input needed for no start

[DRACO A5OG]

84-88, or just 3.2's

[A horse with no name]

Originally Posted by DRACO A5OG

84-88, or just 3.2's

'Thanks'
m

[A horse with no name]

Originally Posted by ischmitz

Ok, now that the ICV is humming you have a powered DME. Great news. The next checks need to focus on the speed and reference sensors. If they are reversed or their gap isn't correct the engine won't fire.

Checking for the speed sensor and whether it's plugged into the correct socket on the engine tower is very straight forward: Disconnect the DME and measure on the harness connector pin 8 and pin 27 with a voltmeter set to AC. When you crank you should see around 2V AC.

For the reference sensor use you LED test light (I seem to remember you built one) and connect it to pin 25 and pin 26 and check for single flash per revolution.

If both tests check out (and please do them again now) your DME needs to issue fuel and spark signals. If not I'd check for the gap of the reference sensor one more time or something inside the DME is wrong.

Ingo

Hi Ingo... I did all of the checks that you had advised me to do, and unfortunately for me that is, I still have a 'no start'. I'm also going to be replacing the alarm module just in case there is still something in it that is toast.

While waiting to receive an Alarm Module replacement, last night I made a new post under the heading of; Need assisatance in Vancouver (BC) asking if there was any Pelican in my area that would be willing to let me check my ECU out on their 3.2's


As a matter of interest, would I be able to do the test on all years of 911 3.2's or just specific years? A Bud on mine has told me that all years will work. I do believe him...But then ~ 'You're de man'

Thanks!

[mysocal911]

Re-read your initial post:

Originally Posted by A horse with no name

Hi, I have the infamous no start issue. I have been reading numerous v good threads on what it could be to no avail.

When I re & re'd the rear suspension, I also replaced the fuel pump, DMT relay, O2, head, speed & reference sensors, including a Steve Wong chip. Since this time, I never made note as to which of the two plugs that the speed and reference sensors went into. I do know that the top one is for the head sensor
I does states that if it doesn't start to just reverse them. After doing this it still did not start.

I have no spark whatsoever at the plugs, and I also cannot smell any fuel. On the ECU #1 pin - coil - I get a 12.8 reading. When testing kohms for the speed and reference sensors, at the end of their connectors, I get 9889. When installing the reference sensor, I did glue a 0.8mm thick washer to set the space between it and the flywheel pin.

I have, for the time being, removed Steve's chip, and reinstalled the original one. It is installed correctly according to Steve's instructions. I did this with the thought that it may possibly make it a little easier for the ECU to sync.

The ECU looks as new. Very clean and shiny, and I could not see any cracked solder joints anywhere.

Prior to changing all of the above sensors, the car ran very well. Even after sitting for a long period it would start within just a couple of turns. The cap, rotor etc. only has about 1000 km -60K miles on them. The car has 126,000 km's - 78K miles.

Any and all thoughts will be greatly appreciated...Thanks in advance.

So, 80+ posts and still no idea of what the problem is. Most likely the only original
problem was the alarm ECU, but after all the parts changing another problem was
caused.

Your posts indicate that you have not followed through with all the recommended testing,
i.e. checking for an injector pulse which would help localizing the problem to the
DME ECU or not. Also, the fuel pump relay (stage 1 of DME relay) should activate while
cranking and cause the FP to run. This also probably has not been checked.

Maybe at this point you need to have the Porsche taken to a capable Porsche repair
shop for a proper diagnosis and not waste additional time and money, which has probably
been the case.

[ischmitz]

Originally Posted by A horse with no name

As a matter of interest, would I be able to do the test on all years of 911 3.2's or just specific years? A Bud on mine has told me that all years will work. I do believe him...But then ~ 'You're de man'

Thanks!

Yes, for a quick start/no-start test any year 3.2 DME is fine. The only difference is the idle speed between earlier and later DME versions and how they deal with an O2 sensor. If mismatched you might see some slight hunting at idle. However, since you only start the engine (hopefully) for a quick 10 seconds it will be stone cold and idle just fine with cold enrichment.

