My '83 US non-start...........

garylewa · garylewa's Garage

Gentlemen,
I am totally stuck......
My 83 US has always started since the day I purchased her. The car would sit all winter hooked to a battery tender and at the first break of nice weather it would fire right up. It has been sitting for ~2.5 months due to my work schedule and travel hooked to a tender. I jumped in it Saturday for a spin and no start, checked everything and still no start. Sunday was the same, as was Monday. I looked at the battery (it's 4 years old) and decided to replace it yesterday after work. I installed the new battery and the same problem. The car will turn over for about three seconds (running rough; which it never did before...always very smooth) and then stall. I checked all electrical connections in the engine and everything looks good, clean and tight. It is getting gas because I can start to smell it after the fourth or fifth time trying to start. I am thinking spark??? I have the shop manuals. I mean it has never done this before; I'm totally stumped....any help or assistance in this would be greatly appreciated before I tow it to my mechanic for "part swapping".
I will post a short video when I get home.

stepson · 10-21-2015, 10:30 AM

It sounds as if your plugs have gotten fouled/your engine is flooded. Try starting the car with the accelerator pedal mashed to the floor.

garylewa · garylewa's Garage

Thanks stepson, I tried to start it with the pedal mashed and the same thing....I am going to pull the plugs next.

stepson · 10-21-2015, 08:14 PM

Okay, you say it "runs" rough for 3 seconds. Is it really running or just turning over? Take the cold air tubes off the timing belt covers and look through the top hole while the key is in the start position.(requires a second set of hands) Is the timing belt tracking and turning as it should?

When you pull the plugs, pay attention to the cylinder from which they are removed.

I would normally repeat Jim Bailey's mantra...relay..relay...relay, but I'm not sure that applies here.

Did you accidently/on purpose set the alarm while locking the car and forget to unset it?

Just some thoughts.

MPDano · MPDano's Garage

Condition of Green Wire?

garylewa · garylewa's Garage

Quote:

Originally Posted by stepson

Okay, you say it "runs" rough for 3 seconds. Is it really running or just turning over? Take the cold air tubes off the timing belt covers and look through the top hole while the key is in the start position.(requires a second set of hands) Is the timing belt tracking and turning as it should?

When you pull the plugs, pay attention to the cylinder from which they are removed.

I would normally repeat Jim Bailey's mantra...relay..relay...relay, but I'm not sure that applies here.

Did you accidently/on purpose set the alarm while locking the car and forget to unset it?

Just some thoughts.

I should clarify, it is just turning over....the timing belt is tracking as it should; no jumped teeth. I pulled the plugs last night, the BOSCH plugs look great; no oil, no detonation damage,dry, color looks good, gaps were perfect etc.
I was and still am thinking relay too......I checked the alarm also, no issues and was not unset. I looked again at all electrical connections and they look great including the green wire.
This car has never done this before; it in the literal sense was "running like a top".....I'm a mechanical engineer and this is driving me nuts; it makes absolutely no sense.....I am taking a half-day today and I am going to comb thru this again....I will promise to post a video today also. Man, it's 75 degrees and beautiful outside this whole week, all I want to do is drive this thing!

stepson · 10-22-2015, 07:14 AM

Dry plugs would indicate that injectors are not firing. Now I will say "Relay....relay....relay"

Fuel injection relay (XVI) 4th from the right on the top (928.615.119.00)

Eric85.5 · 10-22-2015, 08:44 AM

Also might want to check the crank position sensor (?)

garylewa · garylewa's Garage

Quote:

Originally Posted by stepson

Dry plugs would indicate that injectors are not firing. Now I will say "Relay....relay....relay"

Fuel injection relay (XVI) 4th from the right on the top (928.615.119.00)

RELAY, RELAY, RELAY!!
It's funny......great minds must think alike ha ha ha ha. I was driving home from work and the small (I reiterate "very small") light bulb in my head went off "the plugs are dry, no fuel"!
I open up the garage, pulled back the carpet and opened the fuse panel, did a quick once over again on the fuses and pulled the fuel injector relay......what do I find? A relay pin badly corroded.

I fumble through my spare parts cabinet and what do you know, a brand new relay I purchased when I rebuilt the fuse panel; sometimes you just need good luck.
Installed the new relay, turned on the car and it fired right up; unbelievable.....Turned it off,removed the relay and cleaned the socket of all visible corrosion and sprayed it with contact cleaner. Re-installed the relay and the car fired up again. Just returned from giving the car a nice drive through the country and figured I would report back my findings when I read the last two posts........Thanks for your help everyone; I greatly appreciate it.

stepson · 10-22-2015, 11:17 AM

Awesome!! Thanks for the feedback.

aluminum · 10-22-2015, 04:57 PM

Once Again the Flue Injection Relay : The 80 I Bought sat for 15 Years not starting and several Porsche 928 Garages could not find the cause so the owner just parked it under a tree and a rat moved in to The Air Cleaner .
I bought the Car and changed the Flue Injection relay and it stated right up.
Naturally First I cleaned the tank , Flushed the Lines , changed the pump .
run's great and I am still on the same plugs

SolReaver · 10-24-2015, 06:52 PM

YAAAA!!! Congrats to you!

harborman · harborman's Garage

I would pull all the relays and fuses and clean with Deoxit.

shonwood · shonwood's Garage

This is very helpful guys my 82 S is doing the same thing! I just ordered a new relay and I'm hoping that's the issue!

GabrielS · 09:24 AM

Had the same issue with my '84 except it was intermittent. Sometimes it started perfectly other times not. One time this happened in San Francisco as my wife and I were headed to one of the Nob Hill hotels to meet my wife's friend. She stated to us "I'd never rode in a Porsche". When it came time to restart the engine it just cranked without starting. Embarrassed, I replied to my wife's friend "Unfortunately, it's not going to happen today!" For some reason one of the doormen at the hotel saw what was happening, reached in through the drivers window and began rotating the steering wheel back and forth. Puzzled, I couldn't figure out what this would accomplish until I looked over at the other doorman and saw him smiling then felt they were just putting me on. Still not starting we wound up having to push the car out of the way then walked to our nearby destination. Upon returning, The engine fired right up as it should. Once home, I went through all the systems and finally discovering the fuel injection relay had a loose leg. Replacing this inexpensive part restored the dependability and reliability of consistent starting...and saved future embarrassment! Now I keep spare relays and fuses in the glove box just in case.