blaze_125

Got a 93 Delsol that won't start...
I got in it in the morning and it started fine and went to work. Got in the car after work and now it won't start. I only get 1 click out of the main relay and the fuel pump does not prime. Now I know the fuel pump works because if I jump the pin 5 and 7 on the relay, the pump start pumping, yet the car still doesn't start. It turns over but doesn't start.

It ran perfectly until I parked it for the workday.

I tried 3 different relays, all with resoldered connections.
I also tried 2 known good ECUs.

averyvm

iTrader: (1)

Ok does your check engine light come on?

blaze_125

Check engine is solid with the key in and stays solid when I jump the connector
It's wicked hot out here if it makes a difference.

Former User

Check hood fuse 31 (15A) and dash fuses 24 (15A) and 18 (7.5A).

If those are fine, clean and tighten the G101 ground wire attached to the thermostat housing.

blaze_125

Fuses all turned up good, at lunch time I'll take the ground appart and clean the t-stat housing...

blaze_125

Ground on the t-stat is good, still no start. Still no fuel pump priming, still only 1 click out of the relay(s).

blaze_125

bump

blaze_125

Is there such a thing as a "fuel cutoff switch" on our cars?
I know back in the days when I had a Ford Tempo, there was a cutoff switch mounted in the trunk, so if the car was in an accident, the switch would trigger and cutoff the power to the fuel pump. That switch would also randomly trigger during/after spirited driving.

blaze_125

today with a multi-tester I tested every single fuse I could find and they all came out fine.
I re-soldered the main relay again
I tried 2 ECUs and still nothing
I also tested the grounds in the engine bay and that also came back fine.

I thing I noticed... When I disconnect the ground from the t-stat housing, the check engine light goes off. It does not even come ON when I first insert the key and turn to the ON position. Obviously... with that ground disconnected, the fuel pump still doesn't prime.

I also tested the connections on the ignition switch(the soldered connections that is) and they all gave me a reading.

I'm lost now, I don't know what to check anymore...

Former User

You need to check whether power reaches the main relay and the ECU and whether the ECU is properly grounded to G101 on the thermostat housing:

blaze_125

On the first page, everything checked out fine.
On the second page...
I don't have a 'test harness' so I kept the harness connected to the ecu and tried A7/A8 to chassis and got nothing.

When I do the A7-A23, I get a reading but the reading does not disappear after 2 seconds.

blaze_125

I looked at Ron's pages again and realized I may have made a mistake when I tested for continuity between Terminal8 and A7/A8. I realized Terminal 8 was actually the main relay terminal and not just a terminal on a "test harness".

So I went ahead and checked for continuity connecting 1 lead to terminal 8 of the main relay harness, and the other lead onto A7 and then A8.(According to instructions, the main relay is not actualy connected at this point)

My tester beeps when the resistance is below 50 ohms... When I tested those connections, it didn't beep and gave me a reading in the 400 ohms range for both A7 and A8.

Does that mean that's where my problem is?
If that's indeed my problem... I looked at the schematics for the electrical connection to A7/A8 and the GRN/YEL wire starts at the main relay harness and I beleive at some point along the line, that same wire splits into 2 wires and one connects to A7, the other connects to A8. Is that correct?

If that's the case, then I could run 1 wire from the relay harness to the ECU location, and then "T" the wire to connect both A7/A8.

Am I correct?

Former User

You are correct. Have you repeated the test a few times to rule out a technical error? If so, you could try running a new Grn/Yel wire between the main relay and ECU plugs. The risk, however, is that the problem is actually with the main relay or ECU plug. Scrape a little bit of wire insulation near each plug and probe for resistance again. If it's still high, run a new wire. If resistance drops to normal, then one of the plugs or plug terminals is bad.

blaze_125

Yes and I seem to be all over the god damn place...
I just went back, and did the whole flow chart again.

Now I do get continuity between Terminal 8 and A7/A8.
I went ahead and cut the thing anyway. I ran a new wire directly from Terminal 8 to A7/A8 to make sure that that connection would not be the issue.

Yet, the fuel pump still won't prime.

