1994 Corolla Frankencar... Need Help!

[BlownHeadGasket]

So I recently bought a 1994 Corolla 1.6L Automatic DX Wagon off of craigslist. Took it on a rather extensive 20+ mile test drive (rolling backcountry roads and the highway) and it handled tight, accelerated without hesitation, braked awesome and drove extremely well. No leaking fluids, good paint, straight body and otherwise in prime condition for a car with 150K miles. Bought a carfax report and it was clean with only 2 owners. Given these factors, I thought it would be a great car (I owed a 1990 wagon that recently was totaled by an insured driver, also used to own a straight axel 1985 Pick Up which I upgraded for a 1994 extended cab which I still have, so I am familiar with Toyotas and love them).

As I drove it home the check engine light (CEL) came on. Got home, popped the hood and put in the jumper wire to trip the engine code. It came out as a 71, which according to my book means:

EGR gas temp. is 60C (140F) or below for 50
sec. under conditions (a) and (b).
(2 trip detection logic) *
(a) Engine coolant temp.: 60C (140F) or more:
(b) EGR operation possible (EX. A/T in 3rd
speed (5th for M /T), 55 - 60 mph
(88 - 96 km/h), Flat road).
• Open in EGR gas temp. sensor circuit.
• Open or short in VSV circuit for EGR.
• EGR hose disconnected, valve stuck.
• Clogged EGR gas passage.
• ECM
Diagnostic trouble Code Detecting Condition

Trouble Area
DTC 71 EGR System Malfunction (Only California spec.)

I reset the CEL and my wife took it the next day to emissions for testing (a requirement for title transfer in WA state) and it passed, even with the CEL (it came on during the drive there). All of the numbers were low (HC and CO). Car runs fine, but maybe a little on the hot side (temp seems to be in the middle of the gauge, when I am used to seeing it at maybe a 1/4 of the gauge).

That night I popped the hood and consulted my repair manual about the EGR system and low and behold the engine didn’t have one. A little more research into the car revealed I have a CA Emissions Car with what I believe to be a Federal Emissions Engine (can’t tell if the transmission is CA or Federal (if that is even possible)). Owner must have done an engine swap incorrectly.

I want to know if I can salvage this car or it is a lost cause (given its condition and how well it currently drives it would be bummer to just chuck it or sell it to someone as damaged goods). From all of my reading and research I think I have the following options:

1) Leave it as is, with no EGR and drive with the CEL on. What are your thoughts on this? What could the problems with this option be, both long and short term. If the car is already possibly running a little hot, could I burn up the engine (say on a long climb over a mountain pass)?
2) Install an appropriate resistor to trick the computer into thinking the EGR system is in place. Bummer is it would be locked at only one resistance reading (ie only an “on” reading or an “Off” reading when the computer usually expects the reading to change), which could cause more problems. I dunno.
3) Replace the CA ECM with a Federal ECM. Is it as simple as unplugging one and plugging in the other or would it also involve replacing all of the wiring harnesses? Are there other problems this would cause? I do know the CA exhaust (which I have) has 2 oxygen sensors and 2 catalytic converters, while the Federal only has 1.
4) Try and retrofit an EGR system on the Federal Engine so the ECM picks up the correct signal. Would I also need to add other items to the engine? Is this possible? Any ideas on where to start with this one?
5) Replace the engine with a CA spec Emissions Engine
6) Drive the car and myself off of cliff.

You have been a wealth of knowledge in the past when searching for solutions on the internets and I am hoping I can go to well one more time (so to speak).

Thanks and Cheers.

[miib14]

i say leave it as it is... drive it about until lol

then change engine to the correct one...

but thats jus me tho...

[azcorolla]

First, I doubt you would hurt anything by driving it as is. It passed emissions, so WTH?
My 91 Subaru was easily fooled with 5 watt resistor of about 66 Ohms. don't know about the Toyota, but I would try that first, cause it's cheap.

My Corolla has always run with the temp guage showing pretty much exactly in the center.

[speedy25]

I'll add another vote for temp gauge in the center.

EGR problems wont make much of an effect on driveability and wont destroy an engine like ignoring some CEL's. If you confirm that the car actually has the EGR system, most of the time the recirc pipe gets clogged with oily goo. Other times the valve itself seizes up.

Another possibility is maybe you have a CA computer in a non-CA car? I think you can confirm all that with the VIN, or hood sticker.

-SP

[Rip The E Brake]

You can switch computers with no problem. They are plug and play for these cars and are only about $70 on ebay.

[zythr]

Your first clue should have been having a 1.6 liter instead of 1.8 litre engine in the car, when the 1.8 was standard in the wagon, then again there have been reports the 1.8 liter may become an oil burner when it accumulates a lot of miles. I'd suggest getitng the CEL light to go off and enjoy the car Does it have any rust?

[BlownHeadGasket]

Originally Posted by Rip The E Brake

You can switch computers with no problem. They are plug and play for these cars and are only about $70 on ebay.

Other than the computer, are there are any other "brains" (other than mine!) that need to be switched out to make my car compatible with the federal emissions engine?

If not, maybe this is the best route to go. I'll keep you posted.

And to answer someone else's question, no rust on the car. Car has been in the NW away from salt and saltwater its whole life. It looks like it was garaged the entire time as well. Clear coat on the paint is still factory and cherry. Interior is immaculate. Other than this engine deal, it is in great shape (and if this computer deals works out, the engine will be in good shape as well).

[Rip The E Brake]

There might be an electronic transmission computer, but I dont remember honestly.

[thespud]

^^ You just have to make sure the ECU you buy is an A/T ECU. Well, at least here you do. The controlling of the Auto trans is inbuilt into the ECU.

I must say i am unfamilliar with the EGR systems though.

[BigDAT]

if the issue was truly EGR, and the car passes Smog, then you have nothing to worry about.

What you can do, for the engine light issue, is get a switch that has a light in it, install it in the dash panel that holds the dimmer, now open up your cluster and re-route the wires from the CEL to the switch light, flip the switch on if you wanna see if the CEL is active, when you get to the smog check, you can just flip the switch off (or if it is just bugging you).

Alternatively you can get a switch, and split the wires to the CEL, so you can switch it on or off (you dont need to look at it when you dont want to)

Either is simple, costs less then a dollar, and takes very little time.

[BlownHeadGasket]

Originally Posted by BigDAT

if the issue was truly EGR, and the car passes Smog, then you have nothing to worry about.

I have heard that since the EGR System cools down the gas combustion temperatures in the cylinders you can run into problems with the engine running at a hotter temp than expected which the computer may try to overcome by running a leaner mixture which might trigger the knock sensor (under heavy loading) which would retarding/advancing the timing.

Anybody know what the temperature difference would be and if that could cause premature wear on the engine?

Ideally I would love to get this thing as close to what the engineers intended so it could go the distance so to speak.

Thanks everyone for the input so far. I am further along now than I was when I started.

[azcorolla]

Originally Posted by BlownHeadGasket

I have heard that since the EGR System cools down the gas combustion temperatures in the cylinders you can run into problems with the engine running at a hotter temp than expected which the computer may try to overcome by running a leaner mixture which might trigger the knock sensor (under heavy loading) which would retarding/advancing the timing

Just MHO, but if that were true, and it was running that lean, it wouldn't pass emissions. But it's obvious that you want things to be 'right' and get that light off, and I can understand that.

I think there are some good ideas here for you to try. I would start with the computer swap.