Turns but no fire!

[Slo87Gn]

This has got to be something simple. THe car ran good when I pulled the motor last week to have new guides put it it had started smoking a little. While I had it out I found one pison had some small cracks in it from teh blown headgasket it had when I got the car. So the entire motor is rebuilt.

At any rate when I disassembled it I market all wires and hoses even though most plugs will only go one place and the lengths pretty much csho where they go. I tie them all out of the way and nothing was snagged on pullout or reinstall. I got all wires plugged back in and the 4 grounds in the back grounded on a stud on the rear intake bolt. I dont have any wires left over that I can find the crank and cam sensor wires are plugged in. I turned the key and cycled the pumpo she had 50 psi on guage everything seems to work good. So I turn it over to see if it will fire and get no hits or anything.

I pull the cam sensor cap and #1 plud turn it to TDC and all lines up and sensor is turnning properly. I put the Trans Am Sensor cap back on and have my wife turn it over and no light on the cap to show it is in phase. I move it around some just checking and nothing.

I am not sure what I might have missed. Everything looks hooked up and it all worked a week ago when I pulled the motor last week. I did have the battery disconnected for the week. the scan master needs the tuning adjustments put back in but shouldn't have anything to do with no fire.

Any ideas would be greatly appreciated.

 

[TurboBuRick]

Coil pack module plugged in?

Orange wire by the battery plugged in?

Check all fuses........

 

[Slo87Gn]

Coil pack module plugged in?

Orange wire by the battery plugged in?

Check all fuses........

Yes plugged and unplugged the coil packs twice to make sure.

Orange wire is on and has 12v

ECM fuse is good.

Only thing I did that I can think of was spray the crack sensor when it was off with brake cleaner to get grime off. I didnt mess with the adjustment just the bolts on the timing cover. I took it off and put it in with the motor on the stand along with the harmonic balancer.

Trying to make sure I didn't hit anything at the time. I got under the car and it looks like it is fine and has not hit or rubbed against the balancer.

DO the crank sensors go bad that easily?

 

[TurboBuRick]

You can test the crank sensor just like cam sensor. Use a 9 volt battery and a volt meter.

 

[NASSTY]

You can also remove a spark plug or use a spare plug and put the plug wire back on the plug and lay the plug on the valve cover.Then turn the car over and have someone watch the plug to see if you have spark.If you have spark than the crank sensor is good.
I would guess that the cam sensor is out.Was it installed at 25* ATDC on the compression stroke?

 

[Slo87Gn]

You can also remove a spark plug or use a spare plug and put the plug wire back on the plug and lay the plug on the valve cover.Then turn the car over and have someone watch the plug to see if you have spark.If you have spark than the crank sensor is good.
I would guess that the cam sensor is out.Was it installed at 25* ATDC on the compression stroke?

It is a new cam sensor but I have to good old ones also. I am not getting any readings on the blue wire when turning the sensor. Nor am I getting any spark when motor turns over. I put a new crank sensor on it gapped it .030 as it says and still nothing.

Yes I have the 25* marl on my balancer and did try to set it with the light and I get no light.

THanks fo rthe ideas I am tired tonight I will jump back on it tomorrow and use the other cam sensors I have then.

One thing if the key is on is there any voltage to any of the 3 wires from the harness to the cam sensor if it is unplugged or plugged in?

 

[87NAT]

No spark, has inj pulse-check ign module
Has spark, no inj pulse-check cam sensor or ECM
No spark or inj pulse-check crank sesnor or module

 

[Slo87Gn]

Is there suppsed to be 12v with the key on to the Cam sensor's Gray/Red stripe wire? and the same for the Crank sensor's Dark Green Wire? The 86/87 wiring diagram shows those to be 12v signal power?

I know there should be 7.5 v or so from the blue wire when cam sensor is in the window. I get no reading from it but I also get no reading from the grey wire that should feed the sensor power.

ECM/IGN 10amp and CCCI 7.5 amp fuse are new and test good.

Orange wire has power past the fusible link and the plug.

I replaced the crank sensor with a new one and gapped it.

I can not find any wires under or around motor that are loose, unplugged, hanging, or crimped.

Put two stock camp sensors in I know both were working and nothing.

Does the ECM send the 12v to the cam and/or crank sensors or are they hot to start and just send the pulse to the ECM.

 

[Slo87Gn]

I have 12v to both pink wires on the Control module but no volts out on the grey w/red strip or green out wires to the sensors. It acts to me like I missed a ground. Check me and see.

I put the 4 ground wires on the back of intake on a stud with nut.
I put the ground strap from the firewall to the trans bolt.
There are two ground wires on the front of the block one goes to chassies one to battery.

The were 3 wires in the loom that went down to starter two large on the battery post along with battery cable and one small for the soliniod.
One wire from starter to alternator hot post thicker guage than factory.

