97 plymouth slow crank No Start????

I have a 3.3 engine,took the top half off this spring to replace head gaskets, valve cover,seals etc. Put it all back together and it ran fine. I took it off the road to do this work so i haven?t driven it only started it from time to time. After a few times it started cranking real slow then it would start ok. Now its just slow. checked connections, took the starter out and had it checked, was alittle variable on the amps so i replaced it. still the same maybe alittle faster. checked fuel pressure was good. has 157,000 on it and have had it since new with no problems. I?m missing something here, any suggestions would be great. Thanks.

Reply to
punkoboy
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What does fuel pressure have to do with slow crank? And I see no mention of having the battery tested?

Glenn Beasley Chrysler Tech

Reply to
maxpower

yes- you are missing something- the battery is dead from sitting- and needs to be charged or replaced- also the alternator may be bad and not charging

you need to do a charging test on the alt., and a battery load test after it is first charged

Reply to
duty-honor-country

Not so fast!!! I?ve been around the block a few times. It has a new battery out of my 64 pickup. Even if the alternator was bad it still would start. Good guess. I would not be here if it were that simple.

"punkoboy" wrote: > I have a 3.3 engine,took the top half off this spring to > replace head gaskets, valve cover,seals etc. Put it all back > together and it ran fine. I took it off the road to do this > work so i haven't driven it only started it from time to time. > After a few times it started cranking real slow then it would > start ok. Now its just slow. checked connections, took the > starter out and had it checked, was alittle variable on the > amps so i replaced it. still the same maybe alittle faster. > checked fuel pressure was good. has 157,000 on it and have had > it since new with no problems. I'm missing something here, any > suggestions would be great. Thanks.

Reply to
punkoboy

Don't listen to "shirked duty-dishonor-country" aka Charlie Nudo. He's the resident troll.

Nippondenso starters have a characteristic problem with solenoid contacts. If you're cranking slow and not drawing enough current to significantly dim the interior lights, look at the solenoid contacts. You could also check the tightness of the battery cable to the solenoid itself, but ND starters have been prone to this sort of failure since the '70s.

Reply to
DeserTBoB

Use a DVOM, paper and pen. Connect the leads measuring volts at the battery posts, crank the engine and record your reading. You should read 10.5+ V

Next connect one lead to the neg battery post and one to the block, crank the engine and record your reading. You should measure .1v. Just like golf, low scores are good.

Next connect one lead to the pos battery post and the other to the starter motor post, crank your engine and record. You should measure

3v. Again JLGLSAG

If either voltage reading is greater, move the engine side probe closer to the battery and crank until you find your bad connection. You won't be missing anything.

Even after you find the big problem continue testing. With the eng running, Neg bat post to alt case should be .1v. Pos Bat to alt charge post should be .2v

Measure the voltage differential from the battery to the body and eng to body.

Reply to
JustSayGo

No, if the alternator was bad, and you ran the engine for any amount of time, the draw from the ignition, and from repeated starts, would drain the battery in short time.

Don't assume the battery is good just because it's "new" IYO, have a draw test done on it. I've seen many a 5-year warranty battery give up the ghost at 1 year and have to be returned and pro-rated, for a new one.

You also have to do a current draw test on the starter.

Reply to
duty-honor-country

When you have a slow crank problem and you mention checking fuel pressure some people may question how many times you have been around the block!! Not to degrade you in anyway but checking the battery question had to be asked after I read that!!

Glenn

Reply to
maxpower

The DVOM voltage checks prove that the battery has sufficient capibility under load and that battery capability is reaching the starter with an optimal ground connection.

Most cars on the road will not pass each of these tests because of less than optimal connections.

Once you know because you have proved with the DVOM that you have sufficient power and ground to the starter, what is value of starter draw info?

If the engine still cranks slow with excellent connections between a good battery and the starter, either the starter is bad or the engine is too hard to turn because of mechanical problems. In either case starter draw will be beyond specs.

These tests will diagnose the cause of any slow and most no cranking engines.

Perfoming these simple voltage tests and making repairs to high resistance connections on vehicles without any obvios problems, will increase reliability of every electrical component in the future.

Reply to
JustSayGo

Well, a good DMM with an accurate low resistance range will give you current draw anyway. All you have to get is the DC resistance to the same path of which you measure the voltage drop. Ohm's Law works every time: I = E/R.

Reply to
DeserTBoB

I must be confused by reading your post. You can call it Digital Volt Ohm Meter or Digital Multi-Meter.

Are you answering my simple question, "what is the value of measuring or knowing starter draw info?"

How do you use a DMM to measure starter current draw to locate resistance? How do you test useing your low range resistance DMM to diagnose the problem?

Ohms law formula is why the meter reads a differance from one point to the other whenever there is resistance.

Measuring voltage at varios points under load is fast and simple. I don't need to measure or know the amount of resistance because voltage differance indicated by the volt meter will allow me to isolate the resistance and prove that my repair has corrected the problem. I don't need to measure starter draw to know if it is capable of performing its duty.

Measuring ohms of resistance without the load may not help in diagnosis.

Reply to
JustSayGo

Your procedure is the perfect way to locate a external high resistance, looking for high IR drops. The question was how to determine current draw, which in this case of troubleshooting, is irrelevant unless there is a weak or dragging motor, which may be the case here.

Measure the point-to-point resistant from, say, the battery positive . terminal to the starter motor terminal in tenths of an ohm, more resolution if you have a Fluke or other good DMM. Then, measure the IR drop when the motor is cranking. Using Ohm's Law, simply divide the IR drop (voltage) by the circuit resistance, and you have the motor's current draw in amperes. What this WON'T show, of course, is high internal resistances in both the motor itself (bad brushes, burned commutator, etc.) and in the battery itself (low state of charge, sulfated plates, plate and strap corrosion, etc.)

Exactly, and is also why you can easily calculate current draw if you know the external resistance, with the caveats stated above. Thus, if the IR drop between the battery and motor terminal side of the solenoid tested good, you'd want to know just how much that load of the motor is drawing. If current is low when IR drops are low, the trouble is either inside the motor itself, a "floating" ground (more common than most people realize) or a low or sulfated battery.

The only change in resistance will occur when the load heats up the cabling, during which time the DC resistance of the cabling will increase somewhat. Bad connections, such as loose bolts and nuts, as well as battery terminals, will also heat up quickly during a high current draw, and are usually easy to spot by feel...if you dare.

Reply to
DeserTBoB

Thanks to all that have replied to my problem. After more checking, Took the surpintine belt off to check the pulleys and the alternator was locked up, stoping it from turning over. Learn something new every day. Thanks Again

"maxpower" wrote

Reply to
punkoboy

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