My 1998 2-door build is done - Pics, impressions (and need some input)

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Toomanyhobbies

Full Access Member
Joined
Sep 18, 2017
Posts
139
Reaction score
139
So I have posted a couple times about my truck that I bought last September. I picked it up last Friday but I wanted to drive it a number of times to really evaluate before I posted. First the pics...

May 2018 2.jpg
May 2018 4.jpg
May 2018 5.jpg
May 2018 9.jpg
May 2018 10.jpg

I am very happy with the truck. The motor is a new L-31R with a ZZ4 cam some other goodies and a Black Bear tune. It has ebay stainless headers with an 18" Magnaflow 2 in two out full stainless 2.5" exhaust. It makes plenty of power and is as fast as you want to go in a truck (at least for me).

The interior consists of new carpet, NBS titanium colored headliner and seats from a 2010 Tahoe that are so comfortable compared to the old seats. Richmond Seat Covers was kind enough to make me a set of seat covers in Neutral so I was able to leave the rear seat alone because it's in great shape. I did Dynamat on the floor which I don't know why anyone wouldn't do. I replaced basically everything in and including the dash right down to the turn signal stalk and the light switch control. I will take a bunch more interior shots and upload them later.

The brakes are also great. It has a Little Shop MFG disk kit in the rear and a Powerstop heavy duty brake kit up front and an GMT800 Hydroboost from a 2003 Escalade. My mechanic did a beautiful job on the brakes and it stops like a BMW.

The suspension is a 1" crank of the bars in front, new leafs in the rear with 1" shackles and Bilstein 4600's. It's also great except the new leafs already have surface rust and I am going to paint them with Eastwood Antirust from a spray can. Anyone who cheaps out on Bilsteins ought to do the math on the incremental cost per mile on buying better shocks. They make such a difference. I also had a moog steering stabilizer installed not sure how much it helps though. All bushings and front end bits are new urethane.

The paint job, for what I paid for it, it great. The pics speak for themselves.


Here is what's less than great that I could use some input on...

The steering box is a Redhead 454SS box and it is very responsive on a truck that already has a tight turning radius. But the steering feel is way too light, lighter than my old stock '97. I took out the variable assist servo with that stupid U valve that is a $60 piece of metal and it has a brand new pump with the extra outlet for the hydroboost. Any thoughts to reduce the assist (and increase the effort in the wheel)? I could use some help here.

The trans is a "built" 4l60e that was done by a highly reputable shop. I paid a highly reputable price for it so to speak, which is another story. It has upgraded clutches, the 5 planetary gear upgrade, and a shift kit. What I don't like about it is it goes into 4th too easily and almost dodges 3rd on me both up and down. As in it will shift into 4th while I still giving it some throttle in 3rd, and if I step on it hard enough to kick down, it will actually kick down to 2nd at highway speed from 4th, at least briefly, before finding 3rd.

This is particularly important because the ZZ4 cam, while it has a wider range than some would say on the web, really takes off at 3K. But I have a hard time finding 3K on anything but the highway because I am going too fast for regular roads at that point. If the shifts were delayed somewhat and 3rd was a sticker gear the truck would run better. I remember reading somewhere that 3rd was the weak link of this unit so maybe it's set up that way on purpose?

The cold idle is bad, and it seems like there is unburnt fuel on startup and it will even die out sometimes. I turned the idle screw on the trottle body up so that it runs at about 925 when warm, but I don't think it makes any difference really because if it ran right when cold the computer would take over here. When I got it tuned Justin of Black Bear told me that the O2 sensors gave poor readings until they are warm, so the easiest thing to do seems like to replace them. The rears are deleted.

It may be too loud but I haven't decided yet. The 18" is the biggest muffler Magnaflow makes in 2 in 2 out so I may need to change brands. Suggestions here would be great. It sounds great at idle, like a Chevelle, but it's loud when you step on it and a little throaty in the low 2's which I don't entirely love.

I have a list of 27 little odds and ends to do to it to make it perfect starting with finding a nice set of Tahoe emblems for the sides and I am probably forgetting 10 other things. Any good recommendations on junk yards that have a lot of GMT400s and can mail parts to me would be appreciated as well. There are a lot of little bits I need.

More to follow.
 

