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toast54  



Joined: 08 Sep 2014
Posts: 78
Location: Oklahoma City OK

PostPosted: Thu Sep 07, 2017 10:28 am    Post subject: New "no start" thread Reply with quote

I'm going to put it in the shop if I can't get this sorted out. Perhaps someone might have an ah-HAH! and point me in the right direction. 924S will not start and I've gone through several things searching for the reason. Ive tested fuel pressure, coil, sensors, injectors, wiring, connectors, ignition switch, starter and various other items.
1 With the DME relay in the socket, I get NO tach bounce and no start.
2 With the DME relay removed and using the 3 pin jumper, I GET tach bounce and fuel pump kicks in, it will start and run very briefly (and doggedly), perhaps 10-20 seconds. Ive replaced the DME relay, which I replaced a few years ago, and there's no change. I'm getting voltage to the pins in the relay socket and I'm getting voltage to pins 18 and 35 on the ECU connector. I did replace the ignition switch as I wasn't getting voltage to the socket pins and the starter as it began dragging badly. I don't have the luxury of having access to a known good ECU. Might anyone have input on something I might be missing?
I'm not one to throw parts and hope they stick and with fall weather approaching, I'd really like to be ready for fall foliage in the Kiamichi mountains of SE OK
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hdrider19  



Joined: 03 May 2016
Posts: 193
Location: Catawissa Missouri(40 mi sw of St Louis)

PostPosted: Thu Sep 07, 2017 12:24 pm    Post subject: Reply with quote

Take a look at this video. Edredas does some great how to videos. Hope it helps.

http://youtu.be/1WuZuPcVuqM
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87 924S
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edredas  



Joined: 09 Dec 2004
Posts: 851
Location: Charlotte, NC

PostPosted: Thu Sep 07, 2017 1:08 pm    Post subject: Reply with quote

Thanks Hdrider, since that was such a short video I'm actually going to make a longer video where I take a running car and unplug things individually to show the symptoms they cause. This should give people a better idea of what issue they're having...

As for your issue, Toast; it sounds like your DME could be at fault here. That said, there are a few other things you can check.

1. Stick a multimeter into the DME temp sensor plug (blue) and just make sure there is no resistance. If you do get resistance then the wires are shorted out under the boot causing a no start/poor running condition.

2. There were a few guys around here doing early engine swaps so verify that your AFM and DME are a compatible pair. Your 924S' AFM should have 064 as the last three digits. These 064 AFM's will only work properly with DME 121.04 and 121.05 (88 models). If you have an 028 AFM you need DME 111.01.

So if all of that looks good then it very well could be you DME at this point. That said, if you're interested, I'm considering loaning out a few of my spare DME's for people to see if their car will start. I have two spare 064 AFM's and two spare 121.04 DME's. Basically, the person would pay shipping both ways and $75 as collateral. They would get the $75 back when the DME is returned. The idea is just for them to see if a good DME will fix their issue and if its worth repairing or buying a new DME...

I hope that helps!
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'86 944 -Garnet, Fully loaded, Koni suspension
'87 924S -Red, 300hp 951 swap
'87 924S -Red, New Project
'87 924S -White, Automatic
'88 924S -Red, Daily Driver, Bone stock
'93 Mx6 -White, Megan Racing suspension
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toast54  



Joined: 08 Sep 2014
Posts: 78
Location: Oklahoma City OK

PostPosted: Fri Sep 08, 2017 12:50 am    Post subject: Reply with quote

For clarification purposes, I will now call the relay the DME relay and what I'm calling the ECU will now be the DME unit. Pulling the DME relay, a brand new one BTW, and inserting the 3-pin jumper powers up the fuel pump AND the DME unit, correct? So, I am getting signal from the position sensor (tach bounce) when the jumper is in, and the car will start, but only run for about 10-20 seconds, rolling smoke from the exhaust(like it flooded) but NOT when the DME relay is in. I have 2 DME relays and alternated between them, but to no avail. Both sensors at the flywheel measure around 1050 ohms. I did replace the ignition switch a couple of weeks ago as I wasn't getting a change of resistance when turning to the "on" position. If I spray starting fluid in the j-boot, it will start, but only if the jumper is in. If I decide to test the DME unit,Edredas, I'll let you know and we can arrange something
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edredas  



