Gonna do an engine swap and need some info on ECU and wiring harness. Help,please!
06-05-02, 08:13 AM
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QC Motorsports
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Gonna do an engine swap and need some info on ECU and wiring harness. Help,please!
O.K. guys,
The GTU engine was recovered from the wrenck and a friend of mine(kudos to knight1976) found an S4 for sale for $500. Its supposedly in perfect condition except that the engine is bad. I plan on buying it and doing an engine swap. The engine I'm putting in is an S5. I know you have to swap the ECU and the wiring harness, but what else is there and how hard is the whole swap. Not including the engine drop. I have that covered. After I get this car fixed and drive for awhile it will be up for sale if anyone is interested. It'll be about 2 months or so before I sell though. Come on guys lets hear the difficulty.
Charles
The GTU engine was recovered from the wrenck and a friend of mine(kudos to knight1976) found an S4 for sale for $500. Its supposedly in perfect condition except that the engine is bad. I plan on buying it and doing an engine swap. The engine I'm putting in is an S5. I know you have to swap the ECU and the wiring harness, but what else is there and how hard is the whole swap. Not including the engine drop. I have that covered. After I get this car fixed and drive for awhile it will be up for sale if anyone is interested. It'll be about 2 months or so before I sell though. Come on guys lets hear the difficulty.
Charles
06-05-02, 09:13 AM
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It would be a snap. Just swap over the ECU and go!! Installing an engine is tricky, but very do-able. Search for a thread by scathart about a GREAT engine pull How To.
06-05-02, 10:18 AM
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Originally posted by FPrep2ndGenRX7
Use the old harness and ECU with the S5 engine. If your only going to drive it for a few months then max HP shouldn't be a concern. Do the simpliest swap that you can.
Use the old harness and ECU with the S5 engine. If your only going to drive it for a few months then max HP shouldn't be a concern. Do the simpliest swap that you can.
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06-05-02, 01:03 PM
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The series 5 ECU won't plug into the series 4 harness, which means you have to change the dash harness as well, which is not as easy as it sounds. It'd be easier to find a series 5 car. You have to change the front cover, the injectors, the throttle body (dual TPS for s5, single for s4!), and then you need a mechanical metering oil pump, and not to mention most of the sensors won't be right.
06-05-02, 01:11 PM
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Let me clarify what I mean. Use the S5 engine only. The front cover, waterpump housing, intake, wiring, sensor, ECU, etc... will all be S4. To me that is the easiest swap if the car is being sold in a few months.
06-05-02, 01:16 PM
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Personlly, I think it will be a lot easier to swap the harness...With all the vacuum leaks and such you could introduce by changing the intakes and such. Plus, you wouldn't have to pay for gaskets and any parts that might (will) break. And you also have the advantage of all the S5 wiring and intake improvements. Though you still have the S5 metering oil pump, it is a pretty good tradeoff.
06-05-02, 01:46 PM
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whats the deal with everyone bashing the s5 metering pump,
does it suck? if i yank it and run premix does the car still not operate correctly?
or is it an idiot light that some people dont want to deal with?
does it suck? if i yank it and run premix does the car still not operate correctly?
or is it an idiot light that some people dont want to deal with?
06-05-02, 09:58 PM
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Well actually for me the harness isn't a big deal. I have rewired my whole car before and played with the dash harness as well. I know everything you all have suggested but I was wondering more of how hard it all actually is. Well thanks for your help.
06-05-02, 10:30 PM
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Well, I believe the connectors on the S4 & s5 dash harnesses are different, thus resulting in MORE wiring changes, or at least that's what I heard, I started looking into it on my car and I said to hell with that, way to much stuff to change 
06-07-02, 04:22 PM
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Folks,
If by, dash harness, you mean that foot long harness that sits between the front harness and the back of the guages, then I can see doing that. However, if you mean the front harness itself, then you're absolutely farging nuts to pull that out of a car. N.U.T.S. You have to disassemble almost the entire engine bay to get at all of the connectors to pull that harness through the firewall.
I agree with Fprep, stay with the S4 harness, ECU. The injectors for the S4 need to be swapped in (no biggie), and the front cover/OMP. OTOH, you could just leave the 89 front cover on, leave the OMP there (or block it), and run premix. Gotta keep the S4 AFM (unless you want to splice in the S5 connector, waste of time IMHO.
Go real real slow on the injectors clips on the S4 harness, as well as the water temp sensor in the water neck, and AFM (if you remove that), those connectors are as brittle as the interior plastic.
Good luck whichever way you do this. This is exactly what I've done on my car, so far, so good.
PaulC
If by, dash harness, you mean that foot long harness that sits between the front harness and the back of the guages, then I can see doing that. However, if you mean the front harness itself, then you're absolutely farging nuts to pull that out of a car. N.U.T.S. You have to disassemble almost the entire engine bay to get at all of the connectors to pull that harness through the firewall.
I agree with Fprep, stay with the S4 harness, ECU. The injectors for the S4 need to be swapped in (no biggie), and the front cover/OMP. OTOH, you could just leave the 89 front cover on, leave the OMP there (or block it), and run premix. Gotta keep the S4 AFM (unless you want to splice in the S5 connector, waste of time IMHO.
Go real real slow on the injectors clips on the S4 harness, as well as the water temp sensor in the water neck, and AFM (if you remove that), those connectors are as brittle as the interior plastic.
Good luck whichever way you do this. This is exactly what I've done on my car, so far, so good.
PaulC
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