redamaleki

This is my first post, so don't be too harsh.

Back in September I purchased a 98 Honda Civic LX. I had been looking for one for a while, as my new commute is 41 miles one way, and this came along at the right price.

Anyway, it will always cranks but sometimes won't start after it has had a chance to heat soak and has been doing it since day two of ownership. Sometimes I will drive it and it won't start immediately after I've turned it off for a quick stop for up to 30-45 minutes (when it is hot outside). Other times I can start it right away no problem. Basically it is the same symptoms as everyone else that has a bad Main Relay (but I have tried 2 other NEW relays, with the same issue). When it does run, it seems to run perfectly fine (with crappy MPG, 32 max on the freeway).

Let me list the things that I have replaced trying to find the solution:

• Fuel Filter
• Distributor Cap and Rotor
• Spark plugs and wires
• ICM (Igniter) and Ignition Coil
• Main Relay x2 just for fun
• Fuel Pressure Regulator Valve
• A ton of Fuses
• Valve Cover Gasket (not related to the no start issue, but discoverd a leak along the way)
• ECU

I found that when it doesn't start, if I unplug any one fuel injector, doesn't matter which one, it will start. I can plug it back after it starts and it runs fine. I checked the fuel pressure, and it came back as 38 PSI when starting and without the vacuum line connected and 28 PSI when it is running. I also checked the resistance on the injectors, all we're within spec. I get all the spark in the world when it won't start as well.

I know you only need three things, fuel, air and spark. From my testing, I have full fuel pressure (at least up to the injectors), I have spark, and now a fully functional IACV (cleaned with carb cleaner) so I should have the air I need.

Sometimes with the no start, I can get it to start, but it is real groggy and some dark smoke comes out of the exhaust. But other than the fuel injector trick, there is nothing that I can do that will always get my car to start when I have this problem.

I summarized and shortened my original post, so hopefully more people will read this.

grumblemarc

iTrader: (4)

Starter solenoid.

redamaleki

Thanks for the response Marc. My civic has no problem turning over when I have the no start issue. In fact my sister purchased a 2000 Civic shortly after I started having issues with mine. Hers died on her in the middle of the road. It would turn over just like mine, but the thing wouldn't start no matter how long it sat to cool off. It just so happened I had an extra igniter and ignition coil from swapping it on mine. I replaced those on hers and she was up and running again.

Could it still be the starter solenoid when the starter motor has no problem engaging and turning the engine over?

The problem is almost identical to when the main relay starts to go bad and the heat prevents the relay from engaging the fuel pump when you are trying to start the car. My fuel pump always comes on, and when I unplug a fuel injector, doesn't matter which one, the motor will start.

Kista20

I was going to say the battery because I had an eclipse long ago that had a dead cell and it wouldn't crank right after but if you waited like 20-30 min it would start but then you don't have any issues with it cranking.

Sounds like you should at least have your fuel pressure checked. You need air, fuel, and an ignition source for it to run... air generally isn't too much of a problem to get so typically it's one of the other two that's lacking.

Never heard of any issues with heat soak with honda's.

redamaleki

I am leaning towards the fuel pressure being out whack. I don't have easy access to testing the fuel pressure, but buying one for $30 seems better than paying a mechanic more and being able to keep the gauge.

I have my suspicions that the return line is clogged, thus increasing the fuel pressure, and making more fuel burn also reducing my MPG. Is there a way to clear the line? I haven't visually inspected it yet, but as it has no problem starting when the engine is cool, I doubt I will see anything from the outside. I have tried adding the injector cleaner stuff to the gas tank, and like I said, have also replaced the fuel filter, but still have the problem. Maybe injecting as much Seafoam as I can in the return line after the fuel pressure regulator valve would do it?

grumblemarc

iTrader: (4)

I say starter solenoid because I had an old domestic that did the exact same thing. Got hot-crank but no start. Starter was located right next to the exhaust piping. I know it's not the same car but symptoms were the same. Replaced it and never had another issue.

redamaleki

The old domestic that you had, that would crank when hot but not start, would it start if you unplugged one of the fuel injectors (did it have injectors)?