Joined: 09 Dec 2004
Posts: 851
Location: Charlotte, NC

PostPosted: Fri Sep 08, 2017 5:44 am    Post subject: Reply with quote

No problem, we will know what you mean. That said, the DME is the relay. However, it is colloquial on most forums to call the ECU the DME; no idea why since the factory manuals call it the DEE, but that's the way it is.

When you are cranking the car, the DME relay isn't activated until the DME or DEE sees that the engine is rotating at least 200 rpms. If the DME doesn't see this signal the fuel pump will not run and the injectors may not fire properly. Which might be causing your black smoke. So, if both of your sensor are good and you've made sure the wiring harness is fine, then it likely the DME.

I hope that helps!
_________________
'86 944 -Garnet, Fully loaded, Koni suspension
'87 924S -Red, 300hp 951 swap
'87 924S -Red, New Project
'87 924S -White, Automatic
'88 924S -Red, Daily Driver, Bone stock
'93 Mx6 -White, Megan Racing suspension
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toast54  



Joined: 08 Sep 2014
Posts: 78
Location: Oklahoma City OK

PostPosted: Fri Sep 08, 2017 9:49 am    Post subject: May have stumbled onto the issue Reply with quote

I found the brown ground wire that goes to pin 85 (ground to DME) on the DME relay socket had pulled loose and was well hidden behind a much larger wire. Ive re-inserted it, installed the DME relay, reconnected the battery and will attempt to start it after dinner. Wish me luck
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toast54  



Joined: 08 Sep 2014
Posts: 78
Location: Oklahoma City OK

PostPosted: Fri Sep 08, 2017 10:43 am    Post subject: Reply with quote

Welllll...some improvement. On the plus side, it starts with the DME relay in the socket so no need for the jumper. On the not-so-plus, it's still running like crap and dies after a 10-20 seconds of running. Still have to floorboard the accelerator to get it to catch..."endeavor to persevere" Chief Dan George
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Paul  



Joined: 02 Nov 2002
Posts: 9285
Location: Southeast Wisconsin

PostPosted: Fri Sep 08, 2017 12:09 pm    Post subject: Reply with quote

I would check these just to make sure:

Rotor set screw (make sure rotor hasn't turned).

Camshaft timing

Compression test

AFM slider
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
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Paul  



Joined: 02 Nov 2002
Posts: 9285
Location: Southeast Wisconsin

PostPosted: Fri Sep 08, 2017 12:18 pm    Post subject: Reply with quote

Good info here:

http://www.clarks-garage.com/

The good news is that the majority of DME computer problems in 944s are related to bad solder joints which can be repaired. If you are having problems starting the car and suspect a bad DME computer, try tapping on the computer during cranking. If the engine fires while tapping on the box, you have bad solder joints. If it still doesn't start, that doesn't mean the DME computer is good. It may be good. But, it may also mean that the solder joints are very bad or the DME computer has failed for another reason.

The remainder of DME problems are primarily related to water intrusion, especially the later 944s where the DME computer is located in the passenger's footwell below the battery tray.