In addition in your case either swapping you DME into another car or swapping a good DME into yours is fine As a matter of fact I have sent my loaner out several times for folks to do just that in 'stubborn' cases.

Good luck,
Ingo

[A horse with no name]

Being that I'm waiting to check my ECU out with a hospitable local Pelicans car on Saturday morning, I went about rechecked a few items today. When I had checked the coil a few days ago, prior to finding the power issue, the coil was OK.

Today I found that the coil's Primary Resistance to be 4.9? It's supposed to between .4 and .7 ohm. On a plug wire that would be what I would call an 'open wire'...It appears that the coil has had it. The Secondary Resistance of 5.60 is within the spec's of between 5.0 - 8.7 kohms. It's the original coil.

Being that Bosch coils that are manufactured in Brazil have such bad reviews from other Pelicans, what are the alternatives?

[A horse with no name]

I recently returned from a local Pelicans home, 'Hendog -aka- Henri, who had replied to my post for someone with a 3.2 to test my ECU out...He was not only generous in his offer to do so, but when my ECU failed to start his car, he then kindly asked me if I would mind him having a look at it.

Henri's idea of 'having a look at it' was a major resoldering of the board! When doing so, he also found that one of the rear pins,#1, out of the 35 pin section, was loose...Yes!..Heni then resoldered the pin, reinstalled the board into it's box, popped it into his beautiful, low km '87 Venetian blue Carrera Coupe, that has SSI Headers, muffler, SW chipped with Custom Porsche three piece wheels and up it fired!

My 'no start' issue look's like it's 'finally' coming to an end... What was discovered during the week:

1. Dirty contact-points in the alarm module, when cleaned, restored the power to both the DME 35 pin connector and relay, due to a suggestion from '96 911 Targa'

2. After doing doing one more recheck, out of numerous 're-checks that were mainly suggestions from both "Ingo' and '96 911 Targa', I found out that the ignition coil was now toast! I had checked it out previously and found it to be OK.

3. While waiting for an alarm module to arrive, I thought that it would be best to see if I could find a Pelican who would check my ECU out -Draco's suggestion - Walla!

As Jim recently stated, quote: "I just love this Pelican Board!" ...That I whole heartly second!

I not only had a local Pelican test and repair my DME, but most importantly, I was able to meet one heck of a congenial, 'can't do enough for you' guy.

I'm now going to purchase a new coil, replace the alarm module, and once these are installed, I'm now quite sure that 'The Phoenix' will rise from its ashes'

Hat's off to 'Hendog!

Thanks so much 'Henri...Much appreciated!

[A horse with no name]

Hendog 'just' having a look at it

[ischmitz]

Glad it's working. But please let's be 100% clear and not spread wrong information for others:

1. The coil is not being burned out when leaving the ignition on for extended times. That's physically impossible with a DME unless your interior of the DME is charred like in this example below:



Here the ignition driver shorted and subjected the coil to full power and in the process it burned the current shunt. BTW, this was repaired and the DME is working ever since.

2. If a pin "is lose" on the EPROM and it's causing an issue the ICV will not vibrate. Again physically impossible.: If the ICV vibrates the the DME is executing code from the EPROM (chip) and it is ok.

Ingo

[A horse with no name]

Thanks again Ingo...I'll edit my coil info.

'Hendog' found that the #1 pin, of a section of 24 pins, failed a continuity check after finding that it was loose. He soldered in another very small piece of wire as it was actually broken within its plastic insulation. (Btw, he is an electrical technician)

Correction: 'Hendog' repaired #1 pin of the 34 pin main ECU connection section.

Re the coil. I know that the older cars without a PCM, by leaving the ignition on, you could burn the points out. As a matter of interest, have you any idea why the coil went when only days earlier it was OK?...Was it just a coincidence or did I somehow short something out?

Thanks.

