Odd running issue just came up. Please give advice.

[cadence_1]

Hey guys,

I've been out of the game a bit so I was wondering if someone could please help me with this.

My cousin has a CA that he has put close to 50k problem free miles on. Recently he decided to swap out injectors and MAF and add a tune for his larger top mount T3/to4e that he put on. Long story short the tune didn't work out (got screwed on some scam and never had it installed) so he swapped back everything out for stock maf and injectors. Ever since then the thing hasn't wanted to idle very well and tip in from what idle it does have is very sluggish!

Initially he neglected to hook up the number one injector onto the proper plug (using the yellow IACV plug instead of the gray injector plug) But I noticed that the other day and it is now running on all four cylinders. But idle is still crap and tip in off idle is horrible. I dont know how it drives as I have not attempted to take it out of the parking space.

Again, this is a stock CA ecu that has run the car for many many trouble free miles, stock injectors, and stock maf. Just want the car to run like normal again.

Any ideas of where to start?

Thanks for looking.

[r34 gtr]

Strange. Maybe someone could shed a light on how the AICV works, voltage-wise. Perhaps it kept the injector open and hydro locked the cylinder? Just a thought. That would be really awful though...

You say it just didn't fire cylinder #1? Nothing at all? No pop or anything when you fired it up the first time?

[cadence_1]

Ya.. Cylinder 1 was completely dead. It fires now that the injector plug is properly installed. But still have very sluggish running and poor idle. (Well I don't so much know about how it "runs/drives" cause I haven't taken it out of the driveway yet, but the tip in from idle is sluggish and the idle is crap.)

I haven't been able to check into it since I posted this. I am going to check for any codes tomorrow or later tonight and check some things I have on a list. I will report back if I don't come up with anything.

If anyone else has any ideas please feel free to post them.

thank for readin.

[biosehnsucht]

If you haven't pulled the spark plugs, pull them and see if they need cleaning or replacement. ECU freaks out in these kinds of situations and tends to oscillate lean / rich but generally overfuel.

Also reset ECU if you haven't.

How much was it run like this ?

I ran 3cyl a few times and once 2cyl due to bad coil packs, hard to tell on 3cyl since my bottom end is balanced it feels like a 4cyl. No permanent damage. Slow but highway drivable.

[cadence_1]

Ya.. I am going to just go change the spark plugs right now and see if that helps. They are pretty black cause he runs a walbro without an AFPR (its in the mail right now). But he has run this way for over 50K miles or better so i cant see that as the problem. But I imagine the plugs are fouled after all this testing.

I think i am going to clean out the IACV and AAC valves or whatever on the manifold for $hits and Giggles as well to see what happens.

I checked the codes and all is well with code 55 all around.

I have two different MAFS I am going to through in there as well today and give them a go just because. If nothing comes about I will report back.

Thanks.

[ca18detgabby]

are your injectors plugged in, in the right order..... it happens

I would check the plugs(runing a cyclindar w/o fuel is alot different than w/o spark).

more than likely you are having multiple issues do this that.

[cadence_1]

Ok.. so here is the deal.

After swapping out the fouled plugs for a new set it seems to run better. I also went through and cleaned up a few potential vacuum leaks as well. The car runs a lot better than before, especially once warmed up. However there is still a nagging issue that I noticed while idling in the driveway. After a bit I will notice the rpms start to drop the air fuel starts to go lean and then it just keeps falling until the car dies? Can anyone shed some light on this new symptom? It is very odd. That car idles at a pretty good 14.7 - 15.0 on the wideband (even with the Walbro in there with no AFPR) but for some reason after an indeterminate amount of time (maybe a couple minutes or something) I will notice it just starting to get lean and the RPMs drop and the car stalls out.

Could this have something to do with battery/alternator voltage issue? The car had been sitting for quite sometime and everything has seemed to get a lot better after running it for a bit? Could a low voltage situation cause this leaning out in some way? Or am I missing something that this leaning out and subsequent stalling is a result of? (Ooops.. I also forgot to mention that when I turn the lights on the car takes a big hit as well. This really seems voltage related to me. Has anyone had issues like this that I am experienceing with a bad battery/alternator)?