I have ordered a fuel pressure gauge,and will test the pressure as soon as I get it. I am almost positive I will get some high readings. Having already replaced the fuel pressure regulator, the next step would be to figure out how to clear (or at least make sure it is already clear) the return fuel line. I am thinking of disconnecting it from the regulator, and in the back of the car at the fuel tank then hooking up a air compressor. I also am thinking I like the Seafoam idea. Of course I am going to be completely at a loss as to what the next step will be if the fuel pressure comes back as normal.

grumblemarc

iTrader: (4)

No it didn't have injectors. How do you figure it's fuel pressure or a blocked line? If it was then why would it be intermittent? Do the injectors spray fuel during the no start condition?

redamaleki

Too much resistance from the injectors from running hot due to high fuel pressure?

I don't know if they spray during no start, but if I unplug one, the car will start.

redamaleki

Hunting idle today when going to fill up on gas. Pulled out the IACV and was stuck at 1/3 open. Cleaned, and seems to be running better. Can IACV cause a no start?

Will be driving and will report if no start goes away and MPG improves.

redamaleki

Fuel pressure gauge hooked up after no start today. 38 PSI starting and without vacuum hose and 28 PSI with the vacuum line connected. Still getting poor MPG with clean IACV, 32 MPG max on the freeway.

grumblemarc

iTrader: (4)

It should be higher with the hose off.

redamaleki

Sorry, typo. It is 28 with the vacuum line connected and 38 without and when starting. Any suggestions of other tests I might be able to run to figure out what is going on?

grumblemarc

iTrader: (4)

This is all I got.

• No Start Diagnosis Basics

vwjimmy

Unlikely the IAC is the problem for the no start....but it is possible. Are those fuel pressures during a start or a no-start? Also, does the amount of fuel in the tank seem to effect it (example: only no starts hot AND under 1/4 tank or over 3/4...etc etc)?
Restricted exhaust or primary O2 sensor might help your mileage......checking backpressure and O2 crosscounts would be in order......once you resolve the other issue

redamaleki

Fuel pressure is from the no start and when it starts (hence the 28 psi with the vacuum line connected). Otherwise, when starting it is 38 psi (start or no start). Fuel level in the tank doesn't seem to affect the pressure

Marc -
Thanks for the reference. I am not too good with a voltmeter, but was able to test the injector resistance (score U-Tube), I don't think I would be able to test every wire on the car.
There is one note under Fuel on your link that says:"Note #2: Too MUCH fuel will also cause a car not to start. [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."

So could it be the coolant sensor? Also was thinking maybe the O2 sensor(s)? I am think about replacing the O2 sensors (just for fun ) anyway based off some recommondations about changing them every 100k miles.

I haven't read anywhere that the O2 sensors could cause a no start after heat soak, but have read it is a major component in controlling the amount of fuel delivered (Another explanation for the crappy MPG?) Flooding would cause a no start, but then why would it start with an injector unplugged?

redamaleki

Replaced both O2 sensors, did see a minor MPG increase (could be placebo thought) but still have the no start issue.

To my surprise, I never really paid attention to my Ultra-Gauge which shows what the computer reads for the coolant temperature. When starting today with the outside temp being 77 degrees F, and warmer in the cab, the Engine Temp read 32 degrees F. There is no way I had a ice cube in my engine compartment. So that would be my next piece to replace, the engine coolant temperature sensor.

Thanks Marc for pointing me in that direction. It will be even more awesome if this fixes my issues!

Former User

Unplug the ECT sensor to see whether the engine starts.

Any CEL codes?

EG-B20vtec

Did you try an old Main Relay or new?
Try soldering the joints if its old.
I still say ICM. Worn distributor bearings can cause it to heat up terribly...transferring heat to ICM (Ignition Control Module) and giving you heat soak no starts.

redamaleki

Today I got a no start, and unplugged the ECT and it started!! I did notice that it was reading somewhere around 30 degrees F when it wouldn't start before I unplugged it. I plugged it back in, and it still started, but was then reading 180 F. Thirty seconds after it was running, it went back down to 25 F, so I turned it off waited a few seconds, and no start!

Waiting for my $16 replacement to show up tomorrow, which should fix it!

I only get a code when I unplug the ECT, P0118, high input on the ECT. When I unplug it, the idle immediately goes down.

I hope the UPS guy doesn't get lost tomorrow.

redamaleki

I just realized that I never posted the final results. The car has had no hot start issues since replacing the ECT. Totally awesome. With the A/C off, I am getting somewhere around 42 mpg. Thanks everyone for the help, especially Marc for pointing me the ECT.