Ive Tried and it still wont start

[highnitro12187]

hello,

I have a 1991 laser nt and it wont start. i have got 3 tr units and non of them seem to work so im starting to think that the tr is not the problem. what else could cause the car not to start and also have no tach signal.

Thanks,
Matt

 

[ALLBoostAWD]

hello,

I have a 1991 laser nt and it wont start. i have got 3 tr units and non of them seem to work so im starting to think that the tr is not the problem. what else could cause the car not to start and also have no tach signal.

Thanks,
Matt

When you say "tr" you are saying transistor correct? Have you had your ecu looked at for leaky caps? There should be a thread in the FAQ's on how to diagnos it.

There could be a lot of things wrong with it. What is it doing when you crank it??

 

[highnitro12187]

Yes TR mean Power Transistor, when i crank it it just cranks the tach stays at "0" and nothing happens

 

[luv2rallye]

Are you getting spark at the plugs? If not, first check ECU as ALLBoostAWD says which is most likely it (and swap with a known good one if possible). If not it, then check the "crank angle and top dead center sensor".

 

[highnitro12187]

Is there a way i can check the ecu before i go get a new one.

matt

 

[steve]

You can check to see if the ECU is booting by watching to see if the check engine light turns on for five seconds after you turn the ignition on.
If it doesn't you should check the fuses for the MPI circuit and Ignition on the battery positive terminal. You should check the ECU and make sure than the capacitors haven't leaked and damaged the ECU.

Steve

 

[luv2rallye]

i have got 3 tr units and non of them seem to work...

Here's how to test the power transistors:

(Note: The pin numbers for the following are the ones on the power transistor side connector – not the ones on the harness side connector (for which I put the wire color in parenthesis for reference).

On a 91-94 turbo or NT:
Unplug the power transistor 8 pin connector.

To test the power transistor for cylinders 1 & 4:
Connect the negative side of a 1.5V battery to pin 3 (black wire) of the connector. Connect the negative side of a 12V battery also to pin 3. Connect the 12V battery positive to one side of a 12V light bulb. Connect the other side of the 12V light bulb to pin 8 (yellow/green). The light should not be on. Now connect the 1.5V battery positive to pin 7 (yellow). The light should go on.

To test the power transistor for cylinders 2 & 3:
Connect the negative side of a 1.5V battery to pin 3 (black wire) of the connector. Connect the negative side of a 12V battery also to pin 3. Connect the 12V battery positive to one side of a 12V light bulb. Connect the other side of the 12V light bulb to pin 1 (yellow/black). The light should not be on. Now connect the 1.5V battery positive to pin 2 (yellow/red). The light should go on.

 

[AndrewD5418]

Leaks would look kind of obvious when you look at them.
http://upload.wikimedia.org/wikipedia/en/7/79/Bad_Capacitor_01.jpg
http://www.michael-ramsey.com/badcaps/badcaps2.jpg

Just incase you didn't know what a leaked cap. looks like.

 

[highnitro12187]

hey,

i just found out today that my isc came unpluged and i plugged it back in and it still wont start so what would that affect.

Matt

 

[highnitro12187]

I checked my Power Transistor and it was good (it should be cause its new) so what next, also my ecu has no leaky caps. thanks for all your help so far

Matt

 

[steve]

so what next,

You can check to see if the ECU is booting by watching to see if the check engine light turns on for five seconds after you turn the ignition on.
If it doesn't you should check the fuses for the MPI circuit and Ignition on the battery positive terminal.

If the ECU isn't powerering up then your not going to get any spark.

Steve

 

[highnitro12187]

hey,

i check for the check engine light and it doesnt come on so i think i ###### need a new ecu.

Matt

 

[steve]

hey,

i check for the check engine light and it doesnt come on so i think i ###### need a new ecu.

Matt

That might be the case but you need to check the fuses first. The MPI and Ignition fuses on the battery terminal and the room fuse #19 in the drivers footwell are used. Looking at the fuse doesn't count as checking it.

Getting your ECU fixed might be cheaper than replacing it.


Steve

 

[highnitro12187]

couple things, all the fuses are good, what does MPI stand for and what would happen if you had a 30A fuse in there and it needs a 20A.

Thanks,
Matt

 

[Quasimondo]

You risk damaging anything in that circuit if you get a power surge of more than 20 amps simply because it's protected by a bigger fuse that it's not designed for.

MPI = Multi-Port Injection (engineerspeak for one injector per cylinder back when they used to stick 2 injectors at the throttle body and call it a day).

 

[luv2rallye]

You risk damaging anything in that circuit if you get a power surge of more than 20 amps...

Or in layman's terms....PUFF

 

[Newlogics]

.... for one injector per cylinder back when they used to stick 2 injectors at the throttle body and call it a day).

Man I hate my Starion for that... I hated it so much, that dropped a 4G63 in it

 

[steve]

Leaks would look kind of obvious when you look at them.

Just incase you didn't know what a leaked cap. looks like.

I guess I should point out that these examples don't look anything like a leaky capacitor on our ECU. Those pictures were examples of cooked VRM filter caps in PCs. Our caps don't fail by popping the tops but by leaking the electrolyte out the bottom seal and may not be visable for quite awhile, long after the damage is done.


Steve

 

[shingevo]

fried ECU can smell pretty bad too sounds like electrical problems but check if u jumped timing.

 

[Zoltoron]

I guess I should point out that these examples don't look anything like a leaky capacitor on our ECU. Those pictures were examples of cooked VRM filter caps in PCs. Our caps don't fail by popping the tops but by leaking the electrolyte out the bottom seal and may not be visable for quite awhile, long after the damage is done.


Steve

A capacitor is a capacitor. A leak will be noticeable... And yes, those are capacitors.. They hold an electric charge.

 

[steve]

And yes, those are capacitors.. They hold an electric charge.

Thanks for pointing that out to me.

Steve

 

[Jordanbutter]

Hey this might be a loooooong shot but do you have a full ram intake if so did you run over a puddle? Like I said looooong shot but my friend did it in his 3g and his motor went into hydro-lock. Sorry if it has nothing to do with this but hey you never know right?

 

[highnitro12187]

sorry i dont have full ram intake (i wish)

Thanks,
Matt

 

[highnitro12187]

ok i bought me a new ecu today so it should be here on thursday. ill post when the car runs again.

Thanks for all your help,
Matt Wells

 

[highnitro12187]

Today i got the ecu and put it in. The car does run but now i have a new problem. The idle is really weird. When it first starts its at normal. but then i push in the gas and let off and it shoots up to 2500-3000 and wont come down. Im lost here (still new to dsm's and cars in general) Please help. I need to drive the car to work, so quickness would be appreciated.

Thanks,
Matt