fuel pump.

If those are within specs, I would then adjust the mixture screw in the AFM, using the O2 sensor reading on a dwell meter as a guide. I've listed this as the last step because everything else needs to be right before you adjust the mixture. If, for example, you have a bad CPR, adjusting the base mixture will just move the problem around, making the car run better under some conditions and worse under others. Trying for a quick fix by adjusting things without making sure everything else is right first is a recipe for frustration.

This is essentially the sequence I followed on my car. As I went through fixing stuff that wasn't quite right, it gradually went from stalling constantly until it warmed up to idling nicely at any temperature. No one thing made a dramatic difference; it was an assortment of small problems that added up to one big symptom.

[kamzcab86]

It's also possible that the thermo-time switch is faulty, the aux. air regulator is faulty, the cold-start valve is leaking, clogged fuel filter, and/or there's insufficient fuel pressure (when the in-tank pump is making itself known to you that it's on it last legs, the main pump has already been spending time over-working itself and, therefore, is on its way out as well; if the in-tank pump was replaced by itself, check the fuel pressure at the injectors).

When you replaced the idle screw O-ring, did you just screw it back in and call it good, or did you then fine-tune the air-fuel mixure? The two go hand-in-hand; messing with the idle screw alone messes up the air-fuel mixture. http://www.cabby-info.com/cis has step-by-step procedures, including a handy testing chart (well, I found it handy; but there again, that's why I made it ). So, as was said above, make sure everything is functioning correctly; if all parts are found to be good, hook up your dwell or duty cycle meter and start checking the duty cycle and make adjustments as need be.

[mbailey]

Well guess what I was out driving today and the whine returned along with a few hiccups & stalls. made me really nervous as I was about 40 miles from home but we made it. went to searching for a main pump locally and found one at a Zone a couple of towns away plan on installing it in the morning. I sure hope this solves my problem! any install tips or tricks I should know?

[Briano1234]

Well guess what I was out driving today and the whine returned along with a few hiccups & stalls. made me really nervous as I was about 40 miles from home but we made it. went to searching for a main pump locally and found one at a Zone a couple of towns away plan on installing it in the morning. I sure hope this solves my problem! any install tips or tricks I should know?

Open the gas cap to vent the tank..... then no smoking Also if you are using a drop light keep it well away from where gas can spit to it.

My Brother has a friend that just lost a 60 corvette that he was restoring because gas spit at a trouble light...

[gull]

It's also a good idea to pull the fuel pump relay, then crank the engine a few times to help relieve pressure in the fuel system. There'll still be some residual pressure, so be careful. You might want to wrap a rag around the union where the line connects to the pump when you loosen it. Otherwise that little spray of gas tends to aim right for your eyes.

[kamzcab86]

Well guess what I was out driving today and the whine returned along with a few hiccups & stalls. made me really nervous as I was about 40 miles from home but we made it. went to searching for a main pump locally and found one at a Zone a couple of towns away plan on installing it in the morning. I sure hope this solves my problem! any install tips or tricks I should know?

A great step-by-step replacement how-to: http://forums.vwvortex.com/zerothread?id=3961934 .

[mbailey]

well the deed is done so far so good. I'm still having trouble with idle after start. Starts right off idles rough & tries to stall if press the gas pedal. Once we get to moving she does ok pending I don't get the fuel pump symptoms back. So far I've replaced the plugs, both fuel pumps, all Vacuum lines, Air filter & Idle screw screw O-ring but she still feels kinda sluggish to me. next pay check I plan on changing the fuel filter, Dist. cap & rotor,Oxy sensor & checking the timing. I,m posting Pics check'em out Thanks for all the Advice, Especially you Briano & any more Ya'll can Give I appreciate it.