The car still does not recover from a rev to idle as well as I would expect it to. But I will worry about that later unless that is something of note to anyone. I have cleaned the IACV (or whatever the mechanism on top of the intake manifold is called).

On another note, I have some oil supply issues on this stupid thing as well. Could someone please tell me what thread size, and pitch the supply line from the block is. I think I need to make a new line. I have tried to search for "Oil supply" and "supply line" and the search is returning NO RESULTS? WTF?

Thanks for the help guys.

Matt

[biosehnsucht]

you can check the voltage while it's running, but generally if the alt is having problems you'll know because the battery light will come on. if the battery is at fault, usually once it's running it won't matter too much unless the battery has some seriously dead cells or something.

may be the O2 sensor is screwed from being exposed to such bad running conditions, and maybe once the ECU gets out of cold start it's reading a rich condition and leans out trying to correct until it dies. Try disconnecting it and see if it runs longer (it'll not be running *right* but it might help, and if so that's a likely thing to fix). I'm assuming here you have a stock O2 hooked up to the ECU in addition to the wideband ?

Also consider trying unplugging the coolant temp sensor in case it's bad. only try one thing at a time though.

[cadence_1]

Hrmm.. Ya I do have the stock O2 hooked up in addition to the wideband. My only problem with a "bad O2 theory is that it is running fine at idle. atleast 14.7-15.0 afrs. So I dont see why the stock O2 would be trying to lean anything out?

I will disconnect it and see what happens though. Along with disconnecting the water temp sensor as well after testing ruling out the O2.

Thanks for your help.

And if anyone can get me an idea of the threads on that turbo oil supply I wold appreciate it. I really dont want to get down there and pull that thing off.. haha!

[biosehnsucht]

Ah, I thought you meant that after a few minutes at idle it stalls, which can happen with various bad inputs (O2, temp sensor) once it goes out of cold start mode and actually relies on them.

[cadence_1]

I dont know what the hell is going on now. Man I hate fixing other peoples hacked a** s***.

So now today after fixing an oil supply leak I go to start it and it is running super rich. 10:1 and under. The idle is bouncing from 450-600ish the whole time. It isnt going lean anymore but it sure isnt running right. It is missing very frequently and now the plugs are fouled again. (this is most likely why I am getting low AFR readings) But WTH is going on with this thing? It ran perfectly fine a year ago. And now the thing will hardly idle. ARGH! And nothing seems to happen when I try to adjust the idle either. I can pull the idle adjust screw all the way out until I hear air sucking in and the idle isnt affected until that screw comes all the way out? I am sure this is some sort of boost/vacuum leak or some crap. I just cant see where.

I guess I am going to make an adapter tomorrow to check for boost leaks and pressurize the system. One question about this though. How do you get pressure to hold constant when doing this. Won't pressure leak past a closed throttle plate and then leak into the cylinders, not allowing you to tell where a leak actually is forming?

thanks for reading guys.

[cadence_1]

Ok, sorry to bring this back up bit I am still having problems with this car. I thought it might have been a bad fpr as he has been running a walbro on the car for about 50k miles wight he stock one in place. So I set and adjustable to 36psi at atmospheric pressure as I have read.

Next thing I did was start going through the wiring. It seems as though the iacv (grn/yellow) wire I think, was bit hooked up along with the brown wire fir 02 sensor. So I hooked those up via an sr install how-to.

So I go to start the car and when cold the car initially idles somewhere around stoich (I think) but very soon at stick fuel pressure the idle starts to fluctuate and the car dips lean. I can fix this problem by jacking the fuel pressure up but it only fixes the problem till the car is warm.

Once warm, the car idles at 10:0 or worse (acording to wide band) and unplugging the O2 sensor makes no difference. When trying to idle like this when warm it barely runs dipping at 300-600 rpm. But if I dissconnect the iacv solenoid the idle will jump to 1500 ish and about 11.5:1 afrs. Another thing is that disconnecting the iacv while warm and trying to adjust idle with the 10mm screw does nothing till the screw comes completely out. I have cleaned the iacv valve.

