Have 88 L98 from a Formula.

going into a

87 GTA w/ LB9

Mechanic was begining the swap (remember I am taking out LB9 and putting in L98) then called me from work to come and look at what he believes is going to be an issue that could potentially be expensive.

The harness on the L98 will not hook to the connectors that the LB9 harness would hookup to.

What are my options? Can I put LB9 harness on L98. What about computer? I have L98 computer but should I keep LB9 computer? Should I change a chip to get proper performance from L98 while keeping LB9 computer?

 

There is no difference between the harnesses of an LB9 & L98.
The computers should be the same also.
The memcals (chip) are what are different, so use the L98 memcal.

 

So does this mean I can just use the LB9 harness on the L98. Could the reason for the different shapes on some of the connectors on the 2 harnesses be from some changovers from 87 to 88. I also noticed that the LB9 has a V belt setup and the L98 has a Serpentine setup.

 

..Depends on what application your swappin too/from.. im guessing both engines were TPI? If so.. the harness's should be identical, if you dont have a brain for the 350, send your 305 brain to fuelinjection.com, for $250.. they will program it to how you want it.. or any other mail in company

John

 

I can't remember when the distributors changed, but the connectors are different on the small and large cap, but they can be adapted for either one.

I can't really think of anything between those 2 motors that would be siginicantly different since they use the same sensors and ECM.

 

Is it possible to have any issues develop with the chip in the computer? Is the LB9 computer instucting that engine to do some stuff diff than the L98 computer would. Should I just use the computer off of the L98.

 

computers are the same. only difference is the memcal,

All I have is a picture of my modified one.

 

if u use the LB9 mcel (or wtever its called) wouldnt the comp shoot fuel like its a lb9 there fore making it run rich

 

yes

 

Zepher, I got your back

Picture of a stock AXXB (305TPi I think) in its memcal with my modified adapter

 

Now its starting to make a little sense to me.

What do I ask for in a modified chip/memcal or whatever its called?

Also is this a chance to maybe get better performance out of the L98?

 

On the issue of some of the harness having diff conncetors......

Any suggestions on how to handle that?

Can I just use the LB9 harness. I guess some conncetors will still be diff?

I know for a fact some conncetors are diff, I saw them when I went to the shop.

Please give me some guidence on this. I have heard from some that there is no harness diff btwn LB9 and L98 but then some have said there are subtle diffs.

Maybe theres a diff becasue I am dealing w/ 88 L98 going into 87 car made for LB9?

Please share some knowledge on this it is very much appreciated.

 

which connectors are different? are you sure you are trying to use the right connector from the harness?

 

I wish that I would have made note of them today. I will go by tomorrow and write them down. I hope they are open in the morning. If not I will have to do it Monday.

 

87 is v-belt, 88 is serpentine. The alternator and a/c compressor wires and plugs will have to be modified/lengtened, but all of the sensors and stuff should be the same.

 

Use the accessories that go with the harness you have.

Unless you want the later serpentine accessories; in that case go get the '88 harness.

Since the alternator and AC compressor switched sides in '88, it doesn't make sense (to me) to hack up the harness just to accommodate the accessories that came on a used engine.

Oh, the distributor went from large cap w/coil in cap in '86 to small cap remote coil in '87.

 

I'm guessing one of your problems with the connectors being different is probably the relays. 87 and older used square shaped relays, 88 and newer use oval shaped ones. You can use either harness. I'd probably go with the 88 harness since the newer relays are easier to get at the parts store if you ever need to replace one. As the other guys have already said, everything else should be the same, including the computer. Just need to get an 87, 350 prom chip, and you should be good to go.

 

Should I get the 87 L98 PROM Chip even though the engine is an 88 L98? Just want to make sure before I take the plunge.

Is the only place that the engine harness hooks up to the car is at the ECM.

I assume I will be splicing wires to change the conncetors at this conncetion right?

What other places do the harness need to conncet to the car?

Also where do I find a shop manual for this car. I would like to find a detailed description of this swap procedure if possible.

I really appreciate everyones help and advice. If anything else should be added re this subject please let me know.

 

Just use the 88 L98 prom and you should be fine. No splicing is necessary at the ecm either. Both years use identical computers, so it'll plug right in. The other place the harness plugs in to the car is at the junction block on the driver's side of the firewall, near the brake booster. Again, no splicing necessary, just plug it in. There's also a plug in the engine harness back by the distributor that connects to the HVAC controls inside the car. Other than that, it's just a matter of hooking up the miscellaneous ground straps to the motor and the sheetmetal in the engine compartment. You don't even need to change harnesses anyway though. Your 87 LB9 harness will work just fine with the 88 L98.