Still some odd starting/electrical problems

[rgk]

Hello again,

We're having some starting issues with the lady's '88 245. Once in a while it won't crank at all, and once in a while it will die when idling at a stoplight.

The no-crank event is somehow related to a bad ground. I know this because the car will start when I attach a jumper cable from the negative terminal of the battery to the wire that connects the engine block to the body and THEN try to start it.

The dying at idle seems to have improved (meaning it happens less often) since I cleaned the MAF sensor and idle air control valve, but it did happen once after cleaning.

Upon dying at idle it went right into a no-crank event. That's when I attached the jumper.

Previously the car would crank (and start) simply after cleaning the large, threaded block-to-body cable at the rear left side of the block (when facing the block).

The car previously had a rear main seal leak, which gunked up the block. I cleaned it in hopes of that making it more conducive to ground voltage. One time since it has refused to crank.

So it's not a huge problem, but an annoying one nonetheless. The only other thing I can add at the moment is that the car seems to not want to crank when the weather is hot and humid. Here in southern Illinois, humidity always accompanies heat.

Oh, and finally, at normal operating temperature the temperature gauge at the dash stays halfway between middle and bottom. Once in a great while it surges to the top, staying just below the red mark.

So recap:

sometimes stalls
sometimes won't crank
sometimes stalls, then won't crank
seems that it won't crank in hot/humid weather

cleaned maf & iac
seemed to help for a while
died at idle/wouldn't crank

cleaned engine block
seemed to help for a while
wouldn't crank today at hottest part of day
cranked later in the day, drove no problem

problem with temp/thermostat reading

Any ideas? If anyone can help, thanks!!

[billofdurham]

The block to body earth (ground) cable is one of the most overlooked cables on the car and can cause all sorts of problems if it isn't kept in good order. I suggest removing the cable completely and carefully checking it to ensure that it is intact. Whilst it is off clean the contact points on both the block and the body. Do the same with the battery negative lead. Ensure the contact points on the body are clean and free from corrosion.

The temp gauge should sit halfway on the dial. Test the temp sender as in the attached:

240 1988 coolant temperature sensor.pdf

(249.77 KiB) Downloaded 174 times

Bill.

[rgk]

Bill,

I have removed, checked, and cleaned the block-to-body several times. I am considering replacing it but have not been able to find a replacement either at IPD nor FCP nor the neighborhood auto parts store. I should probably replace the battery negative cable as well, as that has been thoroughly cleaned and inspected also.

Thanks!

[rgk]

Well, I suppose I'll just replace the negative battery to ground cable and find a suitable replacement (similar gauge) for the block-to-body ground wire and put the correct-sized eyelets on it. I'm about to go test the coolant temperature unit.

[rgk]

Am I supposed to test the cable going into the coolant temperature sensor? If so, I'm getting a standard 2900 ohms at an ambient temperature of about 80 degrees F. Both of the terminals on the sensor itself, however, show only one ohm.

As for testing it when the car has reached normal operating temperature, that is impossible due to the heat and trembling of the engine. If I am supposed to test the sensor itself, I will have to remove it and test it in a pan of water. If so, what is the standard temperature of the coolant at normal operating temperature?

If I am to test the sensor itself, it seems that I have already determined it to be bad. Agreed?

[rgk]

The plastic part of the coolant sensor that acts as a connection broke off when I tried to remove it from the block. I found a replacement at a local auto parts store and put it in. The temperature gauge still hovers a bit below the halfway point when driving, and just about reaches it when idling after driving, but that might be attributed simply to the gauge being bad. I'm not going to remove it and mess with the circuit just to get it to the midway point.

I also purchased two 10 gauge wires and four eyelets: one for the negative battery terminal (the wire that extends from the main, really thick negative cable to the body), and one as a replacement for the block to body cable. The current block-to-body cable was incredibly thick, and not so much stranded as much as it was weaved. I've never seen a wire like this on a car before. It wasn't even insulated. I suppose I should assume that it was a last-minute replacement.

I tried starting the car and again I got nothing from the starter. I fiddled with things for about half an hour and finally got her to start. Again I am at a loss. When starting the car up again right after shutting it off, it starts, but let it sit for about ten minutes and I have to hold the ignition switch in "start" for about three seconds before the juice activates the starter. It seems that this issue is pronounced when it's hot and humid out.

Bad ignition switch? Probably not, as sometimes the juice goes to the wire that activates the solenoid, and sometimes it doesn't, which points to a bad ground. But I tried the jump trick (jumping the negative circuit at the body terminal of the block-to-body wire straight to the negative battery cable) and it did not start it up immediately, like I would expected it to with a bad ground. I don't know. Maybe the chassis itself inside the screw hole is dirty?

