Figured I would ask before I pay the Dealer $120 to scan and diagnose my problem. It is a 96, and is bone stock. Has a lot of new stuff, plugs, wires, opti, 02 sensors injectors. Previous owner was chasing some sort of problem, and had replaced the plugs, wires, and 02 sensor, intake gaskets, and sent the PCM to Eckler's. I bought the car from his Widow, and don't know for sure what the problem was.

On start up, has high idle and runs nice and smooth for about 6 seconds, then starts adjusting, and idles down to around 700 or so, and misses/lopes until it warms up (closed loop I suppose) then runs better, but still just a little rough. Been thinking about sending the PCM in to have the fans come on without the A/C, but doubt that "tuning" would take care of my miss/lope problem.

Any ideas ?? Running smooth for those first few seconds makes me believe it isn't a burnt valve or anything like that ?? Thanks, Brownie

 

Forgot to mention, have cleaned the IAC and no vacuum leaks

 

Scan the IAC counts in warm mode and everything but the motor off.

Also, you say you cleaned the IAC. Did you do this by taking out the valve or removing the cover plate, IAC housing and cleaning all the passages with brake cleaner? Did you use new gaskets? How did you figure there are no air leaks?

 

Hi aklim, thanks for your response. Well, I did a smoke test, trying to resolve an HVAC problem. Finally got that fixed by running another line from the intake to the HVAC programmer, after I replaced all the plastic lines with hose, and replacing the blend door actuator. I was getting quite a bit of smoke out of the throttle shaft bushings on the throttle body, and changed out the shaft bushings, and at that time, cleaned everything reall good on the IAC.

Exhaust smells like old varnished gas, and this is the 3rd tank of 93 since I bought the thing in Phoenix. Also added some Techron. I think It may have set for over a year before I bought it. No codes. Just about out of things to change, course one of the new ones could still be defective. These things ever run nice and smooth ?? My old TBI Silverado with 244K runs great, as does my Son's 200K Vortec ???

 

Hard to say. I would have sucked out all the old gas instead of diluting the thing. I generally run the gas down to as empty as I can and fill up so I don't get some old gas with the new. Regardless, after 3 tanks it should be pretty decent. Techron just wastes money. If you really need injectors cleaned, and I'll bet they haven't been since they were installed, I'd take them out and send them to FIC for cleaning and testing. I just sent them a set and they called to tell me that it is going to take longer since I have a bad injector. It was flowing and flowing without closing. Checked it when I got it back with the set and you can blow through the thing. The other 8 you couldn't.

Did you check what the IAC counts were? That tells us if the thing is set wrong.

 

Injectors are a new set of Bosch III's I got from FIC. Seemed like it ran better for about 1/2 dozen starts, but could just be my wishful thinking. I don't have a scanner to check the IAC counts. Think the previous owner bought a scanner, saw a receipt in the paperwork, but his Widow didn't mentioned it when I bought the car. I think he was chasing the same problem---probably what killed him.

 

Get one. Beg, borrow or steal as my instructors used to say when we used the excuse "I forgot to bring my.....".

You will find it an indispensable tool so go to Autozone and see if they have a scanner that will work then buy that one. Or buy a Snap On MT2500. It is old but with the right modules, it will pay for itself soon.

 

Well, probably not going to keep the car. I thought my Son could drive it to work a couple days a week, but it is really cramped and uncomfortable for him plus his wife thinks it is a "mid-life crisis car", and he is a "professional" and everyone would see it in the parking lot ?? Anyway, I am a bit of a "seasoned senior citizen" and it is really hard for me to get in and out of the car, guess I should have thought about that before I bought it. Car has lived it's entire life in AZ and Texas, so absolutely no rust. I paid the Widow $6K for the car and have put almost $2K in it, replacing everything from pan gasket, water pump, opti, fuel pump,injectors, tires, HVAC, etc. just about everything a 20 yr. old car would need. So rather than invest in a Scanner, think I will go ahead and replace the IAC and see what happens. Thanks for all the advice----Brownie

 

Before you throw any more parts at it or take it to the dealer run it by Scotty's and let him listen to it. Jay Tell them I sent you

 

Sounds like he needs a new wife if she is so concerned about it being a mid life crisis car.