So going along with the flow chart, I seem to have a problem when I get to A7(+)/A23(-).
According to the chart, I should get a reading for only 2 seconds when the key is turned to the ON position. I get a constent 6.xxV

So far I've always assumed the relays I got are good because I resoldered the connection. I think I'll do the actual test that's described in the manual and make sure they're good.

I have a hard time beleiving both my ECUs would have went bad at the same time. I mean... what are the odds, really?

machine0

I haven't seen it in a while, but does it have remote start or some kind of alarm on it from a PO? My last civic had an alarm that was shoddily installed, and started giving me draining issues and starting problems. Just a thought...

blaze_125

No
Well... actualy it did have an alarm at some point but the alarm control module was removed when I baught the car a few years ago. I think it was only an intrusion alarm that was set off by vibrations.

Former User

Are you using a low impedance digital multimeter for your voltage tests? Since you don't have a test harness, how exactly are you measuring voltage between A7 and A23? Is anything disconnected during the test?

What voltage reading did you get for A25/B1(+) to A23(-)?

blaze_125

I'm using something really similar to this:


To test voltage, I set it on 12v
For continuity, I select the logo at the bottom left between the ohm section and DC10A

To get my constant 6v reading on A7(+)/A23(-)...
Main relay was connected to its harness
All ECU connectors were connected to ECU
Ignition switch was ON II
Positive probe was snugged in with the A7 wire inside the connector
Neg probe was snugged in with the A23 wire inside the connector


I can't remember the reading I got for A25/B1(+) to A23, but if I remember correctly it was much lower than 12V. Don't hold your breath on this reading though, I'll go back out there on my next smoke break.

I actually just came back from there to test the relays. Both relays came up fine according to the flow chart.

Former User

Multimeter is fine, as is how you did the voltage tests.

The A7-A23 and A25/B1-A23 tests should both yield battery voltage, which is the voltage you read across the two battery posts and the two battery connectors. Post values for all of these voltage tests.

blaze_125

I'll just throw random numbers here...
So if the battery posts give me a reading of lets say 11.5V, that means I should get a reading of 11.5V from A7-A23, and I should also be getting 11.5 from A25/B1-A23?

I fear this is not currently the case.
Again, I'll comfirm on my next smoke break but I'm positive I got much lower numbers when I tested at the ECU. I just tested the relays a few minutes ago and I was getting a voltage of 11.xx... much higher than the reading I get from A7-A23.

Shouldn't the reading from A7-A23 drop to 0 after 2 seconds?

Actually... f**k it... I'm a have my other smoke right now... brb with numbers.

Former User

Your tests should be reading the same or similar voltage as battery voltage. If not, that could be a problem.

Did you instead get (higher) battery voltage from the diagram tests done on the main relay plug?

Also, what voltage to body ground do you measure at the two top test tabs of fuses 31 and 24? Click the Test Fuses link in my signature.

blaze_125

Too bad I was already outside when you posted this... Here are the readings I got:

Main relay terminal 1 to body ground : 11.28
Main relay terminal 5 to body ground : 11.28
Main relay terminal 6 to body ground on start : 8

A23(-)/A25(+) : 11.26
A23(-)/1B(+) : 11.25
A7(+)/A23(-) : 6.82
A7/A23 is constant 6.82 for as long as the key is in the ON II position.

All the readings were taken with everything connected.

Former User

A7-A23 should yield ~11.3V like the other tests. My first thought is that terminal 8 of the main relay has poor electrical contact with the corresponding terminal (Grn/Yel wire) in the main relay connector. Any visible damage of this terminal? Your inconsistent resistance measurements of this wire now may suggest a problem.

Try this test similar to the A7-A23 test:
Everything plugged in -- probe the Grn/Yel wire nearest to the main relay for voltage to body ground and then turn the key to ON(II). What voltage do you read? If you get battery voltage (~11.3V), do the same test for the Grn/Yel wire nearest to ECU A7.

blaze_125

Actually, that'd be like testing the continuity between Terminal 8 and A7/A8, but instead I'll check to body ground for voltage? So basically I should get 3 readings?

Terminal 8 to body ground
A7 to body ground
A8 to body ground

That right?
If the readings are different that'll mean that even my new wire is crap?

Former User

Correct, but the A8 test is not necessary. --Everything connected and the key in ON(II).