72T No Start w/Some Newbie Questions

[ntrylvl]

I recently purchased a 72T Targa that has been converted to PMO carbs.

Last weekend, the car was running fine, although I noticed that there is a leak at the heat exchanger to muffler flange on the passenger's side.

I have started, but not driven, the car every couple of days since last Saturday, which was the last time I drove it. I tried to start it up last night, and it was popping like a popcorn machine and simply would not hold idle. At best, it would run for about 30 seconds, then die. So I packed it in for the night.

This morning, I tried to start the car again, and the starter turns over but nothing happens at all.

I am definitely new to these cars, and I'm carefully observing my way through the engine compartment. I noticed some wires that are not attached to anything (pictures below). I assume these are related to the former FI setup and truly don't have a home, but I'm not familiar enough to know if they could be related to my problem. I'm sure many of you can take a look and tell me yay or nay without much thought.




So, I would appreciate any thoughts on the wires, and I would also like to know where to begin in my quest to get the car started again.

BTW, I currently have the front turn signal lens housings (both) and the passenger's side taillight housing removed for refinishing. I cannot imagine these have something to do with the starting issue, but electrical stuff is my weak point, and I guess there is a slim chance that some sort of ground issue is contributing to the problem? Please tell me this is not true....

Thanks for the help!

[Flieger]

Those look to be the wires for the MFI pump's fuel shut-off solenoid. If not, they go to the throttle arm microswitch to activate that solenoid.

I am not good with carbs, I have MFI. As I understand, though, carbs need an experienced technician to choose proper jets and such. It needs a fine touch to get right throughout the RPM range and correct for air density, etc.

[signature65]

if it was running fine before and you have done NOTHING other than started it up here and there, then its fuel.....prob some bad gas or sediment. Drain the tank clean the screen, replace the fuel filter and put fresh gas in.

And yes those look like MFI wires which you do not need.

[ntrylvl]

Bump for some additional thoughts...?

I'm thinking fuel problem as well at this point. It doesn't even really smell like gas at all in the engine compartment after all of the cranking.....

Heading out to try again in a bit. Thanks for the help....

[berettafan]

do you have a fuel pressure gauge in the back?

can you hear the fuel pump when you turn the key on?

[dtw]

Have you checked the plugs? Wonder if you haven't fouled them out from all the starting/idling and not driving.

Those wires are for MFI bits and shouldn't be part of the problem.

[Christien]

When you say it was running fine last weekend, was it completely normal, driveable, etc? Or do you mean just holding an idle? What's the recent history on the car? Is the gas very old? (i.e. several months) Has it been sitting a lot? Have you (or anyone else) played with any of the screws on the carburetor? The symptoms you describe could be many things, one of which is carburetors way out of tune. When I rebuilt my carbs a few years ago, I set the adjustment screws to the baseline and tried to start the car, and it did more or less what you're describing. After some tuning, it ran fine.

[ntrylvl]

Originally Posted by berettafan

do you have a fuel pressure gauge in the back?

can you hear the fuel pump when you turn the key on?

I do have a fuel pressure gauge--the one that came with the PMOs. It's not registering anything when the ignition is turned over. I also have a "clear" style fuel filter before the pressure gauge/regulator, and I can't see ANYTHING happening there. I do hear the fuel pump buzz, but I can't tell if it's doing anything, and it certainly doesn't appear so....

[ntrylvl]

Originally Posted by Christien

When you say it was running fine last weekend, was it completely normal, driveable, etc? Or do you mean just holding an idle? What's the recent history on the car? Is the gas very old? (i.e. several months) Has it been sitting a lot? Have you (or anyone else) played with any of the screws on the carburetor? The symptoms you describe could be many things, one of which is carburetors way out of tune. When I rebuilt my carbs a few years ago, I set the adjustment screws to the baseline and tried to start the car, and it did more or less what you're describing. After some tuning, it ran fine.

Yes-completely normal and driveable. It actually made a 400+ mile trip from Los Angeles to the SF Bay Area.

