ECU Failure or something else? A lot of information inside.

[Dserge]

Ok I had just got done washing my car, and I took off everything is fine then in a middle of an intersection the car just dies.

It took me about 4 more attempts to get it started but after that it ran all the way till I got it home normally.

After that I shut the car off, to let my parents get ready because I was taking them to the mall. I start up the car, pull out of the drive way and everything is still normal.

We get about a mile down the road and my tach just drops to 0, it kicked back up and started going again then dropped to 0 once again, it repeated this a few times. The car makes a crank sound but it won't turn over whatsoever. I get out and checked for the timing belt, it is all still intact and in very good condition.

I called up a DSM buddy of mine and he had me read to him the dash lights, and when I turn the key I get no Check Engine Light so he automatically says it's the ECU.

Some back ground on the car now is:

It would pull very weird, sometimes with insane power, sometimes gutless.
The heat would warm up a little more then it should or sometimes it would be a little colder then it should be never quite vertical where it normally had been. (Not by very much though, very minimal temperature change)..


The car also since I have bought it a year ago has Idle surge while warming up but once warm the idle is fine.

I also noticed the idle would adjust itself, I had it set at 850 and sometimes it would be say 700 and other times just over 1,000 RPMs.

One more thing, prior to all of this the car would start, then struggle to stay running and die if it was warm. I adjusted the idle a little and the problem went away.

The car is stock other then a 3" Exhaust, Intake and a MBC set at stock boost.
Are these all signs of a bad ECU? I also smell no burning smell or hear no clicking from the ECU area....


The car is a 1991 Eagle Talon TSI AWD.

 

[bento]

Could be a bad ecu. If you have 1 laying around i would swap it over and see what happens. But could also be something else electrical, like a bad cas, coil pack, rersistor e.t.c....

 

[Dserge]

Could be a bad ecu. If you have 1 laying around i would swap it over and see what happens. But could also be something else electrical, like a bad cas, coil pack, rersistor e.t.c....

Anything that would lean you towards one or the other?

 

[1SickAuto]

if ## not getting a check engine light and the boost gauge doesnt move when u first turn the key on, then its ## ecu forsure

 

[steve]

Well not for sure but very likely.

The MPI or Ignition fuses on the positive battery terminal can be blown. If the engine cranks but won't start then the Ignition fuse is good but check the MPI one and then pull the ECU and look at it for signs of the capacitors leaking or being originals.

 

[Dserge]

Well not for sure but very likely.

The MPI or Ignition fuses on the positive battery terminal can be blown. If the engine cranks but won't start then the Ignition fuse is good but check the MPI one and then pull the ECU and look at it for signs of the capacitors leaking or being originals.

Fuses are good, both the ignition and MPI fuse.

 

[steve]

Then you know what you need to do next.

 

[Dserge]

Then you know what you need to do next.

Yes sir, here is a picture of my ECU...

Turns out it was an EPROM ECU!!!!! And it appears to be fine... No unusual smells or burn marks on the ECU. Here is a picture.

Only camera I have I don't have the cord for my Digi it is still in Wyoming......

Also the boost gauge moves up to the 0 position when I turn the key on.

<a href="http://img10.imageshack.us/my.php?image=ecu.png" target="_blank"><img src="http://img10.imageshack.us/img10/6603/ecu.th.png" border="0" alt="Free Image Hosting at www.ImageShack.us" /></a><br /><br /><a href="http://img604.imageshack.us/content.php?page=blogpost&files=img10/6603/ecu.png" title="QuickPost"><img src="http://imageshack.us/img/butansn.png" alt="QuickPost" border="0"></a> Quickpost this image to Myspace, Digg, Facebook, and others!

 

[Dserge]

I put my ecu back in and it fired right up. It is running fine as we speak.

 

[Dserge]

Okay, I went to the car wash...Washed the OUTSIDE of the vehicle..And nothing.....
We then went to my friends house, and took apart the Cam Angle Sensor and it had moisture inside of it. We blew as much of it out with an air compressor. We put it back in the car, and it started to run but only on a few cylinders and really rough and rich. Then would just die..

So then we get it towed home again, and another DSM friend helps me do the following tests.



#1 Fuel. Checked relay with logger, its got power and turning the pump on. Pulled the regulator off, we got plenty of fuel getting to the injectors. Pulled the CAS and turned the rotor and can hear the injectors pulsating. Also checked the voltage going to the injectors via multi meter.

#2 spark. Tested spark on all 4 cyl with a spark plug, yes its getting plenty of spark. battery voltage is fine, we swapped my battery to his car. Timing is dead on looking at gears and crank pully and CAS.

#3 air. obviously getting air, but checked anyway. No IC pipes off, MAF plugged in and all.

#4 compression. pretty low on cyl 1 (110-115ish) very low on cyl 2 (95ish)
Also, oil on both of these plugs. Not on 3,4.

I have also been having a coolant loss for sometime now but it never smoked or anything else..

So what are the chances I have a blown head gasket on my hands?

 

[steve]

Yes sir, here is a picture of my ECU...

Turns out it was an EPROM ECU!!!!! And it appears to be fine... No unusual smells or burn marks on the ECU. Here is a picture.

Sorry missed the notification of your post.
The only thing I can tell for sure is that it has original caps. You'll want to replace those ASAP.

 

[Dserge]

Sorry missed the notification of your post.
The only thing I can tell for sure is that it has original caps. You'll want to replace those ASAP.

Looks like it has been replaced before, I checked the caps the are the 120 degree ones.
But did any of the following information help you out in anyway?

