I'm stumped, PLEASE HELP!!!

[twowheeletex]

can someone edit this thread so it reads 2000rpm idle. IDK what I was thiking when I titled it so lamely. . . .

so my car is, for lack of a better word broken. it runs and drives, but when it should be idling it is sitting at around 2000rpm. and there's more. when I cost up to a stop sign the idle bounces, much like the hunting problem listed in the fsm. also there is a delay in the responce to throttle movement. most noticeable when I let off the throttle, it takes a moment to drop. when it dose drop it goes down to about 1000rpm only to shoot up again and bounce for a few moments before swtabilizing between the 1500-2000rpm range. I checked for vacuum leaks by dousing every square inch of vacuum line in carb cleaner, no reaction. at the start I did find one vacuum line that looked like it exploded between the egr actuator (flying saucer thing between the egr and fuel pressure regulator) and the egr valve. I eliminated all the unnecessary parts back there, egr (blocked off the hole to the intake manifold), flying saucer thing, ran the fuel pressure regulator a vacuum line from the elbow on the intake manifold next to the IACV. capped off the solenoid valve behind the head for the pair/charcoal canister systems, and went forward. I replaced the fuel pressure regulator, and knock sensor (because I was getting a code 34). again checked for vacuum leaks using the same method. tested IAW-the FSM, temperature sensor, throttle position sensor, and O2 sensor. I removed cleaned, tested, and replaced the idle air control valve, and iacv air controller IAW-the FSM. there other things I have and haven't done that I can't remember right now, but I won't mention the things I haven't done for fear some unnamed people who know not of what they speak will blindly pick from a list of tasks not performed and say that's the best course of action. that being said somebody please come up with something. I've given a pretty comprehensive overview of my problem and what I have done, I own a factory service manual, and I'm a qualified jet engine mechanic. I just need a little experienced backed guidance.

Modified by twowheeletex at 1:33 AM 5/1/2008
Modified by twowheeletex at 1:36 AM 5/1/2008

[Rucca]

Sounds like your IAC valve is stuck lol

Well, you gave it a good shot... Sounds like there are no vacuum leaks and your air induction system is working well. Have you run a compression test? Checked fuel pressure? Ignition timing? Check resistance between battery ground and engine block?

By delay in response to throttle movement - describe more. Bogging or just a delay?

If you don't find any problems there I can just give the default confused response AKA "Try known good ECM" lol...

[XMSducksauce]

Dirty injectors? Or like Rucca said possibly ECM...I dunno

[Vegascorbin]

Don't really know why but as I read your original post the thought of Timing kept poping into my head.

Give the Timing a check. It won't hurt and might help.

[twowheeletex]

Sounds like your IAC valve is stuck lol

Well, you gave it a good shot... Sounds like there are no vacuum leaks and your air induction system is working well. Have you run a compression test? Checked fuel pressure? Ignition timing? Check resistance between battery ground and engine block?

By delay in response to throttle movement - describe more. Bogging or just a delay?

If you don't find any problems there I can just give the default confused response AKA "Try known good ECM" lol...

I'll give timing a try. it's kinda a pain right now I'm tryng to get my 240 running which requires a lot of time for diagnostics, and keep my volkswagen powered sandrail going which is for now my daily driver. so only allowed a few tests per day, and then on to the bug. thanks for your input. I'm just gunna do timing by ear, and if I get it to a resonable idle, I'll take it to a shop here on base as I have no timing light.

[twowheeletex]

Sounds like your IAC valve is stuck lol

Well, you gave it a good shot... Sounds like there are no vacuum leaks and your air induction system is working well. Have you run a compression test? Checked fuel pressure? Ignition timing? Check resistance between battery ground and engine block?

By delay in response to throttle movement - describe more. Bogging or just a delay?

If you don't find any problems there I can just give the default confused response AKA "Try known good ECM" lol...

I'll give timing a try. it's kinda a pain right now I'm tryng to get my 240 running which requires a lot of time for diagnostics, and keep my volkswagen powered sandrail going which is for now my daily driver. so only allowed a few tests per day, and then on to the bug. thanks for your input. I'm just gunna do timing by ear, and if I get it to a resonable idle, I'll take it to a shop here on base as I have no timing light.

[twowheeletex]

ok, messed with timing. no luck. pulled off IACV again and cleaned it, tested ohms, ran power to the selonoids to make sure they were actuating, removed the epoxy off of the brass plug that holds the spring and adjusted that all the way in. some post I was reading said the spring back there gets weak after a while. I even shimmed it with a piece of vacuum hose as I read to do in the aforementioned post. I pulled apart my IACV-ACC (I believe that's what it's called. located between the intake manifold and the engine block. one electrical connector one vacuum input. the bottom is bolted to the block and has a hole in the bottom) I cleaned it and adjusted it via the small nut located on the back side sealed by some red epoxy. also to no avail. I removed more unnecessary vacuum lines, they're related to the emissions system. re inspected my vacuum lines leading to the pvc valve. re tightened all clamps. and after all that work my idle went down . . . to 1700rpm. I'm about ready to pull what hair I have left out. next on the menu is to replace my TPS and O2 sensor. I'm getting nothing from the computer. at first I got a knock sensor code, but I replaced it. I knew it had little chance of affecting the high idle problem, but I also wanted to se if my computer would clear the code once the malfunction was repaired. computer now gives me the code 55 it's all good code. the o2 sensor checks out as far as the 5 flashes within 10 seconds.

to answer Rucca's question, "By delay in response to throttle movement - describe more. Bogging or just a delay?" it's a delay in reaction.

