Cranks but won't start + smoke from turbo

[GN_Nomad]

I just picked up a non-running GN as a project. I've been reading everything I can and this forum seems a wealth of information, but i can't figure out where to go next. I've gone through the No-Start chart from GNTtype but it is advising to see "Diagnostic aids on facing page", what exactly is that referring to?.
I'm getting spark on each plug, the injectors "pulse" with the test light and the fuel pressure is good. On occasion turns over for just a second before stalling, but typically it only cranks and backfires. When it backfires white smoke comes out of the intake side of the turbo.
Does anyone have an idea of what to test next? (unfortunately ordering a scanmaster is on hold till after Christmas)

Thanks

 

[John Larkin]

Sounds really rich. I think the cam sensor controls injector pulse. Might try pulling the cap and seeing if the rotor is turning properly. The verify it is set properly.

 

[chopped39]

Does it run if starting fluid is used? How long has it been sitting? sounds like a timing issue. If injectors are clogged it wont start might get a few drops of gas and then pop off for a second.

 

[GN_Nomad]

Thanks for the quick replies, i'll check the cam sensor tomorrow morning.
It had been sitting for about 3 years, but the gas was drained. It has fresh gas, new fuel filter and the hot wire fuel pump kit.
Is the smoke not something I should be concerned about?

 

[mikestertwo]

Is the smoke not something I should be concerned about?

The smoke is probably from the back fire. Check the cam sensor setting and make sure you have the plug wires on in the correct order.

 

[GN_Nomad]

Thanks for the replies, its been a crazy 4 months and i've just recently had a change to get back to the GN.
I set the harmonic balancer to 25 ATDC, then adjusted the cam sensor until the voltage dropped from 6.8ish to .02ish. The car cranked the same as it did previous with not change. After a few attempts at starting the car no longer cranks, it only stutters without firing.
Any other ideas what to look at to get it running?

 

[TexasT]

Well, do you have something to check codes? cam sensor, crank sensor, all fuses under the dash good?

How are you measuring fuel pressure? Known good gauge? Put it on your daily or a neighbors to see.

Are the plugs getting wet? Measure the resistance across the coils on the coil pack. Cant recall values but i'm sure someone will know and post.

Compression in all cylinders good? Leakdown?

Battery have a good charge and spins it over with authority?

Previous owner claim it ran when parked?

 

[HouTX87]

Try starting it with the cam sensor unplugged. Have you replaced the spark plugs?

 

[GullsGN]

Backfiring with white smoke. Are you sure your wires are in the correct firing order??
Cam sensor 180* backward?

 

[TurboBuRick]

Does it run if starting fluid is used? How long has it been sitting? sounds like a timing issue. If injectors are clogged it wont start might get a few drops of gas and then pop off for a second.

This^^

 

[GN_Nomad]

Backfiring with white smoke. Are you sure your wires are in the correct firing order??
Cam sensor 180* backward?

It is backfiring and white smoke is coming out of the intake. I have checked the wires a few times and I am rather sure they are in the correct order, getting spark and properly seated. As for the cam sensor 180 backwards; I doubt it? I pulled the first plug and I could feel air come out as I rotated the engine to line up the harmonic balancer. Also the window on the dish was pointed at the driver’s seat. I then set the cap on top and rotated it around until the voltage dropped to .02. This did cause the wires coming off the cap to basically point towards the drivers seat. It didn’t look right, but it made sense that where the dish had the gap the current would drop.

 

[GN_Nomad]

Try starting it with the cam sensor unplugged. Have you replaced the spark plugs?

I have replaced the plugs and plug wires. I’ve also pulled the plugs and made sure they were all firing. Cranking with cam sensor unplugged is on my list for Sat

 

[GN_Nomad]

Well, do you have something to check codes? cam sensor, crank sensor, all fuses under the dash good?

I did just receive the scanmaster, the results of that will come with my Saturday evening post of success or more frustration. When I jumper the ALDL the only code presented is the ‘12’. All of the fuses are good

How are you measuring fuel pressure? Known good gauge? Put it on your daily or a neighbors to see.
I connected a fuel pressure gauge but I don’t recall what the pressure was. Its worth double checking so I will test it on my Jeep then re-test and provide an actual number.

Are the plugs getting wet? Measure the resistance across the coils on the coil pack. Cant recall values but i'm sure someone will know and post.


The plugs are getting wet. I have done nothing with resistance across the coils, I ran through the “no-start” tree and with each plug getting spark I moved on.

Compression in all cylinders good? Leakdown?
I haven’t checked

Battery have a good charge and spins it over with authority?

Previous owner claim it ran when parked?

At the start of last Saturday it was fully charged and cranking strong, but at the end of the day it was clicking a bit. I put the battery the trickle charge and now its charged and ready to go.

Previous owner claim it ran when parked?

The PO said that he drove it home from work, then the next morning it wouldn’t start. He worked on it a little but it didn’t get running again. He said that he drained the gas intending to replace the fuel pump (and there is a spare in the trunk) but never got to it. The car died about 3 months after he replaced the cam sensor himself, which was about 3 years ago. I work with the PO, so I can ask him specific questions, but I’m sure he sold it because he was sick of thinking about it so I try not to harass him too much.

 

[GN_Nomad]

Two other points that may help
When I had the cam sensor cap off I turned the engine by hand and the metal “dish” didn’t turn smoothly. As I rotated the motor the dish would jump rather than sweep. I’m not moving the motor very much but I’m sure that the dish was not moving smoothly and proportionally to the motor. Is this just friction causing the dish to stick a little, or is that play perhaps an issue?
There is an aftermarket alarm which requires a 4 digit code to be entered before it can be started. I enter the code and the light turns green and the engine will crank. I doubt that’s the issue but if there is a way to remove it for troubleshooting PM me. Doesn’t seem like information that should be easy to google but if I can remove a variable I’d like to.

 

[GN_Nomad]

Thank you again for all of the replies; I’m new to turbo’s and this car but this site and you guys are an amazing resource.
My list for Saturday is:
Confirm fuel pressure
Check every plug wire
check cam sensor
Crank motor with cam sensor cap removed
Connect scan master and document results
Anything else to check or try?

 

[chopped39]

Did you try starting fluid? If it starts on that the injectors are clogged and it will never start. You can have fuel pressure at the rail but if injectors are clogged there is no fuel getting delivered to cylinders. Do you have a scope by chance? You can low amp the injectors and look for a pintle bump while cranking.No pintle bump no fuel delivered. I dont like what you said about the sensor jumping.That could be a timing chain issue. hope this helps. If you have a propane torch induce a little into the air inlet and see if it tries to run. Does not take much compression to burn propane. If it does fire or stumbles the chain may have jumped. I hope this helps. good luck

 

[USAFbuickthrust]

Replace ignition module and coil pack, check cam sensor for looseness or play. Combination of the both blew my one muffler at the weld seams...

 

[USAFbuickthrust]

Replace ignition module and coil pack, check cam sensor for looseness or play. Combination of the both blew my one muffler at the weld seams...

You can play around awhile before you'd probably come to that conclusion but it's the one thing that is forgotten

 

[bryesh]

A bad timing sprocket (common) could be the culprit if you run out of other ideas.

 

[USAFbuickthrust]

^^^^that too. The one thing that wasn't wrong with mine