Warning Light Identification (91 Q45)

[trw2k]

I changed the timing guides and soon after this light came on (below). I don't know if it is a check engine light or something else. I guess that looks like an engine?? I searched for information about reading the ECU thinking this was a check engine light but the articles refer to a flashing check engine light. This never flashed...just came on. Also, after reading all the articles on the ECU I still could not figure out how to find it. The RH kick panel I know but is that along the left side of the passenger foot area or under the glove box. These seem like it should all be obvious but I can't seem to figure it out...so I thought I would just ask.Thanks!

[Q451990]

That is your "check engine" light. The light won't flash until you put the ECU into test mode and pull the codes.

The ECU is located on the RH kick panel and would be directly beside a passenger's right foot. It's cover is carpet, and has a 10MM bolt near the firewall.

Do you have any driveability issues?

Heath

[trw2k]

Thanks!It runs great...I got it used and it runs better than ever since changing the guides so I have no complaints other than the vibration at 1800-2000 rpm which seems to be related to mounts or drive line. I will locate the ECU ( I was looking on the left foot side) and see what it says.

[Aussie Q45a]

Also, after reading all the articles on the ECU I still could not figure out how to find it. The RH kick panel I know but is that along the left side of the passenger foot area or under the glove box. These seem like it should all be obvious but I can't seem to figure it out...so I thought I would just ask.Thanks![/QUOTE]It's behind the RH kick panel. Here's a pic. Don't take any notice of the gas pedal as this car has the steering wheel on the right side

[trw2k]

Ahhh! Thanks!

[Q451990]

Actually, that's a picture of the TCU (transmission control unit). The ECU will be larger and square...

Heath

[elwesso]

It looks like the ECU is ALWAYS on the passenger side and the TCU is always on the DRIVERS side, regardless of RHD or LHD

[Aussie Q45a]

Actually, that's a picture of the TCU (transmission control unit). The ECU will be larger and square...

Heath

Just checking to see if you blokes were paying attenion

Here's the real ECU behind the LHS kick panel

Your right again Wes.

[maxnix]

Just checking to see if you blokes were paying attenion

Here's the real ECU behind the LHS kick panel

Your right again Wes.

In US G50:

ECU = R

TCU = L

[maxnix]

I changed the timing guides and soon after this light came on (below)!

Did you torque your main bolt to specification? What's your oil pressure at idle and 5K rpm?

[trw2k]

I am going to retighten the bolt just to be sure. I used a chain wrench before to stop the crank from turning...and a large torque wrench, is this the best way?I have never checked the oil pressure and I just checked the other threads on it but couldn't find anything about where and how I hook up the gauge. Does it connect to the oil filter threads?

[Q451990]

Not that it's a bad idea to retorque, but if crank were slipping you should get an oil pressure light...I would suspect a loose electrical connection or bent terminal.

Whatever code it's pointing to should tell us a lot.

Heath

[trw2k]

As soon as I posted that last post I thought I need to pull the code first..so I will do that tonight and see what it says.

[Aussie Q45a]

In US G50:

ECU = R

TCU = L

So can you identify which is which in the 2 pics I posted????

[elwesso]

The second picture you posted is the ECU..

The ECU connector is about 2x as long as the TCU.. give or take a little.

[trw2k]

Yes, Thanks AussieQ45 I pulled the cover off both sides just to be sure.I just read the codes and got a 32 EGR Function and 34 Knock Sensor.I am going to do a search in the forum and see what I can find.

[trw2k]

Ok so after getting the 32 and 34 codes I cleared the codes. I tightened a bolt on the gas line going to the injector rail on the passengers side where I could see fresh gas ( I had smelled gasoline intermitantly after stopping the car). I retightened the crankshaft bolt and took it for a test drive and the Check Engine Light did not go on. These things are not related to the codes it seems. To be honest I do not know where the EGR or the knock sensor are. I will look those up though. It starts and runs great so I don't know what to think.

For anyone who might be reading this who hasn't done this I added a picture below on how to retrieve the codes and what will flash the codes on the back of the ECU. Refer to this thread for the codes and more detailed instruction zerothread?id=60332

[maxnix]

Nice post.

If you find the thread on the oil pressure sensor, it will identify the threads as being something like an Imperial fine plumbing pitch, not a common thread pitch at all.

[trw2k]

Hi Maxnix,Are you talking about hooking up an oil pressure gauge? I went to a tool rental place and Schucks and when I asked if they had an oil pressure gauge I could rent or buy they both acted like they didn't know what I was talking about. So I haven't checked the oil pressure.