[Hendog]

Originally Posted by A horse with no name

, he also found that one of the rear pins,#1, out of the 24 pin section, was loose...Yes!

To be clear, the open pin was pin #1 of the 34 pin ribbon cable connecting the two board together. I installed a jumper between the two boards at that position. And thank you for the kind words Horse. I was just as happy to hear the car start as you; glad to be of some help.

I'm not sure if 4.9 Ohms is fatal to a coil? I suppose if it should be .4 to .7 then it is rather high, but would that cause a no start condition?

[A horse with no name]

Originally Posted by Hendog

To be clear, the open pin was pin #1 of the 34 pin ribbon cable connecting the two board together. I installed a jumper between the two boards at that position. And thank you for the kind words Horse. I was just as happy to hear the car start as you; glad to be of some help.

Opp's! I best correct that mistake also.

I'm not sure if 4.9 Ohms is fatal to a coil? I suppose if it should be .4 to .7 then it is rather high, but would that cause a no start condition?

As for would a 4.9 kohm reading cause it not to start/...Hmmm?... I best go and find out ay

I had phoned an auto electrical shop yesterday to ask them if a reading like that meant that the coil was gone, and they had replied that 'yes it would'.

I'll let you know in a few minutes.

[DRACO A5OG]

Whoa

Above and Beyond!

[Hendog]

Oh! 4.9Kohm! I misread it as 4.9 ohms. Big difference... Then I suppose that is bad for sure.

[mysocal911]

Originally Posted by A horse with no name

I'm now going to purchase a new coil, replace the alarm module, and once these are installed, I'm now quite sure that 'The Phoenix' will rise from its ashes'.

Hopefully!

[mysocal911]

Originally Posted by Hendog

To be clear, the open pin was pin #1 of the 34 pin ribbon cable connecting the two board together. I installed a jumper between the two boards at that position.

Could of been damaged when separating the two boards, so there still could be an intermittent
in the ECU which may manifest itself later.

[A horse with no name]

Originally Posted by Hendog

Oh! 4.9Kohm! I misread it as 4.9 ohms. Big difference... Then I suppose that is bad for sure.

Henri!- Henri!...The car started exactly how I was telling you...the 'quarter of a turn thing!' After 6 months of being parked, and 'whuump' it started!!!

No more "Sleepless in Vancouver" - Happiness is seeing the German windmill spin again!

[ischmitz]

A reading of 4.9 Ohm could be a measurement error. Depending on quality of the meter, cleanliness of the test leads etc. you quickly make errors in the low ohm range. It's hard to imagine how a primary fails with that kind of reading, just saying....

I assume it started on this coil, correct?

Ingo

[Hendog]

HURRAY!! So glad to hear it started!

Ischmidt is right; 4.9 Ohms is so close to a short it was likely just a poor contact of your probes or any number of things if it was indeed 4.9 and not 4.9k

YEAY!!!

[A horse with no name]

Originally Posted by ischmitz

A reading of 4.9 Ohm could be a measurement error. Depending on quality of the meter, cleanliness of the test leads etc. you quickly make errors in the low ohm range. It's hard to imagine how a primary fails with that kind of reading, just saying....

I assume it started on this coil, correct?

Ingo

Hi Ingo... Yes it did, thanks to Henri wondering if the high resistance would would start it. I had assumed that it won't for an auto electrician shop had told be that with that high of a resistance it could make a coil fail. To me, 'could' was 'would' as it just won't start even though I now had the power back.

Muitimeters: I had one of OTC's higher end multimeter for decades (is that possible-> higher end )... I have had a 177 Fluke for a couple of years now.

This time around, I measured the coils Primary and Secondary resistance three to four times, and I consistently got the same readings. If anything, maybe my first readings were incorrect ay. For preventive maintenance, I'm going to replace the coil anyway, as it appears that it may be on it's way out.

Ingo...I'm 'not so sorry' that I now don't have to send you my ECU to be refurbished

Thanks again for all of your input. Much appreciated!