Problem Starting Up

[Justa_v6]

I’m experiencing problem starting up my 85 GN it starts up for 1-2 seconds then dies out, I try to re-start and nothing just cranks...cranks...cranks...no start

The car has been sitting for 1-2 years. So did the basic spring cleaning dumped out the fuel and cleaned the tank, replaced oil and filter, replaced spark plugs and wires. Before starting the car I removed the cam sensor and primed the oil pump..pressure build up just fine. Then I decied to start up and.....Nothing.

I checked and found two big vacuum leaks at the back of the manifold fixed them... nothing

I checked the vacuum block for leaks...nothing

I have Fuel pressure @40 psi at key on.

I checked for spark and seen that it seemed very weak so I separated the Ignition coil and module and.... (see picture)

I did not think this was normal at all so I decided to upgrade the ignition module as well to an 86-87 with the Casper’s conversion kit. I also ordered the 84-85 module bracket which grounds the module properly but have yet to receive it, so in the meantime I have 3 ground straps connected to see if it will be able to start....nothing

I checked all the connections at ECM and found the smaller connector at ECM to be green with corrosion, seems ECM was getting wet caused by old/deteriorated door seals so I had planned to upgrade the ECM and found an excuse to do so, I swapped it out for an for an 86-87 version along with the TT chip with 009 42lb injectors and a LS1 MAF and Translator Plus. (MAF was not reading any g/s)

I changed the oil pressure sensor also thinking it might not be reading proper pressure....nothing

I checked the Crankshaft sensor and clearance and cam timing with Casper’s timing tool and still nothing, I even got the Casper’s camshaft by-pass tool and the car still does not start.

 

[Jerryl]

Looks like the ignition module replacement was a good call.
Did you get a chance to follow the “no start” diagnostic tree in the sticky?

Since the MAF is not reading, there is something wrong with the translator and/or connections.
Could be a multitude of things and as simple as a fuse, or cam sensor adjustment, corroded ECM connectors, defective ECM, corroded chip socket, defective fuel pump, bad MAF, defective caspers conversion kit etc.

 

[Justa_v6]

The MAF was not reading before I changed it out, thats why I decied to go with the conversion..sorry for the confusion.

 

[Jerryl]

The MAF was not reading before I changed it out, thats why I decied to go with the conversion..sorry for the confusion.

Are you talking about the ignition conversion?

Was the MAF not reading at all?
A bad MAf will not cause a "no start", jut a "bad start/idle" with a std. MAF chip.

If the ECM was getting wet and there is corrosion as you stated, you will need to look there.
The ECM wires are very sensitive to corrosion, and ANY corrosion will cause all kinds of problems!

 

[Justa_v6]

The MAF was not reading and had the honeycomb part of it broken so I converte to LS1 MAF for that reason, (without sounding like a smart ass) I know the MAF would not cause a no-start just decided to replace due to broken/unreliable.

The ignition was converted because the module was bad and would cost the same to replace the 84-85 unit as the 86-87 conversion so I decieded to go with 86-87 ignition conversion.

I have checked and cleaned the connections to the ECM and I beleive they are as clean as I can get them, I performed a voltage drop and checked for resistance throught the wires and connections seem to be good. How would I know if I have a defective ECM? Symptoms? I got the ECM at the local junkyard



Any ideas would be helpfull and appreciated.

 

[Jerryl]

The MAF was not reading and had the honeycomb part of it broken so I converte to LS1 MAF for that reason, (without sounding like a smart ass) I know the MAF would not cause a no-start just decided to replace due to broken/unreliable.

The ignition was converted because the module was bad and would cost the same to replace the 84-85 unit as the 86-87 conversion so I decieded to go with 86-87 ignition conversion.

I have checked and cleaned the connections to the ECM and I beleive they are as clean as I can get them, I performed a voltage drop and checked for resistance throught the wires and connections seem to be good. How would I know if I have a defective ECM? Symptoms? I got the ECM at the local junkyard



Any ideas would be helpfull and appreciated.

Good call on the MAF and glad you are aware of it . . . . lot of people don't.
Hope my post did not come accross as "degrading" your knowledge.
Just trying to ask some questions to help you get down to the root cause.

What is the ECM number?
On a bad ECM, you will sometimes get some weird readings and lots or error codes.

Does the fuel pump prime when you turn the key and what is the pressure when you crank it?
Does the SES come on?
Are the injectors firing?
Plug condition?
Do you have spark?
What method dis you use to install the cam sensor?


That is all I think of for now.

 

[Justa_v6]

Ok so I finnaly had some free time to dedicate to the car
Yes the fuel pump does prime when I turn the key 35psi
when I crank the car over it is 35-40 psi

ECM # 1227148

I have no faults in the ECM

The check engine light does come on when I turn the key to theon position.

The plugs were just replaced before i attempted to start.

I checked all cylinders and have spark, checked the wires and ohmed them and found 2 were OFL/OPEN (out of functional limits)this is what my meter reads.
so I replaced the wires and still nothing.

Continued diagnosis and found cyl 2,4,6 injector were not receiving signal, checked with noid light at connector and ohmed out the harness and foun short/open on cyl
2,4 and 6.

I oredered a new harness hopefully this takes care of the problem.