3.2 starts dies immediately - all tests good
 

OK - i've searched all the forums i can find - this is certainly not an old topic, but i have a problem that seems to defy all the previously posted ideas & solutions

. SOLVED

see below

For those interested in the symptoms & diagnostics:

this is an '89 engine and DME harness, and the DME is 911.618.111.20 Bosch 0 261 200 082, said to have run fine when swapped into a test car (DME came from L.A. Dismantlers, and no appearance of ever being opened)

The engine will fire & run about 3 seconds - then dies (as if it is out of fuel) -

I have correct fuel psi, and have even jumpered the pump to assure that it is still running after startup to assure continuing fuel psi

I have already run thru the entire DME Test Plan - everything checks out to spec,

I have already tried all the obvious and typical ideas in Loren's great posts, et al

http://forums.pelicanparts.com/porsche-911-technical-forum/621262-911-3-2-no-start-troubleshooting.html

http://www.pelicanparts.com/techarticles/911_carrera_start_troubleshoot/911_carrera_start_troubleshoot.htm

http://www.powerprom.com/

http://forums.rennlist.com/rennforums/944-turbo-and-turbo-s-forum/88554-no-start-diagnosis-v-long.html

http://forums.rennlist.com/rennforums/911-forum/531320-carrera-3-2-no-start-big-mystery-2.html

etc

the injectors show OK with noid lite

the fuel pump and the DME Relay are brand new & tested to be working perfectly

it will always fire on Carb-cleaner

it will initially fire on it's own injector gasoline supply on first start attempt, but then dies and only cranks - won't fire again

jumpering the Temp II sensor makes no difference in this behavior, and the sensor tests good

I have tested every DME wire from end-to-end; all ignition wires etc test OK in all ign switch positions, the tach works when it fires (but not when cranking), the oil gages work, etc

etc etc -

Is this where I admit to being frustrated? :confused:

I have read on a couple posts about cases of corrosion or cold-solder in DME, but have not yet opened it up to look for that

I do have another 3.2 ('84) and will try

swapping the AFM even tho the current AFM tests OK per the Test Plan

swapping the DME

- Swapped DME - no change in behavior, see below

I will also be checking the cold start valve to see what it is doing

and i will be trying an old solution of running on a propane feed to see if an extended fuel supply keeps it running (i have those propane tools from 'way back when i worked on american iron)

i am looking for more ideas

???? - oddball stuff that is not discused in the above links, that some of y'all have only maybe seen & solved once ????

I should mention that i have the factory DME test plan - i also have Bentley, and a full factory manual on CD, & and have followed them carefully - and i do have all the correct diagnostics tools (no harbor freight junk)

TIA

Here is the solution - so you don't have to read thru the rest of the thread:

found that injectors 4-5-6 were all stuck

was able to free up 2 of them with my "injector inspector" tool

- engine now starts & idles - just misfiring on that one bad injector

(the hazards of a long-time-storage engine)

hope this helps the next guy


.

Dme
 

Try swaping out the DME.

If a replacement is required, buy the factory unit, and not the uro.

Good luck,

Gerry

test fuel pressure, need CIS pressure test kit. too much pressure will cause car to immediately die like that (not the only thing that can cause it though).

swapped DME - same behavior

noid indicates injectors are pulsing during follow-on cranking after initial die-out

will always fire if fed carb-cleaner

always have residual fuel psi in manifold at test port, so the fuel is available to the injectors


wondering out loud - ? - could this be plugged or contaminated injectors? - ? all of 'em ? - (the engine had not been run for several years & was still on shipping pallet when I got it)

- next, i will put my "injector inspector" on each & thoroughly pulse them all to see if it "loosens up" anything

testing continues

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have you tried the most simple test and swapped the DME Relay?

yes I have a proper test kit - yes the psi is per spec in the Test plan

:D

Hmm, the injectors are getting the signal... I think testing the injectors themsevles, as you suggest, would be a good next step. I'm not sure I can imagine a condition where the injectors open enough to allow some fuel to get into the cylinders and ignite, but then not be able to supply enough to keep it running... but maybe.

How many volts are you getting to the fuel injection system?

Did you check all of the components (AFM, ICV, etc)? Do you have the Bentley manual? What is the battery voltage? Fully charged? If not, then the injectors won't open..

Are you getting a fuel smell from the tailpipe?

What fuel pressure do you get? You say it's in spec, but what is it?

If you have a remote starter, then you can check the reference sensor by removing it and pulsing it against something metal, like the rear fender.

I had a similar problem a couple months ago. Turned out to be the connector to the DME. You might want to try wiggling it.

brand new relay - plus tested and found perfect :D

. SOLVED

found that injectors 4-5-6 all stuck

was able to free up 2 of them with my "injector inspector" tool

- engine now starts & idles - just misfiring on that one bad injector

the hazards of a used and not-run-for-a-long-time engine -

thanks for all your ideas & add this one to your "3.2 no start" files


P.S. if you don't have an injector pulsing tool like i have, try this gimmick
http://www.zcar.com/forum/10-70-83-tech-discussion-forum/270561-anyone-ever-free-up-stuck-injectors.html

.

To test the DME system you really need an oscilloscope. You should be able to find a real good one for less the 100$. (Try Craigslist)

Test the pulses at the injectors. If you are getting it to fire by adding some sort of fuel to the mix then the missing ingredient has to be fuel. You say you have checked the fuel pressure. Do you have a gauge that you can watch while you are cranking to be sure you maintaining pressure?
So assuming that the fuel pressure is consistent then only choices are:
- No fuel
- Not enough fuel.

If the injector pulses stop then you have something to chase. If the pulse width is off then you have something to chase.


Test, test, test... There is nothing about the way these things run that can't be tested.

as stated above - everything was checked and found correct according to factory DME Test Plan - specs are all as indicated in that document, and as also stated above I have all the manuals :D

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Wiggle the connector to the DME and see if that bad injector starts firing. Had the same problem.

Yes, THE "DME Test Plan" is very complete and includes checks with an ocilliscope. I was skeptical that you had and were following the plan, which is why I asked. It sounded to me like the injectors were not opening, which I guess turned out to be the case. That's also why I asked if you were getting gas smell at the tailpipe, what the voltage was, etc etc.

Sometime you want to gently tap on the injectors themselves, as they can stick shut.

When I went looking for an injector service I couldn't find one that people recommended in the SoCal area. I went over to Andial and asked them who they used:
Accurate Injector Service
733 Little Drive
Lake Havasu City, AZ 86406
(928) 486-1241


Very weird to have all of them lock up at once. Was this engine in a car the was left sitting for a major length of time?
I would check the fuel rails, pressure regulator, and filter for contaminates. This is just odd. :confused: I'd want to see a reason why this all went south. Maybe flush the gas tank...

yes - the engine was out of a wreck - probably in storage for at least 3 yrs -

correct answer is that the fuel residue in the system turned to varnish and stuck the injectors :(

all - be forewarned if you buy an engine from a parts-yard SmileWavy

update - 3.2 no start - links
 

here is a new link (Nov 2017) with lots of good troubleshooting ideas embedded, but no solution as of Nov 27....

http://forums.pelicanparts.com/porsche-911-technical-forum/978039-1977-911-3-2-has-been-sitting-wont-start-lets-discuss.html

more links below :)

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