juevi

Ok, I'm going to take a few minutes and give some of you a breakdown of basic diagnostics. I don't answer "I having a problem with my car please help me...." threads because most of you don't even have enough info to even get an intelligent response, and usually the answers are worse than the question.

A car needs Four things to run.
Fuel, Compression, Spark, Timing.
To break down properly, a car needs PROPER Fuel, PROPER Compression, PROPER Spark, and PROPER Timing.
The below is considering the car is cranking over properly and Battery is at FULL CHARGE.

Lets start with...


SPARK:
So your car doesn't start, did you check spark??? How to check spark.

#1. Get a spark tester (very cheap).
#2. Use a spark plug. Take a spark plug, plug it into the wire. Use a pair of INSULATED pliers (the kind with the rubber handles), and hold the spark plug (steel part, base or threads) against a ground on the engine (steel bracket or something steel). So while holding the rubber part of the pliers, holding the plug, and it's touching metal to metal, have someone turn the vehicle over. Does it spark???

A. No, my car does not have spark.
1. Check to make sure the timing belt is turning the cam. (Can be done by removing the top cover, or simply by taking the oil cap off and watching to see if the cam is turning when someone turns your car over).
2. Check grounds.
3. Pull diagrams and start to check wiring with multimeter. The diagrams change from car to car. This step isn’t for everyone, but is what to do to properly find the problem.

B. If you have FULL Battery Voltage, Cam is Turning, Grounds are Good. Then check wiring. Most likely cause is the Coil/Igniter. Other causes could be cam/crank sensors, wiring, etc etc etc. Honda’s do have a Coil issue, it’s pattern failures usually seen at least once during the life of the car.
If it DOES have Spark, what color is it?

A. Bright Blue/White = Good spark.
B. Red/Orange/Yellow = not strong spark

Note: Please understand. Weak spark will STILL NOT fire the car off. Also understand that when using aftermarket or even “Performance” coils, you are creating another variable. Honda Ignition systems have been proven to handle high HP applications. If you replace your coil with a new one that is NOT a Honda Part, don’t keep asking the same questions until you use a NEW Honda part. Aftermarket parts are VERY unreliable, same goes for unkown used.
This goes for MOST Japanese cars. Ask Dealer Technicians. They will tell you how aftermarket parts greatly effect performance, even aftermarket plug wires can keep it from not starting, yes, it’s true.

Note: Another thing you can do if you think your Distributor doesn't have any power is check all the fuses.

You can do this with a test light. Turn your car all the way ON, but don't crank it over, right before crank. Now make sure your test light has a GOOD ground, and touch each side of each fuse (two sides per fuse). It should light up on both sides, if not, it's blown.


COMPRESSION:
Get a compression tester, they are not that expensive. Make sure you lube well before threading into the cylinder (spark plug hole), and don't TORQUE the daylights out of it, a LIGHT snug fit will fulfill the purpose.

Read compression tester instructions, or for basics, just test each hole. Install tester, and have someone turn over (AFTER unpluging distributor/ignition fuse (don't want it to start)). Let it "bump" the tester 3 times. Take the last reading from all cylinders, compare. Usually honda wants the variation between cylinders to be within 28psi or so. In other words, they should be close across the board.
If they are more than 28psi different, then diag further, it could be a problem with head gasket, timing belt, bent valves, bad compression rings, etc etc etc.


FUEL:

You can buy a fuel pressure tester, just like a compression tester. Check fuel pressure to spec. of your car. In general, I've seen very little fuel problems from Honda's. Personally, this would be the last thing I'd check on a Honda.
However, if you don't have a tester, check all the other first, if you think your not getting fuel, you can do it a "ghetto" way You can take out the plugs, look inside the whole with a light and have someone turn over. You should see fuel spray or smell fuel strongly. Careful with fire hazards.

Note: Honda’s are also notorious for having bad “Main Relays”. Search and you can read up on this. This will allow you to have good spark, but will cut off the injectors from firing fuel. It’s a very easy and inexpensive fix. Usually located in under the driver side dash, close t tohe kick panal.

