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1995 Geo Prism - failure to start


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robertsfd2002
User

Apr 28, 2014, 1:04 PM

Post #1 of 28 (4561 views)
  post locked   1995 Geo Prism - failure to start  

I read the "CRANK BUT WON'T START" sticky, but some of it's over my head; if this means I can't be helped, that's understandable, but I thought I'd try.

1995 Geo Prism Lsi 1.8L with 136,000 miles (bought this new 18 years ago and have been the only owner): was running fine, then sits for one week (I've had it sit for several weeks before with no problems). Wife starts it to move it to end of driveway and mentions it is hard to start (takes several tries but it gets moved). Two days later I start it fine and drive it 25 miles with a few stops along the way - no indication of any problem whatsoever. Next day it won't start. Turns over but no start, not even acting like it wants to.

What I did: Starting fluid into throttle body - this does nothing. Pulled plug wires, inserted screwdriver and held to metal block and get a spark across.

Not sure what to do now. Other advice found on Internet for similar problems but I'm not really sure how or what to do as I'm a novice. No tools owned other than basic tools (socket set, screwdrivers, etc).

Any help appreciated. I'd like to keep driving the car and am willing to try fixing it. Wife wants to trash the car, but it was running just fine and has been a great car and I think it must be something small - it's been paid for a long time and is cheap to drive and I don't want to give that up.

Thanks in advance.


Hammer Time
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Apr 28, 2014, 1:15 PM

Post #2 of 28 (4558 views)
  post locked   Re: 1995 Geo Prism - failure to start  

The info in that sticky is really just basics. It gets more complicated after that. Your test results aren't making a lot of sense already. You eliminated spark and fuel so that only leaves compression. If you lost compression then you could have broken a timing belt which could be big problems because you will have a bunch of bent valves..



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Discretesignals
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Apr 28, 2014, 1:22 PM

Post #3 of 28 (4551 views)
  post locked   Re: 1995 Geo Prism - failure to start  

It probably didn't break the timing belt because it wouldn't have spark if that was the case. Don't really see a timing belt causing it to run fine one minute and not the other, but checking compression would be a good idea anyway.

Does it have good spark. You stated you saw spark, but it may not be strong enough. You need to see if the spark will jump at least a 3/4 inch gap. That is how much KV it will take to jump the gap in the plug inside the combustion chamber.

Did you check the rest of the cylinders for spark?





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robertsfd2002
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Apr 28, 2014, 1:33 PM

Post #4 of 28 (4543 views)
  post locked   Re: 1995 Geo Prism - failure to start  

I did check all four plug wires. However, I did not have much of a gap. It is dark right now, but I will do this again in the morning and see if it will arc across 3/4 inch. If it doesn't, does that point to something easy to fix?

I'll report back tomorrow. Thanks for the quick responses. I wish I could be as quick to check this tonight.


Discretesignals
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Apr 28, 2014, 1:37 PM

Post #5 of 28 (4542 views)
  post locked   Re: 1995 Geo Prism - failure to start  

If it can't jump at least a 3/4 inch gap, you could have weak coil and/or plug/coil wire problems.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.


robertsfd2002
User

Apr 29, 2014, 8:01 AM

Post #6 of 28 (4516 views)
  post locked   Re: 1995 Geo Prism - failure to start  

Okay, here's where I'm at: screwdriver in plug wire will spark across about 1/4 gap. Anything further and there's nothing.

I don't know if the spark color would matter, but it seems to be a combination of white and some yellow.

One other thing I tried doing - pulling the spark plugs: I said I was a novice, perhaps I'm also an idiot - but I can't seem to get the spark plugs out. Tried various size sockets and nothing is working. Are there plugs that are other than "normal" - normal being plugs I use for my lawnmower and go-kart?

Anyway, what should I do/try next? How can I tell if the coil is a problem?

Thanks.


Hammer Time
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Apr 29, 2014, 8:03 AM

Post #7 of 28 (4515 views)
  post locked   Re: 1995 Geo Prism - failure to start  

These are 5/6" plugs, not the 13/16 in you lawn mower.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



robertsfd2002
User

Apr 29, 2014, 8:43 AM

Post #8 of 28 (4511 views)
  post locked   Re: 1995 Geo Prism - failure to start  

Do you mean 5/8? Which is what I thought it would be.

I can't get a 3/4 socket in the plug hole, much less anything bigger. If it's 5/6 I assume I need a special spark plug socket (I was trying to use regular sockets when my 5/8 was not working).


Hammer Time
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Apr 29, 2014, 8:54 AM

Post #9 of 28 (4507 views)
  post locked   Re: 1995 Geo Prism - failure to start  

Yes, that was a typo



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Discretesignals
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Apr 29, 2014, 8:55 AM

Post #10 of 28 (4506 views)
  post locked   Re: 1995 Geo Prism - failure to start  


Quote
Okay, here's where I'm at: screwdriver in plug wire will spark across about 1/4 gap. Anything further and there's nothing.



