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The Code 16 blues

2050 Views 6 Replies 3 Participants Last post by  xxpaulcpxx
I got them old code 16 bleuuuuuesssssah...

Here's the deal. I have been getting a code 16, off and on, for a couple of years now. My CRX is driven rarely since I moved out here to Cali, so keep that in mind. The check engine light might pop on once in a blue moon, but the engine never ran funny and the light would clear on the next restart.

Recently, I took a trip back and forth from Las Vegas - about 3 hours away. Hard driving all the way. When I got back, I refilled my tank full and drove home. Couple of days later, no start.

First thing I did was replace the distributer with a brand new one - no luck. Checked the plugs, all looked OK with the same amount of carbon on all. Only thing left was the Code 16.

After pulling the injectors and making sure they all worked OK, I went deep with the diagnostic tree in the FSM and finally found that the injector circuit on the ECU was not putting out any voltage. Bought a new ECU and swapped it in. It took a bit, but it did finally start again.

But now it is running rough at idle, and the moment I give it any gas the CEL comes on and the code 16 starts to flash again. I think this is going to be an electrical issue with the injector circuit, so I am going to be focussing my attention there. Is there anything else I might look at?
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What's code 16? You have a first gen correct?
Oh yeah, I almost forgot... the MAP sensor. when I switched to my Z6 manifold and forgot to hook it up, it idled terrible and didn't give me the code until I gave it gas. You would also notice it running very rich and nearly dying.
No, 16 is the fuel injector system.

Paul, how did you check injector operation?
I went throught the FSM manual the first time and was testing with my multimeter, I just got a new multimeter and will go though each system again.
Looking at the wiring scematic, it's pretty basic:
4 Hots from ECU to Injectors,
check Ohms on injector itself,
Check ohms on resistor box,
Check the flow back to the main relay.

Somewhere along there, whatever is causing my Code 16 also ate my first ECU as it no longer provided voltage to the injectors anymore. My new ECU works, but I don't want to fry that one like I did the first one. Just about to go out now to look at it.

BTW downest, I have a 1G and a 2G. My 1G is in storage at the moment though.
I'm glad I pulled my plugs.

Looking at them showed me that I did not have one (or more) cylinders that was rich or lean... which might happen if an injector is not working properly.

All my electrical connections seemed to be working OK too, from the ECU to the injectors to the resistor box. But the resistor box connects to the main relay! AHA!

If the main relay is bugging out, it will take out connectivity to all the injectors simutaiously, thus they should all look alike as mine do.

I've got the Main Relay pulled at the moment, and will be resoldering the connections in a moment.

Here is what a Volvo repair site has to say about relays:
Relay Repair vs. Replacement. Here's a generic statement about your relay (which I know nothing about) -- this statement displays my bias about the (poor) quality of Bosch wave soldering. If you can pop the cover off the relay, try resoldering all the connections on the circuit board before you replace it. (After all, you have nothing to lose but a few minutes.) The heavy connections that go to large components like the actual relay may need a large soldering iron or gun, whereas the connections at smaller components, such as transistors, should be reflowed using a smaller iron, like a 25-Watt iron. If you're not comfortable soldering, find a friend who is.
[Don Foster:] Over time (like 10 years), the solder used in production manufacturing tends to become crystallized and cracks. The type of solder used in high-volume production is different than that used in an electronics repair shop. The problem with the relays is tiny, almost invisible microscopic cracks in the solder. These cracks usually encircle one (or several) heavy connections, such as from the relay or a main lug connector. Under a bright light, and using a magnifying glass, inspect the soldered connections. Simply resoldering these circuit board very often restores them to perfect performance, and it's a whole lot better (and cheaper) than a $50-$100 replacement part. I have recovered literally dozens of Bosch relays (OD, fuel pump, wipers) to perfect performance this way at $0. In fact, I resoldered ALL the relays in my family's 6 Volvos before a failure stranded us.
Fortunatly, Mark Lamond has a great writeup on this repair - with photos!
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Well, I resoldered the Main relay... FYI, I tried using the new Cold Heat type iron and it didn't work out. Regular soldering gun worked great, and I used high strength silver solder.

But it did not fix my problem... and it would not start. Hmmm. So I started checking fuses... the Alternator Solenoid fuse was blown. I replaced that and it started, but was still having the same problems.

So I went back to the beginnign again. I started going though each ECU to injector wire, checking continuity and ohms on the bare wire alone. Turned out nothing was going through Injector #2 wire. ?Que? Since this is an MPFI car, this was one of my redone wires. I was looking at my wire bundle and I saw this little bayonette connector labled "A2", sitting open next to the one called "A4" which was connected to my ECU. I unplugged the connector for A2 and pluged in this wire - started fine and no code 16! I guess I had accidentally unplugged and replugged that connector into the wrong wire... I had run bayonnett connectores for all the wires I would redo while it was still DPFI, I had plugged it back into an old wire. I also found out a couple of these old connectors still had something going though them, so I sealed them back off again.

Problem solved, I was a dork. I went back and put electrical grease in each connector then sealed them shut with shrinkwrap.
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