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Hi there, Honda technicians. I'm in the process of working out problems with my 00 civic. Here's an overview of my build to cover any confusion:
- LS VTEC Swap w/ GSR head
- Obd2b distributor
- not sure of the engine harness it has now but IT RUNS just with problems listed below
Problems; - Tach (and vtec) doesn't work SOLVED BY REPLACING MY DISTRIBUTOR WITH AN OEM!
- Cooling fan doesn't turn on when it should. (I have replaced my thermostat and sending unit - no dice)
I noticed the tach problem after replacing a bad dizzy. The car runs but possibly a different brand or oem dizzy will fix that? (It was purchased new from eBay so...) Onto the cooling fan problem, I noticed this after extending some wires on my engine harness (In attempt to tuck it). I routinely work and solder wires so I'm careful and tidy with my work but something clearly went wrong in the process. Instead of going back and checking I'd rather replace the harness and start fresh. While I can just get a rywire, I'm on a budget so chances are I'll end up going to the junkyard and pulling a used harness. I'm making this post because I want to make sure the harness I get will work for my build. Correct me if I'm wrong but, I should be looking for a 1999-2000 harness with VTEC and manual trans? (My car is manual)
Apologies for the dumb question but its better to know than not to. Any advice on which harness I should aim for is greatly appreciated. TIA.
Last edited by Nitrozity74; Aug 18, 2021 at 11:12 AM.
Can I get away with something more common like a 99-00 civic harness? @tony_2018
An EM1 engine harness IS a '99-00 Civic harness... it just happens to be a Si. If you are asking if you can use a '99-00 Civic EX engine harness since they are more common... it will need some modifications, but it can be made to work. As for your tach no longer working... the problem starts with the junk distributor that you purchased from EBay. The ignition control module and coil inside are lacking in power and quality, and you either have an unusually weak one on an otherwise stock electrical system, OR more likely, it is not strong/powerful enough to split the signal since you are using an OBD-2B -> OBD-1 adapter harness and an OBD-1 ECU.
So the tach thing started after the distributor swap?
Cooling fan relay signal comes from the ecu and goes into the chassis harness at C131 (the green plug under the dash). So does tach signal (NEP) and VSS on OBD2B cars. You can cut the fan switch wire by accident but the ecu should still force the fan on at some point. On that note, what ecu are you running?
Only 99-00 harnesses will work on you car, not 92-98. As far as which ones, your choices are (in order of favorability, assuming you are running a single plane intake manifold as well)
- 99-00 Si (EM1) - straight in.
- 99-00 EX manual - will require some minor massaging.
- 99-01 CR-V manual - straight in but requires adding vtec wiring.
I know you said you are on a budget, but honestly a new harness from Wireworx or Rywire or CJ's is worth every penny. I wouldn't even flinch at taking it over the 21-22 year old haunted house that is the stock harness you're going to get from god knows where (and then stretch/molest it to get it in place). It makes a huge difference in how well the car runs and how much time you have to spend diagnosing mysterious issues like you are already having. You can order it with you wideband already wired in, and different injector plugs... or you can splice all of that stuff in or cable tie it along the original loom and use injector pigtails and all that mess to create more future issues for yourself. Plus you get to have your 'tucked' harness without hacking anything up.
You also won't need a jumper harness at the ecu if you use a custom harness. A decent jumper harness is >$100 so you need to factor that into your cost (HA Motorsports OBD1-OBD2B jumper is $130). I say 'decent' because none of them are very good and the $40 ones are only good for throwing straight in the trash can.
So here we are, with a good condition OEM harness that still needs massaging that's costing ~$250-$300 and will still be 20 odd years old, then add in a decent quality jumper harness, and you're already at the cost of an entry level brand new harness (but still having issues sooner or later). I think if you actually map out the economies of the whole thing, there's nothing really budget about trying to force an old stock harness into your build. Skip the $100 shift **** and you'll break even.
@JRCivic1
Thanks for the info, The original distributor was borrowed from a friend so I had no choice but to purchase my own, apologies for the confusion! Is there any you can recommend?
@spAdam
Thank you very much for the info and advice. I'm running a P28 ecu with a OBD2B > OBD1 jumper harness. My fan wires aren't cut so I'm not sure where I went wrong with the wire extending seeing I was very patient & everything was soldered & wrapped in heat shrink tubing.
Any way, I did look into Wireworx, CJ's and Rywire harnesses which would be great but the ones within my budget and for my car seem to be sold out. I may have to be patient or find a reseller of Rywire. Just to make sure, in the case I go rywire, I'm looking for a OBD2B harness because my car's 99-00? And this should be plug and play without my current jumper harness? Again I'm using a P28 ecu chipped.