That's a problem. You have weak spark. Inside the combustion chamber with all the pressure, it take more KV to get the spark to jump than it would if you had jumping through your screwdriver out in the open. You need to do a tune-up which includes plugs, wires, cap, and rotor and replace the ignition coil.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.


robertsfd2002
User

Apr 29, 2014, 9:28 AM

Post #11 of 28 (4497 views)
  post locked   Re: 1995 Geo Prism - failure to start  

Here's the real question: will I be able to do this myself? I'd like to try, partly to save a tow charge and labor charges, partly to show myself that I can do this.

My extent of engine repair/maintenance has been changing oil and removing and disassembling and reassembling a carb on a go kart and on my lawnmower.

Without knowing me, what do you think? Is this do-able for the average (or maybe below average) non-mechanic?

Second question: if I do this and it still won't start, what might be the next culprit? I'm guessing $150+ for the plugs, wires, cap, rotor and ignition coil. A distributor or an ignition control module could be another $500. And if it isn't with the ignition system, then what?

I'm limited in funds and ability, so I'm second guessing all this. If $150 gets me back on the road, I'll be happy though.

Any thoughts?

EDIT: additional question - should I test the coil or anything else first? Or if I replace one thing, should everything be replaced?


(This post was edited by robertsfd2002 on Apr 29, 2014, 9:34 AM)


Discretesignals
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Apr 29, 2014, 12:31 PM

Post #12 of 28 (4486 views)
  post locked   Re: 1995 Geo Prism - failure to start  

Not sure if you can do it yourself, but you'll have to remove the distributor from the engine, take the cover off under the rotor, remove the nuts holding the wires to the coil, and then remove the screws holding the coil to the housing. It's not really that difficult. You should also replace the distributor o ring.

Before you remove the distributor, mark the position of the distributor and take note of which direction the rotor is pointing in the distributor. Be gentle with the coil primary wires and put them back in the same spots.

If you have to, take pics with your phone.

Coils do not like when the high secondary voltage they generate can't find ground or has a hard time getting to ground. The voltage has to go someplace and that could be right though plug wire insulation or out the body of the coil if you have too much resistance on the secondary side. 20,000 volts will somehow find a ground other than through the spark plugs' gaps if your wires, cap, or rotor, and/or plugs are worn out.

If the wires and plugs are old or have lots of mileage on them it is a good idea to change them out to give your new coil a chance at a long life.

Another way a coil goes bad is if coil winding short out in either the primary or secondary side of the coil. The constant heating and cooling of the winding will eventually cause breaks or shorts in the windings. Just a fact of life for any ignition coil.

The only other thing that could cause a coil to produce a weak spark would be if the primary turn off time is more than 20 micro seconds or you have resistance in the primary circuits on either the power or ground side.

You can check for ignition voltage using a volt meter at the coil itself. It should be around 10-12 volts while your cranking the engine., but the ground side is going to switch from ignition voltage to near zero really fast. Your volt meter won't be able to see that. You would need a good high end lab scope to see turn off time, and that may be out of the question in your case.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Apr 29, 2014, 12:44 PM)


robertsfd2002
User

Apr 29, 2014, 1:47 PM

Post #13 of 28 (4476 views)
  post locked   Re: 1995 Geo Prism - failure to start  

Okay, another question. Due to my nervousness of spending money to find something else is really the culprit is the reason I ask this.

Could the timing belt cause such a problem? Is there a way to see if that is the problem first? Or if perhaps it's part of the problem?


Hammer Time
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Apr 29, 2014, 2:15 PM

Post #14 of 28 (4471 views)
  post locked   Re: 1995 Geo Prism - failure to start  

The test sequence from the sticky was designed t answer these questions.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



robertsfd2002
User

Apr 29, 2014, 2:33 PM

Post #15 of 28 (4464 views)
  post locked   Re: 1995 Geo Prism - failure to start  

Perhaps I'm not seeing the sticky you are referring to, unless you mean that because timing belt is not mentioned in one of the four tests in the "crank but won't start" sticky that the answer would be no.

I asked this because my father-in-law is insisting that if there is ANY spark it should fire with starter fluid sprayed directly in. Now he is not here to check it out visually, but he's done this on the side for quite some time. And when I initially searched for ideas on what could be wrong, while replacing plugs, wires, coil, etc was mentioned most often, timing belt was second.

Not questioning your expertise, just trying to fully understand what I'm getting into and if timing belt may be an issue particularly due to my father-in-law's advice.

Thanks again.


Discretesignals
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Apr 29, 2014, 2:36 PM

Post #16 of 28 (4462 views)
  post locked   Re: 1995 Geo Prism - failure to start  

A broken timing belt and you have nothing to drive the camshafts which means the distributor doesn't rotate. You won't have any spark if the distributor isn't turning.

A timing belt that jumped a bunch of teeth can cause an engine to not start or run because the valve timing is off, but you would still have spark. If it jumped a couple of teeth it might still run, but it won't have any power.


A compression test might tell you if the belt is way off, but if it jumped a couple of teeth you might still have good compression. You would need to remove the timing belt cover and inspect the timing marks to see if the belt jumped.


