b18cr, wont rev past 5500 rpm & no vtec

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thunderboy

New Member
Hi guys, any help on this one would be much appreciated. (and i have been searching for a few hours now... just finding info on oil/oil clogs)

Right..

I have a 92-95 EG civic, OBD1

Engine B18cR

Ecu, P73 ob2a, running with obd1/obd2a conversion harness..

The problem I am having is driving the car it physically wont rev past approx 5500rpm. and subsequently vtec will not engage.

The car will rev past this in neutral, but obv there is no vtec engagement for this.

Really not sure what to try to solve this problem - any ideas?
 
Convert it all to obd1 and run a chipped p28. That should eliminate those annoying sensors putting you into a "limp" mode. If that doesn't work, than check speed sensor and coolant temp. sensor. There should be a knock sensor as well, wont really be needed when obd1.
 
Convert it all to obd1 and run a chipped p28. That should eliminate those annoying sensors putting you into a "limp" mode. If that doesn't work, than check speed sensor and coolant temp. sensor. There should be a knock sensor as well, wont really be needed when obd1.

Well, that wouldnt really be solving the problem - more trying to avoid it.

I unfortunately do not have a chipped obd1 p28 lying around, so its not really a purchase I want to make if its not going to solve the problem.

in terms of checking the sensors as you say, i've been reading as you say to check VSS, Coolant temp, RPM, Oil Pressure.. Not really sure what is meant by 'check'

As far as the instruments in the car... the tach/speedo/temp all work & not throwing any CEL codes. - so I dont understand what could be wrong.


B18C=JDM Type-R, B18C5=USDM

And he's running a P73.

Ty
 
what happens if your rolling with some speed and put the clutch in to rev it, such as neutral. will it rev past? weird limp mode unlike i've encountered.
 
I have a 92-95 EG civic, OBD1

Engine B18cR

Ecu, P73 ob2a, running with obd1/obd2a conversion harness..

The problem I am having is driving the car it physically wont rev past approx 5500rpm. and subsequently vtec will not engage.

The car will rev past this in neutral, but obv there is no vtec engagement for this.

Really not sure what to try to solve this problem - any ideas?

1) your car is wired for obd1.
2) your engine is obd2b (if 98+ itr)
3) your using an obd2a ecu (p73 which is gsr)

Obd1 is favored over obd2 for the simple fact that it elimates some sensors that your obd2a ecu WILL look for, such as knock, crank position sensor etc.

Your harness/ecu should match the head. Like I said before, to make the most power with 0 headaches, take the obd2a jumper off and get a p28 chipped. Phearable.net - Electronic Fuel Injection Tuning Solutions - Hondata, Neptune, Crome, Uberdata, Ectune, AEM, Honda Tuning, Widebands, Fuel Pumps, Intercoolers, Turbos, LS/VTEC, ECU Chipping, Chipped Ecus, P28 -- you tell them what engine, he will chip a p28 and send it to you for less than $200. Make sure you have sufficient oil pressure and vtec is wired correctly to the ecu. Your problems will go away, bottom line.

You are here asking "us" for help. We are giving you answer's and you argue. Obviously if you understood the situation you would not be here asking. If you do not want to go the best route, as I specified, than don't. Spend hundreds more trying to figure it out.
 
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1) your car is wired for obd1.
2) your engine is obd2b (if 98+ itr)
3) your using an obd2a ecu (p73 which is gsr)

Obd1 is favored over obd2 for the simple fact that it elimates some sensors that your obd2a ecu WILL look for, such as knock, crank position sensor etc.

Your harness/ecu should match the head. Like I said before, to make the most power with 0 headaches, take the obd2a jumper off and get a p28 chipped. Phearable.net - Electronic Fuel Injection Tuning Solutions - Hondata, Neptune, Crome, Uberdata, Ectune, AEM, Honda Tuning, Widebands, Fuel Pumps, Intercoolers, Turbos, LS/VTEC, ECU Chipping, Chipped Ecus, P28 -- you tell them what engine, he will chip a p28 and send it to you for less than $200. Make sure you have sufficient oil pressure and vtec is wired correctly to the ecu. Your problems will go away, bottom line.