If I can pick up a sensor on a part out that will rock, then I will pick up a nice head gasket and go to town...

 

[steve]

Looks like it has been replaced before, I checked the caps the are the 120 degree ones.

They don't look like they have been replaced before to me but I can't see the bottom of the of board to check the soldering.

Are you getting any error codes when it's running badly?

 

[Dserge]

They don't look like they have been replaced before to me but I can't see the bottom of the of board to check the soldering.

Are you getting any error codes when it's running badly?

I can't get it running anymore, it won't run at all.

What could cause low compression and oil on the plugs?

Maybe I should find a used CAS, change the plugs then try it..

Maybe it needs a head gasket also?

 

[e85_4g63]

If the #1 and #2 cylinders are that low on compression I wouldn't be surprised by it not running. I had a tsi with 85 psi in the #3 cylinder (other 3 over 150) and the car wouldn't fire.

 

[Dserge]

Yeah I have heard that too.

But I also heard it is best to do a compression test on a warm engine.

Mine was stone cold and had
been sitting a few days about a quart low on oil.

Any suggestions on what to try?
It really wants to fire you can tell that just hicups and fails.

 

[tunethis]

It seems like everytime you wash the car, it fails. Something has to be shorted out from the moisture. I noticed you said the cas had some moisture in it and you blew it out. Have you ever tried to replace the cas with a known working one?

 

[Dserge]

It seems like everytime you wash the car, it fails. Something has to be shorted out from the moisture. I noticed you said the cas had some moisture in it and you blew it out. Have you ever tried to replace the cas with a known working one?

No Sir but that was my first thing I wanted to try.
I was going to charge up the battery, change the plugs,
install a new CAS then see if it fires.


Do you figure this would be a good starting point?

And yes the CAS had quite a bit of easily visable green engine degreaser in it in which we used washing the motor the day this started all going down.

Now before we blew the CAS out it wouldn't start at all. Just turn over.
The cas has now been blown out and it will start and miss, back fire all that shit and die.

And now it is back to just cranking over, making a hiccup like it wants to start then more cranking.

Are these symptoms of a CAS?

Please help its been awhile since I've driven this thing and miss it! haha.

 

[tunethis]

No Sir but that was my first thing I wanted to try.
I was going to charge up the battery, change the plugs,
install a new CAS then see if it fires.


Do you figure this would be a good starting point?

And yes the CAS had quite a bit of easily visable green engine degreaser in it in which we used washing the motor the day this started all going down.

Now before we blew the CAS out it wouldn't start at all. Just turn over.
The cas has now been blown out and it will start and miss, back fire all that shit and die.

And now it is back to just cranking over, making a hiccup like it wants to start then more cranking.

Are these symptoms of a CAS?

Please help its been awhile since I've driven this thing and miss it! haha.

I would definitely start with the CAS though. Especially, since you blew it out and it seemed to want to start after just cranking prior to blowing it out. I have heard of people having problems with moisture in the cas after washing the engine. Good luck with this, I know how frustrating these type of issues can be.

Do you have any salvage yards near by? The cas sensors from the 2.0's are the same. Just to be safe, stick with a 91-92 cas since they are exactly the same. The 93-94 have a black plastic cap but, I believe they will work too, I'm not 100 percent sure though. The 93-94 cas is supposedly a new, better version.

 

[Dserge]

I would definitely start with the CAS though. Especially, since you blew it out and it seemed to want to start after just cranking prior to blowing it out. I have heard of people having problems with moisture in the cas after washing the engine. Good luck with this, I know how frustrating these type of issues can be.

Do you have any salvage yards near by? The cas sensors from the 2.0's are the same. Just to be safe, stick with a 91-92 cas since they are exactly the same. The 93-94 have a black plastic cap but, I believe they will work too, I'm not 100 percent sure though. The 93-94 cas is supposedly a new, better version.

Alrighty, I just ordered up a CAS from a part out.

Going to go throw my battery on the charger and pick up some

BPR6es plugs and gap them..

Maybe what I thought was oil on the plug was just gas+carbon...

I pulled all plugs today and they all four looked exactly the same..

 

[DSMopar]

Look this isn't rocket science, 1gs always get screwed up when you wash the engine bay. Mine had a load based mis-fire the last time I washed my car and it didn't go away for 2-3 days (this was in summer too). The CAS takes a long time to dry out.

 

[Dserge]

Look this isn't rocket science, 1gs always get screwed up when you wash the engine bay. Mine had a load based mis-fire the last time I washed my car and it didn't go away for 2-3 days (this was in summer too). The CAS takes a long time to dry out.

Yeah well no "drying out" here man.
It's been a month now. Something is fried.


I have spark on all four cylinders.
I have fuel
Timing is dead on.

Engine just cranks and cranks.

The only thing I could think of is the Ignition timing is not correct. So it is not sparking/injecting fuel at the correct times?

I also get gas on my spark plugs...

So as far as I understand the CAS controls the ignition timing and if mine is fried that would result in a no start??? Because it is not sparking at the correct time.

...Someone please confirm my thought process here.

 

[habitatguy187]

Not sure exactly how it works, but when my CAS failed on me sometimes it would start right up and other times it would just crank and crank, it already sounds like yours is fried though the way you described it's insides.

 

[Dserge]

Not sure exactly how it works, but when my CAS failed on me sometimes it would start right up and other times it would just crank and crank, it already sounds like yours is fried though the way you described it's insides.

Was the cas, car is fixed and a running dsm.