Rich Getting Richer
While my engine is getting richer I am getting poorer. It is my hope that I can get a quick reply to my dilemma of my new motor running rich. As my need for my daily driver, with my workload getting heavy and nights without public transportation is upon me.
To start I have a 1987 Corvette with the L98 engine and over 170,000 miles on the odometer. This past October I first encountered what I believed to be a non-operating Water Thermostat, which turned out to be a cracked L98 block between the #8 and 6 pistons. With out any used or rebuilt engines in the San Francisco Bay Area. I ran across an engine builder on CraigsList with a set of Bilstein Shocks for sale that happened to have just built a 350 motor for his 1982 Corvette. I bought this block from him which had pistons stamped with a 10 that my friend and mechanic told me meant this block was bored 10 over making it a 355 ci. The engine builder told me he had installed Flat Top Racing Pistons with 10.5:1 compression & new Crank with Hydraulic Flat Tappet Lifter’s. Along with the following Comp Cam; 12-239-3 - COMP Cams Xtreme 4x4 Camshafts with the following specs:
Cam Style Hydraulic flat tappet
Basic Operating RPM Range 1,300-5,600
Intake Duration at 050 inch Lift 218
Exhaust Duration at 050 inch Lift 226
Duration at 050 inch Lift 218-int./226 exh.
Advertised Intake Duration 262
Advertised Exhaust Duration 270
Advertised Duration 262-int./270 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.462 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.480 in.
Valve Lift with Factory Rocker Arm Ratio 0.462 int./0.480 exh.
Lobe Separation (degrees) 111
Computer-Controlled Compatible No
Grind Number CS X4 262H-11
Using the L98 heads that were sent to a machine shop along with the Runner’s & Plenum to be cleaned and honed. The heads themselves had all new springs, valve’s, retainer’s etc and going from the factory 1.5 to 1.6 Stainless Roller Rocker’s. Yes, I see it states non Computer-Controlled Compatible. The engine builder said it would work and did, as you will see below.
Reusing the Injector’s and most all other parts from the L98 engine, although replacing all of the sensors and many other parts. The Fuel regulator is the original non-adjustable factory model. I have replaced the Spark Control Module.
I also had ordered a new Performance Chip which pictured would replace the factory Memcal in the ECM. It turned out to be one similar to what I had already installed on the L98 engine. What I had on the old L98 was a “Gorilla Chip” spliced into the wires of the IAT. This new (GForce Performance) Chip being the type that you splice into the wiring of the IAT also which is located underneath the Plenum. Let me backup here, when the engine builder & I first started the Corvette upon my picking it up upon completion & with the Gorilla Chip and factory memcal in the ECM it would not start. So I pulled the Gorilla Chip & factory Chip and installed my HyperTech ThermoMaster I had bought some 5 yrs ago. While at the time the HyperTech was too much for a stock L98 it did work with this new engine. Although it had some issues at idle at a stoplight and would go into a low enough idle to stop running, necessitating in a re-start.
Here is where my biggest problem(s) began. Me being the smart non-mechanic I am I at home attempted to install the GForce Chip, which I ordered and was to be programmed with all of the specs of this new engine. Installing it exactly as directed, it did not work. No amount of attempting to start the thing worked. What I did experience is a lot of “popping corn” sounds and 1 final “POP” from whence I do not know. My description of “popping corn” best describes what I heard when trying to start the thing. Like it wanted to start but would not. I checked the #1 plug, black and not at all like a non-rich running plug would look like. Buying a new set of plugs I replaced all. The #1 plug was the only one showing excessive richness. The other 7 plugs showed a small amount of richness but not at all like the #1 plug. It also appeared to have enough spark going to all of the plugs. Again, stock factory injector’s with 170,000 miles that were just cleaned only. (I bet you will tell me I should have changed the injectors to a new set but on a shoestring budget at this time I could not afford it. Now maybe I must afford a new set?)
I went back to the HyperTech Chip, which for over a week of driving gave me no problem. Now even with the HyperTech Chip it won’t start and slowly drains the battery in my attempts to do so. Before I continue to buy parts which I think will cure this problem and which is not curing the problem what should be done? Besides needing to install bigger Runner’s, Plenum and going to a BBK 52mmm Throttle Body, which I think I need more incoming cold air for this Cam and set-up. I am having my Factory Memcal reprogrammed for this new engine and the person doing this asked that I also buy an Adjustable Fuel Regulator. Is this a good recommendation?
I need help and I am not a “master engine builder” by any stretch of the imagination. Although I read this magazine with great interest, not so much understanding but interest. What I don’t understand is explained well enough for me to look up whatever it means that I am reading. Thank you,