Making my auto-to-manual trans work?

[LTRAIN27]

I own a '97 Civic EX that I recently converted from auto to manual transmission. The car runs fine but I'm having small problems that I can't figure out. The auto gear selector light in the gauge with the temp. and gas gauge just flashes at me now, not sure why it's doing that. Also my check engine light is on and will not go off. A mechanic at the local Honda dealership tells me that if the check engine light is on then I have no v-tec because the computer rides over the v-tec to keep from causing damage to the motor unti the problem is fixed. Does anyone know if this is true? I haven't really run the car hard because I'm not sure if I'm going to do damage to the motor or transmission or not. I bought an ECU from a '97 Civic with manual trans and installed it in my car. The car starts and runs with it, but idles between 1,500-1,700 rpms constantly, so I took it out and put the original ECU in. The car is driveable with the factory auto ECU, but I know things are not quite "right". What am I missing or what else do I need to do to finish the job? I didn't expect to have the motor not running properly by changing the ECU. Is a wiring harness from an manual trans car going to fix the lights on the dash such as check engine, and also get the motor running right?
It's getting frustrating........anyone who can help, please feel free to give me some advice.
Thanks

 

[darwins_vtech]

put the manual ecu in and try to adjust the idle. it should be a flat head type of screw on the throttle body. IT DOESN"T STICK OUT so it should be a little hard to locate. On mine it is right above the intake tube.
Does it still throw check engine light with the manual ecu? And get the code checked to be able to diagnoise the problem.

DArin

 

[LTRAIN27]

Thanks for the help. I'll try adjusting the idle and see if that helps any the next time I get the chance to tinker with the ECU again. The check engine light trips on even using the manual ECU, so I'm not sure what the deal is there. One of the guys at my local Honda dealer works on project cars on the side for friends so he is going to help me try to figure out a few things, hopefully soon. I guess I'll have to get the code checked too, just was hoping to avoid paying a shop way too much money just to hook up the computer and run diagnostics on it if I could avoid it.
Thanks

 

[jeffsciv23]

i did the same thing with my 99 ex and have the same probs. with the auto ecu i'm getting a code 70 (auto tranny code) imagine that, and with the manual one i'm getting a code 14 (IACV), and it idles pretty rough and bumps every now and then. i think that the problem is that on manual and auto civics the IACV is differant but i don't know if you can change that wthout havnig to change the whole intake manifold. lemme know what you find out.

 

[ddrcivic]

Yeah its definitly the ecu. When I converted my 92 hatch I did a swap at the same time so I had a manual ecu. still have never thrown a code to this day.

 

[fook]

What are the symptoms if you use the Auto ECU?

Also, are you sure you got the right ECU and not one that is from a DX Manual and doesnt have vtec controls at all?

Im curious because Id like to eventually do the conversion on my 95 EX

 

[jeffsciv23]

Originally posted by ddrcivic@Aug 13 2003, 03:23 PM
Yeah its definitly the ecu. When I converted my 92 hatch I did a swap at the same time so I had a manual ecu. still have never thrown a code to this day.

you swapped everything even the intake manifold that's probably why no codes.

 

[jeffsciv23]

Originally posted by fook@Aug 13 2003, 04:33 PM
What are the symptoms if you use the Auto ECU?

Also, are you sure you got the right ECU and not one that is from a DX Manual and doesnt have vtec controls at all?

Im curious because Id like to eventually do the conversion on my 95 EX

my auto ECU works fine just no VTEC (which sucks). my ECU is the same excact year and model just from a manual, i don't know about him though.

 

[LTRAIN27]

The factory auto ECU works, and the car runs pretty well using it, but it has caused a few minor things. I currently have some of the wiring and solenoids form my auto trans plugged into the engine wiring harness, not sure if I need to have these but thought it would help trick the ECU into thinking nothing was different. The car may run fine without them plugged in, I'm not sure because I've not tried it. I did unplug the solenoids when I tried the manual ECU, but it made no difference. Since the swap I do not have cruise control, not a big deal but it would be nice to get it working, and I currently do not have reverse lights. I guess that doing some wiring would fix the reverse light problem, so I'm told by my friend who works at a dealership. The biggest thing that sucks is the fact that with the check engine light on I don't have vtec kicking in, and really that's the whole point of getting any power out of the motor and changing the transmission in the first place. I don't know what codes I'm throwing with either of the ECU's because I haven't taken it to anyone with electronic diagnostic equipment, and I'm suddenly on a tighter budget so I'm just trying to get the transmission right so I can consider the car a completed project, at least for now.
I know that the ECU from the manual transmission car is the right one and for a vtec motor because I checked part numbers through the dealership before buying it. My next step will be a new engine wiring harness I guess, and see if that will take care of the check engine light so I can get the vtec back. I also had it recommended to me that I could convert from OBD2 to OBD1, but I'm not really looking to do all that. If I can't fix the problem with rewiring it, then I guess I'll live with not having vtec, unless someone comes up with any other answers.

 

[jeffsciv23]

get a paper clip and jump the plug by the ecu and then turn on your car and it the CEL will blink and tell you what codes (count blinks). the long ones=10, short=1.
sounds like you are haveing the exact same probs as me, no reverse lights (they are for fags anyways), no VTEC, and blinking gear indicator. the only thing i can think of now is the IACV because if you read your Haynes or Chiltons it will tell you that they are differant for auto and manuals. but they are in differant places, auto=TB, manual=IM. so i don't know if i am going to have to change the whole IM and TB but i think that would be easier then switching wireing harness.
check your codes and let me know what you got, i bet they are the exact same as mine, auto ecu=70 and manual ecu=14.

 

[fook]

I just swapped an engine from a manual EX into my auto EX....

The only differences were a couple of plugs on each engine harness...obviously the plugs were different on the transmission end. The auto has 2 plugs, the manual I dont remember how many, but I had both, so no biggie.

The other difference was a little black sensor of some sort on the Intake Manifold on the far drivers side. The auto version has one more vacuum line than the manual version did...the common line on both runs to a port on the intake just below where the sensor mounts, and the extra one on the auto went to the vacuum canister on the other side kinda under the battery.

Luckily I had both complete engines, so I had everything I needed to just use the right parts for each application.

 

[jeffsciv23]

so did you swap out the whole engine when you did yours?

 

[fook]

yes. mine had a bad rod bearing and I just got a cheap stock for stock replacement from a guy with a wrecked car and threw it in...used my engine harness and that one sensor I was talking about...

BTW, does anyone know what that sensor is?

 

[jeffsciv23]

i beleive it's the IACV because that's the code i'm getting now and thats whats differant on auto and manuals.

 

[ddrcivic]

jeffsciv, you are correct sir. Idid a B16 sir2 swap at the same time. just alot less hassel that way.

 

[fook]

Originally posted by jeffsciv23@Aug 14 2003, 11:14 PM
i beleive it's the IACV because that's the code i'm getting now and thats whats differant on auto and manuals.

so the difference is that extra port on the auto IACV?

can you just plug it off?

If not, go to a junkyard and snag one.

 

[jeffsciv23]

that's what i was thinking about doing but i'm about to be boosted in a week or so so VTEC isn't really all that important, it would just be nice to have it back and no CEL. i don't know if you can plug it off because you engine needs that sensor to control the idle. seems kinda like a pain in the ass to change the whole manifold though.

 

[jeffsciv23]

Originally posted by fook@Aug 16 2003, 12:53 AM
so the difference is that extra port on the auto IACV?

the differance is that one has three wires and the other has two and they are in differant places. the auto is on the TB and the manual is on the IM.