All Rywire engine harnesses are made with OBD1 (92-95) ECU Connectors. An ECU adapter can be used for OBD2
ECU's if necessary however our harness does not support USDM OBD2 ECU's. Aftermarket ECU's using OBD2 plugs
and Non-US OBD2 ECU's are compatible (except for H22 and GSR stock computers).
Each harness will come with a custom back side sub-harness that will be proprietary to the chassis you choose on
the drop down menu. This way if you ever change chassis you will only need a new sub-harness, not a whole new wire loom!
I would email exact specs, what yr/make/model, what exact engine. If you want it done the 1st time the information is key to getting it. If you want to just spit out 'I got a b-series' sure, go for it.
UPDATE:
I replaced my distributor with an OEM which finally fixed my tachometer. Glad to have that working again but there's still 1 issue and it's my temperature gauge not wanting to move. It's always in the COLD position and doesn't even move a hair when the engine's fully warmed up. I did a test I found on another HT post while looking into my radiator fan problem because it wouldn't kick on when it was supposed to, so I jumped the temperature switch plug, turned on my ignition and the fans kicked on proving that the temperature switch is faulty. But the gauge still doesn't move. I'll be running to the auto parts store to replace the switch but I don't believe that's the cause for my temp gauge problem, someone correct me if I'm wrong?
Due to the new distributor fixing the tach problem I was having, I may or may not continue looking for a replacement engine harness, it depends on whether or not I can figure out this final issue. Any further advice would be greatly appreciated. TIA.
Temp gauge sender is completely separate from the fan switch and ect sensor for the ecu. It's right up under your distributor:
Hey, thanks for clearing that up. I don't think it's my temp gauge sender because it did work at one point and I did notice a problem with my cooling system which may explain the problem. Lately, when the car reaches a warm temperature I notice my upper rad hose filling with coolant and its like the coolant can't circulate - The upper hose gets very warm and fills up to the point where it looks like it will burst, while my lower rad hose is at a cool temp with no coolant flowing through. I believe the coolant isn't reaching the gauge sender which could be the reason I'm not getting anything on the gauge.
What could this indicate? Air bubble in the system, issue with my block, head, or maybe head gasket? Again your info's very appreciative.
Last edited by Nitrozity74; Aug 18, 2021 at 11:08 AM.
So the tach thing started after the distributor swap?
Cooling fan relay signal comes from the ecu and goes into the chassis harness at C131 (the green plug under the dash). So does tach signal (NEP) and VSS on OBD2B cars. You can cut the fan switch wire by accident but the ecu should still force the fan on at some point. On that note, what ecu are you running?
Only 99-00 harnesses will work on you car, not 92-98. As far as which ones, your choices are (in order of favorability, assuming you are running a single plane intake manifold as well)
- 99-00 Si (EM1) - straight in.
- 99-00 EX manual - will require some minor massaging.
- 99-01 CR-V manual - straight in but requires adding vtec wiring.
I know you said you are on a budget, but honestly a new harness from Wireworx or Rywire or CJ's is worth every penny. I wouldn't even flinch at taking it over the 21-22 year old haunted house that is the stock harness you're going to get from god knows where (and then stretch/molest it to get it in place). It makes a huge difference in how well the car runs and how much time you have to spend diagnosing mysterious issues like you are already having. You can order it with you wideband already wired in, and different injector plugs... or you can splice all of that stuff in or cable tie it along the original loom and use injector pigtails and all that mess to create more future issues for yourself. Plus you get to have your 'tucked' harness without hacking anything up.
You also won't need a jumper harness at the ecu if you use a custom harness. A decent jumper harness is >$100 so you need to factor that into your cost (HA Motorsports OBD1-OBD2B jumper is $130). I say 'decent' because none of them are very good and the $40 ones are only good for throwing straight in the trash can.
So here we are, with a good condition OEM harness that still needs massaging that's costing ~$250-$300 and will still be 20 odd years old, then add in a decent quality jumper harness, and you're already at the cost of an entry level brand new harness (but still having issues sooner or later). I think if you actually map out the economies of the whole thing, there's nothing really budget about trying to force an old stock harness into your build. Skip the $100 shift **** and you'll break even.
Agree on the harness. If you don't know what you're doing just buy it new and swallow the bullet. Buy once cry once.
Agree on the harness. If you don't know what you're doing just buy it new and swallow the bullet. Buy once cry once.
I totally see where you're coming from but I'm afraid that a new harness won't fix the problem. My tach has been fixed so that's 1/2 problems scratched off the list. But now, my coolant isn't fully circulating, see my previous reply for more details. I believe it's mechanical rather than electrical related at this point. Just looking for advice on that. TIA.
Need advice on stock engine harnesses