Note #2: Too MUCH fuel will also cause a car not to start. If you have a chipped ECU, or if your Coolant Temp. Sensor (tells computer the coolant temp and adjust fuel accordingly) is bad for example, it can cause the injectors to fire too much fuel and flood the engine. There are other factors that can cause this as well.

Note #3: Vacuum leaks can cause Too MUCH air. The mixture has to be just right for your car to run. If a vacuum line is open or broke, it may be hard for your car to start.


TIMING:

If others check out well, check your timing, OR if COMPRESSION is off, CHECK YOUR TIMING. There are two kinds of TIMING to check. IGNITION TIMING and VALVE TIMING.

Check your valve timing by taking the top cover off of the timing belt and check the belt/cam/crank marks and see if lines up like is supposed to according to the manual.

Check your ignition timing after the Valve Timing has been confirmed to be ok. You will need to use a timing light and research what you have to plug/unplug to get the proper reading. Checking your ignition timing is more for when you have it running. But you can still see if it’s somewhat close with a timing light by just cranking.

A few IMPORTANT notes:

First, make sure your car is in good running order. Honda's are very picky when it comes to tune up parts. MAKE SURE you have good (or better NEW) NGK plugs (proper plugs for car) installed. Next make sure you use a Honda Cap and Rotor AND Ignition Wires. Sure others work, but have seen many issues because of the car simple not working with aftermarket parts. Do things right and buy OEM.

Second, buy some simple tools, spark tester, timing light, compression tester, coolant pressure tester, etc.

Third, if you have no idea what your doing DON'T ask the local parts jocky whats wrong, they are in parts for a reason.

Don’t be afraid to pay 50-100 or watever it cost to have a GOOOOOOOD Independent shop Diagnose it for you. You will probably spend less in the end compared to throwing parts at your car and trying things and making it worse for a professional to figure it out. WARNING: You screw stuff up, it will cost more for you to have a true Technician figure it out.

Any questions regarding the above, or clarity, let me know, this is just a breif overveiw of the basics.



Modified by juevi at 6:52 PM 5/23/2007

juevi

From an old post, from EE_Chris:

He added

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">To add though:

TIMING: Check it first. It's the most non-invasive of the tests mentioned. If the timing checks out, you just verified that you have "a" spark to the #1 plug. What about the others? So just move that inductive pick-up to the next cylinder to see if a spark is there. This does not tell you if the spark is hot enough though. At the same time, take off the oil cap to see if the cams are moving. Just a quick visual to know the timing belt didn't snap and that the cam is turning the distibutor.

SPARK: To check for a hot spark, I'd go with a Thexton 404. If the coil was weak, it might be able to jump the standard spark gap in free air, but put some compressed air/fuel between the gap and it becomes a little harder. So this guy allows you to adjust the gap to your liking, while keeping things safe and hands-free. And using a multimeter to measure the coils primary resistance (or secondary) isn't exactly accurate, nor does it show the whole picture like a scope and inductive amp probe would....but it's better than nothing. If a couple windings in the secondary became shorted internally, your meter would still measure a lot of resistance leaving you thinking it's in spec but a scope would show something different.

COMPRESSION: MAKE SURE TO UNPLUG THE DISTRIBUTOR! Yes, it was stated. I'm just restating it, because it's important. Typically people remove their plug wires, set them aside and then remove the plugs. The problem is, you've got no load for the coil if you start cranking the engine over. And if the distributor is plugged in and it's got the coil charged, when it tries to make a spark and release that voltage, it's going to go somewhere. How often do you see threads "I just did a compression test and now my car won't start back up."? It's not an instant killer of the coil, but for older coils that have some miles on them, it's easier prey. Also make sure to hold the throttle WIDE OPEN. You'll get lower numbers without doing that.

