Babado

Hello All,

Help please!

Just turned 56k miles of which I've put 1k miles, never an issue starting. 2 weeks ago Monday I pulled her out of her garage gave her a wash, backed her into the other garage for a interior detail and when I went to start her cranking but no start ( I'm by no means a mechanic but I thought, she's not getting fuel) tried 3 more times nothing, I decided to push the gas pedal down and she fired up though stumbling a bit she smoothed out after I feathered the pedal, idling at about 1k took her for a 1 minute drive and she run as smooth as normal, idle dropped to 700 when I returned home . Pulled her into her garage and shut her off, fired up again, I figured I'd wait a week, no start again. I figured I would start out simple and buy a new 53 Porsche relay and some new fuses, 53 on the fuel pump and a 15 fuse for the fuel pump oxy sensor. Prior to replacing them I tried to start her and she fired up, she was stumbling a bit so I shut her off and she wouldn't start again. Replaced the fuse and the relay hoping that was it but still the same issue.

I did smell raw fuel at the exhaust after it wouldn't start today.

Is it possible it's the fuel pump? I thought I read they normally completely die. Yes it has gas, not a lot, just above the last white line, last time I filled up I had about the same amount of fuel and drove 35 miles before filling up.

At 55k miles all ignition parts were replaced, fuel lines, fuel filter, etc, more more.

Thanking everyone in advance, Joe

Petza914

Doesn't sound like it's the fuel pump but rather it's flooding. The short trip from the garage to the driveway and driveway to other garage put so much gas into the engine that it wouldn't start. Opening the throttle all the way let a lot more air in to mix with that gas so it would fire them ran rough as it burned the extra fuel. The fact that once it clears and smooths out that it drives fine points to that as well. If it was the file pump or the relay it wouldn't run or drive well.

I also bet if cold start it and drive it around a while that it all seems perfectly normal and that it was the short stint that caused your issue.

Being a 32v engine though, I can't help with as I mostly know the 16v cars.

Mrmerlin

The 85/ 86 cars induction system is prone to over fueling,
this is especially pronounced when the engine is cold started and then shut off before it has reached operating temperature.

Usually most apparent when the car is moved from a garage to the driveway then shut off.
Then a restart is performed and the engine wont start.

Holding the foot to the floor and cranking is how to start a flooded engine.

NOTE it can also happen from a failed damper or FPR,
so pull the vacuum line off and smell for fuel.

NOTE its also possible to have a plenum blow off from a misfire .
( this can dent the hood)
This happens when a spark jumps to a rich cylinder with an open intake valve getting a spark that jumps from an adjacent cylinder,
NOTE replacement of the ignition wires is a good idea if this happens.

Ideally you only want to start a cold engine and then drive it till its reached operating temperature

joejoe

One of my 86.5 had a recent no start. Would crank but had wierd tach. action, (bouncing from 0 to 7) Checked relays fuses and nothing. Remembered something about the ignitors in front, wiggled the wires, gave them a tap.......and car started as before.

Babado

Thank you, I'll put the pedal to the metal tomorrow and report back.

The raw fuel smell from the exhaust should have been a eye opener for me yesterday.

I'll report back tomorrow and never let the car run for short period of time again.

mj1pate

Listen to Mr Merlin’s suggestions and see if that doesn’t improve things.
I have an 86.5 and since over recent years, having MAF, EZK and LH rebuilt, refreshing fuel dampeners, regulator, no such occurrences. Faultless starts… hot, cold, whatever. Great idle.
Of these things that perhaps haven’t been refreshed; try and get those complete.
BTW… it’s appropriate to fear the effects of “rough running” on the cats. They can overheat and matrixes crack. If it needs troubleshooting involving running while rough running. Consider temporarily replacing cats with straight pipes until the rough running is past.

Babado

Thanks mj1 the 928 has never had an issue starting in any weather, fuel dampeners and regulator were all checked during the maintenance last year. Never had rough running issues either, as Stan said probably too much fuel in the system, fingers crossed for tomorrows start!

76FJ55

Just to reiterate your statement. "fuel dampeners and regulator were all checked during the maintenance last year" - "never had an issue starting in any weather"

May want to check them THIS year now that you have starting problems.

Babado

Thank you gentlemen, amazing knowledge on the these forums.

I put the pedal down 1st time it died, 2 time gave a bit more pedal, once it started running I saw a bit of exhaust ( assuming that was old fuel burning off)ran rough for a couple of seconds drove it to temp stopped and put some fuel in and she started right up as normal, running just as well as she did prior.

Mrmerlin

NOTE you dont need to floor the pedal with cold engine if the engine was run up to temperature on its previous start.
AND you dont have any reason to believe that the engine was flooded on a previous start attempt.
Just turn the key and crank it till it starts

NOTE it might be prudent for you to read the owners manual as it has much information about how to use your new machine

Babado

Thank you, I never touch the pedal when starting, I only put the pedal down for the 1st time when I flooded it after running 2x for 15 -20 seconds each. I did need to do it today because it was still flooded from Monday.
​​​​​​Thank you for you help and knowledge Stan!