Have I missed any grounds and does it sound like most of the wires are in the right places. all other plugs are plugged together. I marked everything when I took it apart but who knows.

 

[Slo87Gn]

Ok I have gone through all the test on the No Start diagram.

I notice it says that I should have 6 - 9 volts from Module but when I go from the hot wires at crank and cam sensor it is 5.13 v which is what Bill told me I should see.

At anyrate if I jump the hot to the harnes black gnd as in test it goes to zero but to a block ground it is 5v. Test says the gnd wire from the sensors is not grounded or connedtion is bad or module is bad.

My question is the Modual bracket to the intake the only ground point for this circuit. Are the cam or crank sensor ground wires spliced to any other wires that go to ground in other words?

All diagrams I have seen show me a ground from Module but there are no other wires so I am assuming it is te bracket alone that does it. I have a NEW module that is how i got the 5 v to the sensors.

I wire brushed any and all paint off the bracket where it mounts to module and intake. I wirebursh all nuts and bolts/studs also to ensure clean surfaces.

I did a continuity test from end to end of the terminal plugs and they show good from sensor to module.

 

[Slo87Gn]

Perservere to endeavor! It freaking starts and runs!!!!!

The freaking crank sensor hot wire had a bare spot on it and was pincjed between the two metal fuel lines behind the idler pulley bracket. It could move u p and down like it wasn't caught so I didn't think anything about it. Until I finally just pulled the crank and cam sensor wires out of the harness and on close inspection so the rubbed spot. Fixed it up and rna the test and woot 10+ volts and hooked it all back up she started up!

 

[87NAT]

Perservere to endeavor! It freaking starts and runs!!!!!

The freaking crank sensor hot wire had a bare spot on it and was pincjed between the two metal fuel lines behind the idler pulley bracket. It could move u p and down like it wasn't caught so I didn't think anything about it. Until I finally just pulled the crank and cam sensor wires out of the harness and on close inspection so the rubbed spot. Fixed it up and rna the test and woot 10+ volts and hooked it all back up she started up!

Eric, What did I tell ya...a wire frayed or rubbing somewhere. I knew it was something like that. Glad you got it. Good talking to you the other night. Take care.

ED

 

[TurboBuRick]

Great news, glad to hear....:biggrin: :smile:

 

[Slo87Gn]

Thanks a ton for the help folks!

Ed you were right on I had the feeling it was something like that just had to keep looking! I will have to say it was in some ways worth it for what I learned new about these cars from all the help and reading!

Eric

I have a new issue little one I think.

I have a Scanmaster 2.1 on the car there is no SES light all readings are somewhat normal except the IAC It is way out of wack car stumbles trying to Idle once warm and shows AF of 8/9 and volts of 863. When it is cold it runs semi ok. I can drive it at 2k or more rpms and part throttle between .48 - 2.0. It stumbles and dies if I let it go to idle at .44 TPS and shows rich it will restart only if I open the throttle blades like it is rich and trying to flood.

The IAC is reading 117 -130. I know this should be 10 - 20. is there a test sequence for this issue?

 

[87NAT]

Eric, af needs to be 5-6 at idle. If you have the stock MAF it could have taken a dump on you when you had the motor out. They are very sensitive.

 

[1986TR]

having problems like this is exactly how you gain experience i bet you know youre car alot better now good job:biggrin:

 

[Slo87Gn]

having problems like this is exactly how you gain experience i bet you know youre car alot better now good job:biggrin:

I have been building hot rods for 30 years. I really don't want problems like this to learn more about a car in reality. The only thing I really did not know much about on these cars is the wiring and that is something I really really hate pretty much on all cars!!!!!

But your right I am learning more than I ever wanted to about the wiring and electronic workings of the GN/TR cars. :wink:

 

[TURBOTERRORV6]

gread thread, i will look in to this due to my car not turning on after rebuilt thank!

 

[GNRick]

Thanks a ton for the help folks!

Ed you were right on I had the feeling it was something like that just had to keep looking! I will have to say it was in some ways worth it for what I learned new about these cars from all the help and reading!

Eric

I have a new issue little one I think.

I have a Scanmaster 2.1 on the car there is no SES light all readings are somewhat normal except the IAC It is way out of wack car stumbles trying to Idle once warm and shows AF of 8/9 and volts of 863. When it is cold it runs semi ok. I can drive it at 2k or more rpms and part throttle between .48 - 2.0. It stumbles and dies if I let it go to idle at .44 TPS and shows rich it will restart only if I open the throttle blades like it is rich and trying to flood.

The IAC is reading 117 -130. I know this should be 10 - 20. is there a test sequence for this issue?

My friend's car had readings way out of wack too....his MAF was 230 at idle, etc., I reseated the chip and all was well again.