[jiciheb]

Hi,

My civic won't start. I performed most tests discussed in other similar threads and here are my observations

-I get fire at the 4 spark plugs (I changed the plugs about 3 months ago and they're covered by carbon deposits)
-I get fuel when trying to start the engine

Is timing wrong? How do I check and fix this?

I hear the relay and fuel pump noises when turning the key to "on", the engine rotates but won't start.

I checked all the fuses to make sure and they're all fine.

Disconnecting the MAP sensor did not get the engine to start.

I get no error codes from the ECM but the check engine light stays on when doing the procedure to get the codes.

I thought the ECM might be broken so I tested it. I get a 5V reading between pins D19 and D21 and get readings ranging from 0.5 to 3.0 at the MAP 3-pin connector. This suggests there could be a short somewhere along the D19 wire? Now how do I go about finding the short and fixing it? Any tips?

[jiciheb]

Thanks txgreasemonkey,

I removed the rust from the ground connection (G101) near the thermostat, applied wd-40. The engine started at 2nd attempt, but was stumbling... I gave some gas to keep it running but as soon as I released the accelerator, the engine stalled. I get a reading of 3.5V at the MAP connection now. I get no continuity between pins D19 and D20. What is an 'open'?

I checked the ICM according to the Honda shop manual and voltage values seem right so the ICM seems OK. Couldn't check the Coil because I stripped one screw that has top be removed to perform the test. Got any trick on how I can remove the screw? Should I replace the whole distributor instead?

You think the ECM is fine then?

Thanks

[jiciheb]

After turning the ignition ON, does the "Check Engine Light" go out after 2 seconds?

Yes, it does go out + there is no code stored in the ECM

[jiciheb]

Did you strip the threads going to Terminal A (+) or Terminal B (-) on the coil? A poor connection could cause low secondary voltage and explain the carbon buildup on the spark plugs and possibly why the engine dies when you let up on the accelerator.

Hi txgreasemonkey, in fact I did not ruin the threads of Terminal B but rather the spot where you put the screwdriver point... so I can't remove the screw now. I'm not sure what to do: try to unscrew with pliers or simply drill the screw until it's gone? Any Idea? Let's say the coil is OK, is there a procedure to check the distributor's internal sensors (CYL, CYK, and TDC).

My civic is about 240 000 km = 150 000 miles. I bought it about 3 years ago for peanuts. The previous owner had the car for 10 years when the engine blew up without notice. We got a used engine under the hood, a new starter, new water pump, new radiator, new timing belt and I think a new distributor (not sure).

I measured voltage again at the MAP connector and got 3.5V grounding at the connector or at G101 near the thermostat. Now finding the open along the D19 YEL/GRN (+) won't be easy.. have you got any trick? Do I have to look for a crack in the wire insulation or a break in the copper wire itself? Do I have to cut the wire and replace with a new one?

Now, I've got some interesting facts. My Civic started this evening after the sun came down. The last 7 days have been pretty hot and humid, with daytime temperatures going above 86 degrees F. Conditions changed overnight and today was cool and dry, temperature was about 77 degrees F. The engine started the first time I turned the key. It ran OK but I noticed it seemed to vibrate a bit and seemed to misfire lightly when pushing the throttle. I let the engine run for 5 minutes then stopped it. I turned it on again but this time the engine started and stopped soon after. I tried again for a third time and the engine started and ran almost normally except for some vibration. I haven't checked the main relay as I hear the clicks when I turn the key to on and when I start the engine. You think this could be involved?

I'll try to check the main relay tomorrow to find out. Even though the distributor was changed not too long ago, it might well be the culprit as they have a lousy reputation. I'll try to test the other components in the distributor. Could also be the ECM. My previous car, a Mazda protegé 1991, would start but run like **** with lots of misfiring and stumbling on acceleration because of corrosion in the ECM. I'm not sure what to try as I want to avoid unnecessary costs.

Thanks

[jiciheb]

Forgot to mention I changed the fuel filter, the spark plugs, the air filter, the rotor and distributor cap about 3 months ago. The spark plug wires test fine (below 25 ohms of resistance).

[jiciheb]

Yes I did put some wd-40 on the D harness. I'll try putting some on the MAP sensor connector

[TxGreaseMonkey]

Try a small pair of visegrips or pliers just to break the screw loose. Sears sells "easy out" type of tools but, if you are careful, you can probably free it.