Zdorf

TYF Newbie
Joined
May 31, 2018
Posts
18
Reaction score
11
Location
Dublin, CA
That is a beauty of a hoe!!!!! Took down all your notes. Thank you.
 
OP
OP
T

Toomanyhobbies

Full Access Member
Joined
Sep 18, 2017
Posts
139
Reaction score
139
I drove the blue one for 5 days in a row, and then got behind the wheel of my 2004. It was like a timewarp from when I traded my '97 two door in for the 2004 when it was new. I remember thinking it was positively space age at the time. Now the GMT800 and the 400 feel way more similar than different when both are compared to the new generation of trucks.

I will say that they both have the 4l60e and the 2004 does not have the same adversity to 3rd gear that my rebuilt "built" '98 does so that's something I need to look into further.

The ebay LED interior light kit is a really great inexpensive touch for our trucks FYI. Really makes it feel more modern.
 
OP
OP
T

Toomanyhobbies

Full Access Member
Joined
Sep 18, 2017
Posts
139
Reaction score
139
I have knocked out about a dozen little projects to the truck and probably have 25 more. I replaced the O2 sensors and that did nothing to smooth the cold start so it has to be a tune issue which I will get to eventually.

The hydroboost was leaking and now has subsided to very little.

I got a nice set of "Tahoe" emblems separately on ebay for about $36 a piece. If anyone has the measurements as to how far back they go from the front edge of the door I would appreciate it.

I am no longer questioning if it is too loud anymore, I like the way it sounds.

I took my first real road trip yesterday and today about 60 miles down to my hunting club in Delaware. It is pretty gutless between about 60 and 70 unless you kick it down at which point it usually screams into 2nd begins to hurtle forward. At 70 it's only turning 2K and the cam is not where it wants to be. I have a 3.73 rear and may have to go 4.11 to get it right but I am not doing that now. I also noticed that it was showing different RPM at the same speed depending on load. Meaning going up an overpass it would show as high as 2500 going 73 and on level ground it would show 2100. Does this mean it's not achieving lock up?

It's really fun to drive on 4 lane divided highways and country back roads the way it's set up though.

I settled on a valve to fix the steering pressure. It is WAY too light and twitchy, especially at highway speed. I will post it here later.

On the way home I stopped at the junk yard where I got my hydroboost pedal and got two new passenger A/C vents and already have them in and they look like new. Also got a vanity visor with the plastic tabs intact. Need to change that out another day.

A couple pics below. I will take one of under the hood and post it. I have been cleaning up the engine bay little by little...

At farm.jpg In Driveway.jpg new vents.jpg
 

Squirrelsmith

Full Access Member
Joined
Jan 21, 2018
Posts
914
Reaction score
790
I cant wait to get my hydroboost installed, pulled it out of a astro van. Tell me about this power steering valve. Whay are you doing that?
 
OP
OP
T

Toomanyhobbies

Full Access Member
Joined
Sep 18, 2017
Posts
139
Reaction score
139
The steering is pinky steer, and somewhat wobbly at speed. I need to reduce the steering effort but I don't want to reduce power to the booster. My first plan was to use a bills hot rod kit to reduce the pressure inside the pump but that doesn't solve problem with the booster pressure.

I also got a u joint to replace the rag joint in the steering shaft and will install it at the same time. There is really nothing else to possibly replace or do to the steering after that.

I am also coming around to the realization that I need to put a different cam in to have the truck really suit me. I think I am going to start a different post on this topic.


Sent from my iPhone using Tapatalk
 

YAMBAG

Member
Joined
Aug 3, 2009
Posts
51
Reaction score
6
Location
westport MA
Why did you choose to use the 454SS steering box? I think its a quick ratio box. Maybe going to a stock type unit for your truck would help reduce the steering response a bit??
 
OP
OP
T

Toomanyhobbies

Full Access Member
Joined
Sep 18, 2017
Posts
139
Reaction score
139
Why did you choose to use the 454SS steering box? I think its a quick ratio box. Maybe going to a stock type unit for your truck would help reduce the steering response a bit??

I actually wanted a more responsive steering system so I chose the quick ratio box. There is a difference between "resistance" and responsiveness. I got to drive a newer 911S on Sunday and the steering is incredibly responsive and has nearly the resistance of manual steer.

