check engine light and rough idle..what do you think?

[jumpjet65]

My 94 Q with 56 K suddently began idling roughly and the ck engine light came and off several times but stayed on for a fairly long time once and ten back to intermiten (sp) status. Took it to dealer--he could not get ck engine light to come on, it started and idled ok. Here is what he did..ran the ohm test on injectors and said all were in the normal range except one which tested at 15.25 ohms and when it cooled it went to the 16 ohm mark so he suggested replacement of this injector. I said replace it and while he had the plenum off to also go ahead and replace all the hoses under the manifold. Cost approx $1350. Does this sound like the prudent thing to do? The right thing to do? Should this possibly solve the problem? I know there are many factors involved but I thought I would ask anyway. He is also checking out the MAF.....I would appreciate input on this situation. This is my first problem with this great car as I have done all the regular main. I really love this car! PS..how about this price???????

[DAEDALUS]

Welcome to NICO! First off, you're definitely getting the Dealership In Bay Area Labor Differential (DIBALD). I figure parts were abou$4-500 and labor at about $100+/hr. I hope the other 3 injectors under the plenum don't fail! (One at a time). 16 ohms is not extremely high...I am doubtful it has much to do with the rough idle, but maybe so. Hopefully he checked the injector directly too; I know of one Q that has a bad harness...resistance to 2 injectors is 20ohms in the harness; the injectors are fine. The engine runs pretty well. Given the plenum removal, replacing the hoses was definitely the right thing to do.You don't have many miles on the car, so your trips to the dealership will hopefully be few and far between. Many of us can't afford the dealership everytime something breaks on our cars with over 200k, which is why we DIY. The goal is to aggresively rehab the car until most wear items are replaced, and then drive the car another 200k!

[elwesso]

Plenum Hoses- YES!!! Do them, if he is going to replace an injector, do it! See if you can get parts elsewhere, you may save some money. Also, while hes got the plenum off, have him clean it out, and the TB. Im not sure it would help the idle problem (although cleaning the TB and plenum may help), but it is still something that needs to be done. Your idling problem is most likely a MAF, most likely a corroded connection. Fairly easy fix.

You have a really low mileage Q, make sure you keep it in good running condition, by doing oil changes every 90 days or 3000 miles, whichever comes first! Keep it in good running condition, and it will last you forever. There are members on this board that have Qs with 250k!

[Q45tech]

250k is a milestone [by June 2003] looking forward to 300k and another 3 years,

California gasoline is really tough on injectors. Hopefully the new non MTBE formulation will be better.

[maxnix]

Might want to move any suspect injectors to accessible (no plenum removal required) locations.

Others with experience will confirm if it is 1,4,5,8.

[Chally]

Did the dealer do a Code check? This normally may give you an idea as to what may have played up, as the computer keeps the fault code for a period.

[90Q45blue]

Dennis,

I am at 247,700 now. Let's race to to 250

Nick

[jumpjet65]

So far so good with the replacement of a new injector on my 94 Q. It is running like a charm albeit it has only been one week. Had everything changed under the manifold. What really made sweeter was that my extended warranty picked the entire cost of the injector minus 100 deduct, this really helped given the expense of the plenum work (about 670.00) but anyway I will keep my fingers crossed but I am also afraid that things are going to start breaking given the age of this car even though I maintain it well.

[Q45tech]

The problem is owners don't set up reserve accounts to store the depreciation expense like businesses do. A car depreciates x amount but they don't put the $250 monthly in savings for the expense.

[Steviek1]

Also, while hes got the plenum off, have him clean it out, and the TB. Im not sure it would help the idle problem (although cleaning the TB and plenum may help),

Guys, you keep using these abbreviations and some of us newbie Q-guys haven't a clue what they mean. Can you please tell me what a TB is and where it is located?

Thanks,

Steve:oface

[DAEDALUS]

Yeah, we need a sticky on the homepage or something!TB Throttle Body (at the far end of the plastic intake hose)CAS Crank angle sensorWOT Wide-open throttleMAF Mass Airflow SensorECU Engine Control Unit (ECM--Engine Control Module)TCU transmission Control Unit

I'm sure there's a lot more.