I really don't think an IAC will fix it unless you just get lucky. Electrical parts are not returnable once installed. If you try sell a car that isn't running right, best hope the buyer doesn't come there with a scanner and other testing tools. I do and I am looking for every reason to talk you down.

 

Hi Jay. Thanks for the advice. I did talk to Scotty the other day, and said to bring it down and leave it with him. Seein as how it runs rougher when cold, he would have to cold start it several times, and would essentially go thru the process of checking everything that I have already done, to ensure that I have done it correctly or didn't install a bad part, so still considering that....Thanks, Brownie

 

Well, still trying to find the "lope" in open loop. I changed out the IAC, and no improvement. Changed the Coolant Temp. Sensor, and no change, but it did throw a P1351 code after about a 20 mile test ride. So, installed a new coil and Ignition Control Module, and does not seem to be running any better; although, I haven't driven it anywhere yet. It does seem to be "kicking back" just before it starts, like the timing is far advanced ?? Anyway, the latest round of b/s started with the Coolant Temp Sensor change, so decided to change it back, and was going to go out and drain the AF and get started, then I remembered that the distributor is below the water pump, and last time I changed the Coolant Temp. Sensor, about 1/2 gal of coolant ran out when I removed the Temp Sensor, and must have gone down on the distributor---uuuhhhhh !! Maybe that's why it threw the P1351 code ?? Anyone know if an AIP distributor is sealed ?? I installed that new about 100 miles ago. May still have some antifreeze in it from the Coolant Temp. Sensor change. Between my own FU's and bad parts, may never get this thing to run right. Installed a new AC Delco oil pressure sender, and was shorted out, and new ICM was also bad. Very important to install 1 part at a time.

 

If it is smooth closed loop it is rich open loop and a lope is a classic symptom of an engine running rich. Go to Autozone and have them put ascanner on it for free. Fuel is the only thing closed loop relly changes much.

 

ok, thanks for your response. I called Autozone and O'reilly, and they can only "scan" if I have a code showing, and I don't (cleared the P1351 code) Anyway, they can't "scan", just pull codes off the OBD II.

The car starts up and idles up to about 1000 rpm, and runs real smooth for about 6 seconds, then starts adjusting and searching, and starts running bad, loping, etc. until it warms up, then runs a lot better. I think the previous owner was chasing the same issue, and changed plugs,wires,EGR, intake gaskets and bank 1 upstream 02 sensor. I've changed so much stuff, and no real results, except maybe the 2nd bank upstream o2, when I was under there changing the oil pan gasket. Seems like it had an outright miss before, and that made a difference.

 

Buy a scanner the cost of it far less than a beating you will take selling it if not fixed.

 

Do a compression or leakdown test to rule out a mechanical issue before going any further.

 

Does going closed loop seal rings and valves?? Seriously no action affect connection. Mentioned 120 to have the dealer scan yet can buy a scanner for less and own it or lt it go with the car and add 100 bucks as a maintenance tool should a new owner ever to it.

 

Kinda leaning away from that notion, seeing as how it runs real nice and smooth for about the first 7-10 seconds when it first starts up, then starts "searching around" then runs funky until it warms up ??

 

I was just looking at scanners, and what kind to get. I notice that the previous owner bought an ACTRON scanner. His widow didn't mention it when I bought the car, so must have sold it separately. I have a Harbor Freight scan tool probably cost about $80, but just pulls codes and such. Not sure what I need exactly to diagnose ??

 

I have an Actron for my 91 and works great paid around 100 for it new but old stock. If no one chimes in will run out to the shop tomorrow but busy now with other things.