[rgk]

Eureka. I ran a test today by hooking up one end of my jumper cable to the starter itself and the other end to the negative battery terminal. Whereas the car would not crank at all before running the test, with the jumper attached it started without a problem. So I knew that the starter itself had a ground problem.

I didn't want to do it, because it's no easy job, but I removed the starter. I believe I wrote something up on this forum in the past regarding the most effective way to do this, so look through my posts if you need that particular advice. In any case, I removed the starter, put a rag in the resulting hole, sprayed it, and sprayed the surrounding engine block area with engine degreaser. I prefer a gel formula degreaser, which sticks well to the surface you spray. It takes about fifteen minutes to cut through the grease. Really tough spots need some scrubbing and/or multiple applications. I made especially certain to clean the area around where the starter resides and the bolts which hold the starter to the chassis. I suspect the ground (negative) electrons travel through the bolts.

After cleaning, rinsing and drying, I took out my multimeter and placed the NEGATIVE test lead on one of the bolts that hold the starter to the chassis. I put the POSITIVE test lead on the positive terminal of the BATTERY. Seeing that I was getting 12.6 volts was a good sign, because it meant that the bolts themselves had a current running through them, and that they were thus good grounding material. I attached the starter and it started the car without a problem at all.

Earlier in the day I ran a similar test to see if the starter was getting any power at all. I attached the POSITIVE test lead to the smallest WIRE that runs into the solenoid. This is the signal that simply tells the solenoid to activate and should not be confused with the large cables that power the starter itself. The negative test lead was connected to the NEGATIVE terminal of the BATTERY. A signal is only sent to the solenoid through that small wire when you turn your key to the farthest (crank) position. I did just that and saw that the multimeter read 12.6 volts. This meant that the starter was getting power. However, if the electrons flow to the starter and have no way to return to the battery (because of gunk), they won't power the starter. Think of this as your own circulatory system. Blood picks up oxygen in the lungs and disperses it throughout your body. What happens when blood encounters a blockage? A heart attack, a stroke, a blood clot - nothing desirable. It can't simply turn around and go the other way. An electric current may not be quite as dramatic, as the worst thing that may happen is that you won't get power (or won't get shocked!), but a malfunctioning car may lead to other serious problems.

I hope this long thread motivates you, the reader, to KEEP YOUR CAR (and all other cherished possessions) CLEAN. If your engine is gunky, don't forget to clean it next time you're at the self-service car wash, being careful not to damage or soak any sensitive electronic equipment such as the distributor. They have a special 'engine cleaner' setting on those hoses. This is doubly - no, triply - important if your car is leaking oil. If you have an oil leak, and the oil leaks down, say, the exhaust pipe, the high temperature of the pipe will cause the oil to burn, evaporate, and cake over all your engine block, sensitive equipment, etc., resulting in the confusing and hard to find malfunctions I am writing about. Indeed, that is the exact reason I am having all these ground problems now. We had an oil leak, drove around with it for a couple of months, and fixed it. A couple of months later yet the car would not start with no explanation. Well, it turns out that everything under the hood had filthy oil deposits caked onto it. Did I mention that I cleaned the engine block at the car wash and that the car was OK for a couple of days and then started exhibiting the same behavior? That's because I couldn't get to those darn starter bolts without removing the darn starter.

Clean yer car - inside and out. It will make your life easier and happier.

[mikealder]

Are you still having "fun" with the temp gauge? if so try a new thermostat in it, what you describe earlier in the thread sounds like a stat that has stuck open - Mike

[rgk]

Mike,

Thanks, but no, the temperature gauge goes up to normal operating temperature. I'm pretty sure the stabilizing function on the gauge itself has gone out, as sometimes it wavers above and below the middle, but often times it hits the middle dead-on, so I'm fairly certain the thermostat is not stuck open.

In other news, I figured out that my overdrive relay was bad. I replaced it with one from an old Volvo of mine. The car shifts better and the little arrow on my dash has turned off.

[rgk]

HOWEVER, I must apologize for the long-winded success post above. Yes, the starter is still acting up.

The starter will not crank if it hasn't been cranked for a couple of days.

The starter also will not crank when it's above about 90F outside.

The starter will always crank and start when a jumper cable is hooked up between the starter and the negative terminal on the battery. Because of this, I thought I could attach a permanent jumper cable between the starter and the block, but this just fried the cable.

Seems like a ground problem.

Any ideas? Replace the starter?? Thanks!!