[TxGreaseMonkey]

Did you perform the other voltage tests on the MAP sensor connector?

[jiciheb]

I tested voltage between the YEL/GRN (+) reference (right) D19 and the GRN/BLU (-) neutral (middle) D21 wire and got 3.5V.

I'll have to try testing the WHT (+) signal (left) D17 wire and the GRN/BLU (-) neutral (middle) D21 wire.

[TxGreaseMonkey]

I don't suspect the CYK, CYL, or TDC sensors as being part of your problem. I still suspect it has something to do with the drop in voltage between the ECM and the MAP sensor connector. Make sure G101 is as clean as you can get it and run resistance tests between the ECM connector and the MAP sensor connector. I'm not sure I can help you pinpoint it any more than that--just use your common sense. You really need approximately 5 volts and you are only getting 3.5 volts. Keep in mind that the ECM and the MAP sensor work together to control timing and air/fuel mixture. These are tough and frustrating problems; however, you learn so much from them and the victory, when it comes, is huge.

Remember to check your main relay. Fluctuating performance, based on temperature changes, is characteristic of failing main relays. There are only a handful of components to realistically consider: ECM, main relay, MAP sensor, ICM, and coil.

[CroCivic91]

I noticed one funny thing with my car 2 days ago. The cable that connects to the negative battery terminal can sometimes get a little loose on the battery. When it does get a bit loose, my car will hesitate to accelerate and make me feel like I'm on a rodeo (jumping back and forth) if I press the gas pedal suddenly. If I tighten the cable a bit then, it would run fine again. If I loosen the cable a bit again, it would run like crap.

So, check that out.

[kean]

May I ask,
I checked for the voltage in D19 and D21 of my ECM and I get only more or less 2V and sometimes 3V, but before I did that I removed first the ECM from the body of the car, I mean I removed the 4 bolts holding it. Was it correct would there be some grounding issue? Do the ECM get its ground from these bolts attached to the body of the car? Is my ECM BAD?

Thanks

[TxGreaseMonkey]

Kean, the ECM does not ground through the bolts whatsoever. Your ECM is bad, if you are only getting 2 to 3 volts between D19(+) and D21(-).

[jiciheb]

Sorry txgreasemonkey, I was confusing D17 and D19 wires. I do get 5V from the YEL/GRN (+) reference (right) D19 and the GRN/BLU (-) neutral (middle) D21 wire at the MAP connector. On the other hand, testing the WHT (+) signal (left) D17 wire and the GRN/BLU (-) neutral (middle) D21 wire gave me 3.5V? Is this normal? If so, the ECM must be fine right?

I checked the distributor's internal sensors (CYL, CYK, and TDC) and got normal values so everything seems OK on the distributor's side. I haven't yet been able to test the coil but if it was bad, I wouldn't be able to get spark?

I took the main relay out and the solder seems cracked on some pins. Maybe it was affected just enough to mess up the ignition process on hot humid days. Still, it must have been good enough to deliver power because I was always able to hear the humming sound coming from the fuel pump and the clicks the main relay usually makes. I'll try to fix the relay tomorrow.

[jiciheb]

By the way, my civic has started at every attempt (6x) since last night, even after letting the engine run until it reaches normal temperature and even this afternoon when the sun heated the dash.

[TxGreaseMonkey]

Now, I think your ECM and MAP sensor wiring are fine. The problem appears to be your main relay--easy fix.

[jiciheb]

Thanks for your help txgreasemonkey.

I'll let you know how things go

[TxGreaseMonkey]

OK, I think you've solved your problem.

[jiciheb]

Hi,

I resoldered the main relay... the car starts every time so far. The future will tell if that was the problem. Had to buy a used relay 25$ because one pin got loose while desoldering my original relay and I could not get it back in its hole.

For those wanting to resolder their relay, I would recommend using a 30W solder iron and a desoldering pump. I tried using a 15W soldering iron and it would take forever for the solder to melt.

Anybody wanting to resolder the main relay must look at this page:

http://techauto.tripod.com/


All the steps are very well detailed and they show what to do very well.

[TxGreaseMonkey]

You are a doer--I'd want you on my team. Nice job!