Cold Start Relay

For several weeks now I've noticed that It's been increasingly difficult to start the Volvo from a cold start. Warm starts are fine, but that first start of the day usually takes about 6 tries while keeping the throttle sightly open. Suspecting a faulty cold start relay, I performed a barrage of electrical tests on the unit to see if the terminals would open or close - nothing ... it was dead. Good thing, Bosch still makes new replacement relays! Unfortunately, they look too modern for the Volvo; black plastic and all. Fortunately, I was able to source a working, used, "old school" unit from iRoll Motors

Before:

After:

Above and below are some before-and-after shots of the replacement cold start relay after sanding and polishing. The car now starts on the first or second try, but I still have to keep my foot on the gas pedal to keep the throttle slightly open ... must be an old car thing.

Before:

After:

Anti-Corrosive Paste

Found a tube of anti-corrosive paste for electrical connections in my local ACE Hardware store under the brand "Ox-Gard", Anti-Oxidant Compound by Gardner Bender. The stuff sells for $3 - $4 a tube and how it differs from dielectric grease is, in addition to its anti-corrosive properties, the paste is also conductive. Whereas dielectric grease works great for protecting brand new connections from the elements, on old cars where electrical connections have already degraded, anti-corrosive paste works way better in preventing further degradation and improves connectivity via its conductive properties ... from what I read anyways ... I'll let you know in 20 years if it's true. In the meantime, it can't hurt. All I know is, because it is conductive, care must be taken to wipe off any access to avoid current "jumping" to adjacent connections. Here's a list of other anti-corrosive products and their manufacturers from the K1TTT Amateur Radio Station website.

So, armed with a tube of Ox-Gard and some fresh fuses to get my multi-meter working again, I set out to restore all the electrical connections I could find under the hood to ensure corrosion free leads and proper grounding. To pick-up from where I left off with the main fuel injection relay, I was able to determine that input to the relay was indeed 12V, but output from the relay to the coil was still 10V indicating that the voltage drop was happening via the relay. Perhaps this is how its supposed to work by design? Or perhaps, the additional voltage is kicked in at ignition point? Who knows ... I have bigger problems to solve right now ... like the no-start situation. That's why I placed an order for the "Bosch Fuel Injection & Engine Management" book on a tip from blog reader George Downs of Bartlesville, OK (thanks George!). This book may be found in IPD's P1800 book section.

Oh yes, I'm also pretty sure at this point that the cause of the no-start is due to a faulty starter. I applied the following "stupid starter tricks" that I knew off and arrived at the conclusion that it's dead:

• My favorite - Banging on the starter solenoid with a hammer while attempting to start with the key. Sometimes the contacts in the solenoid get stuck and this low-tech approach may sometimes "free" them.
• Check that the starter is getting the full 12V via the lead directly from the battery - it is.
• Placing the transmission in gear and rocking the car back-and-forth before attempting to start. Sometimes the starter pinion gets stuck with the gears in the flywheel casing. This procedure should free it.
• The screwdriver trick - If the solenoid fails, the starter can be "jumped" by engaging the ignition to the "on" position and placing a screwdriver across the 2 leads on the starter. Screwdriver was too cumbersome, so I used 2 cables with aligator terminals instead - Lots of sparks, still no start!

Just for the heck of it, I also ran some tests found in this Volvo Fuel Injection Fault Tracing handbook downloaded from the Volvo 1800 Picture Gallery website, and found that my air temperature sensor was faulty. The resistance reading of a working air temperature sensor should be between 260 to 340 ohms - Mine was 400 ohms. Could this little thing be causing the no-start? If anything it should affect engine performance instead of preventing it from starting ... right? I'm not stating this as a fact as I'm obviously not the person to ask about these things. Merely thinking out loud or talking to myself ... which is not out of the ordinary. I really need to read that book!

Coil Not Getting Full 12V

When I installed the Pertronix Flame-Thrower ignition coil last weekend, I discovered that the coil was not receiving the full 12 volts required for optimum performance (I was reading only 10V on my volt-meter). The installation literature suggests that there is a resistor somewhere in the circuit that needs to be removed in order to get the full 12 volts. Well, first of all I don't even know what a resistor looks like, and a close inspection of the wiring schematic didn't reveal any resistors leading to the positive terminal of the coil. Here's a link to a nice wiring diagram in PDF format that you can zoom in on for a 1972 1800E (should be the same for a 1971 1800E ... I think?!!) Of course, me reading an electrical schematic is like a 3 year old reading the Wall Street Journal.

So, either there really is a resistor, or there's a voltage bleed somewhere somewhere in the circuit leading to the positive terminal of the coil. From what I can tell, the 2 brown wires feeding into the positive terminal of the coil are from the main fuel injection relay and from the horn relay via fuse #6 in the fusebox. In this 1st photo, the twin brown wires are shown connected to the positive (top) terminal of the coil. Red wire from negative terminal of coil goes to the tach. Figuring out the wire colors was a task all by itself since all my wires are black ... they're either spray-painted black by some previous owner or black from years of grease and dirt fusing to the wire jackets! Only with some 1-on-1 time with the rotary tool did I manage to coax the wires to reveal their "true colors".

Fuel Injection Relay - Before:

Fuel Injection Relay - After:

A volt-meter test on the battery showed a full 12 volts, so I decided to trace the source of the voltage drop by removing the main fuel injection relay, cleaning up all connections with the rotary tool and some electronic contact cleaner, reattaching all connections, and ensure proper grounding. The only thing missing is I need to get my hands on some anti-corrosive zinc paste that I read about in this excellent article about electrical connections in our old Volvos. This guy is almost fanatical about the stuff, needless to say, I found new religion. I also extended the session with the rotary tool to include the restoration of the relay housing pictured in the before-and-after photos above. First, a rotary paper sanding bit was used to remove surface impurities, followed by the stainless steel rotary brush to get that brushed steel finish.

Of course, after hooking everything back up and in my haste to test the voltage, I mistakenly set the multi-meter to test resistance and completely fried the unit! I probably just blew the fuse in it. In any case, I wouldn't know the results of my efforts until I have the fuse replaced and my multi-meter working again ... story of my life.