Won’t start

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11 May 2021 19:59 #21873 by DHS
Won’t start was created by DHS
Five days of ownership, so tonight would not start, good battery, turns over well I get a initial fire but that’s all. Not more than a second then nothing. Turns over but nothing. So I know the L Jetronic system from my Alfa and D Jetronic from the Jag, so what is in the 87? When I turn the key on I do not hear the fuel pump run for a few seconds like my other cars. Is there a cold start injector? It ran well here from Florida no starting issues at all. Even with a bad cold start injector can you start the engine.
Dan
87 five speed. :(

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12 May 2021 11:34 #21874 by Rich928
Replied by Rich928 on topic Won’t start
Wow, sorry to hear you're having problems.

With most no-start issues, I ALWAYS recommend replacing these relays: fuel pump, EZF and LH. All three are necessary for the engine to run. They may be the original. I would recommend to all 928 owners who don't know if the relays have been replaced to install new ones due to the age.

There should be is a very short "pulse" of the fuel pump turning on prior to engine crank. You'd have to be down at the pump to hear it.

I'm sending a PM with an overview of the fuel and spark system that will help you understand the system.

Best regards,
Rich

Rich
Membership Chairman
Charter Member
1993 928 GTS Cover Girl
1987 928 S4
1979 928 5-speed rescue
1979 928 5-liter track beast

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12 May 2021 14:46 #21875 by stepson
Replied by stepson on topic Won’t start
Are you sure that it's a fuel related problem?
As Rich says, replace those 3 relays first.
Remove the airbox and try spritzing the throttle body while cranking. If it fires when you spritz it, it is definitely fuel related.
Is your fuel pump functional? Remove the relay XX (top row and 4th from the right) and use a jumper wire from terminal 30 to terminal 87. This will power your fuel pump constantly whether the key is on or off, so don't leave it jumpered when you are not working on it. Is your fuel pump working with the jumper? If not, check the fuse( fuse #42) If it is still not working, the fuel pump is probably FUBAR and needs to be replaced. REMOVE THE FUEL PUMP JUMPER WIRE WHEN YOU ARE NOT TESTING YOUR FUEL PUMP!!!!
Keep us posted after you test.

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12 May 2021 17:15 #21878 by Rich928
Replied by Rich928 on topic Won’t start
Attached is the overview of the 1987 and newer 928 spark and fuel systems.

Relay puller pliers are a must for the 928 owner. They can be difficult to remove and can be damaged, or the relay socket can be damaged if improperly yanked.



Lisle 46950 Relay Puller Pliers are what I purchased and recommend.

I use an old relay as a jumper, I wrap a wire around the relay pin 30 (always has 12V) and 87 (switched output) ... so this bypasses the switching function of the relay and becomes the jumper.



As Stepson noted, remove the jumper immediately after the test as the circuit remains powered when the jumper is in place. I keep this jumpered relay in my glove box so I always can always make a quick jump check if needed.

Rich
Membership Chairman
Charter Member
1993 928 GTS Cover Girl
1987 928 S4
1979 928 5-speed rescue
1979 928 5-liter track beast

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12 May 2021 20:28 #21880 by DHS
Replied by DHS on topic Won’t start
Have ordered new relays with the resistor, got 6 to have spares, and a set of CARAX fuses that glow when blown, got the big set and will change out every fuse. Jumped the pump relay and can hear the pump running, so it looks like Saturday will be trouble shooting the system.
Will get the relay puller, always fun buying new tools and Lisle makes some great tools.

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15 May 2021 19:40 #21882 by DHS
Replied by DHS on topic Won’t start
So my A&P came by today he had a timing gun we put the pickup on a plug wire and when I cranked the light flashed, then we pulled the air cleaner and sprayed engine starter into the throttle bode and it ran. So it looks like a fuel issue since I have spark. I guess next would be pull the ECU and air flow body and have them rebuilt.
The fuel pump runs with the relay jumped.
Dan

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15 May 2021 23:21 #21883 by stepson
Replied by stepson on topic Won’t start
Dan, was this car sitting for a while and not being driven?

If so, your injectors may be clogged up. You can unclog them with various chemicals (my fav is Berryman's B-12). I made a jig to apply 9 volts to the uninstalled injector to which I attach a vacuum source to the top of the injector. I dip the nozzle end into the Berryman's, apply the vacuum, and alternate the 9v power between on and off. When the vacuum begins sucking the Berryman's through the injector, I move to the next injector.

There are also several commercial injector cleaners to which you can send your injectors for cleaning. It's pricey but cheaper than replacing injectors.

You can also use a noid light to test the power to your injectors prior to cleaning. If your injectors are clogged, however, even if your noid light says the injector is working, what is actually telling you is that the injector solenoid is working, but no fuel will be injected.

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16 May 2021 09:24 #21884 by DHS
Replied by DHS on topic Won’t start
Well the long time owner had it 10 years in Michigan, he passed away last summer and his son drove it to Florida in September. Up for sale Toby got it six months ago and drove it to the Keys, I have driven it to Georgia 850 miles last Saturday. So clogged injectors are low on the list, my guess is still fuel. I do not believe this car was ever basket case because everything is very clean.
Dan

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17 May 2021 02:23 #21885 by stepson
Replied by stepson on topic Won’t start
Ok great!
If you already replaced your fuel injection relay, and you still have the no-start, you could have a bad fuel injection ground or you need to have the LH rebuilt.

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15 Jun 2021 13:21 #21898 by stepson
Replied by stepson on topic Won’t start
DHS,
I see you are in Georgia. There are several folks there that have a LH based fueled 928 that could test your LH in their car prior to having it rebuilt.
OR
You can send it to me and I will put it in one of mine to test. If it tests bad, I can contact you and find out your wishes and send it for you wherever you want to have it repaired.

I do believe that both Louie Ott and Rich Andrade will test your LH for free and I would not hesitate to send it to either one of those guys. Do not try to send it to a local rebuilder. You will not be happy with the result.

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15 Jun 2021 13:57 #21899 by DHS
Replied by DHS on topic Won’t start
I sent the unit and MAF to Rich, just got them back, spent the last week cleaning ground points, have the new relays in and am pulling and cleaning each fuse. will probably be Saturday when I have her put back together, and will see what happens.
Will update then.
Dan

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15 Jun 2021 15:19 #21900 by stepson
Replied by stepson on topic Won’t start
Sounds like a great plan! Good Luck :)

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