No start/die on the road, but engine turns over fuse 18 maybe the problem

ASSISTANCE Stock Engine-Bay Components
1

So, like the title says no start/die on the road, but engine turns over. this has been happening for the past 2 weeks.

I would be able to start it regardless the weather conditions or time of day. but same goes for a no start.

Conditions are MIL stay on wont turn off. fuel pump won’t prime. but after couple/several key turn it will prime and start. or after it runs it needs to sit for 1-2 hr or even longer. So that tells me…that there is problem is ignition system

what ive checked thought past 2 weeks is (switched parts, tested parts with test light and multi meter)

Fuses are ALL good - visually and tested with test light. Some with multi meter.
Main relay is good - switched it out with new 1 and known working one
Ignition switch is good - got a new 1 and known working one
Battery is good - 12.6v
Alarm checks out!
I get power to the ECU. (maybe code zero? but runs perfectly when it starts)
I did all test for ECU and MR via copy of service manual. - all good.
is good - switch with known working one and tested it with multi meter.
Checked and cleaned all grounds even the ones in the inside the car. :argh:
I’ve checked for possible loose/cut/broken wires and fixed them.

Now this past Monday it did it again, i had it towed home. The following day after a few minutes of dicking around with it…it started :bang::bang:

what i did was pulled and inspect fuse 18 started signal fuse it was good. After it started i tested the fuse out via visually, tested with test light and multi meter for continuity…good.

So now im stuck and Im here for help.

Now my question is how does pulling a fuse out that is good have something to do with not starting.

It cant be clutch switch (its bypass)
I can here starter relay click, even when MR won’t.
Fuse 18 has something to do with the ICU but everything works inside regardless.
would the fuse box be broken…?
could a bad cluster cause it not start or die on the road.

EDIT: ??? i can only get an auto ECU. would that work with a manual car?

2

auto ecu should work on a manual car.
you checked/cleaned the grounds on the t-stat housing? those are ecu grounds.
what you can also do is back probe at the ecu. test across the keyed power pin and one of the ecu grounds with a meter. see if it loses power when the car dies

3

[QUOTE=welfare;2325500]auto ecu should work on a manual car.
you checked/cleaned the grounds on the t-stat housing? those are ecu grounds.
what you can also do is back probe at the ecu. test across the keyed power pin and one of the ecu grounds with a meter. see if it loses power when the car dies[/QUOTE]

OK, good to know about the auto ecu.

I cleaned ALL main harness ground and battery ground, even the ones in the inside kick panel, checked for cut/loose wires and fixed it

I’ve tested the ECU with multi meter per manual step by step.

whats i don’t get is if its dead/bad ECU i shouldn’t be able to start it, at all…and my car runs fine when it starts/runs…:bang:

4

gf’s crx did this same thing… bad fuel pump. the problem with electric motors is they dont just die like that… they die… then they work… then they die… then they work. i would probably look into swapping that first (hope you have a 92-93) otherwise you are dropping the tank

5

fuel pump primes when i ground it via MR after it dies and ALL DA’s you need to drop the tank to get to the pump.

6

what’s the year and model? please
unless you are testing during the conditions that the vehicle will not start, testing using the manuals instructions will be futile. and even still, if you’re ohm testing, as the manual will typically instruct you to do, it’s nearly as good as useless

7

93 LS.

ive tested as it died.

ive just pulled my starter relay out, gonna test that now. EDIT: its good…:think::shrug:

FYI: its just left and back of the glove box top of RAD fan relay. bolted to the center duct. your gonna need a long screw driver.

8

how exactly did you test?

9

what ive checked thought past 2 weeks is switched parts, tested parts with test light and multi meter, as it died.

10

what exactly is the procedure you performed with your meter, while it died? in detail, please

11

Heres the thing also this car was not stock when i got it. so that must contribute to its now problems. (previous tried wire tucking it)

ok, on with it…

what i cant pin point is that it wont prime, no signal to ecu, but pump is good, ecu is good. it runs good when it runs.

the last 3 x it died.

this 1 was i parked it.

  1. i reset the ECU.

  2. opened both doors and removed my drive side bottom panel to “cool” the MFR. no good

  3. opened the hood to cool the igniter down also put wet rage against it. no good

  4. i just closed it up and walked away for 2 hrs came back BAM it started.

The next time it stopped was on the freeway

same deal but this time i had new/old parts to switch and had tools with me.

no good the others part didn’t worked.

I tested each sensors (map, TPS, ECT, IACV …ect) by unplugging it to see if that will start it or find a short in the system. nope.

this time it started 40min later with hood open.

Next time was last Monday it started find 1 click. warmed it up drove 16 miles freeway no problem

got to work. got off early. here we go…no start. (i was glad, actually)

started testing for OHM and continuity. followed the manual. 98% all good and what i found got fixed.

I tested for continuity of the grounds at Thermo housing, both left and right plugs. also into the interior.

…nothing no start but it cranks. got it towed home.

NOW…i started dicking around with and within minutes it started. this time by pulling fuse 18 signal starter, but was a good fuse.

I must have an active short somewhere under the dash. :down::down:

…:tmi:?

12

i would do as i’d mentioned and back probe the ecm keyed power pin. run your meter between the power pin and one of the ecm ground pins, as apposed to supplying battery ground. this way you confirm power as well as at least one ecm ground.
resistance testing is a complete waste of time for an intermittent issue.

13

ok just been able get back into it, again.

was able trigger the MIL and create the NO start with solid cel.

from the ECU A23 neg to A25 + and B1+ to see if there is voltage. there is, but all of sudden my MIL turned on and off. redid the test and it di the same thing.

NOW…manual says that need to check ground to tremo to ecu…(used DVM) it checks out. pushed in the pins on the ECU.

failing ECU?

now what? lol

14

okay. now, after inducing the problem again, you want to back probe at the ecm, the mfr/resistor box output pin. if no voltage, replace the ecm

15

that would be the #4 blu/wht wire? its later here for me to be cranking the car. (paper thin walls, neighors:blah:) til morning then

16

A7 grn/blu

17

update: replaced the MFR and Distributor both new to complete rule those out. tested again for A7 for power, NONE but there is continuity (?) this probed at the MFR #8 even cranking it. From the ECU A8 to A7 there is continuity but no power even cranking it. but there is voltage reading on A7 to A23 when ON.

i need to wait MIL to turn off on it own now (cuss i fully warmed up the car and drove it around. ran good doh)…:gay:

NOW just need to look for another ECU…

is there a place where i can send the ECU for repairs?