Fly Navy

Any troubleshooting ideas you all can offer?

I'm guilty of doing three "bad" things...

1) Listed it for sale
2) Let it sit for 2 weeks (garaged), but in our coldest snap this year without starting or driving it.
3) Let it sit with a nearly empty gas tank.

Tried to start it yesterday - would turnover, but not start and lights dimmed as I kept ignition engaged. Figured it was the battery - opened up the compartment, very clean, no corrosion - so hooked up a slow-charge to it for 8-hrs and tried again...same thing (headlights, radio, all-worked on battery and at same time?).

So, I took the Interstate battery out (at least 5 1/2 yrs old as I've owned the car since Nov 03) and had Autozone put it on their tester...machine readout said it had gone bad (I watched him put a load on it and agreed).

Installed a Duralast 48-DL (7-yr, 700 cold cranking Amps) ventilated battery - fit perfect. Added 2 gallons of premium to the tank.

But same thing, seems to engage with a bit more oomph, but will only turn over, won't start. No smoke out back pipe, but an unpleasant odor.

Changed fuel filter approx 11,000 miles ago - but due it's light annual mileage, that's now 3 yrs ago. Previous to this, car has always started with first turn of the key.

Thoughts?

928worldwide

check the coils for spark? Wiggle the relays?

tailpipe

Check the three primaries, first make sure there is fuel in the tank and the pump is working, second make sure there is spark, third make sure the timing/compresion is where its suposed to be

AO

Relay, relay, relay.

Mrmerlin

HOLD the pedal to the floor and crank it, if it got cold and didnt start there is a good chance the plugs are frosted, you could also try a quick squirt of ether this will tell you if you have spark

928worldwide

Some are spooky about ether. I love it! It's the greatest- use ether to see if it fires up. the claim is that it can harm the MAF- but never happened to me or anyone I know.

Fly Navy

I'll seat and reseat the relays and post back if I get lite off...

Found this fuse/relay chart on the web with links to the parts - posted FYI.

https://www.928gt.com/t-8788fuse.aspx

SeanR

Ensure the fuel pump is running by using the 30-87 jumper. Take that step first and then let us know.

Bill Ball

Ether itself won't harm the MAF. Brake clearner can due to the acetone content that can soften plastic parts. The issue with ether is potential to have a backfire. I've never had a problem with giving a short squirt, letting it sit a second or two, then trying to start the car. If it runs briefly, you have spark and probably have a fueling issue (e.g., fuel pump not running or injectors not firing).

Fly Navy

The relay "wiggle" didn't work. For just a moment, it sounded like it would lite off and start, but didn't.

Couldn't remove even one relay, so could only wiggle and press on each one - was afraid to pull too hard on any for fear I'd break the plastic motherboard.

Disconnected the battery for the time being (snow storm rolled into Williamsburg - and all other points east) - will try a shot of ether next.

Sean - not familiar with a "30-87 jumper"?

As always - thanks for ideas! Mike

dr bob

Stop by Home Depot on your way home and grab a few paint can openers, the ones with a little bent flat end on them and a T handle bent into the user end. Complete the bend at the end so it's 90º, and you then then use a pair of them to pry out a relay from the board. One on each side of the relay, pressed so the finger goes under the victim relay base. Good idea to disconnect the ground wire while you do this, in case the metal 'puller' meets the wrong pins during the extraction.

The 30 -> 87 jumper refers to the terminal numbers on the relay itself. In DIN-speak, the terminals are numbered based on thir functions, and are standard for all DIN-spec'd relays. The 30 terminal is always the voltage source for the switched circuit. When a relay is actuated, that 30 terminal routes current to terminal 87. Look at the numbers on the bottom of the relay, and identify the terminals in the CE panel where those pins sit. Make a short jumper with a section of wire, and a male 1/4" spade terminal crimped on to each end. If you want to get fancy, put a switch in the middle. Fancier yet includes a fuseholder too. Plug the ends of the jumper into thoe CE panel where the 30 and 87 pins from the relay fit, and you've effectively bypassed the relay function and powered the circuit directly. It's a handy tool for diagnosing problems with relays themselves, and also for the circuits that feed the relay.

Fly Navy

Doc - thanks.

If I can get it out, was thinking I could substitute the horn relay (horn works) for the LH, and then fuel pump relay (if still no start) - believe they're all the same type.

I probably should have these spares on hand, especially at a cost of $9-12 each.

Mike

Nightfly

Bizzarely I had the same problem; let it sit more than a week or so and it won't start. It'll crank till the cows come home though. For me I think it's something voltage related, because it cranks fast, starts to catch, then stops. So, I charged the battery till 100% on the meter, put the battery back into the car, make sure the battery terminals are clean. hold down the gas pedal and crank, and it starts, runs a bit rough at first, but smooths out in about two minutes and then is fine. I went through this twice, now I just make sure I run the car regularly. No more problems. I think there's a ghost in the machine that gets pissed off at me when I don't take her for a ride regularly.

dprantl

Or... sometimes when the TempII sensor starts to go, it only goes at a certain temp range, like when it's cold. So when it fails that way and makes the mixture too rich, the car gets flooded when trying to start and will only catch and then just crank. If you hold the gas pedal to the floor while cranking, there is enough air put in to make the car start and sputter until all the excess gas is burned. It doesn't take long for the coolant temp to warm up a couple of degrees and make the problem seemingly disappear. Everyone should replace their TempII sensors; they are cheap, a no-brainer to replace and can be a source of many no-start problems.

Dan
'91 928GT S/C 475hp/460lb.ft

Nicole

A few years ago there was a car at DEVEK days that would not start at the end of the day. As it turned out, there was a grounding issue (I believe on the battery-to-body strap). That was all.

Since you say that even with charged battery, the lights dim, I am wondering, if you have a grounding issue...