OR get a new harness for complete OBD2a and remove the damn'd OBD1 harness all together. the emission's center will give you a hug too.

edit. didnt see the b. thought they were both 2a. rywire.com make a harness maybe? i think that would be cheaper than an ECU
 
OR get a new harness for complete OBD2a and remove the damn'd OBD1 harness all together. the emission's center will give you a hug too.

edit. didnt see the b. thought they were both 2a. rywire.com make a harness maybe? i think that would be cheaper than an ECU

His car is already wired for obd1. He is using a jumper harness to run the obd2a ecu (p73). With this, additional wiring is needed on the engine harness for this engine to function properly. You cannot simply put an obd1-obd2a jumper onto an eg harness (obd1) and run an obd2a ecu. It will run like ass.

EDIT: The emmissions center won't love him, they will reject him. Either way, the car is obd1, so there will be no use of scanning from the obd2 port, being that it does not exist. They use a sniffer in the exhaust tail-pipe when testing emmissions on cars pre-95.
 
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His car is already wired for obd1. He is using a jumper harness to run the obd2a ecu (p73). With this, additional wiring is needed on the engine harness for this engine to function properly. You cannot simply put an obd1-obd2a jumper onto an eg harness (obd1) and run an obd2a ecu. It will run like ass.

sorry for not correcting what i said. i didnt mean it to sound like that. i was trying to say, why cant he replace his engine harness. remove the OBD1 engine harness from the motor to ecu, and put in a motor harness appropriate. but then i realized, the motor and ecu arn't like OBD, so I tried saying to suggest using an OBD2b harness which will have all wires for all sensors, and then convert that harness to obd2a for the ecu. but idk if that would be cheaper.

on a different note, maybe i need to go to sleep. it's real late. ^_^
 
He would need to re-wire the whole car. Judging by his knowledge I don't think its something he can do on his own. He will end up spending a lot for that engine harness, and ontop of it he will spend a lot more for a shop to do the wiring. He is going to need an engine harness that clips from the shock tower. Finding one that is obd2 isn't exactly easy today, but possible.
 
My friend has a 95 eg hatch, with a 2001 ITR swap complete with obd2 engine harness and all. Runs great. Another friend of mine has a 92 eg hatch with a 2001 itr swap, running on the stock engine harness, with an obd1 distributor and a chipped p28. The chipped p28 out performed the obd2 hatch every time, and he was on stock manifolds. The obd2 hatch had I/H/E. The chipped p28 hatch has only I/E. You do the math. :)
 
ok ok that's fine. i was brainstorming other maybeee cheaper ways to look into. ur probably right tho. i have less experiance there.


but, I myself have a 2000 ex coupe (obd2a) with an OBD1 B16, that was through a conversion harness, but I cut it apart and wired it all up directly. and integrated it with the chassis, which was no problem because the chassis was higher OBD spec than the motor, which otherwise, yeah you'd need a fuel pressure sensor for one, and not much else but still with his experiance, i get ya.
 
I did it for ease of tunability and emissions doesnt care out here ;)
 
ok ok that's fine. i was brainstorming other maybeee cheaper ways to look into. ur probably right tho. i have less experiance there.


but, I myself have a 2000 ex coupe (obd2a) with an OBD1 B16, that was through a conversion harness, but I cut it apart and wired it all up directly. and integrated it with the chassis, which was no problem because the chassis was higher OBD spec than the motor, which otherwise, yeah you'd need a fuel pressure sensor for one, and not much else but still with his experiance, i get ya.


I don't mean to be a dick, but your car is a 2000 civic ex? That would make it obd2b not obd2a. ;l
 
yeah ur right. eh i havnt payed much attention after getting the right diagrams. this is the only car i've done work on. but the right most plug was unused in mine. so yes. u got me :)
 
hmmmmmm. sure? i dont remember now. it was an auto... i'm lookin it up. dang lol

Oh I am sure ;] 96-98 = obd2a. 99-00 = obd2b.
Automatic or standard, it doesn't make a difference. OBD = On-Board-Diagnostics. Nothing relating to the transmission.
 
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