[Q451990]

The EGR valve is located on the left (driver's side) of the engine near the firewall and master cylinder. I suspect you have a CA Q if you're getting a code for EGR function on a 91? (EDIT: Just notice the A50/P28 sticker in your picture. You have an ECU for an Active CA Q ) The valve itself looks like a flying saucer landed on a pipe that bolts into the plenum. You should be able to push it closed by pushing upward on the valve from the bottom... At idle this should slow the RPMs or even kill the engine... If there's no change you have a major carbon blockage.

In your case, I suspect that there's a sensor bolted into the plenum that fits into the port that leads from the EGR to the intake. This is the sensor that is not sensing the hot gases at the appropriate time... so you now get to figure out why! Typically the port in the plenum will gunk up with carbon to restrict the air flow. Since it looks like you're on the way to pulling the plenum to replace knock sensors anyway - plan on spending some time with a dental pick and bottle brushes getting everything decrusted and back to new looking!

Now... rev the car from idle to about 3000 rpms, while touching the bottom of the EGR valve (the part you pushed upward earlier). It should rise and flutter as the RPM increases, and then cut out quickly at about 3000 RPM. If it doesn't move, start checking your vacuum connections for broken hoses, and make sure the terminals on the control solenoid are not corroded.

In case you're wondering... the EGR Valve (short for Exhaust Gas Recirculating) introduces exhaust gases into the combustion chamber during cruise. The idea is to slow combustion and prevent spark knock. It also reduces emissions.

Good luck!

Heath

[Q451990]

Oh... knock sensors. Those are buried under the plenum. Typically they won't trigger the check engine light. Might be worth your time to try to tap on their connections with a long screwdriver or dowel. Sometimes you can get them to come back for a while. They are a very common failure item though... when you replace them be sure to have all of the rubber hoses under there on hand. Replace the harness too... they frequently fail for some reason.

Heath

[trw2k]

Thanks Q451990 for all the info. When I did the guides I took both valve covers off and I think I took the EGR off as well and it was gunked up but I cleaned it then. I will do the EGR tests you described and see what happens. I did just drove it 20 miles and the lights all stayed off. If this was a continuous problem shouldn't the light come back on?

< "You have an ECU for an Active CA Q"> I have to admit I don't what sort of Q this is other than a 91 Q45. I didn't go looking for a Q45 , my mother in law gave this to my 16 year old daughter which at the time seem awfully nice. Then I learned of the chain guides and then I realized how powerful the car is and it just seems crazy at this point for her first car to be this one. Anyway..., I do know it did come from California. What does "Active CA Q" mean?

[Q45tech]

California Active Suspensioned Q had an EGR temperature sensor that told ecu that warm exhaust was probably flowing into plenum double checked to try to perform diagnosis and to make sure egr didn't flow until coolant warmed up enough.

[elwesso]

all 94s have this as well.

[trw2k]

The cap on the radiator tube next to the engine was not sealing very well and so I replaced it. Would lack of a good cap seal have kept the water from heating up enough and triggered the EGR code?

[maxnix]

Well, hope itwas on OEM cap. Cheapo retail auto parts store ones fail frequently, even when they appear to be working.

[trw2k]

Thanks Q45Tech,I don't want to stray to far fromt he original subect matter but does this car have an active suspension? There is no A after the Q45 on the trunk. I was just reading an excellent thread on the Active Suspension zerothread?id=80448 Foe some reason I am thinking my 91 Q45 does not have the active suspension. I saw an active suspension system for sale on Ebay and was wondering if it can be added to the Q's that don't have it and is it worth it?

[Q451990]

The active system is very expensive to maintain correctly. When working properly it's pretty cool - but many, many, many Q owners have de-converted to a standard suspension. If you have an active, it should have a ride height switch in the center console, and some vents in the cladding of the fender well on the driver's front wheel.

I went back and looked at the TSB, and I may be reading the chart wrong... in fact I'm pretty sure that chart is messed up. In any case we now know that your car has the California emissions.

Heath
Modified by Q451990 at 1:42 PM 5/14/2006

[trw2k]

Ok cool, The word "Active" made me wonder...it refers to the emissions though.THANKS!

[Q451990]

Actually "active" refers to the suspension. Essentially the "A" cars had a very advanced hydraulic system and an array of sensors that kept the car level in corners...

In case anyone wants it - I corrected the ECU identification .pdf



Heath