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Car won't start by Andreeas
Started on: 09-12-2011 05:34 PM
Replies: 50 (851 views)
Last post by: Gall757 on 07-28-2013 10:01 AM
Gall757
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Report this Post04-29-2012 05:02 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
Did you do the Phonedawgz test to determine if the injectors are getting a signal?...it's the 'backprobe' post. If you have battery tested the injectors and they all click, chances are they will all work if they are getting the signal to open from the ECM.
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weloveour86se
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Report this Post04-30-2012 01:40 AM Click Here to See the Profile for weloveour86seSend a Private Message to weloveour86seEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Andreeas:

The tachmeter bounces/moves when I start the engine. It moves to around 2-300 when I crank. When the engine fires up it moves to around 1500-2000. when I used startgas it did show about 2000 rpms...'

The SES-light works fine I think. When I put it into diagnostic mode it gives me first 12 then 34 then 42.

It think that when I crank in diagnostic-mode the SES flickers a lot. Is this good/bad? If it is not good, I'll check this again (just so it just not another Fiero-nightmare :-) )

Have anyone had a ticking noise from around the IAC/TPS when in diagnostic-mode? When the car is in diagnostic-mode (limp-home) ang I turn the key to ON, I hear some ticking from somewhere around the throttle. When I try to start the car, the engine runs for some secs then dies. The ticking noise continues until I turn key to OFF. Is this normal?

Thanks for the information about startergas...



12 is the computer telling you its going into diognostic mode. 34 is MAP sensor IIRC and 42 is rich or lean exhaust. Code 34 is probably from all the damm starter fluid and code 42 is your O2 sensor going bonkers because of all of the starter fluid as well.

Maybe I'm wrong but it's what I've seen on 2 of our 3 fieros so far. Make sure that check engine light comes on when you put the key in the run position first.

I can only imagine how many fieros have been junked because of this...

Edit 2 of or 3 fieros had a Previous owner that tried to jump the battery backwards.

[This message has been edited by weloveour86se (edited 04-30-2012).]

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Andreeas
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Report this Post08-02-2012 02:00 PM Click Here to See the Profile for AndreeasClick Here to Email AndreeasSend a Private Message to AndreeasEdit/Delete MessageReply w/QuoteDirect Link to This Post
Havent checked if the injectors are getting signal... Why? Because its difficult when the plenum is on... But I have heard them "clicking"...

Have tested some more things but still havent got it running..

Whatever it is - the problem occurs both in "normal" mode and in "limp-home".. What does that tell me? What kind of problems will affect the engine in both modes?

Spoke to a guy today that thought it was the MAP-sensor that is broken. The phenomenon that I can keep the engine running by "pumping" the gas pedal would in that case be that I tell the car to "Accelerate" (give more gas)... Is this possible???
I've got the error-code 34. IF it is the MAP-sensor that is broken/incorrect - would that problem affect the engine even in limp-home?

Earlier I said I got a error-code 42... It doesn't seem to be the ICM as I wrote... Isn't it the ECM? I've read about this in the servicemanual but I got the feeling that his problem isn't so important right now. Am I right?

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phonedawgz
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Report this Post08-02-2012 02:07 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
As a test of the MAP sensor - Unplug it electrically. If that makes the car run good then the MAP sensor, or the vacuum line to it is bad.

If the car runs the same, then the MAP sensor is not the cause of the trouble.

--

With no input on the MAP sensor the ECM will ignore the MAP sensor input and do it's best to guess the right amount of gas to inject. The engine will run fairly well this way.

However if the MAP sensor failed to where it is still telling the ECM an input, however that input is not what it should be, the ECM will be trying to adjust the gas to that bad input.

[This message has been edited by phonedawgz (edited 08-02-2012).]

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Andreeas
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Report this Post08-02-2012 02:12 PM Click Here to See the Profile for AndreeasClick Here to Email AndreeasSend a Private Message to AndreeasEdit/Delete MessageReply w/QuoteDirect Link to This Post
I have tested unplugging it electrically ... it doesn't change anything...

The engine runs for some seconds - then dies... I've thought that this depends on the cold start injector... But if thats right - the injectors still have to work.. The cold start injector squirts into the fuelrail, doesn't it?