All this leads me to believe that there is a huge vacuum leak. But I can't seem to track it down. Could a bad temp sensor cause any if this stuff? This is just so odd cause if you read my original post this was all changed back to stock working parts that have run this car fine for quote sometime. So I j ow the expaination for all of this is going to be a stupid simple one.

Thanks again for reading and your help. And I apologize for any grammatical errors as I am posting this on my phone.

[biosehnsucht]

if its a bad temp sensor, unplugging the temp sensor should help.

yes, it does sound like a huge leak. there's a mess of stuff that can leak..

[busteds13]

i would suggest, double checking the wiring for the Idle Controll Valve an the O2 since unplugging it helps, and the O2 sensor may be cooked, i know theyre expensive, and a pain, but a brand spankin new one may be worth it, check your fuel filter and make sure all your grounds are cleangoodluck

[cadence_1]

Ok.. figured I would give you all a bit of an update And ask some more questions.

Finally pressure tested the system and there were leaks all over the place. Mainly in the IC piping that my cousin had a "friend" do for him. And the FMIC itself had a huge hole in it from a screw. ( I know I know WTF right). Not my car.. haha!

So after I fixed what vacuum leaks I could find I hooked the maf directly to the intake pipe to see if it would run any better and I will say it ran much much better. (yes idle air supply line is hooked up post maf correctly) Tip-in response was much improved. There were some light misses but I think those were mainly cause we are running on some pretty fouled plugs I suspect at this point. My only issue(as I have not put the car back together yet) is that when I started the car it would rev up to ~1500 rpm and never came back down. I suspect at this point that there is a stuck thermostat (best case scenario) and that proper temperature coolant wasn't getting to the coolant temp sensor so it wasn't properly adjusting idle. Can someone confirm or deny this theory? To reiterate, if I had a bad temp sensor (either because it was bad or that coolant wasn't passing by it) what would the car act like?

The car idled for about 10 minutes and I finally noticed that the top radiator hose was very pressurized and the radiator started to leak. I am hoping that the radiator was just that old and frail, and that the thermostat didn't open causing this higher pressure situation. A slight issue with that was that the lower hose was also pretty hot.... Usually it would be much much cooler if the thermo wasn't opening.. But I am crossing my fingers at this point.

Any insight would be delightful. And thanks again to all of you that gave you opinions on this thing.

Man I hate fixing peoples hacked swaps! Even if they are in the family. haha!

[progman]

I do not think the coolant temp sensor output could make the idle go up. The idle is basically set to how much air is able to get into the engine. If the coolant sensor was reading ambient or something faulty it would make the car run rich if anything at all. That sensor as far as I know is only for cold start enrichment. If it is idling at 1500 and never comes down I would suspect vacuum leaks. Since you already checked for that the next thing to check is the IAC valve. it's that thing under the throttle body with two air lines going to it and a 2-pin plug. This thing is computer controlled and it will allow your car to "fast idle". Once the car starts to warm up the computer will close the IAC valve and the idle will go back down to 850 or whatever you have the idle set to. Might be worth it to double check for vacuum leaks, they can be difficult to find sometimes.

Do you remember the reading on the dash temperature gauge? If the thermostat was stuck you might notice it reading colder than normal. after 10 minutes it should have been fully warmed up. I would probably just replace the thermostat since they are only 10 dollars or so. Make sure you have some extra coolant on hand to top it off when you are done. oh yeah, good luck finding a gasket for it. I usually have to cut myself one every time.

gook luck.

[cadence_1]

Hrmm.. interesting.

I have cleaned that valve already. And there is always a possability of more vacuum leaks yes.. ahha! So I will check that again.

I am going ahead and putting a new radiator and thermostat in this week. (thermostat was junk for sure). So after that and getting the IC fixed not to mention cleaning up some wireing. I will give it another go.

Will report back later.

Any other ideas as far as the fast idle would be greatly appreciated.

thanks again guys.