Performance Concerns After Hot Wire and Walbro

[mmarlett]

Hello Forum Members,

After installing a new Walbro fuel pump from Full Throttle, Item Code: 834GMHP, and a Recetronix Hotwire kit, the boost is maxing out around 10.5 PSI (per dash gauge) and the car has trouble pulling beyond 4,000 rpm (per dash gauge) under WOT. The first start after installation was immediate and idles fine. Prior to this install the boost would run up to redline on the dash gauge.

I am looking for ideas on why the car is running sluggish and not building boost at highr rpm's. Were do I start?

Did I need a new fuel pressure regulator with the install of the Pump and Hot Wire kit?

The car is an 87' GN with 30,000 miles that I purchased last June. Prior to me, the car was completly stock down to the original air cleaner.

Prior to the Hot Wire Kit and Pump, the car was ran to empty the gas tank. However, I did also syphon out the last 5 gallons prior to the installs.

For directions, I used the postings from others here on the forums.

Since last summer, I have spent significant hours reading through all forums. Therefore, nn addition, 200 miles prior to the Pump and Hot Wire upgrades, I have also completed the "spring cleaning" that includes new:

8.5mm plug wires
AC Delco Plugs with .34 gap
K&N air filter in original air box
Fuel Filter
All fluids

Regards,
Matt

 

[GNVYUS 1]

You'll need an adjustable fuel pressure regulator (AFPR) as different fuel pumps put our more volume and cause fuel pressure creeping issues at idle.

You need a way to monitor your engine, I'd recommend a Scanmaster, you can find these through vendors that support this board.

Boost going down after the install seems a bit odd and using the dash gauge for boost is an easy way to blow headgaskets. You might have a vacuum leak on the FPR line or the FPR vacuum line popped off and the cars detonating and pulling timing etc like crazy.

There are tons of threads in here to check out, do a bunch of searches, read up and find a local GN shop and/or member to help you along. Enjoy

 

[mmarlett]

Thanks for the responce Mike. After extensive reading, I see how valauble a Scan Master can be. I was hoping these intial upgrades would not require the use of this tool yet.

I will be looking under hood this weekend at the vacuum lines. I have also read these can leak and cause troubles for many of the turbo owners.

Matt
Milwaukee Suburb

 

[GottaBuick]

Not trying to steal your thread, but I didn't know you had to get a new adj FPR when purchasing this drop in pump. Is this true?

The reason I asked is because I have a stock GN with about the same miles as you and planned on buying a new pump this spring (just for realiability and preventive maintenance) but figured the stock FPR was fine. Because I wasn't needing anymore pressure/volume. Thanks.

 

[Pronto]

A fuel pressure gauge on the fuel rail is also important so you can set the fuel pressure to what is recommended by the chip maker.
PS, don't trust the stock boost or rpm gauges, an aftermarket boost gauge is definately recommended.

 

[forcefed3.8's]

Did you install a hose in place of the pulsator?

 

[mmarlett]

Hold everything! I came home from work and went to the garage to look into a possible bad vacuum hose/ fpr hose. What I found was a loose hose clamp that holds the rubber coupling that connects the turbo to the intercooler.

I believe this was loose from the day I purchased the car. It only became more obvious on the dash gauges after completing the upgrades.

In conclusion, I re-sealed this coupling and went for a test ride. Wow!!! The car has never performed like this! WOT now prevents me from getting any traction. Fantastic!!!

The rubber hose did replace the pulsator.

Thanks everyone!

Matt

 

[TURBO 6]

Like it was said before, never trust the factory boost gauge and tach.