I have an 84, 245 with a 2.3 thats fuel injected and its having some cold start problems. Here is everything I've done to the car so far to try and correct it...replaced the mass air flow sensor (used part from a u pull it yard and made sure it was spotless inside and out before i pulled it), replaced the fuel injector/temp sensor under the intake (Its was the dual wire one that goes to ECU), complete tune up.
When the car is cold it starts after the engine cranks over a few times every time, but runs very rich and runs rough until it warms up to driving temp. This usually takes about 5 minutes. Some times I can start it up and let it run for a half a minute then shut it off completely, wait a few seconds, and restart it and it will smooth out after 20 seconds or so. Other times it will continue to run rough until warm.
Any ideas on what I might be forgetting ?
Also, do I need to reset the computer after eplacing the Mass Air Flow unit and fuel injector/temp sensor ? If so, how do I do this ?
Any help would be awesome...I love this wagon, and when its warm, it runs great even with 280,000 miles on her.

 

Thats normal. The ECT tells the ECU to run rich when the block is cold, to help it start. Sometimes it overcompensates and soaks the plugs, but if you can start it, don't worry.

 

Burn Stains...thanks for your quick reply. I think it might help if I was a bit more specific....it runs ROUGH, as in I cant let the clutch out and even drive it until it warms up, its running that rich on fuel.
Thats why I also wondered if you had to reset the ECU/computer in order for it to run smoother after the cold starts. If so, is it a simple task as in disconnecting the battery and unplugging the ECU for a few minutes, then reversing this process ?

 

Resetting the ecu is as simple as pulling the battery cable for a few minutes. It's best to reset after making changes in sensors. I sometimes don't when I'm in a hurry...still, it's best to start w/ a clean slate IMO. Are you certain the AMM is the same? The last 3 digits must match. In 84, I think they were still using LH2.0 which has the aluminum cased AMM and...I think it was an 001. In 85 they went to LH2.2 and used the black plastic AMM w/ 007 as the last digits. Pretty sure your car has the cold start injector and, obviously, it is richening the mixture too much. Try unplugging the electrical connector and see if that helps. How far you go to cure this depends on your climate. Here in Texas, I've been known to leave the CSI unplugged all winter but if you're up north, you'll want it to work properly.

 

SJ44...I live in Oregon where its been a cool 28-30 in the morning. I pulled my AMM out of an 83 I believe. Its aluminum housing with same pin pattern. I think I'll unplug it and plug it back in before I disconnect the battery to reset ECU.
I have not replaced the cold start injector yet.
I do appreciate the answers I've received. Thank you very much.

 

Examine the AMM connector plug too...those tiny connectors sometimes work out of place.

 

I'll double check them, as I was told by a mechanic friend of mine to do before I pulled the part. Also, who's not to say the used part I got isn't bad either, as I've found out this is fairly common for the AMM to go out in the mid eighty models.

 

Well, heck, none of the parts are newish anymore that's for sure. Do you have access to a manual to see how to check the AMM using a digital volt meter?

 

I would go ahead and do the suggested unplug the cold start injector before replacing it, if you even want to bother replacing it.

Does it run rough, and then instantly smooth out? Or is it gradual? An instant smooth out should indicate a working AMM, as it does not operate on first start-up, then kicks in. Gradual would indicate failing ECT.

 

SJ44...No I do not have a manual to check the AMM using a meter. I think if I want to keep this car, I might want to invest in one. This will be a labor of love.

Burn Stains..where is the cold start injector located ? Its a balmy 40 degrees outside....perfect weather for cold start diagnosis'. lol

I also feel a bit of my past from 25 years ago resurfacing, when I owned nothing but air cooled bugs, and the learning curve was steep. At this pace I'll have the mid 80's 245 figured out top to bottom.

 

Here's two pics of the intake manifold w/ cold start injector shown in second pic. The first pic shows the intake right side up as it is on the car. The CSI is hidden from view. In the second, the intake is flipped over showing the CSI. To loosen the connector, I use an old screwdriver sharpened to a point as there is no way to simply press in and remove by hand.
My apologies for the cell phone crappy quality.........



If not evident, the CSI is in the center and has the black connector...

 

SW44...dont apologize for a blurry picture. You are the man...I would've spent all day trying to find a 5th injector not inline with a fuel rail. Thank you oh so very much. I'm off to try a couple different things after I start it up cold and see where it takes me. I foresee an order to IPD tomorrow morning for something or another. 15 mpg city and 19 mpg highway is killing me. I'll post back later what the diagnosis was.

 

Swiftjustice....first time I started the car after it sat over night since I reset the ECU and it ran a bit rough but alot better than before. It idled for a couple of minutes and I revved it up then turned it off. It started right up and smoothed out almost immediately. I did unplug the MAD and it stumbled on idle a little bit. I'm going to replace the spark plugs one more time and just drive it. Im going to hope the ECU was sending out a false signal. Now I have some direction if the problem becomes reoccurring . Thanks again everybody.

 

MAF ...... not MAD. Smartphone isn't too smart.

 

That's promising! The older LH ecu's are rather "dumb" but still take a bit to learn. A couple of days of normal driving are often needed so don't buy parts just yet.

 

Cold start injector should only work in -15F degree temperatures. Did you unplug it when you reset the ECU?

 

Burn Stains...no I did not unplug it when I reset the ECU.

 

Sounds like the issue is resolved, but try and unplug it and see if it makes a difference.

 

Burn Stains...I thought about doing what you're suggesting. It was running pretty bad this morning when I first started it up. Outside temp was 32 degrees. It took about 5 minutes to get to operating temp before I could drive it.
I do have another question....I heard in a chat forum that the ECU in my car only notices up to 3 codes at a time. So, after I try unplugging the cold start injector, if to no avail, maybe try resetting the ECU ? Or did it wipe out all codes after I reset it the other day?

 

I believe in order to retrieve more than three codes, you have to properly erase the present codes by doing that with the OBD-1, then more will appear. But if you remove the battery, all codes are gone, unless there is a problem, then that code will show right back up.