L98 Top End Upgrade Progress




Although I still have a lot of cleaning to do, the end is in sight finally after almost a year. Lots of time spent gone and struggle with receiving parts made a huge delay.
Currently, I am waiting on a throttle bracket for the Miniram to come in the mail as it was missed initially in the shipping process. They were awesome about making sure it was sent out the same day. Along with that, I need to get some washers for my water pump pully as I currently have some old nuts as spacers to get it on temporarily. I also need to swap my crank center bolt for the new ARP one which should be pretty quick and simple as well.
A couple of hours ago I got it all tidied up for a temporary run just to check to time and make sure the distributor was place properly. Well, during this I found out that I was getting almost 0 fuel pressure at the rail and when I manually turned the pump on by jumping pin G on the ALDL, I found my pump was definitely shot from sitting around and sounded horrible. Thankfully, I have a new racetronix pump and wiring harness I ordered and planned on swapping in anyways to keep up with the new demand. I was able to spray some starting fluid into the intake and turn her over and get a second or 2 of hearing the car run which was nice.
Hopefully tomorrow I can get the new pump and harness swapped in and see if that does the trick.
Here are some pics of everything as it sits. I still need to do some final cleaning and wire routing but for the most part, it is damn near complete!








I was able to install the new pump and routed the new harness as just a test fit to see if the pump worked or not. Got it all wired in and turned the key and nothing for the pump. Decided to do some checking and hookup up a motorcycle battery to the old pump and it seemed to work just fine, but whatever because I was replacing it anyways.
So then, I started feeling for relays clicking and the fuel pump relay did click and I checked voltage at the connector before the in tank harness. It showed about 12V. Didn't get a super good reading as I checked it off the 2 second priming circuit, but it did get voltage.
Not sure exactly where to go from here, but I will probably be pulling the sending unit back out and checking the in tank harness connectors from both sides and making sure all grounds are clean and secure.
If anyone has any thoughts or ideas, I’d love to hear them. I’m also wondering if the pump has the polarity reversed. There’s a note about it in the install sheet and I could’ve swore I checked it and it was correct, but it’s worth a double check on my end for sure.




Either way, got that fixed, and everything put together needed to run the engine for 5-10 minutes or so a couple of different times. Found some minor issues such as a couple of vacuum lines not sealing perfectly. I ordered some new lines and in 2 days I should have them and be starting the install on them. Just 2 of them thankfully and one happens to be for the FPR.
I have the fuel pressure set to about 40psi with the key on and running it drops to around 36 or so and if I unplug the vacuum line it goes to about 38-40 again. I am not entirely sure these are the right numbers, but it's running and doesn't smell rich or get extremely hot indicating too lean or set any codes. I will be doing more research to find some better numbers to go off of and get it dialed in once my data logging cable arrives. Might also get a wideband setup if I can find a good one and have it as an external gauge as they are very useful.
When running it is idling at about 800 once warm and I am assuming that is the setting from PCM of NC and I set my ignition timing to about 6-8 degrees with the wire disconnected. It is hard to tell exactly due to the timing cover tab type. While idling at about 800-850 with the DST wire connected, the timing light is showing about 30 degrees on the hub with the flash of light. Also not sure how accurate this is or should be.
Everything seems to run pretty smooth and strong, but I did get a backfire one time out the intake when I hit the throttle to full for a second and let off and quickly did it again from about 6k rpm to about idle and back to about 5500 rpm. I would bet this is due to being slightly lean mixed with a possible vacuum leak 3as I have no way to check currently. I ordered a data logging cable the other day and am hoping it gets here soon. Should be next Thursday/Friday. That should tell me more about what I am experiencing and hopefully, someone here can help review the logs with me as I am nowhere close to an expert.
I think that about sums my progress. She seems to be running pretty dang smooth and sounds awesome. There are a couple of kinks to work out, but nothing is ever perfect on the first try.







