A non DSM question

[Redslayer]

Long story short my brothers truck (02 I think, Cadillac Escalade).

I've been searching the net a bit to see if I could find something concrete enough to suggest to him. Figured I'd ask here in case one of you knows what could cause it.

It wont start, it turns over and you can smell raw fuel after he turns it over for a few seconds (strong from the exhaust) then when he releases the key, it will act like maybe one or two cylinders are trying to fire for a few seconds then stops, sometimes it will act like its going to fire when he first turns the key, and then just turns over. And then does the chugging when he stops trying.

I've never actually ran into this one before, never seen a vehicle do that after trying to start. So any idea what would cause this?

Sorry for the non DSM related post, but I'm at a loss here, and I am not part of any other car forums .

 

[BogusSVO]

What engine?

 

[hediki12]

Cadilac truks come with lq1or lq2 a iron version of the ls1/2 check the dizzy make sure ## getting spark

 

[Redslayer]

What engine?

I just know its a V8.

And I will have to check for spark, but if its stumbling like that after he releases the key there has to be at least some spark somewhere heh.

 

[reddragon1]

Cadilac truks come with lq1or lq2 a iron version of the ls1/2 check the dizzy make sure ## getting spark

I think you mean the lq9 a aluminum block 6.0. I would check for spark like he said. Also they have coil per cylinder if it is a ls based engine if not then its still the old vortec with the spider injector system then I would start looking at fuel pressure to make sure an injector is not sticking open.

 

[Diamond Star Werks]

Kinda sounds like the crank sensor to me. Giving week signal or in and out signal.

 

[hediki12]

Wouldnt crank sensor kill the injectors?

 

[300hpbound]

Crank sensor would kill spark, I don't think it would take out the injectors though. It would be my bet that the Crank sensor is out. If it goes out, the ECU doesn't know when to send spark so it would just sit there and crank away.

 

[BogusSVO]

Another possiablity is the ignition switch has failed, allowing no spark in crank, then just a moment of spark when it falls into the run.

Any CELs?

 

[Diamond Star Werks]

Wouldnt crank sensor kill the injectors?

No crank controls the spark and Cam sensor controls the injectors. Crank because piston and spark are related. Cam because valve and injectors are related. This is how it is on the majority of vehicles.

 

[badas93tsi]

Sounds goofy, and simple I know, but my Z28 has done the same thing twice. The first time the fuse for the gauges blew and it wouldnt fire. The second time the plugs had just gotten fouled and wouldnt let it start. I'd change the plugs, and try it out.

 

[clipto]

I thought I would chime in and say this is the part where you say you should of bought a dsm.

 

[Redslayer]

Ok, little update here. its a 5.7 liter V8 Vortec engine. We replaced the spark plugs (they were grimy and reaked of fuel) and before we put them back in, I pulled the Fuel pump relay and we stuck them against the block one by one. And it sparked for all 8 cylinders.

So its getting fuel and its getting spark. Now, while cranking it tries to catch and will sound like its about to fire and then wont. And it will randomly 'backfire' out of the throttle body / intake so what would cause that?

Edit : Could it be a timing issue? Kind of random it would pop up after sitting for a couple days, ran fine before.

Edit 2 : He had a couple wires misplaced that was causing the backfire out of the intake.

This is what its doing now (with a battery charger also attached to it)

http://www.youtube.com/watch?v=ZgEqEB_acrI&feature=youtu.be

Sorry about the blurryness didn't auto focus for some reason.

 

[ontario AWD]

My 01 chevy 2500 hd was doing the same thing.The cat had fell apart on the inside and was plugged up tight.Try unbolting the exaust and see if it runs.

 

[wrencher]

OK that's the old L31.
2 things common to these to cause issues.
By the sound of that video look @ this 1st;
1st thing, cap & rotors are more than common to go bad on these.
Dont cheap out replace them with delco OEM parts.
They will crossfire in the cap, sometimes it's really hard to chase. The cap is rerouted/reprogrammed to route the wires easily.
EDIT; watching that video again definitely do the cap & rotor first.

2nd is the fuel pump.
These things need about 55 psi to start.
They have an injector with a line that clips to a port inside the intake above the intake valve.
On the end of that line it's a poppet valve not unlike a diesel engine.
It has to have the proper rail pressure so once the injector is activated, the fuel sent down the line is a high enough pressure to open the poppet valve.
If it's not enough, it'll put a very small amount of fuel in or none at all.
Continuous cranking can flood them, I know odd but seen it before.

 

[DSM1G90]

The issue above is a common for GM and their V6 and 8 series .. usually the ignition module controlled by the ECU, or the ECU itself.

Bet if he pulled plugs, they be soot black from a weak yellow spark- due to a dying module.

This problem began when GM started to put the coil on top of the distributor and it's all controlled by a ignition module and magnified when ECU's came into being. Modules were dying left and right and spendy to replace.

Hope the owner has lots of green lining his pockets for this aint a cheap fix.

If GM used Denso or Bosch ignition, you'd never see any problems...

 

[Redslayer]

The spark at the plugs should be blue right?

 

[reddragon1]

The spark at the plugs should be blue right?

Yes thats a good thing. Now check fuel pressure to see what it is doing. Like it was said before the spider injection system needs at least 55 psi to fire the injectors. If you have that then I would leave the tester hooked up and wacth how much the pressure drops with in 10 minutes to an hour.

 

[Mullet_GST]

To check the Timing chain do a back up test Turn it from the crank with a ratchet. Take the cap off so you can see the rotor move. Turn it clock wise or counter clockwise from the crank and see how much play you have in the chain if the rotor moves instantly chains fine,

How many miles did you say it had?

 

[Redslayer]

To check the Timing chain do a back up test Turn it from the crank with a ratchet. Take the cap off so you can see the rotor move. Turn it clock wise or counter clockwise from the crank and see how much play you have in the chain if the rotor moves instantly chains fine,

How many miles did you say it had?

It has about 60-70k on this motor IIRC.

Also, the spark is yellow/orange, and wont jump from the wires to a ground (like it will on my car) so I suggested this being the issue at the start, that's why he replaced the plugs.

My spark jumped an inch past the end of my wires to a ground on my car , it wouldn't jump from his even when I put the wire partially over top of a bolt.

It would be nice if all it is, is the coil or something. I wasn't 100% sure about the spark color though and forgot to mention that before x.x my bad .

 

[BogusSVO]

yes yellow/orange at the spark plug gap is not good, coil is on the way out or gone.

Should be a blue/white in color.

 

[Redslayer]

yes yellow/orange at the spark plug gap is not good, coil is on the way out or gone.

Should be a blue/white in color.

That's what I'm figuring, we tried a ignition control module to see if that made any difference, but no go. So it almost has to be the coil at this point. But he's frustrated (impatient when it comes to mechanics, probably why he let me have my car back when it was stock and he blew the trans up haha) and said he's just gonna take it somewhere.

 

[DSM1G90]

Coils are easy to change out.

 

[Redslayer]

Coils are easy to change out.

Yeah he wound up trying it because they were cheaper than the ignition control module (they allowed him to swap it out) and its a no go still wont fire.

Its puffing a bit of smoke out of the breather (noticed this when I was watching him try to start it and the tube was out of the hole) is that normal? Seems odd to me.

Strong gas smell remains when ever cranking.

 

[NeMiZiS]

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