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A couple of years ago I had trouble with a hesitation and miss that I couldn't track down, then one day going over connections and and vacuum hoses I stumbled on a corroded ground near the driver's side headlight. I cleaned it up and miraculously all my troubles cleared up.
I posted this revelation here and an excert appears in the FAQ now. At the time Lucid posted that that ground has nothing to do with fuel injection and therefore shouldn't have been the cause or solution to my problems. Well, 2 years later, I think he's right. I had been keeping notes on all the chages I had been making, trying to fix my problem and checking my notes I realized that I had removed the distributor cap and cleaned the shaft that day too.
And that leads me to my questions: I have been able to affect this grounding issue just by removing and replacing the distributor cap (loose wires get jostled? - checked that a dozen times).
I noticed that the distributor shaft has considerable vertical play (it's an old 240 style distributor mounted vertically near the front of the block) - could this cause any problems?
After I replace the cap I noticed copper oxide (or greenish powdery deposits) at the electrodes within a few hundred miles. They appear only at one edge of the electrode - is this indicative of a flaky connection somewhere?
Finally, I have checked and removed and replaced every ground I can find, but am thinking of splicing into the coil ground (Rex/Regina) and giving it it's own ground - is this a good idea? Is the black wire from the coil ground?
I would really appreciate some input on this one.
Thanks,
Ron
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As a general rule I pull all the connections (especially engine controls, nothing on the O2 sensor or the ECU) I can get access to and push some dielectric grease into the female plugs. I started this after freaky issues with variable RPM on the BRICK shown below and everything else tested fine. Issue went away and never came back in 10 years.
My 91 740 B230FT LH2.4 started with a little hiccup off idle and 1 month later it progressed to full blown dying ECU.
good luck
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My 93 940 surges with the turn signal, is hard starting, and the mileage has dropped down to around 20-22. This is my project for the week and I will be watching this post to see what you find with grounding.
the surging with the turn signals makes me think I have a groung issue at the rear of the car
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Replacing my radio suppression relay (RSR)solved a hard start problem a few months ago. These can be resoldered as well. I would check the ground that is near the passenger side headlight on the fender as this grounds the RSR. I am still working on my issues - they are mostly minor but enough to have me fail the emission test. I have moved on to rechecking for a small vacuum leak which also explains some of my symptoms.
Good luck,
Ron
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The grounding terminals that you mention only have a few wires to them.
I think that they provide ground to items that cannot ground themselves, like a light bulb in a plastic fixture.
It is my opinion that most components still ground through contact with the engine or body, etc.
Examples - the spark plugs, the glove box light - anything that does not have an obvious ground wire.
--
'96 855R,'64 PV544 driver, '67 P1800 basket case, '95 855, '95 854, the first three are mine, heh, heh, 485,000 miles put on 9 bricks
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I think that there are more grounds than you might think. I have read of two straps on the engine and I personally had problems with a '90 744 TI dying when the high beams were turned on.
During that adventure I found that the power stage and the bracket for the anti lock brakes seemed to have important grounds.
If the grounds go bad over time, what about power connections?
I was told to clean all connections and protect them with dielectric grease. Examine all pins inside plugs to make sure they have not been pushed back.
--
'96 855R,'64 PV544 driver, '67 P1800 basket case, '95 855, '95 854, the first three are mine, heh, heh, 485,000 miles put on 9 bricks
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I'll double check that bracket. I have removed and cleaned the ground strap from the block to the firewall (what's in that black box that's about 5" square that has a common bolt with the ground strap anyway) and redone the 2 fuel injector ground straps. I have replace the radio suppression relay.
Thanks for the advice,
Ron
93 944 320,000 km
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Dear ronald,
Hope you're well. The black box is a weight, which is affixed to the firewall, to damp certain vibrations (harmonics). While this item has no moving parts, it helps to keep the car quiet. Thus, do not remove it.
Hope this helps.
Yours faithfully,.
Spook
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Thanks for the information! I think I had that knowledge somewhere back there but completely forgot it.
Ron
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Dear Ronald,
Hope you're well. When were the plug and coil wires last changed? Are they made by Bougicord, the firm that supplies these to Volvo?
The greenish deposits are corrosion, likely caused by humidity. Perhaps a thin coat of dielectric grease will seal the wire end-cap to electrode connection. If moist air is kept-out, corrosion will not occur.
You might want to remove the coil from its base, and clean the contacts on the coil and on the base. I suspect you'll find some corrosion there.
Hope this helps.
Yours faithfully,
Spook
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Hi,
The wires are all new Bougicord from FCP Groton. They are class C, which concerned me as the FAQ suggests class F are OEM and at least class E are recommended. I will try the grease on all connectors.
The coil is only 2 years old, but I will try removing it from the heat sink and checking for a poor connection.
Thanks,
Ron
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I could imagine that a wobbly distributor shaft would contribute to miss and hesitation. If the spark gap varies, the spark quality will too. The shaft really should not wobble horizontally and maybe you need a new distributor.
Another tip: there are a number of grounding planes around the car. I would clean the contacts on each one and protect using OxGard conductive grease.
--
See the 700/900 "FAQ" at the menu bar top screen left side.
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I have found 2 of those grounding planes - one behind each headlight and have cleaned them up but not used conductive grease. The last thing I did was to run a ground wire from the passenger side plate to the main battery ground with no change in performance noted.
The distributor wobble is not side to side at all.
Thanks,
Ron
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