Here's a break down of the history.

This truck sat for about 8 months, basically abandoned in a Walmart parking lot. I finally left my name and number on it, and was going to just see if I could buy it as a parts truck.

Couple weeks later, guy met me at it with title and sold it to me for 1000 bucks. Could not test it etc as it was totally dead.

Went back the next day with a new Batt. and 5 gallons of new Gas, First thing I noticed on putting in Battery was the gas tank was bone dry. Poured in the 5 gallons, and the truck started on the first crank and I drove it home.

No codes showing on the dash but ABS and that stupid service engine. Trucks a 96 SE has 181k on it. As it turned out the int. was so nice, and the body in such good shape I couldn't part it.

So, I have been slowly rebuilding it over the last 4 weeks. New valley pan gasket, new valve cover gaskets, new headers cats and muffler, new headliner, door springs, dash curl fixer, radiator hoses, oil, power steering hoses etc...

Anyways...

I currently can not drive the truck very far due to the shocks being totally shot. But I have driven it to the muffler shop 4 times 14 miles each way.

The muffler shop didn't have the right y pipe and had to order it, so I drove it back home. Now this whole time, the truck doesn't seem to want to hold idle, no matter where I turn it to. Always wants to idle down to about 100 200 RMPs and almost die.

On the way back home to wait for the part, the truck threw code P1316. The rear o2 sensors had been unplugged so I chalked it up to that. Truck seemed to run ok...

Today I went down and got it with the new mufflers on, O2 rehooked up etc.

Had Advance run the codes getting me that p1316 and then they cleared it. I drove it home 14 miles and it ran like **** the whole way. Missing, running really rich, you can see the black smoke from unburned fuel out the muffler.

The engine engine itself, No Ticks. No unusual noises.

When I had the valve covers off they were full of sludge. I cleaned them up, at first thought this might be burn off from that. Now not sure.

Does not explain this idle issue. Oh, and I have replace every single vacuum line also.

Here is a video shot tonight of it running on my driveway... I'm hoping that one of you rover guru's can listen to this and see if you can tell me where to go next.

Thanks!

http://www.youtube.com/watch?v=PJjdMZWc0Ls

 

2 things to check out.
1-clean the idle air control valve.
If that does not fix it then look into a new TPS.

Keep in mind that the tach on the dash is far from accurate, only a OBDII scanner with live data will give you a actual rpm reading.

 

Thanks for the info Spike, I'll clean the IAVC today and see. Is there a good way to test the TPS? Could it be a flakey VSS?

The main reason I gave all that history I have was to show that is did sit for quite some time with no gas in it... So I was wondering about the damage that could have been caused to the injectors and other parts.

 

You can just take the TPS off, unplug it, and fire up the truck. If the TPS is the problem the truck will high idle probably around 2500 RPM's. If it is still low idling and trying to die I would look elsewhere for the problem. I have been driving my truck around for about a month now with no TPS on it at all. You don't really want to do that cause it could send the ECU into limp mode but you can always get it reset by someone with testbook. If it is the TPS and you replace it you will need to have it reset with testbook anyway. I have an indie near me that reset mine with testbook and didn't even charge me.

 

Ok, took off the idle air controller, cleaned it up really well and put it back on, no difference. Did find a site that sells them for 27 bucks....

http://www.rockauto.com/catalog/rafr...416922-2169450

I unplugged the TPS and started the truck, It went to 2k idle and stayed there. So by Discomedic it's leaning toward needing a new one.

Since it something that require being set, I guess my best bet would to just take it into off-road outback in chattanooga and let them fix it.

 

I too have a '96 and it is located on the front of the t-body. If you aren't clear on the t-body just start at the airbox, follow it back past the MAF, and around to the t-body. The IACV and TPS are located right next to each other on the front side of the t-body. The IACV is kinda a funky diamond shape where it mounts with a body sticking out of it, the harness plugs in at a 90 degree angle. The TPS is kinda the funky triangle shape with the harness on it. Good luck!

 

Did you clean the ports that the IACV sits into also?

 

No, but I just did a Valley Pan gasket on it last week, while the plenum was off I cleaned it inside and out. I'll pull the IACV again and take a good look just to make sure though.

This TPS, is it something I can pull off and put back on without this "testbook" thing? Could I take the TPS off my 98 V8i and try it to see for sure that it's the problem?

I don't want to frel my 98 as it's my daily driver...

Oh, and it looks like I'll need to buy a metric Allen wrench for the TPS bolts, any clue as to what size I need so I don't have to go and get the whole set?

 

The whole metric allen set is $5, you will need the whole set eventually.
No you cannot remove the TPS without messing it up.
But your problem is with the IACV, I did not know you had the intake plenum apart already, if you moved the plunger on the IACV at all you messed up its calibration.
The IACV is what regulated the amount of air the engine gets at idle, your truck is running rich at idle, we know this because of the black smoke out the tailpipe.
Running to rich will bog down a engine, just like running your lawnmower at full choke when it is already warmed up, it chugs, puffs black smoke and eventually dies.
So either your IACV is bad or out of calibration.
We know its not weak spark because you did a complete tune up.
We know it is not a clogged air filter because it runs fine at higher speeds.
So it must be the IACV.

 

Cool, so how do I calibrate a IACV? I'm guessing it requires a special tool of some sort? I had not removed it when I had the plenum off. I went out a took off the IACV again and cleaned up the port hole for it like new. When I took it off the original time the other day, it did have quite a bit of crap on it that I cleaned off. One thing is that the plunger doesn't seem to move at all... should it?

One the TCP... thats an oh crap also.. following the troubleshooting above to test it, I removed it... So I'm guessing I'm fubar anyway? and will most likely have to take it over to a shop that can calibrate this stuff. If that's the case then I might as well go and buy new for both anyways.

I did find another bad hose... looked good etc but I happen to be standing on the passenger and happen to look at it. It's the hose "Valve cover to Ram housing" It was collapsing on itself due to the vacuum. I swapped it for the one on my other truck but it didn't seem to make any noticeable difference, but it's obviously bad and needs a new one.

Now, I'm also starting to wonder about the Throttle body heater plate. maybe I should replace it also. The reason is I noticed some deposit buildup in the cooling system when I did the valley pan, which I of course cleaned up, and plane on doing a flush, but It never crossed my mind to check that heater plate, and I'm betting its in pretty tough shape inside.

Fun project, as usual I'm doing things twice, but at least I'm having fun and learning as I go.