I just havn't ever seen a T belt cause an engine to not run one instance and then run fine the next.


Quote
Wife starts it to move it to end of driveway and mentions it is hard to start (takes several tries but it gets moved). Two days later I start it fine and drive it 25 miles with a few stops along the way - no indication of any problem whatsoever. Next day it won't start. Turns over but no start, not even acting like it wants to.






Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Apr 29, 2014, 2:41 PM)


Discretesignals
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Apr 29, 2014, 3:01 PM

Post #17 of 28 (4457 views)
  post locked   Re: 1995 Geo Prism - failure to start  

I'll tell you what. At work we currently have a 92 Corolla with a 4AFE in for a power steering leak. I'll go test the coil output at one of the plug wires tomorrow and let you know if the spark can jump more than a 1/4 inch gap.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Apr 29, 2014, 3:06 PM)


robertsfd2002
User

Apr 29, 2014, 3:31 PM

Post #18 of 28 (4451 views)
  post locked   Re: 1995 Geo Prism - failure to start  

Thanks. I'm just trying to make sure I understand all this. I do truly appreciate all the help. And when I get this thing running again, you'll get much of the credit. I just hope I can avoid towing it to the mechanic.

I'm going to bed now and try to dream of success. Cool


Discretesignals
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Apr 30, 2014, 2:00 AM

Post #19 of 28 (4441 views)
  post locked   Re: 1995 Geo Prism - failure to start  

Went ahead and tested the coil on this Toyota with a 1.6L 4AFE this morning.

During cranking the required voltage to ionize the gap in the plug was around 30,000 volts during engine cranking right before it started. Then as fuel was injected the KV dropped to around 12,000 volts. I verified this by using a spark tester and the spark easily jumped a 3/4 inch gap in the tester which equates to around 20 KV. You need a coil and tune up.







Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Apr 30, 2014, 2:05 AM)


robertsfd2002
User

Apr 30, 2014, 7:16 AM

Post #20 of 28 (4423 views)
  post locked   Re: 1995 Geo Prism - failure to start  

Discretesignals and Hammer Time, thank you both for your input.

Okay, I'm going to do this. I've got some time in a week or two when I can get this done. I'll report back then to let you know how it goes.

Thanks again!


robertsfd2002
User

May 8, 2014, 2:50 PM

Post #21 of 28 (4369 views)
  post locked   Re: 1995 Geo Prism - failure to start  

OK, I'm getting close. While waiting for enough time to try to do this during daylight, I bought a Haynes repair manual and did some reading and more looking around for similar type problems. Something gave me the thought that perhaps it could be the distributor. Then I had someone suggest the same thing saying they knew this type of vehicle and that was their recommended fix (to replace the distributor). At $250 for a distributor, I wanted to get you guys' opinion so as not to waste money.

Thanks for any advice.


robertsfd2002
User

May 9, 2014, 7:08 AM

Post #22 of 28 (4359 views)
  post locked   Re: 1995 Geo Prism - failure to start  

One more thing I've come across that was the culprit in some similar type problems: the crankshaft position sensor. Sounds like replacing this might be advisable.

I'm thinking I might just do all this. I know guessing and throwing parts at it isn't the right approach, but with a mechanic I'd probably end up with the same total cost after labor.


Hammer Time
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May 9, 2014, 9:37 AM

Post #23 of 28 (4355 views)
  post locked   Re: 1995 Geo Prism - failure to start  

Or you could spend 3 times what a professional diagnostic would cost you in wasted parts.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on May 9, 2014, 9:37 AM)


Discretesignals
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May 9, 2014, 12:45 PM

Post #24 of 28 (4348 views)
  post locked   Re: 1995 Geo Prism - failure to start  

The position sensors are all inside the distributor, so if you replace the whole distributor you'll get the coil and igniter along with it. I don't think an NE or G sensor would cause a weak spark though.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on May 9, 2014, 12:48 PM)


robertsfd2002
User

May 11, 2014, 12:48 PM

Post #25 of 28 (4328 views)
  post locked   Re: 1995 Geo Prism - failure to start  

Problem solved!!! Thank you for the help. Only about $110 spent (found 35% off coupon code online for parts); probably less than a tow and diagnostic charge alone.

My plan was to replace what you first suggested: cap, rotor, ignition coil, wires, and plugs. Then distributor if that didn't fix it. Didn't have to get to the distributor. The first was the problem. She's running better than before, so this was needed even without the no-start problem. Not sure the coil needed replacement - I tested the old one, with resistance of primary seeming to be out of range, but new one tested showed exact same resistance, so it may not have needed replacement.

I spent a lot of time researching and reading. Probably 30 hours total. Total fix took less than an hour. But I learned a lot in the process of researching and reading. Car has 135K miles and never had timing belt changed. I think I'm going to gamble and not replace that right now as it seems like a job that could easily go wrong for someone like me. But in the future, I should be closer to a fix due to this experience.

I'm happy for now. Thanks again!






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