ANYONE HAVE ANYMORE IDEAS???

[Rucca]

ECM? MAF? TPS? Oh sorry I'm just naming random parts. I have no idea what your problem is lol.

Seriously though. Is your throttle position sensor voltage correct? Refer to engine controls in the FSM for test procedures. Could be that someone messed with it prior to you getting the car. or the connection is loose or corroded maybe?

Or just pioneer the first jet powered 240, might be easier for you.

[twowheeletex]

here's what I got from my tps.

w/clip on top(1 2 3)closed ← 9.6Ω → measured from pin 1&3closed 8.9Ω 1.2Ω measured between pins 1&2, & 2&3

opened ← 9.6Ω → measured from pin 1&3opened 1.6Ω 8.6Ω measured between pins 1&2, & 2&3

my question, is my tps bad judging by these readings.

the FSM says:

w/clip on toppetal conditions (1 2 3)fully released 2Ω measured between pins 2&3partially depressed 2Ω - 10Ω measured between pins 2&3fully depressed 10Ω measured between pins 2&3

also to isnpect the voltage between pin 3 and ground to find voltage of 5v within 5 seconds of the ignition switch being turned to the ON position.

also to run the car till warmed up, then check that the voltage across pins 1&2 are .5V ± .2V. if not adjust accordingly, then disconnect TPS for a few seconds then reconnect t.

I'm thinking my number are low Ω for both opened and closed readings, which may mean I'm out of adjustment. I'm going to check the adjustment just to be sure. but by all accounts my TPS seems to be okay. maybe the O2 sensor. IDK
Modified by twowheeletex at 2:59 AM 5/10/2008

[RunCool]

When you were disconnecting all your vacuum lines you didn't accidentally disconnecting the one going to the intake runners. That will can cause your rough idle problems. Also check your MAF, sounds like your Ecm is not reading the correct amount of air entering the throttle body at idle.

[180sxn]

ECU...bad ground on tps...check maf wires to maf...shielding could be corroded

[twowheeletex]

ok, it's not the MAF, I used a friends maf, and the thing still ran the same. in face I put his MAF, ECU, and O2 sensor in and even with all three out of his car in mine there was no difference in performance. I did notice that I have a JIM Wolf ECU. also, my O2 sensor was white, the probe end looks like it got so hot it bleached the metal. I checked my plugs and they don't look bad, a little burnt. I even put my maf and ecu in his car and it ran his car just the same as it did with his parts in it. I did however need to re adjust my IACV to make it run worth a damn. RPM was all over the place, and for a split second I thaught I had it whipped. to no avail, it jumped right back up.

I did notice that when I'm under power, and put in the clutch, as when rolling up to a light, the rpm's fall to a normal idle and spike back up immediately. like a stumble.

next is to check the wiring harness. one thing has been bothering me, my cooling system keeps getting bubbles in it. I have bled it several times f few different ways, and no change. I wonder if I have a head gasket leak into my cooling system. no water in oil, or oil in water. let me know what you think.

[danielsan]

maybe your running lean? how do your spark plugs look?

[twowheeletex]

burnt. a little white. I figured I was running lean, now the important question is whay. what is causing it. then when I know what the problem is I can fix it. somthing I left out of the tread is quite some time before all of this happened, I put in a new cam from a 95 240. It was one of the reccommended swaps from the forums here. I know that jumping a tooth will cause bad things, but I don't know about this long after the fact, and the symtoms would be different. none the less I wanted to make sure not to leave athing out.

thanks for the help so far. keep it comming. I know someone has to have had a similar problem, these cars are to old for me to be the first. and when I figure it out, this thread will hopefully help out some other poor soul in the same perdiciment. keep it comming.

[XMSducksauce]

Check your injectors like I said earliar...seriously I've seen them cause this much poop before. Run some injector cleaner in them and follow whatever directions are on the bottle and see what that does...it may fix it for a while then it goes back and at that point you could rule the injectors out...but give it a shot cause injector cleaner doesn't cost much and it can't do anything but help =]

[twowheeletex]

I ran b-12 chemtool, then on the next tank marvel mystery oil, then STP fuel system cleaner, then a tank of just premium fuel, then back to mid grade which I've been running in it since I got the car. nothing had any effect. on the start of this tank I dumped in some more B-12 chemtool. the plugs that are in it where new a week before I started having problems.

[twowheeletex]

ok, I OHMed out my injectors, retested my TPS, and everything is good. still idling high. ggot to check harness now. and I'm still not convinced it's not some type of vacuum leak, even though I rechecked by spraying starting fluid over every place a leak is even possible. this car is kicking my ***.

when I pull off the oil fill cap on the valve cover my idle goes down. any ideas as to whether this is a symptom of a problem or something normal. when I pull off the cap, I have positive air pressure escaping.

[rogoman]

If your engine continues to idle real high after it's warmed up, check the air regulator unit. It's located on the passenger side of the engine, below the intake manifold, near the rear. There's a hose connecting to it. Pinch the hose when you are having the high idle condition. If the idle speed drops, there's a problem with the unit. Also check the electrical ground connections on the engine for looseness and oxydation. Another thing to check for is a major vacuum leak somewhere along the intake plenum between the MAF and the Throttle Valve.