Can the ECM for any reason fire the injectors for som seconds - but then stop trying to fire them? Would it in that case be a broken pickup-coil?


edit because of spelling-problems... :-)

[This message has been edited by Andreeas (edited 08-02-2012).]

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Andreeas
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Report this Post08-02-2012 02:28 PM Click Here to See the Profile for AndreeasClick Here to Email AndreeasSend a Private Message to AndreeasEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by phonedawgz:


With no input on the MAP sensor the ECM will ignore the MAP sensor input and do it's best to guess the right amount of gas to inject. The engine will run fairly well this way.

However if the MAP sensor failed to where it is still telling the ECM an input, however that input is not what it should be, the ECM will be trying to adjust the gas to that bad input.



I that this as even it doesn't matter if the MAP-sensor is good/bad /working/not working - the engine would run anyway?
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Andreeas
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Report this Post08-05-2012 02:44 AM Click Here to See the Profile for AndreeasClick Here to Email AndreeasSend a Private Message to AndreeasEdit/Delete MessageReply w/QuoteDirect Link to This Post
A question about the injectors... As I understand it is the ICM that gives signal to the ECM when to fire the injectors. Correct? Does this include even in startup /cranking?

I've read a lot in the 87 service manual and from what I understand the ICM doesn't do this job in the beginning - something else is. Am I right? In that case - what?
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marc-alan
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Report this Post08-05-2012 06:56 AM Click Here to See the Profile for marc-alanSend a Private Message to marc-alanEdit/Delete MessageReply w/QuoteDirect Link to This Post
Do you have a spare ECM to try? I have had two 2.8 fiero's that had been sitting for an extended period of time. Both had bad ECM's and needed replacement. The symptoms were as you described. Would only start and run with starter fluid. Would run a bit (cold start injector would fire), then die.

I was not able to keep it running as you describe with pushing of the gas pedal though, so it may be a different cause. I also would get code 12 only from the SES.

[This message has been edited by marc-alan (edited 08-05-2012).]

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Andreeas
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Report this Post08-05-2012 05:52 PM Click Here to See the Profile for AndreeasClick Here to Email AndreeasSend a Private Message to AndreeasEdit/Delete MessageReply w/QuoteDirect Link to This Post
Too bad I dont have any spare ECM...

But I found some tips in the 87 fiero service manual. There were some charts for troubleshooting that I'm going to try out..

Anyone who can explain about what triggers/fires the injectors??

From what I've read and Steen in the service manual theres à separate inkector for the coldstart. Thats right? (haven't been able to check on the engine by my own.)

Is it possible that "my problem" is the ICM??
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Andreeas
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Report this Post07-28-2013 04:11 AM Click Here to See the Profile for AndreeasClick Here to Email AndreeasSend a Private Message to AndreeasEdit/Delete MessageReply w/QuoteDirect Link to This Post
So, I felt I hade to update this thread.... I feel REALLY silly this time...

The car runs now... To make the story short - I think the original problem (when the car died up on my father-in-law) was the ICM... When I got the car in august three years ago I found two cables in the trunk that just lied there. One of them was connected to a second fuelpump. My father-in-law was lazy when he swapped engine so instead of replaceing the fuelpump inside the tank he installed another one outside the tank. When I was troubleshooting the car I disconnected this pump. After a while I didn't remember this second pump was disconnected. When I checked the fuelpressure I used a meter which only read to 6 psi. I thought this meter showed "times ten" so I thought the pressure were about 45-50 PSI - but it was 4 - 6 PSI. When I read about the fuelpressure on 4-cylinder engines it all made sense. Tried the extra fuelpump, but before I checked the pressure I found out that I had a leak in the fuellines underneath the car right after the fueltank. Dismounted the tank, changed the in-tank fuelpump to the one made for V6, checked the lines. Mounted it again... Fired up!!

Now I have a code 23, have to tune up the ignition timing, check brakes (not stuck but is not quite working) and so on..
Just emptied the cooling system so next thing is to fill it up again.

So I just wanna say - thanks for all help. Hopefully I've learned something about troubleshooting...
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Gall757
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Report this Post07-28-2013 10:01 AM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
Thank you for the update. In many cases, the solution is something silly, and that is instructive for the next reader.
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