diagnosis help: turns over, no start

BrokeMyCar · 01-10-2011, 05:03 PM

Hi folks,

My daily driver 200k 83 SC wouldn't start this morning. The battery was low so I hooked it up to my portable jumpstarter and it turns over quickly and keeps going while the ignition key is pushed, but doesn't start up. It doesn't smell like gas during this time. I tried several times, and swapped out the red fuel-pump relay for a new one, but gave up to do the day's work (it is VERY busy these days).

Any advice for quick and dirty diagnosis?

It's got to be spark, fuel, or compression. My first guess is fuel, as I heard a strange whirr-winding down sound id last week I turning off the car. I have metal-wire fuel lines - is there a way to test to see if fuel is going through them? Or a voltage test on the fuel pump?

For spark I was thinking of pulling a spark plug cable, putting in a new spark plug and turning it over to see if I see a spark.

For compression testing I was going to rotate the pulley on the back of the engine and see if it goes through the same hard/easy-to-rotate pattern that I remember from before.

Any help appreciated! Thanks in advance-

Babak

PS I should add that I've been having electrical issues with the rear brake lights, I suspect because the bulbs intermittently sit in their sockets. The reverse lights also don't work, I have yet to get under the car to check the switch at the transmission.

Flat6pac · 01-10-2011, 06:19 PM

Jump wire the fuel pump relay between post 30 and 87A. This makes the pump run, lift the air flow sensor under the air filter for a few seconds. If the pump is flowing you will feel the resistance in the air flow sensor and hear it charge the system to start. See if it starts.

Bruce

BrokeMyCar · 01-10-2011, 06:28 PM

Thanks Bruce - should the ignition be in ACC during this test?

boyt911sc · boyt911sc's Garage

Quote:

Originally Posted by BrokeMyCar

Thanks Bruce - should the ignition be in ACC during this test?

Babak,

Set the ignition switch @ RUN/ON position (not start). Follow Bruce's instruction. But before you do that, make sure you have ignition sparks otherwise, all your effort would be futile without the presence of sparks (ignition). Are you sure your battery is fully charged? Keep us posted.

Tony

BrokeMyCar · 01-11-2011, 10:18 PM

Thanks for the tips all - I have to travel until Monday but I'll do the following when I return:

1) Either charge the battery with my Powerpack 450 or put in a fresh battery
2) Look for spark
3) Set ignition to run, jump posts 30/87A at the fuel pumprelay, push up air-flow sensor and listen for the fuel pump.

I must admit I'm kinda hoping it's the fuel pump so I can also fix the fuel sending gauge while I'm working around that area.

Thanks all, I'll let you know how it goes -

Babak

Topgun63 · Topgun63's Garage

Not to be a smarta**, but last time this happened to me, I was out of gas. I chased a ghost for 3 days..just a thought.

Alan Lindquist · 01-13-2011, 10:10 PM

On my 1980 SC, I had occasional starting problems same as yours. Would crank, but not fire. Problem got worse. One day, I just wouldn't start. It was the CD box. It got bad over time. These engines need A LOT of juice. If your CD box (Ignition amp) isn't healthy, you'll crank, but not run. Could be something else, but this is worth checking. My mechanic identified the problem in 15 minutes by putting a "known" good CD box in and firing the engine instantly. You have a choice of converting to MSD, PermaTune, or going with the stock unit or a rebuilt unit. All have a different cost and each does "about" the same thing depending on what you expect from your motor.

dfk911sc · 01-14-2011, 06:51 AM

Babak,

if you do "upgrade" the CD box...stay away from permatune, the original Bosch or MSD is the way to go...1st hand experience.

T77911S · 01-14-2011, 08:08 AM

Quote:

Originally Posted by Topgun63

Not to be a smarta**, but last time this happened to me, I was out of gas. I chased a ghost for 3 days..just a thought.

glad i am not te only one that spent 3 days chasing an empty tank.

G450X · G450X's Garage

and it's an easy check (stock '82 3.0 with CIS). Check the airbox for a stuck open and/or blown off pop off valve - if your '83 has one (seems like they all do).

I had a slight back fire after a bunch of work last winter (SSI's, M&K, valve adjust, new plug wires, etc..) and then it would not hit a lick. I knew I had a pop-off valve so I didn't think it could be that. The slight back fire I had blew the entire pop-off valve out of its hole. I guess the old epoxy was brittle and gave way. I sanded the old stuff off and re-epoxied it, and she fired right up - and has run great since.

BrokeMyCar · 01-22-2011, 12:34 PM

Thanks all! I returned from my business trip and spent some time in the garage this morning.

1) With the fuel pump relay jumpered, the pump whirrs as soon as the ignition is turned.

2) With the fuel pump relay in place as usual, and the ignition turned, the pump whirrs when the air-flow sensor is pushed. Video here:

YouTube - Testing fuel pump

Is that sound normal? Seems awfully loud.

3) The engine turns over manually with a pattern of hard-easy parts of the rotation. Is the fuel pump testing flooding the engine? Because after the test the first rotation made a slightly different sound.

4) The battery is pretty toast, even when plugged into the Duracell Powerpack 450 booster it barely turns over so I'm off to Kraagen to get a new battery.

5) The pop-off valve appears intact and operational.

6) Fuel gauge (which is iffy) says I have gas, and based on the # miles since the last fill-up I should have more than a third of a tank in there.

Anything else I should check while I'm at it? I'll check the board when I return with the new battery.

Thanks,

Babak

BrokeMyCar · 01-22-2011, 04:16 PM

Complete fail on buying the battery - 4 stores, two had the Optima 75/35 in their system as in stock but couldn't find it anywhere. One had a liquid-cell battery that would fit, but it cost even more than the Optima! The hunt continues, possibly online.

If anyone gets a chance, can you listen to the video of the fuel pump (link: YouTube - Testing fuel pump) and tell me if that sounds like I should also order a fuel pump while I am at it?

Thanks,

Babak

faverymi · 01-22-2011, 04:22 PM

if you can get your hands on a fuel pressure gauge, then you can discard fuel pump issues very reliably.

Can't remember but shouldn't be around 30psi?

steely · 01-22-2011, 05:35 PM

Bummer on the battery search.
Don't forget to check for spark like Tony said once you get it.
Can't comment on the pump sound (I don't have CIS) although it does sound unique.
best of luck!!

BrokeMyCar · 01-23-2011, 11:06 PM

Oh boy, ends up the entire problem was just a failing battery! I replaced it with a new Optima, polished all the terminal connections and now the car starts fine and even the electrical lighting issues I was fighting earlier have resolved themselves. It seems the old battery's voltage was low enough that I wasn't getting spark.

Thanks everyone for your advice and encouragement!

Babak