PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

changing a 98 computer car to a 99+

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Old Sep 22, 2006 | 02:54 PM
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Default changing a 98 computer car to a 99+

Whats involved? How much of a headache am I expecting if I do it?
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Old Sep 22, 2006 | 03:07 PM
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So you have a '98 f-body? What do you want to change to '99+ & why?? If you're talking swapping to a '99 pcm its not worth your trouble....you have to re-pin the entire harness and change several sensors.
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Old Sep 22, 2006 | 03:14 PM
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I'm guessing he might want to swap engines.
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Old Sep 22, 2006 | 03:47 PM
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or its because or the tunning issues
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Old Sep 22, 2006 | 04:51 PM
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I like to play with cars and I would like to have tuning capabilities. I hear with the 98, yur just about fawked on that end, thats why everyone goes with a 99+ . Sort of like a Speed density versus a MAF tuned unit, both are good, but, one you can tweak much better. Unfortionatly, I did not know at the time I got my clunker.
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Old Sep 22, 2006 | 06:19 PM
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Do you mean tuning by hptuners or ls1edit and software like that? If so, I thought there was software out there for '98 f-bodys.
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Old Sep 22, 2006 | 06:26 PM
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a 98 can be tuned, i wouldnt swap the pcm just for tuning
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Old Sep 22, 2006 | 06:27 PM
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2 Bar Speed Density is out for the 98's now bro, just get the software and go to town.

Nate
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Old Sep 22, 2006 | 09:15 PM
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You just can't get the "cool" features of the tuning software that drastically speed up the process with the 98's, like HPT's realtime tuning and autotuning. For the most part, you can still tune a 98 "just as good" as a 99+, it'll just take longer.
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Old Sep 22, 2006 | 09:58 PM
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Originally Posted by jmm98LS1
You just can't get the "cool" features of the tuning software that drastically speed up the process with the 98's, like HPT's realtime tuning and autotuning. For the most part, you can still tune a 98 "just as good" as a 99+, it'll just take longer.
Thats the thing, I am between a techie and a gear head, so, I dont know if the 98 computer is going to limit me as I would want to play with every possible option I could. Back when andrew was playing with LT1 computer interfaces and just had a schematic on them, I was right beside him soldering them together (well, not physically but in my own side of the world, lol), I was probably one og the first to have one on my block for a good 4 months. 98's could be tuned, but I like the idea of real time tuning and such. Unfortionatly at this time I do not know about the two systems to make judgement on them either way. Need to look into them a little more.
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Old Sep 23, 2006 | 04:38 AM
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Actually having done the swap myself I can say it was worth it to me. Although, in order for the car to be fully functional you will have to do more than "swap the pins and replace a bunch of sensors..." As a matter of fact, the only sensor(s) I replaced were the knock sensors. The ECT is not necessary as the newer one only has two leads vice 98 3, the third being for the Instrumenet Cluster IC.

You will need a 99+up IC, fuel sending unit-(just get a plastic tank w/newer fuel pump), PCM, swap diagrams, lable maker, Software, wideband. Patience.

There are many benefits for a 98 owner that wants to stick with his/her car and wants to get the maximum performance out of it. Do a search on custom operating systems and their applications.
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Old Sep 23, 2006 | 10:58 AM
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I had Speartech setup my 02 engine harness to plug into my 98 Z28's dash harness. Hopefully it will alwork out.

The biggest differnce is the 98 engine harness has three plugs coming throught he firewall and plugging into the dash harness. 2 for the cluster and one is for the fuel sending unit.

The 99+ engine harnesses only have 2 plugs coming through the firewall to their dash harness. I had Speratech rewire the hanress and pin out the plugs to work with my 98 dash harness. From 2 plugs to 3. The third one being the fuel sending unit plug. The iffy one is te fuel plug. All in all it may work out it may not. If it doesnt I have my 98 PCM and engine harness that I will put back into the car while I find another 98 harness to repin. Eigther way I will have the 02 PCM in my car at some point.
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Old Sep 23, 2006 | 12:16 PM
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WickedRed,
Let me know how this works out...I thought the sending units outputs were different besides routing the signal to the pcm vice the Instrument Cluster(IC). The calibration data for the fueling in EFI Live btw 98/99 is different. I have talked with a precious few who have done 98 swaps and those who have kept their 98 ICs have told me their fuel gages don't work. Maybe others who have actually done or had this done to their cars can speak up. My car is fully functional with a 2000 cluster, pcm, plastic tank w/racetronix 99+up pump/wiring upgrade.
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Old Sep 23, 2006 | 07:13 PM
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I've got a 98 engine that I'll be running a 99 PCM and harness on. Would anyone mind clarifying which sensors need to be replaced for this to work? I won't have to worry about the fuel pump or gauges since this is going in an RX7, but I see someone mentioned the knock sensors and I was unaware that they were different. Any advice would be appreciated.
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Old Sep 23, 2006 | 07:15 PM
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Doc:
Will do. I am not sure if the fuel sending unit will work or not. If it doesnt I will decide wether or not to run an aftermarket fuel gauge or get a 99+ fuel tank sending unit and cluster. I do know you can adjust the out put range in HPTuners 2.1 to work with the sending units out put range. The signal is the iffy part. We'll see what happens.
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Old Sep 24, 2006 | 12:26 AM
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Well, it is nice to know it can be done, but, I think that would be too much work for this POS I have. Guess I am just gonna get her into half way decent shape, drive her around for a while then sell it. Time to go 99+ with auto!!
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Old Sep 24, 2006 | 10:14 AM
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Honestly that would be a better option. I have way to much $$$ in my 98 now. No way I can sell it. I have considered selling it as a roller and picking up a 99+ roller to pull all my stuff in. Problem is I would have to pick up a 99+ roller first and pull all of the stock suspension off and put all my tubular suspeniosn on it and vice versa. To much work.
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Old Sep 24, 2006 | 04:52 PM
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I had my 2000 flashed with 2002 base tune software. It uses 2002 HP Tuners to tune my car. I would try and go that route. I was told that GM made improvements as the years went by.
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Old Sep 24, 2006 | 06:17 PM
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Originally Posted by 02 BLK WS6
I had my 2000 flashed with 2002 base tune software. It uses 2002 HP Tuners to tune my car. I would try and go that route. I was told that GM made improvements as the years went by.
It doesn't work like that, 98's PCM wires go to different locations on the PCM connectors. Not to mention 98 PCM's are physically different than 99+.

Like they said above, if you want 99+ PCM options for tuning, you have to rewire stuff, its not a software option.
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Old Sep 28, 2006 | 02:47 PM
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I just finished the swap and it really was not bad at all. I repinned my factory harness, bought a pcm for $50.00, a instrument cluster for $90.00,and a complete 99 fuel tank and sender for $80.00.
I have not installed the IC or tank yet and everything works but the fuel gauge. I am thinking about Trying a couple of wiring variations before I swap stuff. I will let you guys know if it works.
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