TOPIC: 2002 4.2L GMC Envoy

Hi Everybody

Has anybody done a 4.2 Liter Denali, it run with drive by wire throttle body. I will grooving one tomorrow so if there is anything I should know before hand that just might come in handy.

Thanks Aaron

Hi Aaron!

Are you sure it is a 4.2L? The Denali came with a V8, probably a 5.3 or 6.0. The GMC Envoy came with the 4.2L Inline 6.

If it is the Envoy, I have not done one yet, but hopefully soon. Use the business card folded in half to position the throttle plate, unless you have a scan tool to determine throttle position at start-up.

I do have to work tomorrow at the dealership, so if I come across a similar engine, I will observe vac lines.

By the way, gas prices just hit $4.00 here. The time is right for the Groove!

Hi Scott

Just got a hold of the customer and he said it supposed to be a denali and it says denali on the side of fender but he is pretty sure it an envoy, denali's didn't get produced until 2005. It is an 02 gmc envoy 4.2L thanks for the heads up Scott. And fuel prices here are around $1.28 per liter, some folks around here are saying it's going to hit $1.50 this summer.

Aaron

I just LOVE Wikipedia! It is so useful in issues like this. Here's what's posted on Wkipedia on the GMC Denali (excerpt)
"The Denali nameplate started as the top-of-the-line version of the GMC Yukon for the 1999 model year. It was also GM's first attempt to cannibalize sales from the new-for-1998 Lincoln Navigator. At the time of it's introduction General Motors decided to give Cadillac its own luxury SUV so the Denali's exterior was shared with the 1999 Cadillac Escalade, with only the front fascia and lower side body panels differing from the standard Yukon. Even though the Yukon was redesigned alongside the Chevrolet Suburban and Chevrolet Tahoe in 2000, the Denali and Escalade retained their 1990s base design."



(From Google Images)

So, the Denali actually started in '99 as a spin on the Yukon, and carries on today.

Hi Folks

This is a disppointing Envoy, I remove throttle body from air intake manifold (very easy to get to) and discovered the throttle plate is right at the edge of housing that bolt to the manifold there's nothing there to run the groove in let alone using the business card for a spacer, so I put her back together let customer know it couldn't be done due to design but there may be a possible solution for this throttle body. I will post pics. later.

Aaron

Can you take a picture with the throttle body turned 180 degrees as it looks alot like the 6.2 L I did last week and there was just enough room for the middle size bit. Remember the idle air pos on the butterfly is about where it sets with no voltage applied. Look close as at first it looks like there is no room but I had just enough room it will take a steady hand when applying the groove as it is paper thin at the edge. Dan gadgetman Mo.

Hi Dan

Here is picture, also are you saying that the plate will be off 0.0% TPS will igintion turn off.

Aaron

I mean turn the other picture around so I can see how close the butterfly is to the edge thanks dan

Hi Aaron,

If the ecu is controlling the Throttle plate position, there is a difference between the "off" position and the 'zero' position.

My '07 Avalanche is fly by wire, it caught me off guard until I realized that the fully closed position is way different than the "off" position.

This allows it to adjust at startup without hitting an 'end stop'.

You need to check the idle position with the OBDII scanner to get the correct position for the groove. Once you have that you can pull the TB off, leave it plugged in, turn the ignition key to the 'on' position so the ECU and scanner will talk and you can move the throttle plate to the idle position by watching your OBD scanner. If this TB is like mine there is not enough room for a credit card or anything else so you will want to take your bit and scribe a line in the TB wall as a guide for the groove.

You'll find it necessary to hold the plate in place while you apply the groove.

This is the "off" position




This is the "idle" position




Ain't this fun

Karl Fortner
Tacoma, Wa.
Gadgetman Tacoma

Question, Why can't you just make up a 1/4" spacer put the groove in the spacer problem solved.

Craig

yes that will work with a spacer as long as the groove is still in the close path of the butterfly Dan gadgetman mo.

Hello Orrist hear in manitoba
I have a problem done the Groove on my sisters 2004 Envoy 4.2 six.I used the med bit and cut thrue in three places.filled them with JB and am shure ther are no leaks there.My problem is the truck wants to run away when driving.Hear are some numbers

SHRFT +1.6 TO -14.8
LONGFT -0.8 Dose not move
MAP psi +6.1 to 5.8
o2B1S1 + 0.885 to 0.215
o2BS2 0.890 to0.050
It had a P0016 code whitch is crankshaft position , Camshaft Position, Corrilation bank 1 sensor A she has been told you have to pull the moter apart to get ride of that code I cleared the code but it comes back the next time you start it.Reset the computer severl times would having the groove to close to the throtal plate do this I checked for vacume leaks unless there is a intake manifold leak I can not find it any help I could get would be grate

Orrist