Knock Sensor and Misc Questions...

[94c4lt1]

3 really quick questions:

1. Can you tell me the location of the knock sensor (detailed)?

2. Any sites or locations with detailed schematics of a syclone engine or assembly?

3. Are there any good service manuals for a GMC syclone?


Thanks

 

[dgoodhue]

Re: Knock Sensor and Misc Questions...

3 really quick questions:

1. Can you tell me the location of the knock sensor (detailed)?

2. Any sites or locations with detailed schematics of a syclone engine or assembly?

3. Are there any good service manuals for a GMC syclone?

The KS is behind the distributor, as for good manuals get the Helms.

 

[94c4lt1]

Re: Knock Sensor and Misc Questions...

3 really quick questions:

1. Can you tell me the location of the knock sensor (detailed)?

2. Any sites or locations with detailed schematics of a syclone engine or assembly?

3. Are there any good service manuals for a GMC syclone?

The KS is behind the distributor, as for good manuals get the Helms.

Great man, thanks...

Now we have another problem. The electrical connection to the KS...we can't figure out how to take it off. We have been playing with it for a while and can't get a good grip on it. Do we need to take something else out to get to it (currently we have removed the wiper assembly, cowl, hood and ignition coil)? We can see and touch it but we are not sure if it pulls straight out or clips in or what?

Sorry, thanks for the help.

 

[mrweelr]

You should be able to get clean access to the knock sensor by marking and pulling the distributor. At least that's what I did, and I had my hood on. The second time, I actually changed my knock sensor with the distributor still in place (not fun!). Anyway, the blue wire going to knock sensor is a bitch. You have the squeeze it really hard and then just pull straight up. Some needle nose pliers may help too; just try not to damage the connector. Good luck.

 

[Loeryder]

nawwwwww

We got it out by taking the coil off and then having the Heather Tool reach all the way back there.
It is on the back of the Driver's side Head, the one with valves in it...

the KS itself has just a "nipple" on it and the single drk blue wire has a connector that grabs on both sides of the sensor and it can spin freely.
Get to the bottom edge and pry off one of the "legs" and it will slide right off.

 

[94c4lt1]

nawwwwww

We got it out by taking the coil off and then having the Heather Tool reach all the way back there.
It is on the back of the Driver's side Head, the one with valves in it...

the KS itself has just a "nipple" on it and the single drk blue wire has a connector that grabs on both sides of the sensor and it can spin freely.
Get to the bottom edge and pry off one of the "legs" and it will slide right off.

Well, we got the knock sensor out and replaced it (PITA but what isn't when working on a syclone...tough with everything crammed in there), replaced the boost silenoid and did a full tune up!

We are still having our problem, but we are replacing everything one part at a time. Basically what the truck is doing is the truck is cutting out during WOT and starting really hard (takes a while to turn over). Also when power braking (holding in the brake and reving the engine to try to build boost) the rpm's won't go past 1500 RPM and the turbo starts to spool but we don't get any/very little boost, ANY IDEAS would be great!

But mostly I wanted to THANK everyone on this forum for there continued help in our work! You guys have helped us out so much and I just wanted to say THANKS!!!

Scott

 

[Loeryder]

cutting out during WOT

Cutting out like the fuel cutout and the truck just stalls?
Pull your codes, that sounds a lot like Overboost.
Adjust the wastegate rod..

Other reasons for not building full boost could be the vac lines at hte turbo.
There are 2 one from the compressor housing to the WG solenoid, and one for the solenoid to the actuator.
Look right on top of the turbo, those hard plastic lines and rubber elbows are probably quite brittle. replace them with some vac lines and zip ties and you're good.

 

[94c4lt1]

cutting out during WOT

Cutting out like the fuel cutout and the truck just stalls?
Pull your codes, that sounds a lot like Overboost.
Adjust the wastegate rod..

Other reasons for not building full boost could be the vac lines at hte turbo.
There are 2 one from the compressor housing to the WG solenoid, and one for the solenoid to the actuator.
Look right on top of the turbo, those hard plastic lines and rubber elbows are probably quite brittle. replace them with some vac lines and zip ties and you're good.

No, actually the truck doesn't stall and I am not sure if it is the fuel cutting out (I believe so, but it could be a misfire). Just when it hits about 1500 RPM under WOT it cuts out (no stall though), and when power braking it only hits 1500 RPMs and won't go any higher.

We just replaced all the vac lines when we installed the new turbo and we double checked all of them. But I will give it another look.

Thanks for all your help...

 

[94c4lt1]

Anybody got any ideas...please?

Could it be the ignition coil? Any clue?

Oh, and it pulls code 43...

thanks,..

 

[leroy]

I'm guessing you got the wrong knock sensor, unless you had the code before the change. The local GM dealer sold me the wrong one, once.

Make sure the tan wire is connected also.

HTH,

Jim

 

[leroy]

I'm not sure my previous post made sense after reading it again. I was referring to the code 43 problem.

I think you have a separate problem causing the cutout. My first guess there is ignition problem (wires or plugs most likely). Second guess is a weak fuel pump.

Good luck.

Jim

 

[MattGE]

Shot in the dark, but maybe a clogged fuel filter?

 

[GM TURBO]

IMO, hard starts are fuel related. Either fuel pump or fuel filter. That has been my observation - but I have been wrong before - and I'll be wrong again.