Ok guys (and gals) here are the symptoms of a 1993 del sol S just stalling all of the sudden.

Wife called and said the car stalled while driving about 45 mph.

She pulled over and tried to start it, with no luck, but one thing stands out, she said that it almost started.

Got the car towed home and was about to test for spark, and found the car started right away and idled fine. As soon as you started to give some gas it would stall.

Trying to start the car after stalling proved difficult, several turns of the starter and eventually it would stay running idling pretty well, until you moved the throttle.

Seeing that the spark was evident, I figured on one or two things, 1) fuel filter clogged (has never been changed) or 2) fuel pump faulty.


TEST 1: R and R fuel filter = no change

TEST 2: Once started disconnected the Idle Air Control Valve and noticed that the car stalled. But also noticed that while plugged in the IACV emitted a pretty noticable hum , when the key is int he on position with the engine not running.

TEST 3: hooked up a volt meter to the Throttle Position Sensor's red/blue wire and with the key to ON and engine off noticed the volts reading from .502 v fully closed and 4.5 v at WOT.

TEST 4: removed throttle body and IACV and used throttle body cleaner to clean up all the passages and nasty black goop. Reinstalled everything and after a long time cranking, the motor was able to stay running. I did notice that the idle was way worse than before.
If you gingerly move the throttle pass 1000rpm it would run normally. I was able to run the car up and down the street, it was when I stopped the car that I had to be careful to get it up the drive way.

Given that I can run the car up and down the street, I don't think it is the fuel pump or regulator. I'm leaning towards the IACV since the freshly cleaned IACV caused it to idle poorly.

Again the symptom is if running and the throttle is moved from idle even a tiny bit it stalls. Another point is that it just happened out of the blue no progressively worse symtpoms.

Any ideas?

 

Is the CEL ON? If not, check the mechanical timing. The timing belt may have skipped a tooth.

When checking whether the cam and crank are synchronized at TDC1, turn the crank pulley only counterclockwise.

 

No the CEL is not on. I'm suspect of wrong timing as once it is running the idle is pretty good and if gently move the throtle past 1000 rpm it runs fine.

I have a used IACV on the way , so we'll see.

I can hear my IACV after the engine stalls, humming pretty loadly, until I tap it with a hammer. My 97 accord's 4 cyl IACV doesn't humm.

 

Crap - got the used IACV from another vehicle today and it does the same thing...including the hum after the car stalls..

If you keep cranking the motor 80% of the time it will eventually cath stay running.. It will idle fine until you either move the throttle pass idle too fast or turn on the a/c. The latter it will gently lower the RPMs until around 600 where is will abrubtly stall.

 

you say pretty good for idling.. is there a missfire? can you feel the motor vibrate when at idle? pull each spark plug when the car is idling and see which cylinder doesnt kill teh motor.

you can check for back pressure as well...possibly a clogged cat.

i recall you saying tps sensor was checked...try checking map sensor.

dont rule out fuel filter being clogged..it very well could be. disconnect your fuel filter and run a straight hose to the rail to bypass for testing.

 

The idle, once running, is actually quite good, and if you gently get past 1000rpm it runs fine from then on.

The TPS sensor checked out fine within specs.
The fuel fitler was the first thing I changed.
The fuel pump I don't think is an issue since I can actually go down the street at a good clip, provided I can get is started and past 1000 rpm.
Tonight I checked the MAP sensor and according to documentation the white lead wire should read "aproximately 5v" when the ignition is in ON, but engine not running and connector not connected to sensor, ditto for the yellow lead...they both read 4.7 volts.
With the connector conencted, ignition in ON, engine not running the voltage of white lead is 2.8v and steadily goes down to .6 volts when there is vaccuum applied , I squeezed the vaccuum down to 25 hg to get .6 volts.

I also checked the distributor's leads for TDC, CKP and CYP according to documentation, the documentation states that the OHMs between B/F, C/G and D/H should all be between 350-700, mine are all reading 389 roughly. But to be honest the way they state to test doesn't make sense to me, they have you test the leads on the connector going into the distributor rather than the connector that the one from the distributor.
example: engine harness ----- female connector -> <- Male connector -----distributor. They have you test at the male connector.


At this point I thin k it is the ECU.

I'm going to check with Tampa Bay Racing to see if there is somebody close by that will let me test their ECU for $20.00 before I buy one.

 

Fuel Pressure Regulator...might be worth checking it out too. Seems to me that the FPR can cause the exact symptoms you are talking about.

It is cheaper than a new ECU...

 

on the odyssey and accord there's been alot problem with the ign harness.
it's the one where your key cyclinder is located.
we had it replaced and the problem was solved.
you can try moving the harness around while the engine is on to see if that's the problem.
good luck,

sam

 

It's pretty easy to check the mechanical timing. You could be one tooth off.

 

Initially the mech thought it was the Fuel Pump

It was not the fuel pump, through daignostics on the ecu whilst the car was FINALY running (hard to do), the mech was able to see it was the distributor.

Unfortunately for me he replaced the whole distributor rather than just the ignitor which he said smelled like burnt electronics.

$280 for new distributor with 1 year warranty
$20 for remove/reinstall distributor

the distrbutor from RockAuto.com is 143.00 and the ignitor is 70.00

oh well.

Thought everyone would appreciate the update as to what the real problem and resolution was.

 

So you actually lacked spark?

 

nope had spark most of the time, whilst cranking I guess it would have been off and on, whilst running had spark, but for whatever reason, if you came off idle no spark.

since I could sometimes go up and down the block, if I got the rpm above 1000, I figured I had spark.


On the first day I ruled out not having spark since as soon I towed the car home it started on the first try, until I opened the throttle slightly then it would die. From then on it was very hard to start, had to crank and crank and crank. And you could hear that sometimes it would want to catch, but then not...until finaly it would start andrun and idle.

With those symptoms, lack of spark was not on my radar. I'l know better next time