Inspecting

Remove the DME computer from the vehicle using DME-01.
Using the appropriate steps of DME-02, open the DME computer as if you were going to replace the computer chip. The DME computer has two separate circuit boards which are mounted facing each other and are connected by a flexible ribbon cable. In order to inspect the circuit boards, you'll have to separate the circuit boards. This process is explained in DME-02.
When you have the two circuit boards separated (still connected to each other by the ribbon cable), inspect all the solder joints with a magnifying glass. If the solders are dull grey in appearance as opposed to shiny silver, they should be resoldered. Most solders now have some type of rosin core flux to promote better solder flow. However, the flux will frequently leave a brownish residue on the solder joint which many manufacturers neglect to clean off. This can make a good solder joint appear bad. So, before you condemn what appears to be a bad solder joint, first clean the joint with a cotton swab and alcohol to remove any flux residue.
When you inspect the solder joints on the circuit boards, pay particular attention to those joints at the connectors for the ribbon cable that connects the two circuit boards. Historically, those solder joints are the most susceptable to being broken or otherwise bad.
Then you inspect the inside of the DME computer, look for evidence of water intrusion. Typically, this will be a white residue on portions of the circuit boards or as a visible white line (water line) on the inside of the computer casing.
After you've inspected the DME computer, repair any questionable solder joints.
After you've repaired any questionable solder joints, reassemble the computer, install, and attempt to test drive the vehicle (assuming the DME is now working), to check the operation of the computer.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
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toast54  



Joined: 08 Sep 2014
Posts: 78
Location: Oklahoma City OK

PostPosted: Sat Sep 09, 2017 11:40 am    Post subject: Reply with quote

Removed the snorkel and air filter housing and found about 2 cups of what appears to be thinned out oil in the bottom of the housing. I'd post a photo if I knew how . Sucking that up certainly would explain all the smoke. I'll clean the housing and MAF tomorrow and go from there.
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toast54  



Joined: 08 Sep 2014
Posts: 78
Location: Oklahoma City OK

PostPosted: Sun Sep 10, 2017 12:21 am    Post subject: Reply with quote

Apparently, the o-rings in my AOS have failed...catastrophically, I might add, allowing a great deal of thinned oil (I'd say about 16 ozs)to enter into the throttle body bellows, making it's way back into the filter box. I'm going to disassemble everything from the throttle body to the snorkel and clean it up. I'd still like to be able to start it
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toast54  



Joined: 08 Sep 2014
Posts: 78
Location: Oklahoma City OK

PostPosted: Sun Sep 10, 2017 9:56 am    Post subject: Reply with quote

Took the airbox, j-boot, MAF off, cleaned it all out with MAF cleaner. Then fired it up. It took about 30 seconds to fill the airbox with about 8 ounces of oil. You would have thought I was rolling coal, too. AOS is more than i want to deal with, so I'll probably sell it...or donate it. Thanks for all the input with all the issues Ive had
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edredas  



Joined: 09 Dec 2004
Posts: 851
Location: Charlotte, NC

PostPosted: Sun Sep 10, 2017 10:28 am    Post subject: Reply with quote

Check the oil level... while the AOS seal will cause oil to get in the engine, it shouldn't be that bad. The oil should only be up to the top thin line on the dipstick. If it up to the top of the flat spot it has a quart too much and it will suck it up in to the engine and airbox.

I hope that helps!
_________________
'86 944 -Garnet, Fully loaded, Koni suspension
'87 924S -Red, 300hp 951 swap
'87 924S -Red, New Project
'87 924S -White, Automatic
'88 924S -Red, Daily Driver, Bone stock
'93 Mx6 -White, Megan Racing suspension
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toast54  



Joined: 08 Sep 2014
Posts: 78
Location: Oklahoma City OK

PostPosted: Mon Sep 11, 2017 4:01 am    Post subject: Reply with quote

Just for gits n shiggles I blocked the AOS to j-boot and started it up. It ran but pushed an enormous amount of oily fluid out through the canister in the left fender and blew bluish smoke all the while, but it didn't smell oily.
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toast54  



Joined: 08 Sep 2014
Posts: 78
Location: Oklahoma City OK

PostPosted: Tue Sep 12, 2017 6:57 am    Post subject: I'm going to keep it Reply with quote

I've decided that too much blood, sweat and tears have been invested in this car....and money, sooooooo I'll work on it when I can. I did sort out the no-start issue, so progress is being made.
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