I don't expect it to be like a 911, but I know I can do a lot better. I have't gotten the above mentioned work done yet which I will explain below.
 
Last edited:
OP
OP
T

Toomanyhobbies

Full Access Member
Joined
Sep 18, 2017
Posts
139
Reaction score
139
So I ordered an Autocal from Blackbear and I was able to figure out that I had a bad O2 sensor and a bad MAP sensor. The combination of which has made the truck run like crap and get about 7.5 mpg. I think the MAP sensor died a slow intermittent death with an intermittent CEL to go with it, starting the very day I got the tune done, which made it hard to diagnose. The O2 sensor I changed at suggestion of Justin and BB during the tune, but it was either defective or it didn't work because I put dielectric grease on the connection which I read online is a no no.

Here are the MAP sensors, old was was total trash. Idle is already way better. New O2 sensor comes tomorrow. I am really looking forward to being back to full power. Will report back.

MAP Valve.jpg
 

RED TAHOE LS

Full Access Member
Joined
Jan 2, 2017
Posts
774
Reaction score
410
Location
Rossville, Georgia USA
Nice work, and a good looking Tahoe. IMO this could correct a major problem with your engine

Justin of Black Bear told me that the O2 sensors gave poor readings until they are warm, so the easiest thing to do seems like to replace them. The rears are deleted.

Good luck,
David g...……..:)
 

Upper tanker

TYF Newbie
Joined
Dec 4, 2015
Posts
27
Reaction score
5
I have a 97 2 door 4x4 with a mild build vortec 350 (CC 08-501-8 cam with supporting head work), OBX stainless headers, 3" true duals, a BB tune, and "built" 4l60e, and I'm experiencing what I think is a smiliar trans issues as you. However, I went from 3.42 to 4.10 gears front and rear. I also find that it shifts from 2 to 3 then almost instantly into 4th. I also find that while whether cruising at 45-50 or 70-75, even a slight tap on the pedal instantly makes the TC unlock, just for a second before quickly locking up again.

Your hard start issue....I also have a similar issue. When it's a very hot day, and I have driven it for a while and park it, it is a real pain to get started again without giving it a little gas. My rear 2 O2s are also deleted, and the front two were new when I did the motor about 4k miles ago.I wonder if one of my O2s are bad. I have never replaced my MAP sensor, so I wonder if I should.

I'm also having a slight misfire at idle on cylinders 2 and 4 that nobody can figure out, and I'm leaning towards a valve train issue (but I'm REALLY hoping it's not since the head work was done by a reputable builder with all new parts).
 

east302

Full Access Member
Joined
Dec 21, 2016
Posts
1,687
Reaction score
1,686
Location
Mississippi
What trouble codes are you getting?

Your hard start issue....I also have a similar issue. When it's a very hot day, and I have driven it for a while and park it, it is a real pain to get started again without giving it a little gas.

If you have a scanner, see what the coolant temperature sensor is reporting. It’s the one by the thermostat.

It should be reading close to ambient when cold and around the thermostat setpoint when hot. If it is reporting some real oddball temperature, the sensor may be flaking out and fooling the computer into calling for too much fuel when starting.

Holding the gas to the floor while cranking is sometimes a remedy as this puts it into “clear flood” mode, temporarily stopping injector flow.



Sent from my iPhone using Tapatalk
 

Upper tanker

TYF Newbie
Joined
Dec 4, 2015
Posts
27
Reaction score
5
If you have a scanner, see what the coolant temperature sensor is reporting. It’s the one by the thermostat.

It should be reading close to ambient when cold and around the thermostat setpoint when hot. If it is reporting some real oddball temperature, the sensor may be flaking out and fooling the computer into calling for too much fuel when starting.

Holding the gas to the floor while cranking is sometimes a remedy as this puts it into “clear flood” mode, temporarily stopping injector flow.



Sent from my iPhone using Tapatalk

I do have a scanner, but not with me. I do have one of the Bluetooth OBD2 things that I could check it with. I paid the extra money for all of the extra PIDs. So, that would just be the engine temperature, correct?
 

Forum statistics

Threads
138,037
Posts
1,997,601
Members
102,974
Latest member
kikeap
Back
Top