The car has recently had work done on the fuel system, including cleaning and resealing the fuel tank. The gas is brand new, and the car has only sat with that tank of gas for a week. Nobody has touched the carbs, that I know of. In fact, I haven't touched ANYTHING in the engine compartment yet.

Thanks!

[berettafan]

i too have those darned clear fuel filters. a local weber guru looked at them and gave me the part number for a vw fuel filter that, per him, actually does something other than present a fire hazard.

anyways if you see no fuel pressure on the gauge then you're problem is most definitely fuel supply. the next question is at what point.

possibilities include:
tank screen (drain, remove and clean also checking interior of tank for rust/deposits)
fuel pump not doing its job (could be gummed up inside...still makes some noise but no real pressure)
clogged filter in engine bay
collapsed line somewhere
fuel pump pulling instead of pushing
etc etc etc.

[berettafan]

also be very careful of running the fuel pump with no fuel going through it. i believe this is not good for many styles. a kinked line at the tank could be causing this.

the proper test here, as i recall, is to remove the lines from the carbs, put them in a bucket or bottle and turn on the fuel pump. you are looking for a specific flow rate over time (have to look that up as i don't recall).

[signature65]

Ok this is a simple one.....are you SURE you have fuel in the tank. Your fuel gauge may be incorrectly registering.

[ntrylvl]

Yes, I have fuel in the tank. I just filled it up the last time I drove the car (a week ago).

The fuel pump comes on when I turn the key, but it certainly doesn't seem like it's doing anything. I replaced the fuel filter, just to make sure that it wasn't clogged because of residual sediment from when my tank was pulled/cleaned, and when I tried to turn it over again, nothing happened...not even any fuel moving into the fuel filter.

[ntrylvl]

Originally Posted by berettafan

i too have those darned clear fuel filters. a local weber guru looked at them and gave me the part number for a vw fuel filter that, per him, actually does something other than present a fire hazard.

anyways if you see no fuel pressure on the gauge then you're problem is most definitely fuel supply. the next question is at what point.

possibilities include:
tank screen (drain, remove and clean also checking interior of tank for rust/deposits)
fuel pump not doing its job (could be gummed up inside...still makes some noise but no real pressure)
clogged filter in engine bay
collapsed line somewhere
fuel pump pulling instead of pushing
etc etc etc.

I will probably replace with a better fuel filter, but I know this isn't the source of my problem.

Fuel supply = definitely the problem. It's not the tank screen or clogged filter in the engine bay. I think the fuel pump isn't working correctly, although I suppose there could be a collapsed line somewhere. I hear you on the "pulling versus pushing" factor; I will consider moving the fuel pump to the front of the car....

Thanks.

[Christien]

Originally Posted by ntrylvl

I do have a fuel pressure gauge--the one that came with the PMOs. It's not registering anything when the ignition is turned over. I also have a "clear" style fuel filter before the pressure gauge/regulator, and I can't see ANYTHING happening there. I do hear the fuel pump buzz, but I can't tell if it's doing anything, and it certainly doesn't appear so....

No pressure on the gauge and nothing happening in the filter window tells me you've got a blocked line or a dead pump somewhere. I would pull a hose off the carbs, put it in a container and run the pump for just a few seconds to make sure you're getting ANY gas at all coming through.

I've got a filter in the lines in the engine bay, and you can clearly see gas moving through there when the car's running.

[berettafan]

if you move the pump be aware that the tunnel exit line and the hard line that passes into the engine compartment may be different diameters (mine are) and without the pump in line you will need to deal with this size difference.

[dtw]

Have you pulled a plug yet.

[ntrylvl]

Thanks, everyone, for your help.

It turned out to be the fuel pump. It was making noise, but not pumping anything. I think it must have gotten clogged up with all of the sediment that was in the system BEFORE my fuel tank was pulled, cleaned, then re-installed. We did NOT change the fuel pump AFTER the fuel tank was replaced.

I was having trouble diagnosing because the pump seemed to be turning on, so I took the car to my mechanic today, and we replaced the fuel pump with a Facet pump that I had bought from the local Kragen.