juevi (old)

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.


Lets start with...

SPARK:

So your car doesn't start, did you check spark??? Then don't post before you do. 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???

If not, then post NO SPARK, where do I go from here????

If it does, what color is it, Bright Blue = Good spark. Red/Orange/Yellow = not strong spark

note: Honda's have notorious coil problems, sometimes you have spark, but then again it's not strong enough to light the fuel off. Remember that.

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.

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 IGNITION timing first. Get a timing light (not expensive), check the timing according to manual. If it is off, why?

It can be from messed up 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.


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 most the time, and DON'T post on here expecting to get answers that help. WHY, because if you have no idea, as in very new or mechanically inep, then no one will be able to help you in most cases. I don't say this to not help you, but say this to save confusion. Listen, I see many on here post that shouldn't, in other words, if you don't have a clue, others who don't have a clue are going to lead you astray, you've been warned.

If the above is the case, Pay 50-100 or watever it cost to have a GOOOOOOOD Independent shop Diagnos 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.

em1mike

nice write up , this will help lotta ppl...

EE_Chris

Helluva' post.

And thanks to em1mike, it's double the length for no reason.

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 **** 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.

juevi (old)

Agreed with the additional info, thank you.

juevi (old)

Bump for you people to read.