86BirdSE

I've got a bad suspicion that I've got a dying fuel pump. It bogs out and pings like crazy, and won't go above about 3000 RPM under load...

BUT

NAPA says there's 2 fuel pumps? Doing some quick research, a chevy k10 4x4 350, auto tranny fuel pump looks like the one my LG4, but costs more. Is it a fix should my in-tank( if it exists?) pump be shot causing the commotion under the hood when the secondaries open?

Or could this be an ignition coil issue?

Only Mods are Dynomax exhaust and Chevy Tk Air cleaner lid with taller air filter and Bosch Plat. 2 sparkplugs on Accel Spiral Wires, new cap and rotor w/brass inserts.

Auggie

Start with the basics. Check the fuel filter first.

Auggie

86BirdSE

I replaced it this morning. Timing checks ok, vacuum is a rock solid 20 inches at idle. The carb is clean inside, and all linkages are free and not sticking.

New Air Filter, new PCV valve, new Fuel filter are all installed. All vacuum hoses are connected and the EGR seems to be in working order.

The only thing I have not tested is the pump pressure because I do not have a large enough fitting on my vac/pressure gauge.

Auggie

Well, I would lock out the sec. air valves and run on the pri's only. I used a real heavy spring. There are some sec. fuel pick up tube problems and this is a quick and dirty way to check that out. If it run's good on the pri's only I have some ideas.

Auggie

86BirdSE

I'll have to give that a try... though it bogs off throttle at times. Any more ideas?

Auggie

Not right now, but that worked for me so give it a try and let me know the results.

Auggie

five7kid

iTrader: (14)

Ignition.

Most "carb" problems are actually ignition. Since you say it "won't go above about 3000 RPM under load", that sounds more like spark blowing out than any fuel-related problem.

As for two fuel pumps, in '87 the factory used an in-tank electric as well as an on-engine mechanical to address vapor lock problems. If a customer complained about vapor lock to the dealer, a kit was available to retrofit the electric to earlier model years. Only if yours had that kit installed would it have two fuel pumps.

86BirdSE

The little work I did on running with just the primaries proved decent, but still not "right" The car surges at part-throttle and only goes to about 3500 RPM on primaries only.

I'm going to try to tackle the spark issue tonight. The cap/rotor/plugs and wires are new (under 5,000 miles). OE module and coil still remain. I'll try a different OE coil I have that I know works, then I'll try an ignition module that I have no idea works or not if the coil doesn't solve it.

86BirdSE

I engineered a fitting to work with the fuel pressure gauge I have. It was a bouncy 6 lbs, and went immediately to zero when I stopped cranking the engine.

I installed a pump form a chevy truck, and have yet to try it because while I was under the car, I found my radiator is shot. So once I find a good radiator, new hoses and fluch the block and heater core, I'lll give it a shot again.

It's always something...

Auggie

Well, you know what they say "Work in Progress". Anyhow if you happen to remenber let us know what you find.

Auggie

86BirdSE

As usual five7kid was right. The fuel pump fixed the idle problem, but it still hits the wall at 3500 RPM.

Timing advance total is only aprox. 5 degrees, with as close to zero as I can get at idle. It's gotten so bad that when it goes into closed loop, it barely accelerates.

I'm at a loss as to how the ECM controls timing. All electrical connections are ok, and I have no trouble codes.... Bad ECM? My scan tool shows steady readings of the MAP sensors, TPS and a good cycle on the 02 sensor.

The only red flags I saw were the 4th gear switch was on in Park, and my ac clutch was constantly on, thugh there is no a/c request.

I think I'm just going back to my parts bin and putting my ol truck carb and vacuum advance distributor on this thing.... if the 350 didn't need a rebuild, I'd through the whole setup in it tommrrow...

Any ideas?

86BirdSE

The car simply isn't drivable anymore. The cheapest reman ecm is from Auto Zone at 79.99, and it's 5 days away...

That said, I can rebuild a 17059216 Carter made Q-Jet I have laying around with a 1112880 vacuum advance distributor for about half that ($40), plus my time to install it and have greater flexibility when it comes to tuning. I will also be eliminating some of the electrical strain as well, and have more voltage at idle.

It seems like the carb has all of the same vacuum ports as the CCC Q-Jet.

We shall see how the results come out in a few hours!!

86BirdSE

it's not right. I took everythign apart to get to the timing chain, and guess what we had...

A cracked tooth on the nylon gear and a liitle over 1/16" of chain stretch compared to a new OEM chain. It looks like the crank gear may have skipped a tooth, as it is worn pretty badly. live and learn I guess.

five7kid

iTrader: (14)

Just out of curiousity, were you disconnecting the ECM wiring from the distributor before checking the timing?

The timing chain/gears situation doesn't sound deadly, even though it isn't ideal. Chains rarely skip a tooth.

86BirdSE

yes the ECM was disconnected.

The new chain and gear are a ton tighter that the old one was, except, I'm in the process of dropping the oil pan to get the timing cover back on. It's a drop the starter, drop the Tranny dust cover and I think drop the y-pipe job.

I'm hoping to have it back together for about 3 a.m. est tonight. It's my daily driver and I gotta have it done.

86BirdSE

Anyone who thinks that the CCC carb is a piece of junk is horridly wrong.

Case in point. I swapped in a Smograjet and a standard vac. Advance distributor in place of my CCC Quad, and I'm not happy with it.

I averaged 11 MPG on the last tank (previous to my "timing" issue I was getting upwards of 19 MPG) and I can't adjust idle mixture because they're sealed off. I think the float in the carb is shot because there seems to be an over abundance of gas-smell in my exhaust. Tommrrow I will do what it takes to reinstall my CCC components.

It turns out my "advance issue" was a plugged catalytic convertor. For the time being and newly passed Smog laws in PA, I gutted the cat until I get the coin for a dynomax direct-fit unit. PA now is requiring a visual inspection for emmissions equipment.

For anyone who seems to have a fuel-pump, timing or other issue, check the cat first (especially if it's your original unit), then ignition and so forth.