FUEL: As stated - get a fuel pressure gauge. It'll tell a majority of the story for sure. You can go a step further and get a set of noid lights to verify that the injectors are actually being triggered though.

Important Notes: Don't expletive around with 3rd party ignition parts. Just stick to OEM. As juevi said, others may work, but they've also been the continued cause of a persons problem...or the source of a new problem. Coils, ICM's, whole distributors - I'd def shy away from AutoZone and the like.

To round out the tools, add a meter...and a Helms.

Of course, if your car was running fine, suddenly dies and the CEL comes on - I'd start there first.

</TD></TR></TABLE>

FalkenSiR

good ****

pm a mod to add it to the faq

Let me add that my car was running great but it suddenly stalled and died. Just cranked away.

New distributor fixed it

whookidb18c

i know its old post but still great info

thatEFboy

Let me add this:

Check spark first. If you don't have spark then pull a plug to see if fuel is getting in the cylinder. If you have no spark and no fuel in cylider, change the distributor. I've seen this on many Honda's (SOHC and DOHC).

chipman

I have no spark. I changed out the distributor. Still no spark. Could it be the computer? Thanks for any advise

97civic07gsxr

I have weak intermittent spark, and I am getting fuel. And I've fried two ignition coils. but no start. think it's dizzy

Kohen

Fantastic information. I think this is a bump-worthy thread. Since this kind of question gets asked 5 times a day, people can either link others here or memorize this information and tell other people it.

grumblemarc

iTrader: (4)

Considering this link is part of the FAQs and stickied at the top of the forum it didn't really need to be bumped.

Kohen

Oh. I see that now. But no one reads the FAQs anyways... Hahaha

hussain-vtec

Good info.

spoolnpsi

What does a #15 code mean.Weak ignition signal. Right? I just changed out the dizzy but it WASN'T a Honda part. Did I just waste my money?It starts and runs but when it gets to operating temp it loses all ignition and dies.

oehawks3

This is good ****!

GregB

Thanks ... very well done... Greg

Steveojonez2112

Ok I have a 97 Civic and replaced the distributor. Fired up and I let it run. I pressed the gas a little and it was missing a bit, then died. I started it back up and removed the battery cables from the truck I started it from and it died again and wouldnt start.

So I got another distributor and new spark plugs and wires and it won't start. I check the module, cap, and coil. everything seems fine but I have no clue why it wont start again.

Please help. This is my only car

Thanks Stephen

Kohen

Check your firing order

GregB

5th coil ... this time it was a Honda coil...lasted a few days maybe 100 miles... plus new distributor cap, rotor, wires & plugs...The coils are getting so hot they almost blow apart...A Honda tech said it could't be a ground or we would see a lot of other problems.....Any ideas what would cause a coil to get that hot... thanks Greg

Bluhr

Say it doesnt turn over but I can start it by touching meyal to the starter and runs fine. New staryer got it checked. Checked my relay, batterys fine. Its a 90 ef hatch. Im so lost. Spark plugs are good.

KimvdLinde

I got stranded last Friday after squeal and a few bobs, and I could not start it again. My first thought was that the ignition coil got burned. I tested it, coil is fine. Towed it home. Got it diagnosed by an expert, timing belt is off. Today, I replaced the timing belt (I was not sure the previous owner had replaced it in time), and the timing should be fine now. Car starts, BUT does not sustain itself in idle (shuts off) and feel rough. Could it be that the timing belt is still a notch off, or is this an indication that the valves are bent?

grumblemarc

iTrader: (4)

Did you verify everything was in time?

KimvdLinde

To dark, do that in the morning.

grumblemarc

iTrader: (4)

Then maybe check back after you've verified it? Ignition and mechanical? Right now you don't have enough information to say.

KimvdLinde

Will do.

KimvdLinde

Timing belt is installed correctly, the marks on both shafts line up perfectly.

grumblemarc

iTrader: (4)

I think I said ignition and mechanical timing. If you didn't use a timing gun you didn't do it right.