1999 Chevy Tahoe Electrical Issues/Robbed Power Post Perfor

Tiny
NWP
  • MEMBER
  • 1999 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 163,000 MILES
I have a 1999 Chevy Tahoe Z71. I recently replaced the 5.7 with a GM Performance HT383E engine. The engine is touted to have 322 HP and over 430 lb ft of torque when mated with OEM injection, exhaust intake, parts. While the engine is stronger, it is not representative of the claimed increases. I had already fitted the 5.7 with edlbrock headers, a flowmaster cat back system, an AEM Brutforce Intake, and a SUPERCHIPS power programmer. These additions made significant and noticeable gains on the OEM engine with 160K miles. When I put the new engine in, I was able to mate all those bolt-ons in the swap. However, it doesn't produce the neck snap one would expect with almost 100 more HP and 100 more lb ft of torque from factory specs. It just seems to be starving. It sounds really mean and has a noticeable lope with the stroker configuration, and it is a little more peppy, but opting for a $5k upgrade instead of a $2k upgrade is simply not being realized. I'm wondering if I need a high-output igntion system to aid in the burning of the fuel. I've noticed that the residue leaving the tailpipe is leaving a good bit of soot, indicating unburned gas escaping.

Now. Onto other new issues. The truck idles with a slight surge, sometimes elevating to a rise in RPMs, countered by a reduction that almost mimicks dieseling. In addition, my wipers only work randomly and start and stop on their own. My AC blower is also not working all the time. Sometimes all the settings work and sometimes only some of the settings work, and sometimes none at all. Also. My previous engine lost oil pressure and the gauge moved a bit back and forth for a few minutes. When the truck was returned to me after the swap, the oil pressure gauge was stuck on a wide open (far beyond the highest pressure reading) position. It does not fluctuate or bounce at all regardless of engine speed.

So. That's about it. I love my truck. I was eagerly anticipating the performance beast I put under the hood. It seems I didn't get much of a bang for my buck and I now have "gremlins or ghosts in the electrical system". Any ideas?
Do you
have the same problem?
Yes
No
Tuesday, September 23rd, 2008 AT 2:38 PM

3 Replies

Tiny
JACK42
  • MEMBER
The wipers- be sure the ground is good to the motor assembly, might be a bad wiper control module, GM had issues with those.
A/C blower- could be the motor is going out, need to use a test light and check for power at the motor when it isnt working
Oil press gauge-Sometimes when you unhook a battery on GM vehicles the gauges "spike" and go too far. This can usually be remedied by manually moving the needle back to 0 which requires removal of the instrument cluster
Driveability- Any check engine light? Need to start there to see if the PCM sees an issue. Sometimes the cam loping will mess with the vacuum signal and the PCM thinks there is a problem. Is fuel pressure up to spec? Check for a blown fuel pressure regulator, by using a manual gauge the pressure should jump up when engine is revved, if not reg is probably blown.
Was this
answer
helpful?
Yes
No
Friday, September 26th, 2008 AT 8:16 AM
Tiny
10313317
  • MEMBER
On the wiper problem, I had the same issue. If you take the black plate off the motor it will expose the circuit panel. It come out easy. There are 3 soldered contact points that heat up and have to be resoldered. The brake loose only one time. Factory defect. I soldered mine over a year ago and have not had problems since. On the guages going crazy mine just stared.I found the problem is in the fuse block. The was one fuse connection in the block.I pulled the fuse off and saw that one contact in the block was brokin. All I did was twick the fuse cantacts and put the fuse back in and worked fine. When your gauges would go crazy my blower for the air cond would blow half its speed.
Was this
answer
helpful?
Yes
No
Friday, October 3rd, 2008 AT 8:21 PM
Tiny
JACK42
  • MEMBER
Good info. Some really good finds too, thanks for sharing it
Was this
answer
helpful?
Yes
No
Saturday, October 4th, 2008 AT 7:42 AM

Please login or register to post a reply.

Recommended Guides